View Full Version : Re: antimatter, feynman diagram, gravity
Uncle Al
Apr7-04, 08:42 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Danny Ross Lunsford wrote:\n>\n> Uncle Al wrote:\n>\n> > Charge conjugation is an internal symmetry. Properties derived from\n> > internal symmetries transform fields amongst themselves leaving\n> > physical states (translation, rotation) invariant: U(1) symmetry in\n> > electromagnetism, U(2) symmetry in electroweak theory, SU(3) in strong\n> > force theory.\n>\n> Uncle Al is one of my heroes so it pains me to disagree with him :) But...\n\nYou are not disagreeing, you are disproving. Quality counts towards\neverybody\'s bottom line.\n\n> The unit pseudoscalar on spacetime is (in full tensorial form)\n>\n> P = 1/24 epstensor_mnab gamma_m...gamma_b\n>\n> This form is fixed by the interpretation of the gammas as forming a\n> local frame, the "square root" of the metric via Clifford\n>\n> { gamma_m, gamma_n } = 2 g_mn\n>\n> Now the epsilon tensor is not just a permutation symbol - to make it a\n> tensor you have to prepend a factor of sqrt(det(g)). But det(g) is\n> negative, so the square root is imaginary. Thus epstensor_0123 = i and\n>\n> P = i gamma_0..gamma_3\n>\n> Under Hermitian conjugation\n>\n> P* = -i gamma_3* ..gamma_0*\n> = i gamma_3 .. gamma_0 (gamma_i is anti-Hermitian)\n> = i gamma_0 .. gamma_3 = P\n>\n> Writing the Dirac equation coupled to A\n>\n> ( gamma_m (dm + ieAm) + i M ) psi = 0\n>\n> Pulling through P\n>\n> ( gamma_m (dm + ieAm) - i M ) P psi = 0\n>\n> so P psi satisfies the same equation with the sign of the mass changed.\n>\n> The adjoint is\n>\n> psi* P gamma_0 ( gamma_m (dm - ieAm) + i M ) = 0\n>\n> or\n>\n> psibar P ( gamma_m (dm - ieAm) + i M ) = 0\n>\n> There is a conserved current\n>\n> J_m = psibar P gamma_m P psi = -psibar gamma_m psi\n>\n> which is the original current reversed. That is, matter and antimatter\n> have been interchanged.\n>\n> So, matter-antimatter conjugation is certainly associated with spacetime\n> symmetry. Note that the above description is given only in terms of\n> actual Lorentz-invariant objects.\n\nI\'m a good sport! I don\'t doubt Lorentz invariance, too. Metric\ntheories of gravitation are parity-symmetric. Affine theories of\ngravitation can be parity-antisymmetric. If you have successfully\ndemonstrated that matter-antimatter comparison is deeper than the\nclassical internal symmetry, right on!\n\nHow do you secure the boojum (or rather, the antiboojum) and do the\ntest to sufficient accuracy?\n\nI have described and calculated a novel Equivalence Principle test\nusing left-handed vs. right-handed single crystal alpha-quartz test\nmasses of identical chemical composition and macroscopic form\n(spherical balls, equal diameter and height right cylinders, or\nfacetted cylinders with three identical moments of inertia ) in an\nunmodified existing Eotvos balance,\n\nhttp://www.mazepath.com/uncleal/qz.pdf\n(Graphs are presented for paired 3.44x10^17-atom single crystal test\nmasses. We currently have data to 7.33x10^17 atoms or 0.26 mm\ndiameter. We hope to hit 9x10^18 atoms and 0.60 mm diameter in the\ncurrent 16 Opteron-848 cluster run, then quit forever. If anybody has\na 128-bit precision math library and a teraFL0PS cluster supercomputer\nwith a month of slack time, we can do some *serious* diameters.)\n\nHow would you fabricate and test an antimatter body? Other physics\nconstrains the maximum Equivalence Principle violation to no more than\n100 parts-per-trillion difference/average. Even claiming 10\nparts-per-trillion will be met with loud doubt absent convincing\nmeasurements. Matter interferometers are only good to about 1000\nparts-per-million (with an "m" not a "t;" Colella-Overhauser-Werner\nand Bonse-Wroblewski neutron interferometers; Kasevich-Chu atom\ninterferometer) Manufacturing and containing a gram of antimatter\nwill be infeasible for cost and safety (43 kilotonne blast plus EPA\nsanctions).\n\n--\nUncle Al\nhttp://www.mazepath.com/uncleal/qz.pdf\nhttp://www.mazepath.com/uncleal/eotvos.htm\n(Do something naughty to physics)\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Danny Ross Lunsford wrote:
>
> Uncle Al wrote:
>
> > Charge conjugation is an internal symmetry. Properties derived from
> > internal symmetries transform fields amongst themselves leaving
> > physical states (translation, rotation) invariant: U(1) symmetry in
> > electromagnetism, U(2) symmetry in electroweak theory, SU(3) in strong
> > force theory.
>
> Uncle Al is one of my heroes so it pains me to disagree with him :) But...
You are not disagreeing, you are disproving. Quality counts towards
everybody's bottom line.
> The unit pseudoscalar on spacetime is (in full tensorial form)
>
> P = 1/24 epstensor_mnab \gamma_m...\gamma_b
>
> This form is fixed by the interpretation of the gammas as forming a
> local frame, the "square root" of the metric via Clifford
>
> { \gamma_m, \gamma_n } = 2 g_{mn}
>
> Now the \epsilon tensor is not just a permutation symbol - to make it a
> tensor you have to prepend a factor of \sqrt(det(g)). But det(g) is
> negative, so the square root is imaginary. Thus epstensor_0123 = i and
>
> P = i \gamma_0..\gamma_3
>
> Under Hermitian conjugation
>
> P* = -i \gamma_3* ..\gamma_0*
> = i \gamma_3 .. \gamma_0 (\gamma_i is anti-Hermitian)
> = i \gamma_0 .. \gamma_3 = P
>
> Writing the Dirac equation coupled to A
>
> ( \gamma_m (dm + ieAm) + i M ) \psi =
>
> Pulling through P
>
> ( \gamma_m (dm + ieAm) - i M ) P \psi =
>
> so P \psi satisfies the same equation with the sign of the mass changed.
>
> The adjoint is
>
> \psi* P \gamma_0 ( \gamma_m (dm - ieAm) + i M ) =
>
> or
>
> psibar P ( \gamma_m (dm - ieAm) + i M ) =
>
> There is a conserved current
>
> J_m = psibar P \gamma_m P \psi = -psibar \gamma_m \psi
>
> which is the original current reversed. That is, matter and antimatter
> have been interchanged.
>
> So, matter-antimatter conjugation is certainly associated with spacetime
> symmetry. Note that the above description is given only in terms of
> actual Lorentz-invariant objects.
I'm a good sport! I don't doubt Lorentz invariance, too. Metric
theories of gravitation are parity-symmetric. Affine theories of
gravitation can be parity-antisymmetric. If you have successfully
demonstrated that matter-antimatter comparison is deeper than the
classical internal symmetry, right on!
How do you secure the boojum (or rather, the antiboojum) and do the
test to sufficient accuracy?
I have described and calculated a novel Equivalence Principle test
using left-handed vs. right-handed single crystal \alpha-quartz test
masses of identical chemical composition and macroscopic form
(spherical balls, equal diameter and height right cylinders, or
facetted cylinders with three identical moments of inertia ) in an
unmodified existing Eotvos balance,
http://www.mazepath.com/uncleal/qz.pdf
(Graphs are presented for paired 3.44x10^17-atom single crystal test
masses. We currently have data to 7.33x10^17 atoms or .26 mm
diameter. We hope to hit 9x10^18 atoms and .60 mm diameter in the
current 16 Opteron-848 cluster run, then quit forever. If anybody has
a 128-bit precision math library and a teraFL0PS cluster supercomputer
with a month of slack time, we can do some *serious* diameters.)
How would you fabricate and test an antimatter body? Other physics
constrains the maximum Equivalence Principle violation to no more than
100 parts-per-trillion difference/average. Even claiming 10
parts-per-trillion will be met with loud doubt absent convincing
measurements. Matter interferometers are only good to about 1000
parts-per-million (with an "m" not a "t;" Colella-Overhauser-Werner
and Bonse-Wroblewski neutron interferometers; Kasevich-Chu atom
interferometer) Manufacturing and containing a gram of antimatter
will be infeasible for cost and safety (43 kilotonne blast plus EPA
sanctions).
--
Uncle Al
http://www.mazepath.com/uncleal/qz.pdf
http://www.mazepath.com/uncleal/eotvos.htm
(Do something naughty to physics)
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes\n\n>Thus it would be entirely possible to work always in terms of negative\n>mass and avoid the problematic interpretation of "backward in time" that\n>gets algebraically introduced by plain complex conjugation.\n\nOoohhh... that\'ll raise some eyebrows...\n\n>If one takes this seriously, then one has to consider the Schwarzschild\n>solution with the integration constant corresponding to the mass of the\n>body taken to have the opposite sign. Matter and antimatter would then\n>definitely be distinguised gravitationally.\n\nOoooohhh ... not mainstream (but in many ways nice).\nNote that this matches well with Charles Francis\' formulation of\nteleparallel quantum gravity and the naive particle-antiparticle BB\nradiation.\n\n>*Should* we take it seriously?\n\nEr, um, I have enough problem here anyway ...\n\n>I only point out that in one case, we\n>have a simple change in sign of the mass, and everything is sight is a\n>straightforward spacetime covariant based on the Dirac algebra, while in\n>the other, the unnatural looking charge-conjugation operator\n>\n>C = i gamma_2 gamma_0\n>\n>and the complex conjugate of the Dirac equation, must be introduced, not\n>to mention the problematic idea of "backward in time".\n>\n>Moreover, when one goes over to Fermization (second quantization) the\n>action of the charge conjugation operator itself changes (sign change).\n>This is highly unsatisfactory.\n\nAm I to interpret this as a statement that its mathematically more\nelegant to take antiparticles as having negative mass but moving forward\nin time?\n\nIf so, why is it considered somewhat crankish?\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes
>Thus it would be entirely possible to work always in terms of negative
>mass and avoid the problematic interpretation of "backward in time" that
>gets algebraically introduced by plain complex conjugation.
Ooohhh... that'll raise some eyebrows...
>If one takes this seriously, then one has to consider the Schwarzschild
>solution with the integration constant corresponding to the mass of the
>body taken to have the opposite sign. Matter and antimatter would then
>definitely be distinguised gravitationally.
Ooooohhh ... not mainstream (but in many ways nice).
Note that this matches well with Charles Francis' formulation of
teleparallel quantum gravity and the naive particle-antiparticle BB
radiation.
>*Should* we take it seriously?
Er, um, I have enough problem here anyway ...
>I only point out that in one case, we
>have a simple change in sign of the mass, and everything is sight is a
>straightforward spacetime covariant based on the Dirac algebra, while in
>the other, the unnatural looking charge-conjugation operator
>
>C = i \gamma_2 \gamma_0
>
>and the complex conjugate of the Dirac equation, must be introduced, not
>to mention the problematic idea of "backward in time".
>
>Moreover, when one goes over to Fermization (second quantization) the
>action of the charge conjugation operator itself changes (sign change).
>This is highly unsatisfactory.
Am I to interpret this as a statement that its mathematically more
elegant to take antiparticles as having negative mass but moving forward
in time?
If so, why is it considered somewhat crankish?
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Esa A E Peuha <esa.peuha@helsinki.fi> writes\n\n>Antimatter will certainly fall just like ordinary matter, regardless of\n>whether it has positive or negative mass.\n\nI presume this is just a statement saying all bodies follow a geodesic.\n\n>The question is whether\n>antimatter will attract (in case of positive mass) or repel (negative\n>mass) anything else.\n\nI am unclear about this though. Will a large antimatter body repel\nordinary matter or attract it, similarly for antimatter. Its all those\ndouble and triple negatives that confuse the heck out of me. You suggest\nthat they behave gravitationally differently but your first statement\n(above) suggests they don\'t.\n\nIts the old saw about negative mass being attracted by a negative force\nresults in attraction. Makes my head hurt ....\n\nOne has a horrible feeling that even devising a test to determine if\nnegative mass exists might be difficult.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Esa A E Peuha <esa.peuha@helsinki.fi> writes
>Antimatter will certainly fall just like ordinary matter, regardless of
>whether it has positive or negative mass.
I presume this is just a statement saying all bodies follow a geodesic.
>The question is whether
>antimatter will attract (in case of positive mass) or repel (negative
>mass) anything else.
I am unclear about this though. Will a large antimatter body repel
ordinary matter or attract it, similarly for antimatter. Its all those
double and triple negatives that confuse the heck out of me. You suggest
that they behave gravitationally differently but your first statement
(above) suggests they don't.
Its the old saw about negative mass being attracted by a negative force
results in attraction. Makes my head hurt ....
One has a horrible feeling that even devising a test to determine if
negative mass exists might be difficult.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes\n>Oz wrote:\n>\n>> Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes\n>\n>> One can get terribly confused by negatives of negatives on these\n>> situations. I am easily confused....\n>>\n>> However there may be one scenario where the difference may make a\n>> difference, or there again not.\n>>\n>> If one postulated that spacetime and matter popped into existence at t=0\n>> then is it plausible to consider that antimatter immediately started to\n>> head in the -t direction and matter in the +t direction.\n>\n>That is GREAT!! Of COURSE! It all ran off into the past!\n\nWell, I have suggested it before. Seems quite a nice idea to me.\n\n>Let\'s pray that the world does not have closed time loops - a whole\n>boatload of angry antimatter might be headed this way!\n\nWe ought to see quite a few photons well in advance, so some warning\nmight be forthcoming.\n\n>> Of course it wouldn\'t be a simple process as each \'bunch\' would continually be\n>> producing both particles and antiparticles and there would be quite a\n>> bit of mutual annihilation. One might imagine it as initially\n>> symmetrical (in the time direction) but becoming increasingly biassed\n>> towards antiparticles in the -t direction and particles in the +t\n>> direction. After some (probably quite brief but busy) period one might\n>> imagine each lobe would become separated (in time). Heuristically this\n>> (until shot down in flames by Those Who Know) might be a mechanism for\n>> explaining why we live in a (+ve) particulate universe where there isn\'t\n>> much mass left.\n>\n>I don\'t think there is a great mystery about the local lack of\n>antimatter. Hannes Alfven showed in simple terms that that\n>observationally, at best matter and its mirror are separated at the\n>level of galaxy clusters. An interesting aspect of his analysis - if you\n>have a tenuous gas of matter and one of antimatter and allow them to\n>interact, a boundary area of annihilation sets up and the radiation\n>pressure from it tends to keep them separated.\n\nSounds highly plausible, except that this radiation should be quite\nevident, particularly in the early universe.\n\n>An exactly analogous\n>thing happens when you drip water onto a hot surface - the water boils\n>at the surface of the drop and the outgassing of steam lifts the drop up\n>off the hot surface - allowing the water drop to live an unexpectedly\n>long time ("Leidenfrost effect").\n\nIt also hovercrafts round at high speed.\n\n>The main problem with Alfven\'s symmetric cosmology - explaining the\n>thermalization of the annihilation radiation.\n\nHis model doesn\'t seem to have much in common with my suggestion.\n\nI am proposing it for the *very* early universe, certainly before\n10^-12s. At this time radiation pressure would (I guess) be\ninsignificant compared to the energy of the particles. I would expect\nparticles and antiparticles to have very short mean free paths (in 4-D)\nso the universe initially expanded symmetrically (that is equally in the\n+t and -t) directions, it would be (looking from 5-D) a hypersphere.\nHowever there would be a drift of antiparticles in the -t direction and\na drift of particles in the +t direction. The whole time, in each small\nvolume, particles and antiparticles would be being produced but\nprogressively the +t direction would be depleted in antiparticles, and\nthe -t in particles to produce two lobes. I expect it to end up as some\nhorrible diffusion-like equation. Something roughly analogous a ball of\nhot plasma in an intense electrical field where ionisation is repeatedly\nhappening until the paths start to line up with the electric field.\n\nHah! Could a distant bunch of negative mass give us an accelerating\nexpansion? I don\'t know, seems unlikely.\n\n\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes
>Oz wrote:
>
>> Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes
>
>> One can get terribly confused by negatives of negatives on these
>> situations. I am easily confused....
>>
>> However there may be one scenario where the difference may make a
>> difference, or there again not.
>>
>> If one postulated that spacetime and matter popped into existence at t=0
>> then is it plausible to consider that antimatter immediately started to
>> head in the -t direction and matter in the +t direction.
>
>That is GREAT!! Of COURSE! It all ran off into the past!
Well, I have suggested it before. Seems quite a nice idea to me.
>Let's pray that the world does not have closed time loops - a whole
>boatload of angry antimatter might be headed this way!
We ought to see quite a few photons well in advance, so some warning
might be forthcoming.
>> Of course it wouldn't be a simple process as each 'bunch' would continually be
>> producing both particles and antiparticles and there would be quite a
>> bit of mutual annihilation. One might imagine it as initially
>> symmetrical (in the time direction) but becoming increasingly biassed
>> towards antiparticles in the -t direction and particles in the +t
>> direction. After some (probably quite brief but busy) period one might
>> imagine each lobe would become separated (in time). Heuristically this
>> (until shot down in flames by Those Who Know) might be a mechanism for
>> explaining why we live in a (+ve) particulate universe where there isn't
>> much mass left.
>
>I don't think there is a great mystery about the local lack of
>antimatter. Hannes Alfven showed in simple terms that that
>observationally, at best matter and its mirror are separated at the
>level of galaxy clusters. An interesting aspect of his analysis - if you
>have a tenuous gas of matter and one of antimatter and allow them to
>interact, a boundary area of annihilation sets up and the radiation
>pressure from it tends to keep them separated.
Sounds highly plausible, except that this radiation should be quite
evident, particularly in the early universe.
>An exactly analogous
>thing happens when you drip water onto a hot surface - the water boils
>at the surface of the drop and the outgassing of steam lifts the drop up
>off the hot surface - allowing the water drop to live an unexpectedly
>long time ("Leidenfrost effect").
It also hovercrafts round at high speed.
>The main problem with Alfven's symmetric cosmology - explaining the
>thermalization of the annihilation radiation.
His model doesn't seem to have much in common with my suggestion.
I am proposing it for the *very* early universe, certainly before
10^-12s. At this time radiation pressure would (I guess) be
insignificant compared to the energy of the particles. I would expect
particles and antiparticles to have very short mean free paths (in 4-D)
so the universe initially expanded symmetrically (that is equally in the
+t and -t) directions, it would be (looking from 5-D) a hypersphere.
However there would be a drift of antiparticles in the -t direction and
a drift of particles in the +t direction. The whole time, in each small
volume, particles and antiparticles would be being produced but
progressively the +t direction would be depleted in antiparticles, and
the -t in particles to produce two lobes. I expect it to end up as some
horrible diffusion-like equation. Something roughly analogous a ball of
hot plasma in an intense electrical field where ionisation is repeatedly
happening until the paths start to line up with the electric field.
Hah! Could a distant bunch of negative mass give us an accelerating
expansion? I don't know, seems unlikely.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>EjP <nospam@hackers.are.bad> writes\n>It\'s not really about lifetime, it\'s about energy. We routinely\n>store antiprotons for many days, but they\'re moving so fast that\n>gravity is negligible. In order to get any *individual* particles\n>(matter or antimatter) moving slowly enough that you can see\n>gravitational effects, they have to be very cold.\n\nWouldn\'t it be possible to use the same techniques of a neutron\nspallation source to produce very slow antineutrons?\n\nThe only problem is that theory may well suggest that they would still\nfall in the same manner as neutrons. If so (which would seem likely) a\nnull result would be expected either way.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>EjP <nospam@hackers.are.bad> writes
>It's not really about lifetime, it's about energy. We routinely
>store antiprotons for many days, but they're moving so fast that
>gravity is negligible. In order to get any *individual* particles
>(matter or antimatter) moving slowly enough that you can see
>gravitational effects, they have to be very cold.
Wouldn't it be possible to use the same techniques of a neutron
spallation source to produce very slow antineutrons?
The only problem is that theory may well suggest that they would still
fall in the same manner as neutrons. If so (which would seem likely) a
null result would be expected either way.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
Esa A E Peuha
Apr7-04, 08:59 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Oz <acoohdb@btopenworld.com> writes:\n\n> Esa A E Peuha <esa.peuha@helsinki.fi> writes\n>\n> >Antimatter will certainly fall just like ordinary matter, regardless of\n> >whether it has positive or negative mass.\n>\n> I presume this is just a statement saying all bodies follow a geodesic.\n\nYes.\n\n> >The question is whether\n> >antimatter will attract (in case of positive mass) or repel (negative\n> >mass) anything else.\n>\n> I am unclear about this though. Will a large antimatter body repel\n> ordinary matter or attract it, similarly for antimatter.\n\nSince antimatter is not known to have negative mass, I\'ll use PMM\n(positive mass matter) and NMM (negative mass matter) to avoid any\nconfusion. Now PMM will attract anything gravitationally, and NMM will\nrepel everything, so if you have equal amounts of PMM and NMM\ninteracting only by gravitation next to each other, then the PMM will\naccelerate away from the NMM and the NMM will follow the PMM. However\nif these matters have also electric charge (and the gravitational\ninteraction can be ignored), things can look different; if they have the\nsame charge, the PMM will still accelerate away from the NMM and the NMM\nwill still accelerate towards the PMM (because for the NMM force and\nacceleration vectors must point to opposite directions), but if they\nhave opposite charges, the NMM will run away and the PMM will follow.\n\n> One has a horrible feeling that even devising a test to determine if\n> negative mass exists might be difficult.\n\nActually it\'s pretty easy to see that at least antiparticles of ordinary\nparticles have positive mass; if, for example, the positron had negative\nmass, we would see vast amounts of positrons chased by electrons at very\nnear light speed, since positron-electron pairs are known to be created\nby cosmic radiation and other reasons. Also, positrons and antiprotons\nare known to form antihydrogen atoms (or is that hydrogen antiatoms)\nwhich would be impossible if they had negative masses.\n\n--\nEsa Peuha\nstudent of mathematics at the University of Helsinki\nhttp://www.helsinki.fi/~peuha/\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Oz <acoohdb@btopenworld.com> writes:
> Esa A E Peuha <esa.peuha@helsinki.fi> writes
>
> >Antimatter will certainly fall just like ordinary matter, regardless of
> >whether it has positive or negative mass.
>
> I presume this is just a statement saying all bodies follow a geodesic.
Yes.
> >The question is whether
> >antimatter will attract (in case of positive mass) or repel (negative
> >mass) anything else.
>
> I am unclear about this though. Will a large antimatter body repel
> ordinary matter or attract it, similarly for antimatter.
Since antimatter is not known to have negative mass, I'll use PMM
(positive mass matter) and NMM (negative mass matter) to avoid any
confusion. Now PMM will attract anything gravitationally, and NMM will
repel everything, so if you have equal amounts of PMM and NMM
interacting only by gravitation next to each other, then the PMM will
accelerate away from the NMM and the NMM will follow the PMM. However
if these matters have also electric charge (and the gravitational
interaction can be ignored), things can look different; if they have the
same charge, the PMM will still accelerate away from the NMM and the NMM
will still accelerate towards the PMM (because for the NMM force and
acceleration vectors must point to opposite directions), but if they
have opposite charges, the NMM will run away and the PMM will follow.
> One has a horrible feeling that even devising a test to determine if
> negative mass exists might be difficult.
Actually it's pretty easy to see that at least antiparticles of ordinary
particles have positive mass; if, for example, the positron had negative
mass, we would see vast amounts of positrons chased by electrons at very
near light speed, since positron-electron pairs are known to be created
by cosmic radiation and other reasons. Also, positrons and antiprotons
are known to form antihydrogen atoms (or is that hydrogen antiatoms)
which would be impossible if they had negative masses.
--
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/
Danny Ross Lunsford
Apr7-04, 09:05 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\nEsa A E Peuha wrote:\n\n\\> Since antimatter is not known to have negative mass, I\'ll use PMM\n\\> (positive mass matter) and NMM (negative mass matter) to avoid any\n\\> confusion.\n\nUnfortunately that doesn\'t work - the sign on the mass is a matter of\nconvention and the issue becomes - it is legitimate to use both\nconventions at once, as is usually done? That is, there is a very\ndefinite operation on a negative energy solution to the Dirac equation\nthat inverts the sign on the mass of a jabber and dresses it up as a\npositive-energy antijabber - and one uses *both* conventions at the same\ntime in the subsequent development. All of the odd, paradoxical behavior\nin the Dirac theory can be traced back to this choice.\n\n\\> Now PMM will attract anything gravitationally, and NMM will\n\\> repel everything...\n\nHang on, this is not at all clear. If gravity is polar with respect to\nmatter and antimatter, then the polarity can\'t be the simple kind found\nin the vector field theory (electrodynamics). So it may be that\nantimatter gravitationally repels other antimatter, while the mutual\ngravitational interaction of matter and antimatter is a total unknown -\nthere is no place in GR for introducing the distinction (one would have\nto have a theory in which the volume element itself was a dynamical\nvariable because the distinction of matter and antimatter is ultimately\na consequence of spacetime parity).\n\n\\> Actually it\'s pretty easy to see that at least antiparticles of ordinary\n\\> particles have positive mass; if, for example, the positron had negative\n\\> mass, we would see vast amounts of positrons chased by electrons at very\n\\> near light speed, since positron-electron pairs are known to be created\n\\> by cosmic radiation and other reasons.\n\nThe "chasing" behavior is based on the tacit assumption that for\nantimatter, Minertial = Mgravitational. Because there is no place in the\nusual formalism of GR for the idea of matter-antimatter and mutual\ncreation-annihilation, we just don\'t know - the experiment really has to\nbe done to guide the formalism.\n\n\\> ... Also, positrons and antiprotons\n\\> are known to form antihydrogen atoms (or is that hydrogen antiatoms)\n\\> which would be impossible if they had negative masses.\n\nThis is certainly not true - we can reconvene and call the existing\nhydrogen "antihydrogen" and lament that we have no koinohydrogen to play\nwith. In introducing the local charge conjugation operator iy2y0 one has\ntacitly assumed that it is possible to redefine the two everywhere\nglobally (I\'m working on localizing this to see if any new information\nemerges).\n\n-drl\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Esa A E Peuha wrote:
> Since antimatter is not known to have negative mass, I'll use PMM
> (positive mass matter) and NMM (negative mass matter) to avoid any
> confusion.
Unfortunately that doesn't work - the sign on the mass is a matter of
convention and the issue becomes - it is legitimate to use both
conventions at once, as is usually done? That is, there is a very
definite operation on a negative energy solution to the Dirac equation
that inverts the sign on the mass of a jabber and dresses it up as a
positive-energy antijabber - and one uses *both* conventions at the same
time in the subsequent development. All of the odd, paradoxical behavior
in the Dirac theory can be traced back to this choice.
> Now PMM will attract anything gravitationally, and NMM will
> repel everything...
Hang on, this is not at all clear. If gravity is polar with respect to
matter and antimatter, then the polarity can't be the simple kind found
in the vector field theory (electrodynamics). So it may be that
antimatter gravitationally repels other antimatter, while the mutual
gravitational interaction of matter and antimatter is a total unknown -
there is no place in GR for introducing the distinction (one would have
to have a theory in which the volume element itself was a dynamical
variable because the distinction of matter and antimatter is ultimately
a consequence of spacetime parity).
> Actually it's pretty easy to see that at least antiparticles of ordinary
> particles have positive mass; if, for example, the positron had negative
> mass, we would see vast amounts of positrons chased by electrons at very
> near light speed, since positron-electron pairs are known to be created
> by cosmic radiation and other reasons.
The "chasing" behavior is based on the tacit assumption that for
antimatter, Minertial = Mgravitational. Because there is no place in the
usual formalism of GR for the idea of matter-antimatter and mutual
creation-annihilation, we just don't know - the experiment really has to
be done to guide the formalism.
> ... Also, positrons and antiprotons
> are known to form antihydrogen atoms (or is that hydrogen antiatoms)
> which would be impossible if they had negative masses.
This is certainly not true - we can reconvene and call the existing
hydrogen "antihydrogen" and lament that we have no koinohydrogen to play
with. In introducing the local charge conjugation operator iy2y0 one has
tacitly assumed that it is possible to redefine the two everywhere
globally (I'm working on localizing this to see if any new information
emerges).
-drl
Danny Ross Lunsford
Apr7-04, 09:05 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\nOz wrote:\n\n\\> Am I to interpret this as a statement that its mathematically more\n\\> elegant to take antiparticles as having negative mass but moving forward\n\\> in time?\n\nWell it\'s certainly more in the spirit of invariant theory. When you\ntake the complex conjugate of the Dirac eqn you are in effect\ninterchanging the past and future light cones. This erases the effect of\nparity in the full Lorentz group as far as time is concerned, so to get\nit back you have to pick a bivector (in spacetime, 2 directions) which\nthen defines a plane in spacetime normal to it, and then one gets back\nparity by reflection in this plane. But, this is a kind of choice of\ngauge and for every possible frame you have to pick another one - the\ncommon choice is what is called the charge conjugation operator\nmentioned before i gamma_2 gamma_0. It is far more natural to work\ndirectly with negative mass, so parity has a frame-independent\nrepresentation.\n\nIs it crankish? No one thinks about these things any more, everyone\nassumes they know everything there is to be known about the Dirac\nequation. Call it "eccentric" then.\n\n-drl\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Oz wrote:
> Am I to interpret this as a statement that its mathematically more
> elegant to take antiparticles as having negative mass but moving forward
> in time?
Well it's certainly more in the spirit of invariant theory. When you
take the complex conjugate of the Dirac eqn you are in effect
interchanging the past and future light cones. This erases the effect of
parity in the full Lorentz group as far as time is concerned, so to get
it back you have to pick a bivector (in spacetime, 2 directions) which
then defines a plane in spacetime normal to it, and then one gets back
parity by reflection in this plane. But, this is a kind of choice of
gauge and for every possible frame you have to pick another one - the
common choice is what is called the charge conjugation operator
mentioned before i \gamma_2 \gamma_0. It is far more natural to work
directly with negative mass, so parity has a frame-independent
representation.
Is it crankish? No one thinks about these things any more, everyone
assumes they know everything there is to be known about the Dirac
equation. Call it "eccentric" then.
-drl
Danny Ross Lunsford
Apr7-04, 09:08 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Oz wrote:\n\n> If one postulated that spacetime and matter popped into existence at t=0\n> then is it plausible to consider that antimatter immediately started to\n> head in the -t direction and matter in the +t direction.\n\nYou know, this is disturbing me Oz. In fact this might be an amazing\ninsight. How can one reconcile the Big Bang scenario with the simple\nlogical fact that at t=0 there is no past to go into? The only possible\nway out is a time-symmetric cosmology with the valid mirror image of a\ngradually accelerating collapse to nothingness, with the end phase being\ndeflationary. This is clearly impossible, so the choices are 1) backward\nin time is untenable 2) t=0 is impossible.\n\n-drl\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Oz wrote:
> If one postulated that spacetime and matter popped into existence at t=0
> then is it plausible to consider that antimatter immediately started to
> head in the -t direction and matter in the +t direction.
You know, this is disturbing me Oz. In fact this might be an amazing
insight. How can one reconcile the Big Bang scenario with the simple
logical fact that at t=0 there is no past to go into? The only possible
way out is a time-symmetric cosmology with the valid mirror image of a
gradually accelerating collapse to nothingness, with the end phase being
deflationary. This is clearly impossible, so the choices are 1) backward
in time is untenable 2) t=0 is impossible.
-drl
Esa A E Peuha
Apr7-04, 09:13 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>"Michael Varney" <varney@colorado_no_spam.edu> writes:\n\n> "Esa A E Peuha" <esa.peuha@helsinki.fi> wrote in message\n> news:86pptat2w6s.fsf@sirppi.helsinki.fi...\n> > Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes:\n> >\n> > > However, the experiment has never been done, so the jury is out,\n> > > physically speaking. Until a piece of antimatter can be made that lives\n> > > long enough to fall in a vacuum, we won\'t "really" know.\n> >\n> > Antimatter will certainly fall just like ordinary matter\n>\n> Are you certain? Physics is an experimental science, and until this\n> conjecture is experimentally verified, it cannot be stated with certainty.\n\nOf course the result of any experiment can\'t be predicted with absolute\ncertainty. However, if the experiment shows that antimatter does fall\nup, it violates general relativity on a very fundamental level. Now\ngeneral relativity has been tested by hundreds of experiments (with\nwhich no other known theory of gravity completely agrees), so it would\nbe extremely surprising if antimatter did fall up.\n\n--\nEsa Peuha\nstudent of mathematics at the University of Helsinki\nhttp://www.helsinki.fi/~peuha/\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Michael Varney" <varney@colorado_no_spam.edu> writes:
> "Esa A E Peuha" <esa.peuha@helsinki.fi> wrote in message
> news:86pptat2w6s.fsf@sirppi.helsinki.fi...
> > Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes:
> >
> > > However, the experiment has never been done, so the jury is out,
> > > physically speaking. Until a piece of antimatter can be made that lives
> > > long enough to fall in a vacuum, we won't "really" know.
> >
> > Antimatter will certainly fall just like ordinary matter
>
> Are you certain? Physics is an experimental science, and until this
> conjecture is experimentally verified, it cannot be stated with certainty.
Of course the result of any experiment can't be predicted with absolute
certainty. However, if the experiment shows that antimatter does fall
up, it violates general relativity on a very fundamental level. Now
general relativity has been tested by hundreds of experiments (with
which no other known theory of gravity completely agrees), so it would
be extremely surprising if antimatter did fall up.
--
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Esa A E Peuha <esa.peuha@helsinki.fi> writes\n\n>Since antimatter is not known to have negative mass, I\'ll use PMM\n>(positive mass matter) and NMM (negative mass matter) to avoid any\n>confusion. Now PMM will attract anything gravitationally, and NMM will\n>repel everything, so if you have equal amounts of PMM and NMM\n>interacting only by gravitation next to each other, then the PMM will\n>accelerate away from the NMM and the NMM will follow the PMM.\n\nAhh, yes. I remember a long thread about this some years ago.\n\n>However\n>if these matters have also electric charge (and the gravitational\n>interaction can be ignored), things can look different; if they have the\n>same charge, the PMM will still accelerate away from the NMM and the NMM\n>will still accelerate towards the PMM (because for the NMM force and\n>acceleration vectors must point to opposite directions), but if they\n>have opposite charges, the NMM will run away and the PMM will follow.\n\nHmmm. Not the sort of behaviour one usually expects.\n\n>> One has a horrible feeling that even devising a test to determine if\n>> negative mass exists might be difficult.\n>\n>Actually it\'s pretty easy to see that at least antiparticles of ordinary\n>particles have positive mass; if, for example, the positron had negative\n>mass, we would see vast amounts of positrons chased by electrons at very\n>near light speed, since positron-electron pairs are known to be created\n>by cosmic radiation and other reasons. Also, positrons and antiprotons\n>are known to form antihydrogen atoms (or is that hydrogen antiatoms)\n>which would be impossible if they had negative masses.\n\nSo perhaps better to take antiparticles as particles going backwards in\ntime? Or are you able to show that this has flaws too?\n\n<sigh>\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Esa A E Peuha <esa.peuha@helsinki.fi> writes
>Since antimatter is not known to have negative mass, I'll use PMM
>(positive mass matter) and NMM (negative mass matter) to avoid any
>confusion. Now PMM will attract anything gravitationally, and NMM will
>repel everything, so if you have equal amounts of PMM and NMM
>interacting only by gravitation next to each other, then the PMM will
>accelerate away from the NMM and the NMM will follow the PMM.
Ahh, yes. I remember a long thread about this some years ago.
>However
>if these matters have also electric charge (and the gravitational
>interaction can be ignored), things can look different; if they have the
>same charge, the PMM will still accelerate away from the NMM and the NMM
>will still accelerate towards the PMM (because for the NMM force and
>acceleration vectors must point to opposite directions), but if they
>have opposite charges, the NMM will run away and the PMM will follow.
Hmmm. Not the sort of behaviour one usually expects.
>> One has a horrible feeling that even devising a test to determine if
>> negative mass exists might be difficult.
>
>Actually it's pretty easy to see that at least antiparticles of ordinary
>particles have positive mass; if, for example, the positron had negative
>mass, we would see vast amounts of positrons chased by electrons at very
>near light speed, since positron-electron pairs are known to be created
>by cosmic radiation and other reasons. Also, positrons and antiprotons
>are known to form antihydrogen atoms (or is that hydrogen antiatoms)
>which would be impossible if they had negative masses.
So perhaps better to take antiparticles as particles going backwards in
time? Or are you able to show that this has flaws too?
<sigh>
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
John Baez
Apr7-04, 03:12 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <iHM3pEEXhlbAFwWt@btopenworld.com>,\nOz <oz@farmeroz.port995.com> wrote:\n\n>Esa A E Peuha <esa.peuha@helsinki.fi> writes\n\n>>Antimatter will certainly fall just like ordinary matter, regardless of\n>>whether it has positive or negative mass.\n\nRight! - as long as general relativity applies, that is.\n\n>I presume this is just a statement saying all bodies follow a geodesic.\n\nRight, and it\'s worth noting this pattern:\n\nthe geodesic is timelike <=> mass^2 > 0 (tardyons)\nthe geodesic is lightlike <=> mass^2 = 0 (luxons)\nthe geodesic is spacelike <=> mass^2 < 0 (tachyons)\n\nSo, you can tell a little about the mass of a particle by the\nsort of geodesic it follows, but not the *sign* of its mass.\n\n>>The question is whether antimatter will attract (in case of positive\n>>mass) or repel (negative mass) anything else.\n\n>I am unclear about this though. Will a large antimatter body repel\n>ordinary matter or attract it, similarly for antimatter. Its all those\n>double and triple negatives that confuse the heck out of me.\n\nRight, they\'re confusing - and I never worked them out myself until we\ndiscussed this a couple of times here on sci.physics.research. But now\nI know how it goes. As long as general relativity applies:\n\nA positive-mass body will curve spacetime in a way that bends geodesics\n"towards" it, so it will *attract* other bodies regardless of the sign\nof their mass.\n\nA negative-mass body will curve spacetime in a way that bends geodesics\n"away from" it, so it will *repel* other bodies regardless of the sign\nof their mass.\n\nNow you\'ve got all the necessary knowledge to take a crack at this:\n\nPUZZLE:\n\nFigure out what happens if you have two planets near each\nother: Earth and Anti-Earth, the first with positive mass, the\nsecond with an "equal but opposite" negative mass.\n\n(We\'ve already discussed *everything* here. We\'ve even been through\na discussion before about how "equal and opposite" is a slightly stupid\nthing to say - but we all know what it means.)\n\n>Its the old saw about negative mass being attracted by a negative force\n>results in attraction. Makes my head hurt ....\n\nYes, but it\'s not much worse than - x - = +... which of course some\npeople never get around to grokking.\n\n>One has a horrible feeling that even devising a test to determine if\n>negative mass exists might be difficult.\n\nThis is an interesting question, but you should do the puzzle\nfirst.\n\nBy the way, it currently seems like I\'ll be in Oxford this July 7-9,\nto speak at the Workshop on Gerbes: Recent Developments and Future\nPerspectives, at Oxford, organized by Nuno Reis. So, maybe we can\nget together while I\'m there. (There\'s a chance this workshop won\'t\nactually happen, due to funding issues, but regardless of that I\'ll\nbe in Cambridge from July 1st to September 8th, modulo a few side-trips.)\n\n-------------------------------------------------------------------------\nPuzzle #19:\n\nAs of February 2004, five of the ten richest people in the world had\nthe same last name. What is it?\n\nIf you give up, try:\n\nhttp://math.ucr.edu/home/baez/puzzles/19.html\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <iHM3pEEXhlbAFwWt@btopenworld.com>,
Oz <oz@farmeroz.port995.com> wrote:
>Esa A E Peuha <esa.peuha@helsinki.fi> writes
>>Antimatter will certainly fall just like ordinary matter, regardless of
>>whether it has positive or negative mass.
Right! - as long as general relativity applies, that is.
>I presume this is just a statement saying all bodies follow a geodesic.
Right, and it's worth noting this pattern:
the geodesic is timelike <=> mass^2 > (tardyons)
the geodesic is lightlike <=> mass^2 = (luxons)
the geodesic is spacelike <=> mass^2 < (tachyons)
So, you can tell a little about the mass of a particle by the
sort of geodesic it follows, but not the *sign* of its mass.
>>The question is whether antimatter will attract (in case of positive
>>mass) or repel (negative mass) anything else.
>I am unclear about this though. Will a large antimatter body repel
>ordinary matter or attract it, similarly for antimatter. Its all those
>double and triple negatives that confuse the heck out of me.
Right, they're confusing - and I never worked them out myself until we
discussed this a couple of times here on sci.physics.research. But now
I know how it goes. As long as general relativity applies:
A positive-mass body will curve spacetime in a way that bends geodesics
"towards" it, so it will *attract* other bodies regardless of the sign
of their mass.
A negative-mass body will curve spacetime in a way that bends geodesics
"away from" it, so it will *repel* other bodies regardless of the sign
of their mass.
Now you've got all the necessary knowledge to take a crack at this:
PUZZLE:
Figure out what happens if you have two planets near each
other: Earth and Anti-Earth, the first with positive mass, the
second with an "equal but opposite" negative mass.
(We've already discussed *everything* here. We've even been through
a discussion before about how "equal and opposite" is a slightly stupid
thing to say - but we all know what it means.)
>Its the old saw about negative mass being attracted by a negative force
>results in attraction. Makes my head hurt ....
Yes, but it's not much worse than - x - = +... which of course some
people never get around to grokking.
>One has a horrible feeling that even devising a test to determine if
>negative mass exists might be difficult.
This is an interesting question, but you should do the puzzle
first.
By the way, it currently seems like I'll be in Oxford this July 7-9,
to speak at the Workshop on Gerbes: Recent Developments and Future
Perspectives, at Oxford, organized by Nuno Reis. So, maybe we can
get together while I'm there. (There's a chance this workshop won't
actually happen, due to funding issues, but regardless of that I'll
be in Cambridge from July 1st to September 8th, modulo a few side-trips.)
-------------------------------------------------------------------------
Puzzle #19:
As of February 2004, five of the ten richest people in the world had
the same last name. What is it?
If you give up, try:
http://math.ucr.edu/home/baez/puzzles/19.html
Michael Varney
Apr7-04, 03:13 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>"Esa A E Peuha" <esa.peuha@helsinki.fi> wrote in message\nnews:86pisge2198.fsf@sirppi.helsinki.fi.. .\n> "Michael Varney" <varney@colorado_no_spam.edu> writes:\n>\n> > "Esa A E Peuha" <esa.peuha@helsinki.fi> wrote in message\n> > news:86pptat2w6s.fsf@sirppi.helsinki.fi...\n> > > Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes:\n> > >\n> > > > However, the experiment has never been done, so the jury is out,\n> > > > physically speaking. Until a piece of antimatter can be made that\nlives\n> > > > long enough to fall in a vacuum, we won\'t "really" know.\n> > >\n> > > Antimatter will certainly fall just like ordinary matter\n> >\n> > Are you certain? Physics is an experimental science, and until this\n> > conjecture is experimentally verified, it cannot be stated with\ncertainty.\n>\n> Of course the result of any experiment can\'t be predicted with absolute\n> certainty. However, if the experiment shows that antimatter does fall\n> up, it violates general relativity on a very fundamental level.\n\nWhich is why it is an important experiment to perform.\n\n\n> Now\n> general relativity has been tested by hundreds of experiments (with\n> which no other known theory of gravity completely agrees), so it would\n> be extremely surprising if antimatter did fall up.\n\nIt would be surprising. However, the experiment needs to be done, and to\nstate with certainty that antimatter will fall like matter is an incorrect\nthing to do in science.\n\n\n---\nMichael Varney\nDepartment of Physics\nUniversity of Colorado, Boulder\nhttp://rintintin.colorado.edu/~varney\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Esa A E Peuha" <esa.peuha@helsinki.fi> wrote in message
news:86pisge2198.fsf@sirppi.helsinki.fi...
> "Michael Varney" <varney@colorado_no_spam.edu> writes:
>
> > "Esa A E Peuha" <esa.peuha@helsinki.fi> wrote in message
> > news:86pptat2w6s.fsf@sirppi.helsinki.fi...
> > > Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes:
> > >
> > > > However, the experiment has never been done, so the jury is out,
> > > > physically speaking. Until a piece of antimatter can be made that
lives
> > > > long enough to fall in a vacuum, we won't "really" know.
> > >
> > > Antimatter will certainly fall just like ordinary matter
> >
> > Are you certain? Physics is an experimental science, and until this
> > conjecture is experimentally verified, it cannot be stated with
certainty.
>
> Of course the result of any experiment can't be predicted with absolute
> certainty. However, if the experiment shows that antimatter does fall
> up, it violates general relativity on a very fundamental level.
Which is why it is an important experiment to perform.
> Now
> general relativity has been tested by hundreds of experiments (with
> which no other known theory of gravity completely agrees), so it would
> be extremely surprising if antimatter did fall up.
It would be surprising. However, the experiment needs to be done, and to
state with certainty that antimatter will fall like matter is an incorrect
thing to do in science.
---
Michael Varney
Department of Physics
University of Colorado, Boulder
http://rintintin.colorado.edu/~varney
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>John Baez <baez@galaxy.ucr.edu> writes\n>In article <iHM3pEEXhlbAFwWt@btopenworld.com>,\n>Oz <oz@farmeroz.port995.com> wrote:\n>\n> and triple negatives that confuse the heck out of me.\n>\n>Right, they\'re confusing - and I never worked them out myself until we\n>discussed this a couple of times here on sci.physics.research. But now\n>I know how it goes. As long as general relativity applies:\n>\n>A positive-mass body will curve spacetime in a way that bends geodesics\n>"towards" it, so it will *attract* other bodies regardless of the sign\n>of their mass.\n>\n>A negative-mass body will curve spacetime in a way that bends geodesics\n>"away from" it, so it will *repel* other bodies regardless of the sign\n>of their mass.\n\nThat strikes me as very reasonable. Of course we must be careful to\ndistinguish between a positive and negative inertia, too. In this sort\nof scenario I don\'t think we can assume mass and inertia will\nnecessarily be either the same, or a different, sign. Fortunately in GR\nwhen following a geodesic, there is no acceleration so this can be\nconveniently swept under the carpet.\n\n>Now you\'ve got all the necessary knowledge to take a crack at this:\n\nOh .. my .. god! He never changes! Straight into homework.\n\n>PUZZLE:\n>\n> Figure out what happens if you have two planets near each\n> other: Earth and Anti-Earth, the first with positive mass, the\n> second with an "equal but opposite" negative mass.\n\nI expect we will have the \'accelerate across the universe\' scenario...\n\nThis needs some thought. I trust you are not expecting me to solve an\nequivalent of schild metric for this scenario?\nIf so you are out of luck.\nI assume embedded in an otherwise empty flat spacetime. For convenience\nI will consider the masses as point particles.\n\nNow what?\nWell, there will be a point halfway between the two which will be\nlocally flat. Eh? No, that can\'t be right. A test particle on the\nrepulsive body will fall straight down and hit the attractive one, since\nit will be repelled by the repulsive and attracted by the attractive.\n\nSo if both bodies were dust then the repulsive one would expand and the\nattractive one would collapse. If they were solid enough to resist\ngravitational forces then they clearly would accelerate across the\nuniverse, trailing their gravitational fields behind them. If they were\norbiting each other as well, then they would have a complex circular\npath (probably).\n\nWhat if they were different sized masses?\n\nWell a -m particle would orbit a large +m particle, but presumably in\nits immediate vicinity space would be less curved. I think this means it\nhas a slightly larger orbit. The two bodies will orbit round a centre of\nmass that will be outside the line between them. This will be a patch of\nflat spacetime. For an infinitely small orbiting mass, the only patch of\nflat spacetime (not at inf) will be the saddle on the major body,\nclearly a -ve mass will push this further away from the -ve particle.\n\nAs their masses tend to being equal and opposite then this patch will\nrecede to infinity and we get the \'follow my leader\' scenario again.\n\nMy head hurts ....\n\n>>Its the old saw about negative mass being attracted by a negative force\n>>results in attraction. Makes my head hurt ....\n>\n>Yes, but it\'s not much worse than - x - = +... which of course some\n>people never get around to grokking.\n>\n>>One has a horrible feeling that even devising a test to determine if\n>>negative mass exists might be difficult.\n\nI note that time-reversing the above scenarios reverses -ve and +ve\nmass.\n\n>By the way, it currently seems like I\'ll be in Oxford this July 7-9,\n>to speak at the Workshop on Gerbes: Recent Developments and Future\n>Perspectives, at Oxford, organized by Nuno Reis. So, maybe we can\n>get together while I\'m there.\n\nShould be fine.\nI can\'t contact you, but you can contact me using reply-to of this post.\n\n>(There\'s a chance this workshop won\'t\n>actually happen, due to funding issues, but regardless of that I\'ll\n>be in Cambridge from July 1st to September 8th, modulo a few side-trips.)\n\nWill be outside claire\'s termtime I think.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>John Baez <baez@galaxy.ucr.edu> writes
>In article <iHM3pEEXhlbAFwWt@btopenworld.com>,
>Oz <oz@farmeroz.port995.com> wrote:
>
> and triple negatives that confuse the heck out of me.
>
>Right, they're confusing - and I never worked them out myself until we
>discussed this a couple of times here on sci.physics.research. But now
>I know how it goes. As long as general relativity applies:
>
>A positive-mass body will curve spacetime in a way that bends geodesics
>"towards" it, so it will *attract* other bodies regardless of the sign
>of their mass.
>
>A negative-mass body will curve spacetime in a way that bends geodesics
>"away from" it, so it will *repel* other bodies regardless of the sign
>of their mass.
That strikes me as very reasonable. Of course we must be careful to
distinguish between a positive and negative inertia, too. In this sort
of scenario I don't think we can assume mass and inertia will
necessarily be either the same, or a different, sign. Fortunately in GR
when following a geodesic, there is no acceleration so this can be
conveniently swept under the carpet.
>Now you've got all the necessary knowledge to take a crack at this:
Oh .. my .. god! He never changes! Straight into homework.
>PUZZLE:
>
> Figure out what happens if you have two planets near each
> other: Earth and Anti-Earth, the first with positive mass, the
> second with an "equal but opposite" negative mass.
I expect we will have the 'accelerate across the universe' scenario...
This needs some thought. I trust you are not expecting me to solve an
equivalent of schild metric for this scenario?
If so you are out of luck.
I assume embedded in an otherwise empty flat spacetime. For convenience
I will consider the masses as point particles.
Now what?
Well, there will be a point halfway between the two which will be
locally flat. Eh? No, that can't be right. A test particle on the
repulsive body will fall straight down and hit the attractive one, since
it will be repelled by the repulsive and attracted by the attractive.
So if both bodies were dust then the repulsive one would expand and the
attractive one would collapse. If they were solid enough to resist
gravitational forces then they clearly would accelerate across the
universe, trailing their gravitational fields behind them. If they were
orbiting each other as well, then they would have a complex circular
path (probably).
What if they were different sized masses?
Well a -m particle would orbit a large +m particle, but presumably in
its immediate vicinity space would be less curved. I think this means it
has a slightly larger orbit. The two bodies will orbit round a centre of
mass that will be outside the line between them. This will be a patch of
flat spacetime. For an infinitely small orbiting mass, the only patch of
flat spacetime (not at inf) will be the saddle on the major body,
clearly a -ve mass will push this further away from the -ve particle.
As their masses tend to being equal and opposite then this patch will
recede to infinity and we get the 'follow my leader' scenario again.
My head hurts ....
>>Its the old saw about negative mass being attracted by a negative force
>>results in attraction. Makes my head hurt ....
>
>Yes, but it's not much worse than - x - = +... which of course some
>people never get around to grokking.
>
>>One has a horrible feeling that even devising a test to determine if
>>negative mass exists might be difficult.
I note that time-reversing the above scenarios reverses -ve and +ve
mass.
>By the way, it currently seems like I'll be in Oxford this July 7-9,
>to speak at the Workshop on Gerbes: Recent Developments and Future
>Perspectives, at Oxford, organized by Nuno Reis. So, maybe we can
>get together while I'm there.
Should be fine.
I can't contact you, but you can contact me using reply-to of this post.
>(There's a chance this workshop won't
>actually happen, due to funding issues, but regardless of that I'll
>be in Cambridge from July 1st to September 8th, modulo a few side-trips.)
Will be outside claire's termtime I think.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
carlip@no-physics-spam.ucdavis.edu
Apr8-04, 02:28 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Danny Ross Lunsford <antimatter33@yahoo.nose-pam.com> wrote:\n> Oz wrote:\n\n> > If one postulated that spacetime and matter popped into existence at t=0\n> > then is it plausible to consider that antimatter immediately started to\n> > head in the -t direction and matter in the +t direction.\n\n> You know, this is disturbing me Oz. In fact this might be an amazing\n> insight. How can one reconcile the Big Bang scenario with the simple\n> logical fact that at t=0 there is no past to go into?\n\nIf you are sticking with standard general relativity (with a Lorentzian\nmetric), t=0 is a singularity, anyway, so it\'s not clear that you should\nexpect any reconciliation. If you accept the Hartle-Hawking picture of\nquantum cosmology, though, in which the metric near t=0 is Riemannian,\nthere\'s a nice answer -- in fact, the geometry naturally picks out the\ndecomposition into positive and negative frequencies. See Gibbons and\nPohle, "Complex Numbers, Quantum Mechanics and the Beginning of Time,"\ngr-qc/9302002.\n\nSteve Carlip\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Danny Ross Lunsford <antimatter33@yahoo.nose-pam.com> wrote:
> Oz wrote:
> > If one postulated that spacetime and matter popped into existence at t=0
> > then is it plausible to consider that antimatter immediately started to
> > head in the -t direction and matter in the +t direction.
> You know, this is disturbing me Oz. In fact this might be an amazing
> insight. How can one reconcile the Big Bang scenario with the simple
> logical fact that at t=0 there is no past to go into?
If you are sticking with standard general relativity (with a Lorentzian
metric), t=0 is a singularity, anyway, so it's not clear that you should
expect any reconciliation. If you accept the Hartle-Hawking picture of
quantum cosmology, though, in which the metric near t=0 is Riemannian,
there's a nice answer -- in fact, the geometry naturally picks out the
decomposition into positive and negative frequencies. See Gibbons and
Pohle, "Complex Numbers, Quantum Mechanics and the Beginning of Time,"
gr-qc/9302002.
Steve Carlip
Esa A E Peuha
Apr8-04, 06:35 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes:\n\n> Unfortunately that doesn\'t work - the sign on the mass is a matter of\n> convention and the issue becomes - it is legitimate to use both\n> conventions at once, as is usually done?\n\nThat depends on the context. GR itself has no problem with having\nmatter with negative mass.\n\n> > Now PMM will attract anything gravitationally, and NMM will\n> > repel everything...\n>\n> Hang on, this is not at all clear.\n\nIt is perfectly clear in GR.\n\n> If gravity is polar with respect to\n> matter and antimatter, then the polarity can\'t be the simple kind found\n> in the vector field theory (electrodynamics). So it may be that\n> antimatter gravitationally repels other antimatter, while the mutual\n> gravitational interaction of matter and antimatter is a total unknown -\n> there is no place in GR for introducing the distinction\n\nWhat do you mean? In GR, any given object either attracts everything or\nrepels everything gravitationally, so the gravitational interaction\nbetween matter and antimatter is definitely predicted no matter what we\nassume about the mass of antimatter (even if it turns out to be wrong).\n\n> (one would have\n> to have a theory in which the volume element itself was a dynamical\n> variable because the distinction of matter and antimatter is ultimately\n> a consequence of spacetime parity).\n\nI don\'t understand; the volume element dx /\\ dy /\\ dz does change sign\nwhen spacetime parity is reversed (if that\'s what you mean).\n\n> > Actually it\'s pretty easy to see that at least antiparticles of ordinary\n> > particles have positive mass; if, for example, the positron had negative\n> > mass, we would see vast amounts of positrons chased by electrons at very\n> > near light speed, since positron-electron pairs are known to be created\n> > by cosmic radiation and other reasons.\n>\n> The "chasing" behavior is based on the tacit assumption that for\n> antimatter, Minertial = Mgravitational.\n\nIn the case of gravitation, yes, but electric force only involves the\ninertial mass. Since the electric force between an electron and a\npositron is several orders of magnitude greater than the gravitational\nforce, it is quite clear that positron must have the same sign of\ninertial mass as electron.\n\n> Because there is no place in the\n> usual formalism of GR for the idea of matter-antimatter and mutual\n> creation-annihilation, we just don\'t know - the experiment really has to\n> be done to guide the formalism.\n\nI agree that the experiment should be done, but if it turns out that\nantimatter falls up, then we will have no theory of gravity that can\nagree with all experiments, and no idea how to construct one.\n\n> > ... Also, positrons and antiprotons\n> > are known to form antihydrogen atoms (or is that hydrogen antiatoms)\n> > which would be impossible if they had negative masses.\n>\n> This is certainly not true - we can reconvene and call the existing\n> hydrogen "antihydrogen" and lament that we have no koinohydrogen to play\n> with.\n\nAntihydrogen has been observed at Fermilab in 1997.\n\n--\nEsa Peuha\nstudent of mathematics at the University of Helsinki\nhttp://www.helsinki.fi/~peuha/\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes:
> Unfortunately that doesn't work - the sign on the mass is a matter of
> convention and the issue becomes - it is legitimate to use both
> conventions at once, as is usually done?
That depends on the context. GR itself has no problem with having
matter with negative mass.
> > Now PMM will attract anything gravitationally, and NMM will
> > repel everything...
>
> Hang on, this is not at all clear.
It is perfectly clear in GR.
> If gravity is polar with respect to
> matter and antimatter, then the polarity can't be the simple kind found
> in the vector field theory (electrodynamics). So it may be that
> antimatter gravitationally repels other antimatter, while the mutual
> gravitational interaction of matter and antimatter is a total unknown -
> there is no place in GR for introducing the distinction
What do you mean? In GR, any given object either attracts everything or
repels everything gravitationally, so the gravitational interaction
between matter and antimatter is definitely predicted no matter what we
assume about the mass of antimatter (even if it turns out to be wrong).
> (one would have
> to have a theory in which the volume element itself was a dynamical
> variable because the distinction of matter and antimatter is ultimately
> a consequence of spacetime parity).
I don't understand; the volume element dx /\ dy /\ dz does change sign
when spacetime parity is reversed (if that's what you mean).
> > Actually it's pretty easy to see that at least antiparticles of ordinary
> > particles have positive mass; if, for example, the positron had negative
> > mass, we would see vast amounts of positrons chased by electrons at very
> > near light speed, since positron-electron pairs are known to be created
> > by cosmic radiation and other reasons.
>
> The "chasing" behavior is based on the tacit assumption that for
> antimatter, Minertial = Mgravitational.
In the case of gravitation, yes, but electric force only involves the
inertial mass. Since the electric force between an electron and a
positron is several orders of magnitude greater than the gravitational
force, it is quite clear that positron must have the same sign of
inertial mass as electron.
> Because there is no place in the
> usual formalism of GR for the idea of matter-antimatter and mutual
> creation-annihilation, we just don't know - the experiment really has to
> be done to guide the formalism.
I agree that the experiment should be done, but if it turns out that
antimatter falls up, then we will have no theory of gravity that can
agree with all experiments, and no idea how to construct one.
> > ... Also, positrons and antiprotons
> > are known to form antihydrogen atoms (or is that hydrogen antiatoms)
> > which would be impossible if they had negative masses.
>
> This is certainly not true - we can reconvene and call the existing
> hydrogen "antihydrogen" and lament that we have no koinohydrogen to play
> with.
Antihydrogen has been observed at Fermilab in 1997.
--
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/
Danny Ross Lunsford
Apr8-04, 06:39 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>John Baez wrote:\n\n>>I am unclear about this though. Will a large antimatter body repel\n>>ordinary matter or attract it, similarly for antimatter. Its all those\n>>double and triple negatives that confuse the heck out of me.\n>\n> Right, they\'re confusing - and I never worked them out myself until we\n> discussed this a couple of times here on sci.physics.research. But now\n> I know how it goes. As long as general relativity applies:\n>\n> A positive-mass body will curve spacetime in a way that bends geodesics\n> "towards" it, so it will *attract* other bodies regardless of the sign\n> of their mass.\n>\n> A negative-mass body will curve spacetime in a way that bends geodesics\n> "away from" it, so it will *repel* other bodies regardless of the sign\n> of their mass.\n\nThis is consistent with taking the other sign for 2M in the\nSchwarzschild solution. I suppose that was done.\n\n\n> Now you\'ve got all the necessary knowledge to take a crack at this:\n>\n> PUZZLE:\n>\n> Figure out what happens if you have two planets near each\n> other: Earth and Anti-Earth, the first with positive mass, the\n> second with an "equal but opposite" negative mass.\n>\n> (We\'ve already discussed *everything* here. We\'ve even been through\n> a discussion before about how "equal and opposite" is a slightly stupid\n> thing to say - but we all know what it means.)\n\nWithout looking up the answer, if it\'s going to be realistic then the\ntwo have to be capable of erasing each other into some kind of\nradiation. So they must be capable of forming some odd topogical\nrelation. This is like a magnetic pole in the vicinity of an electric one.\n\n\n> -------------------------------------------------------------------------\n> Puzzle #19:\n>\n> As of February 2004, five of the ten richest people in the world had\n> the same last name. What is it?\n\nThis was too easy.\n\n-drl\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>John Baez wrote:
>>I am unclear about this though. Will a large antimatter body repel
>>ordinary matter or attract it, similarly for antimatter. Its all those
>>double and triple negatives that confuse the heck out of me.
>
> Right, they're confusing - and I never worked them out myself until we
> discussed this a couple of times here on sci.physics.research. But now
> I know how it goes. As long as general relativity applies:
>
> A positive-mass body will curve spacetime in a way that bends geodesics
> "towards" it, so it will *attract* other bodies regardless of the sign
> of their mass.
>
> A negative-mass body will curve spacetime in a way that bends geodesics
> "away from" it, so it will *repel* other bodies regardless of the sign
> of their mass.
This is consistent with taking the other sign for 2M in the
Schwarzschild solution. I suppose that was done.
> Now you've got all the necessary knowledge to take a crack at this:
>
> PUZZLE:
>
> Figure out what happens if you have two planets near each
> other: Earth and Anti-Earth, the first with positive mass, the
> second with an "equal but opposite" negative mass.
>
> (We've already discussed *everything* here. We've even been through
> a discussion before about how "equal and opposite" is a slightly stupid
> thing to say - but we all know what it means.)
Without looking up the answer, if it's going to be realistic then the
two have to be capable of erasing each other into some kind of
radiation. So they must be capable of forming some odd topogical
relation. This is like a magnetic pole in the vicinity of an electric one.
> -------------------------------------------------------------------------
> Puzzle #19:
>
> As of February 2004, five of the ten richest people in the world had
> the same last name. What is it?
This was too easy.
-drl
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>"Michael Varney" <varney@colorado_no_spam.edu> wrote in message news:<y5Lcc.48\\$fE1.69091@news.uswest.net>...\n> > Now\n> > general relativity has been tested by hundreds of experiments (with\n> > which no other known theory of gravity completely agrees), so it would\n> > be extremely surprising if antimatter did fall up.\n>\n> It would be surprising. However, the experiment needs to be done, and to\n> state with certainty that antimatter will fall like matter is an incorrect\n> thing to do in science.\n>\n\nIt\'s also incorrect to make up a conjecture that violates well\nestablished physics, and then refuse to believe it\'s not true unless\nsomeone physically performs an experiment. The mass of an antiparticle\nis identical to its corresponding particle, and there is no reason to\nthink they are effected by gravity any differently. You could just as\neasily theorize that an elephant covered with peanut butter will fall\nup when thrown off a cliff, and if someone remarks that that would\nviolate general relativity, retort "It would be surprising. However,\nthe experiment needs to be done, and to state with certainty that\nelephants covered with peanut butter will fall like other objects is\nan incorrect thing to do in science."\n\nDavid\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Michael Varney" <varney@colorado_no_spam.edu> wrote in message news:<y5Lcc.48$fE1.69091@news.uswest.net>...
> > Now
> > general relativity has been tested by hundreds of experiments (with
> > which no other known theory of gravity completely agrees), so it would
> > be extremely surprising if antimatter did fall up.
>
> It would be surprising. However, the experiment needs to be done, and to
> state with certainty that antimatter will fall like matter is an incorrect
> thing to do in science.
>
It's also incorrect to make up a conjecture that violates well
established physics, and then refuse to believe it's not true unless
someone physically performs an experiment. The mass of an antiparticle
is identical to its corresponding particle, and there is no reason to
think they are effected by gravity any differently. You could just as
easily theorize that an elephant covered with peanut butter will fall
up when thrown off a cliff, and if someone remarks that that would
violate general relativity, retort "It would be surprising. However,
the experiment needs to be done, and to state with certainty that
elephants covered with peanut butter will fall like other objects is
an incorrect thing to do in science."
David
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <53ca460a.0404081116.6ce11471@posting.google.com >, Ulmo\n<ulmo@cheerful.com> wrote:\n\n> "Michael Varney" <varney@colorado_no_spam.edu> wrote in message\n> news:<y5Lcc.48\\$fE1.69091@news.uswest.net>...\n> > > Now\n> > > general relativity has been tested by hundreds of experiments (with\n> > > which no other known theory of gravity completely agrees), so it would\n> > > be extremely surprising if antimatter did fall up.\n> >\n> > It would be surprising. However, the experiment needs to be done, and to\n> > state with certainty that antimatter will fall like matter is an incorrect\n> > thing to do in science.\n> >\n>\n> It\'s also incorrect to make up a conjecture that violates well\n> established physics, and then refuse to believe it\'s not true unless\n> someone physically performs an experiment. The mass of an antiparticle\n> is identical to its corresponding particle, and there is no reason to\n> think they are effected by gravity any differently. You could just as\n> easily theorize that an elephant covered with peanut butter will fall\n> up when thrown off a cliff, and if someone remarks that that would\n> violate general relativity, retort "It would be surprising. However,\n> the experiment needs to be done, and to state with certainty that\n> elephants covered with peanut butter will fall like other objects is\n> an incorrect thing to do in science."\n>\n> David\n\nLet\'s take just your first sentence\'s assertion and leave out the\nelephant stuff.\n\nIf I could cite an instance of well established physics which is\nbelieved by nearly everyone ever exposed to even the most mediocre\nphysics course and suggest or conjecture that the interpretation of the\ndata which has led people to believe in a certain behavior of matter\ncan be reanalyzed to yield a completely different hypothesis\n(concerning this behavior) yet still provide the same data set then\nwould you change your mind?\n\nParticularly if the extrapolation of the new hypothesis yields a\ncompletely new physics that also is consistent with all known data and\nphysical phenomena?\n\nTo suppose that \'well established physics\' is necessarily correct may\nbe precisely why physics as a discipline is mired in confusion and\ncomplexity, and is presently not a finished science.\n\nCCRyder\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <53ca460a.0404081116.6ce11471@posting.google.com>, Ulmo
<ulmo@cheerful.com> wrote:
> "Michael Varney" <varney@colorado_no_spam.edu> wrote in message
> news:<y5Lcc.48$fE1.69091@news.uswest.net>...
> > > Now
> > > general relativity has been tested by hundreds of experiments (with
> > > which no other known theory of gravity completely agrees), so it would
> > > be extremely surprising if antimatter did fall up.
> >
> > It would be surprising. However, the experiment needs to be done, and to
> > state with certainty that antimatter will fall like matter is an incorrect
> > thing to do in science.
> >
>
> It's also incorrect to make up a conjecture that violates well
> established physics, and then refuse to believe it's not true unless
> someone physically performs an experiment. The mass of an antiparticle
> is identical to its corresponding particle, and there is no reason to
> think they are effected by gravity any differently. You could just as
> easily theorize that an elephant covered with peanut butter will fall
> up when thrown off a cliff, and if someone remarks that that would
> violate general relativity, retort "It would be surprising. However,
> the experiment needs to be done, and to state with certainty that
> elephants covered with peanut butter will fall like other objects is
> an incorrect thing to do in science."
>
> David
Let's take just your first sentence's assertion and leave out the
elephant stuff.
If I could cite an instance of well established physics which is
believed by nearly everyone ever exposed to even the most mediocre
physics course and suggest or conjecture that the interpretation of the
data which has led people to believe in a certain behavior of matter
can be reanalyzed to yield a completely different hypothesis
(concerning this behavior) yet still provide the same data set then
would you change your mind?
Particularly if the extrapolation of the new hypothesis yields a
completely new physics that also is consistent with all known data and
physical phenomena?
To suppose that 'well established physics' is necessarily correct may
be precisely why physics as a discipline is mired in confusion and
complexity, and is presently not a finished science.
CCRyder
Danny Ross Lunsford
Apr11-04, 11:44 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\nCCRyder wrote:\n\n> If I could cite an instance of well established physics which is\n> believed by nearly everyone ever exposed to even the most mediocre\n> physics course and suggest or conjecture that the interpretation of the\n> data which has led people to believe in a certain behavior of matter\n> can be reanalyzed to yield a completely different hypothesis\n> (concerning this behavior) yet still provide the same data set then\n> would you change your mind?\n>\n> Particularly if the extrapolation of the new hypothesis yields a\n> completely new physics that also is consistent with all known data and\n> physical phenomena?\n>\n> To suppose that \'well established physics\' is necessarily correct may\n> be precisely why physics as a discipline is mired in confusion and\n> complexity, and is presently not a finished science.\n\nWell it\'s only natural to keep probing at the foundations. There is a\nlot of subtle behavior in something like the Dirac equation. And there\nare examples of statements in the texts that are plain wrong - for\nexample identifying the particle velocity as the operator Alpha and then\nscratching the head when the eigenvalues come out to be +-c. It never\nhurts to poke around in the basement.\n\n-drl\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>CCRyder wrote:
> If I could cite an instance of well established physics which is
> believed by nearly everyone ever exposed to even the most mediocre
> physics course and suggest or conjecture that the interpretation of the
> data which has led people to believe in a certain behavior of matter
> can be reanalyzed to yield a completely different hypothesis
> (concerning this behavior) yet still provide the same data set then
> would you change your mind?
>
> Particularly if the extrapolation of the new hypothesis yields a
> completely new physics that also is consistent with all known data and
> physical phenomena?
>
> To suppose that 'well established physics' is necessarily correct may
> be precisely why physics as a discipline is mired in confusion and
> complexity, and is presently not a finished science.
Well it's only natural to keep probing at the foundations. There is a
lot of subtle behavior in something like the Dirac equation. And there
are examples of statements in the texts that are plain wrong - for
example identifying the particle velocity as the operator \Alpha and then
scratching the head when the eigenvalues come out to be +-c. It never
hurts to poke around in the basement.
-drl
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\nEsa A E Peuha <esa.peuha@helsinki.fi> writes\n\n>What do you mean? In GR, any given object either attracts everything or\n>repels everything gravitationally, so the gravitational interaction\n>between matter and antimatter is definitely predicted no matter what we\n>assume about the mass of antimatter (even if it turns out to be wrong).\n\nOK, that\'s fine. We don\'t want to break GR as well!\n\nLet\'s for the moment investigate what a body that repels everything\nmight look like. I have been castigated by a moderator who says that,\ntime-reversed or no: attractive bodies attract. The logic of this is to\ntime reverse a film. Bodies still follow the normal newtonian path,\nwhich is completely true. I know this, I am not thinking straight.\n\nA large repulsive body would have no stable orbits, its not a matter of\ntime reversal since that just means backwards orbits. A negative-mass\nuniverse would be totally different from a positive mass universe,\nalthough I guess electric and nuclear combinations will still form,\nlarger, gravitationally bound ones will not. There would be no stars and\nvery little interaction. I\'m not even sure how one would interpret\nenergy, which on the face of it would be negative. One imagines that\nthis would produce an energy-free annihilation between a +ve and -ve\nmass electron, which is not what we see.\n\nThat said, and all the other implausible scenarios that go with allowing\n-ve mass matter, I am forced to conclude that the evidence for its\nexistence is on the \'very unlikely\' side of \'very doubtful\'.\nEr ... if that\'s not a double negative too ...\n\nNow I am confused again. Ross has claimed that antiparticles can be\nconsidered as negative matter or time reversed (I hope not both\nsimultaneously). Given the implausibility of it being negative mass\nmatter, is it reasonable to take antiparticles as simply time-reversed\nparticles, since the other alternative doesn\'t look good at all?\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Esa A E Peuha <esa.peuha@helsinki.fi> writes
>What do you mean? In GR, any given object either attracts everything or
>repels everything gravitationally, so the gravitational interaction
>between matter and antimatter is definitely predicted no matter what we
>assume about the mass of antimatter (even if it turns out to be wrong).
OK, that's fine. We don't want to break GR as well!
Let's for the moment investigate what a body that repels everything
might look like. I have been castigated by a moderator who says that,
time-reversed or no: attractive bodies attract. The logic of this is to
time reverse a film. Bodies still follow the normal newtonian path,
which is completely true. I know this, I am not thinking straight.
A large repulsive body would have no stable orbits, its not a matter of
time reversal since that just means backwards orbits. A negative-mass
universe would be totally different from a positive mass universe,
although I guess electric and nuclear combinations will still form,
larger, gravitationally bound ones will not. There would be no stars and
very little interaction. I'm not even sure how one would interpret
energy, which on the face of it would be negative. One imagines that
this would produce an energy-free annihilation between a +ve and -ve
mass electron, which is not what we see.
That said, and all the other implausible scenarios that go with allowing
-ve mass matter, I am forced to conclude that the evidence for its
existence is on the 'very unlikely' side of 'very doubtful'.
Er ... if that's not a double negative too ...
Now I am confused again. Ross has claimed that antiparticles can be
considered as negative matter or time reversed (I hope not both
simultaneously). Given the implausibility of it being negative mass
matter, is it reasonable to take antiparticles as simply time-reversed
particles, since the other alternative doesn't look good at all?
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>carlip@no-physics-spam.ucdavis.edu writes\n>Danny Ross Lunsford <antimatter33@yahoo.nose-pam.com> wrote:\n>> Oz wrote:\n>\n>> > If one postulated that spacetime and matter popped into existence at t=0\n>> > then is it plausible to consider that antimatter immediately started to\n>> > head in the -t direction and matter in the +t direction.\n>\n>> You know, this is disturbing me Oz. In fact this might be an amazing\n>> insight. How can one reconcile the Big Bang scenario with the simple\n>> logical fact that at t=0 there is no past to go into?\n>\n>If you are sticking with standard general relativity (with a Lorentzian\n>metric), t=0 is a singularity, anyway, so it\'s not clear that you should\n>expect any reconciliation. If you accept the Hartle-Hawking picture of\n>quantum cosmology, though, in which the metric near t=0 is Riemannian,\n>there\'s a nice answer -- in fact, the geometry naturally picks out the\n>decomposition into positive and negative frequencies. See Gibbons and\n>Pohle, "Complex Numbers, Quantum Mechanics and the Beginning of Time,"\n>gr-qc/9302002.\n\nIt has taken me a while to figure out what you might be saying.\n\nAre you saying that time-reversed particles will head towards a\nsingularity and so you can\'t have the rather nice 4-spere symmetry at\nthe early stages of the universe because nothing can cross from -t to +t\nand vice-versa (assuming a singularity at t=0)? I put this in typical\ncrude Oz-style.\n\nI\'m not quite sure that is necessarily precisely correct (he says in\nfear and trepidation), although it took me several minutes to work out\nwhy I thought it so. Naturally my explanation will be a tad confused,\nand probably unclear, but no matter.\n\nObviously if matter is to move through t=0 then it had better not go\nthrough (0,0,0,0), but \'round\' the singularity. That is when it gets\nback to t=0, there had better be some space to get round\n[space=/=(0,0,0)].\n\nI assume backward-moving particles have their proper time reversed.\nI\'m not sure (as in I don\'t know) if reversing the proper time of a\nbunch of particles (but not others) will result in everything returning\nto where it was some time previously.\n\nHowever I doubt, in a quantum mechanical world, whether a particle going\nbackwards is guaranteed to perfectly reverse all its quantum-mechanical\ninteractions. Well, it doesn\'t seem to going forwards, anyway: there is\na great deal of random processes that make this unlikely. There will be\na plethora of quantum mechanical processes between creation and the\n\'return\' of a backwards-moving particle (which has likely only existed\nfor femtosecs or very much less).\n\nThat hopefully being so, then a particle going past t=0 is unlikely to\nsee everything conveniently coming together in perfect unison to\nprecisely produce a singularity. In fact I would hazard a guess that\nit\'s very highly improbable. Sure it will go through a high-density\nregion, but not a singularity. There will be some space to go round.\n\nI probably haven\'t expressed this well or accurately.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\nDEMON address no longer in use.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>carlip@no-physics-spam.ucdavis.edu writes
>Danny Ross Lunsford <antimatter33@yahoo.nose-pam.com> wrote:
>> Oz wrote:
>
>> > If one postulated that spacetime and matter popped into existence at t=0
>> > then is it plausible to consider that antimatter immediately started to
>> > head in the -t direction and matter in the +t direction.
>
>> You know, this is disturbing me Oz. In fact this might be an amazing
>> insight. How can one reconcile the Big Bang scenario with the simple
>> logical fact that at t=0 there is no past to go into?
>
>If you are sticking with standard general relativity (with a Lorentzian
>metric), t=0 is a singularity, anyway, so it's not clear that you should
>expect any reconciliation. If you accept the Hartle-Hawking picture of
>quantum cosmology, though, in which the metric near t=0 is Riemannian,
>there's a nice answer -- in fact, the geometry naturally picks out the
>decomposition into positive and negative frequencies. See Gibbons and
>Pohle, "Complex Numbers, Quantum Mechanics and the Beginning of Time,"
>gr-qc/9302002.
It has taken me a while to figure out what you might be saying.
Are you saying that time-reversed particles will head towards a
singularity and so you can't have the rather nice 4-spere symmetry at
the early stages of the universe because nothing can cross from -t to +t
and vice-versa (assuming a singularity at t=0)? I put this in typical
crude Oz-style.
I'm not quite sure that is necessarily precisely correct (he says in
fear and trepidation), although it took me several minutes to work out
why I thought it so. Naturally my explanation will be a tad confused,
and probably unclear, but no matter.
Obviously if matter is to move through t=0 then it had better not go
through (0,0,0,0), but 'round' the singularity. That is when it gets
back to t=0, there had better be some space to get round
[space=/=(0,0,0)].
I assume backward-moving particles have their proper time reversed.
I'm not sure (as in I don't know) if reversing the proper time of a
bunch of particles (but not others) will result in everything returning
to where it was some time previously.
However I doubt, in a quantum mechanical world, whether a particle going
backwards is guaranteed to perfectly reverse all its quantum-mechanical
interactions. Well, it doesn't seem to going forwards, anyway: there is
a great deal of random processes that make this unlikely. There will be
a plethora of quantum mechanical processes between creation and the
'return' of a backwards-moving particle (which has likely only existed
for femtosecs or very much less).
That hopefully being so, then a particle going past t=0 is unlikely to
see everything conveniently coming together in perfect unison to
precisely produce a singularity. In fact I would hazard a guess that
it's very highly improbable. Sure it will go through a high-density
region, but not a singularity. There will be some space to go round.
I probably haven't expressed this well or accurately.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
Igor Khavkine
Apr15-04, 11:17 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>baez@galaxy.ucr.edu (John Baez) wrote in message news:<c4vns4\\$il1\\$1@glue.ucr.edu>...\n\n> A positive-mass body will curve spacetime in a way that bends geodesics\n> "towards" it, so it will *attract* other bodies regardless of the sign\n> of their mass.\n>\n> A negative-mass body will curve spacetime in a way that bends geodesics\n> "away from" it, so it will *repel* other bodies regardless of the sign\n> of their mass.\n>\n> Now you\'ve got all the necessary knowledge to take a crack at this:\n>\n> PUZZLE:\n>\n> Figure out what happens if you have two planets near each\n> other: Earth and Anti-Earth, the first with positive mass, the\n> second with an "equal but opposite" negative mass.\n\nGoing on what\'s written above, I think Anti-Earth will be attracted\nto Earth, while Earth will be repelled by Anti-Earth. As a result,\nthey will both start moving, Earth running away from Anti-Earth and\nAnti-Earth trying to catch up. This situation is rather strange since\nthe overall momentum of the system is not conserved so something\nis fishy here. (Yes, I know that momentum need not be conserved in GR,\nbut lets assume weak fields, and whatever niceties that allow it). This\neffect is in principle observable, but I have not heard any such\nobservations.\n\nAlso, if negative masses repell each other, we wouldn\'t find any really\nlarge clumps of it around, since they would be unstable.\n\nIgor\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>baez@galaxy.ucr.edu (John Baez) wrote in message news:<c4vns4$il1$1@glue.ucr.edu>...
> A positive-mass body will curve spacetime in a way that bends geodesics
> "towards" it, so it will *attract* other bodies regardless of the sign
> of their mass.
>
> A negative-mass body will curve spacetime in a way that bends geodesics
> "away from" it, so it will *repel* other bodies regardless of the sign
> of their mass.
>
> Now you've got all the necessary knowledge to take a crack at this:
>
> PUZZLE:
>
> Figure out what happens if you have two planets near each
> other: Earth and Anti-Earth, the first with positive mass, the
> second with an "equal but opposite" negative mass.
Going on what's written above, I think Anti-Earth will be attracted
to Earth, while Earth will be repelled by Anti-Earth. As a result,
they will both start moving, Earth running away from Anti-Earth and
Anti-Earth trying to catch up. This situation is rather strange since
the overall momentum of the system is not conserved so something
is fishy here. (Yes, I know that momentum need not be conserved in GR,
but lets assume weak fields, and whatever niceties that allow it). This
effect is in principle observable, but I have not heard any such
observations.
Also, if negative masses repell each other, we wouldn't find any really
large clumps of it around, since they would be unstable.
Igor
Dushan Mitrovich
Apr17-04, 05:09 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>k_igor_k@lycos.com (Igor Khavkine) wrote:\n`baez@galaxy.ucr.edu (John Baez) wrote in message news:<c4vns4\\$il1\\$1@glue.ucr.edu>...\n`\n`> A positive-mass body will curve spacetime in a way that bends geodesics\n`> "towards" it, so it will *attract* other bodies regardless of the sign\n`> of their mass.\n`>\n`> A negative-mass body will curve spacetime in a way that bends geodesics\n`> "away from" it, so it will *repel* other bodies regardless of the sign\n`> of their mass.\n`>\n`> Now you\'ve got all the necessary knowledge to take a crack at this:\n`>\n`> PUZZLE:\n`>\n`> Figure out what happens if you have two planets near each\n`> other: Earth and Anti-Earth, the first with positive mass, the\n`> second with an "equal but opposite" negative mass.\n`\n` Going on what\'s written above, I think Anti-Earth will be attracted\n` to Earth, while Earth will be repelled by Anti-Earth. As a result,\n` they will both start moving, Earth running away from Anti-Earth and\n` Anti-Earth trying to catch up. This situation is rather strange since\n` the overall momentum of the system is not conserved so something\n` is fishy here. (Yes, I know that momentum need not be conserved in GR,\n` but lets assume weak fields, and whatever niceties that allow it). This\n` effect is in principle observable, but I have not heard any such\n` observations.\n\nWhat \'overall momentum\'? The total mass is zero.\n\n- Dushan Mitrovich\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>k_{igor_k}@lycos.com (Igor Khavkine) wrote:
`baez@galaxy.ucr.edu (John Baez) wrote in message news:<c4vns4$il1$1@glue.ucr.edu>...
`
`> A positive-mass body will curve spacetime in a way that bends geodesics
`> "towards" it, so it will *attract* other bodies regardless of the sign
`> of their mass.
`>
`> A negative-mass body will curve spacetime in a way that bends geodesics
`> "away from" it, so it will *repel* other bodies regardless of the sign
`> of their mass.
`>
`> Now you've got all the necessary knowledge to take a crack at this:
`>
`> PUZZLE:
`>
`> Figure out what happens if you have two planets near each
`> other: Earth and Anti-Earth, the first with positive mass, the
`> second with an "equal but opposite" negative mass.
`
` Going on what's written above, I think Anti-Earth will be attracted
` to Earth, while Earth will be repelled by Anti-Earth. As a result,
` they will both start moving, Earth running away from Anti-Earth and
` Anti-Earth trying to catch up. This situation is rather strange since
` the overall momentum of the system is not conserved so something
` is fishy here. (Yes, I know that momentum need not be conserved in GR,
` but lets assume weak fields, and whatever niceties that allow it). This
` effect is in principle observable, but I have not heard any such
` observations.
What 'overall momentum'? The total mass is zero.
- Dushan Mitrovich
Charles Francis
Apr18-04, 03:51 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <c4v8t3\\$dk2\\$1@lfa222122.richmond.edu>, Oz\n<oz@farmeroz.port995.com> writes\n>So perhaps better to take antiparticles as particles going backwards in\n>time? Or are you able to show that this has flaws too?\n\nNo, it has no mathematical flaws. It\'s quite simple mathematically.\n\n\nRegards\n\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <c4v8t3$dk2$1@lfa222122.richmond.edu>, Oz
<oz@farmeroz.port995.com> writes
>So perhaps better to take antiparticles as particles going backwards in
>time? Or are you able to show that this has flaws too?
No, it has no mathematical flaws. It's quite simple mathematically.
Regards
--
Charles Francis
Esa A E Peuha
Apr19-04, 01:51 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>k_igor_k@lycos.com (Igor Khavkine) writes:\n\n> Going on what\'s written above, I think Anti-Earth will be attracted\n> to Earth, while Earth will be repelled by Anti-Earth. As a result,\n> they will both start moving, Earth running away from Anti-Earth and\n> Anti-Earth trying to catch up.\n\nRight.\n\n> This situation is rather strange since\n> the overall momentum of the system is not conserved so something\n> is fishy here.\n\nWrong. Total momentum is most definitely conserved: momentum of Earth\nis m_Ev and momentum of Anti-Earth is m_Av, so total momentum is\n(m_E + m_A)v which is zero since m_E + m_A is zero.\n\n--\nEsa Peuha\nstudent of mathematics at the University of Helsinki\nhttp://www.helsinki.fi/~peuha/\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>k_{igor_k}@lycos.com (Igor Khavkine) writes:
> Going on what's written above, I think Anti-Earth will be attracted
> to Earth, while Earth will be repelled by Anti-Earth. As a result,
> they will both start moving, Earth running away from Anti-Earth and
> Anti-Earth trying to catch up.
Right.
> This situation is rather strange since
> the overall momentum of the system is not conserved so something
> is fishy here.
Wrong. Total momentum is most definitely conserved: momentum of Earth
is m_{Ev} and momentum of Anti-Earth is m_{Av}, so total momentum is
(m_E + m_A)v which is zero since m_E + m_A is zero.
--
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/
Charles Francis
Apr19-04, 02:08 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <c4s9pi\\$c8g\\$1@lfa222122.richmond.edu>, Oz\n<acoohdb@btopenworld.com> writes\n>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes\n>\n>\n>Ooohhh... that\'ll raise some eyebrows...\n>\n>>If one takes this seriously, then one has to consider the Schwarzschild\n>>solution with the integration constant corresponding to the mass of the\n>>body taken to have the opposite sign. Matter and antimatter would then\n>>definitely be distinguised gravitationally.\n\nActually not. I like to think of (m,0,0,0) as representing the rest\nmomentum of a particle. An antiparticle has negative m, so is\nrepresented by a vector pointing backwards in time. The active\ngravitational effect is the same as for a positive m particle\nrepresented by a vector pointing forwards in time.\n\n>\n>Ooooohhh ... not mainstream (but in many ways nice).\n>Note that this matches well with Charles Francis\' formulation of\n>teleparallel quantum gravity and the naive particle-antiparticle BB\n>radiation.\n\nOuch. I didn\'t think so.\n>\n>>*Should* we take it seriously?\n\nYes, but we have to be *very* careful about signs.\n>\n>Am I to interpret this as a statement that its mathematically more\n>elegant to take antiparticles as having negative mass but moving forward\n>in time?\n\nNo, you can\'t do that. They have negative mass moving backwards in time,\nand this manifests as positive mass moving forwards in time.\n\n\n\nRegards\n\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <c4s9pi$c8g$1@lfa222122.richmond.edu>, Oz
<acoohdb@btopenworld.com> writes
>Danny Ross Lunsford <antimatter33@yahoo.NOSE-PAM.com> writes
>
>
>Ooohhh... that'll raise some eyebrows...
>
>>If one takes this seriously, then one has to consider the Schwarzschild
>>solution with the integration constant corresponding to the mass of the
>>body taken to have the opposite sign. Matter and antimatter would then
>>definitely be distinguised gravitationally.
Actually not. I like to think of (m,0,0,0) as representing the rest
momentum of a particle. An antiparticle has negative m, so is
represented by a vector pointing backwards in time. The active
gravitational effect is the same as for a positive m particle
represented by a vector pointing forwards in time.
>
>Ooooohhh ... not mainstream (but in many ways nice).
>Note that this matches well with Charles Francis' formulation of
>teleparallel quantum gravity and the naive particle-antiparticle BB
>radiation.
Ouch. I didn't think so.
>
>>*Should* we take it seriously?
Yes, but we have to be *very* careful about signs.
>
>Am I to interpret this as a statement that its mathematically more
>elegant to take antiparticles as having negative mass but moving forward
>in time?
No, you can't do that. They have negative mass moving backwards in time,
and this manifests as positive mass moving forwards in time.
Regards
--
Charles Francis
Charles Francis
Apr19-04, 02:08 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <c5hn29\\$uj1\\$1@lfa222122.richmond.edu>, Oz\n<oz@farmeroz.port995.com> writes\n\n>I assume backward-moving particles have their proper time reversed.\n\nYes.\n\n>I\'m not sure (as in I don\'t know) if reversing the proper time of a\n>bunch of particles (but not others) will result in everything returning\n>to where it was some time previously.\n\n?\n>\n>However I doubt, in a quantum mechanical world, whether a particle going\n>backwards is guaranteed to perfectly reverse all its quantum-mechanical\n>interactions.\n\nSomething about weak interactions, but otherwise it\'s perfect\n\n>\n>That hopefully being so, then a particle going past t=0 is unlikely to\n>see everything conveniently coming together in perfect unison to\n>precisely produce a singularity.\n\nI don\'t see why not, except that I doubt it is possible to talk of time\nand space in the same way near the singularity. That is to say I expect\nthe physics to break down *before* you get to the mathematical\nsingularity.\n\n\n\n\nRegards\n\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <c5hn29$uj1$1@lfa222122.richmond.edu>, Oz
<oz@farmeroz.port995.com> writes
>I assume backward-moving particles have their proper time reversed.
Yes.
>I'm not sure (as in I don't know) if reversing the proper time of a
>bunch of particles (but not others) will result in everything returning
>to where it was some time previously.
?
>
>However I doubt, in a quantum mechanical world, whether a particle going
>backwards is guaranteed to perfectly reverse all its quantum-mechanical
>interactions.
Something about weak interactions, but otherwise it's perfect
>
>That hopefully being so, then a particle going past t=0 is unlikely to
>see everything conveniently coming together in perfect unison to
>precisely produce a singularity.
I don't see why not, except that I doubt it is possible to talk of time
and space in the same way near the singularity. That is to say I expect
the physics to break down *before* you get to the mathematical
singularity.
Regards
--
Charles Francis
Charles Francis
Apr19-04, 02:10 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <ZM6JLBCV7PdAFwAA@btopenworld.com>, Oz\n<oz@farmeroz.port995.com> writes\n>John Baez <baez@galaxy.ucr.edu> writes\n>>\n>>Now you\'ve got all the necessary knowledge to take a crack at this:\n>\n>Oh .. my .. god! He never changes! Straight into homework.\n\nNow you see where I get it from.\n>\n>So if both bodies were dust then the repulsive one would expand and the\n>attractive one would collapse. If they were solid enough to resist\n>gravitational forces then they clearly would accelerate across the\n>universe, trailing their gravitational fields behind them. If they were\n>orbiting each other as well, then they would have a complex circular\n>path (probably).\n\nI think there is a missing minus sign. A negative mass particle moves\nbackwards in time, according to the rest momentum vector, (m,0,0,0). But\nthe active gravitational mass (effect on curvature) depends on the\nmagnitude of this vector.\n\n>>>One has a horrible feeling that even devising a test to determine if\n>>>negative mass exists might be difficult.\n\nantiparticles are observed.\n\n\n\nRegards\n\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <ZM6JLBCV7PdAFwAA@btopenworld.com>, Oz
<oz@farmeroz.port995.com> writes
>John Baez <baez@galaxy.ucr.edu> writes
>>
>>Now you've got all the necessary knowledge to take a crack at this:
>
>Oh .. my .. god! He never changes! Straight into homework.
Now you see where I get it from.
>
>So if both bodies were dust then the repulsive one would expand and the
>attractive one would collapse. If they were solid enough to resist
>gravitational forces then they clearly would accelerate across the
>universe, trailing their gravitational fields behind them. If they were
>orbiting each other as well, then they would have a complex circular
>path (probably).
I think there is a missing minus sign. A negative mass particle moves
backwards in time, according to the rest momentum vector, (m,0,0,0). But
the active gravitational mass (effect on curvature) depends on the
magnitude of this vector.
>>>One has a horrible feeling that even devising a test to determine if
>>>negative mass exists might be difficult.
antiparticles are observed.
Regards
--
Charles Francis
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Charles Francis <charles@clef.demon.co.uk> writes\n>In article <c4v8t3\\$dk2\\$1@lfa222122.richmond.edu>, Oz\n><oz@farmeroz.port995.com> writes\n>>So perhaps better to take antiparticles as particles going backwards in\n>>time? Or are you able to show that this has flaws too?\n>\n>No, it has no mathematical flaws. It\'s quite simple mathematically.\n\nIts an odd thing, but I find this an interesting concept.\n\nHowever, whenever I try and discuss it here there is a dearth of replies\nas if the experts are in some way afraid of it.\n\nI suspect the reason may be that one of necessity seem to have to reject\na minkowski spacetime if you are to include QM, and this is surely by\nits very nature a qm \'feature\'. I am not very convinced, in fact I have\nconvinced myself of the reverse, that the worldines of \'backward\nrunning\' particles do NOT see global time reversed. The trouble is that\nthis also implies that particles taking a different (relativistic) path\nprobably don\'t see all other paths taking a time-reversible (or do I\nmean trajectory-reversible?) path either (in a curved spacetime).\n\nIn a way its just an extension of the problems of having global\nanything-much in a curved spacetime. Does a \'global time\' in GR even\nmake sense even before you allow backward-time-running particles? I\nsuspect not.\n\nThat has quite interesting possibilities, but I don\'t know enough to\nrefine, or even accurately say, what it is I am trying to say in the\nclear unambiguous way that so many experts require.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\n\nDEMON address no longer in use.\nBTOPENWORLD address about to cease.\n>>Use oz@farmeroz.port995.com (whitelist check on first post)<<\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Charles Francis <charles@clef.demon.co.uk> writes
>In article <c4v8t3$dk2$1@lfa222122.richmond.edu>, Oz
><oz@farmeroz.port995.com> writes
>>So perhaps better to take antiparticles as particles going backwards in
>>time? Or are you able to show that this has flaws too?
>
>No, it has no mathematical flaws. It's quite simple mathematically.
Its an odd thing, but I find this an interesting concept.
However, whenever I try and discuss it here there is a dearth of replies
as if the experts are in some way afraid of it.
I suspect the reason may be that one of necessity seem to have to reject
a minkowski spacetime if you are to include QM, and this is surely by
its very nature a qm 'feature'. I am not very convinced, in fact I have
convinced myself of the reverse, that the worldines of 'backward
running' particles do NOT see global time reversed. The trouble is that
this also implies that particles taking a different (relativistic) path
probably don't see all other paths taking a time-reversible (or do I
mean trajectory-reversible?) path either (in a curved spacetime).
In a way its just an extension of the problems of having global
anything-much in a curved spacetime. Does a 'global time' in GR even
make sense even before you allow backward-time-running particles? I
suspect not.
That has quite interesting possibilities, but I don't know enough to
refine, or even accurately say, what it is I am trying to say in the
clear unambiguous way that so many experts require.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
BTOPENWORLD address about to cease.
>>Use oz@farmeroz.port995.com (whitelist check on first post)<<
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Charles Francis <charles@clef.demon.co.uk> writes\n>In article <c5hn29\\$uj1\\$1@lfa222122.richmond.edu>, Oz\n><oz@farmeroz.port995.com> writes\n>\n>>I assume backward-moving particles have their proper time reversed.\n>\n>Yes.\n>\n>>I\'m not sure (as in I don\'t know) if reversing the proper time of a\n>>bunch of particles (but not others) will result in everything returning\n>>to where it was some time previously.\n>\n>?\n>>\n>>However I doubt, in a quantum mechanical world, whether a particle going\n>>backwards is guaranteed to perfectly reverse all its quantum-mechanical\n>>interactions.\n>\n>Something about weak interactions, but otherwise it\'s perfect\n\nHow do we know? One presumes that for a time-reversed particle,\nbackwards time seems precisely the same as particles see forward time.\n\nSince the behaviour of an individual particle is not precisely\npredictable in forward time, why should it be so for backwards-running\nparticles? Quantum behaviour is inherently unpredictable, and should be\nso in both time directions.\n\nSo, if we are to have time-reversed particles then QM should break the\nperfection of the past. That is, I think I am groping myself towards\nbelieving that spacetime itself is somehow local to a body (or\nparticle). I don;t see how else you can generalise QM with reversed-time\nparticles making forward and backwards symmetrical.\n\nThe problem we have is that we have no real idea of the detail, since\n(to a high degree of perfection) we live in a world entirely populated\nby forward-travelling particles.\n\nIts a bit of a mindbender, but surely someone has seriously considered\nit before.\n\n>>That hopefully being so, then a particle going past t=0 is unlikely to\n>>see everything conveniently coming together in perfect unison to\n>>precisely produce a singularity.\n>\n>I don\'t see why not,\n\nWell, it breaks the unpredictability of QM. Why should QM be\nunpredictable in our time direction, but predictable in a reversible\ndirection?\n\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\n\nDEMON address no longer in use.\nBTOPENWORLD address about to cease.\n>>Use oz@farmeroz.port995.com (whitelist check on first post)<<\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Charles Francis <charles@clef.demon.co.uk> writes
>In article <c5hn29$uj1$1@lfa222122.richmond.edu>, Oz
><oz@farmeroz.port995.com> writes
>
>>I assume backward-moving particles have their proper time reversed.
>
>Yes.
>
>>I'm not sure (as in I don't know) if reversing the proper time of a
>>bunch of particles (but not others) will result in everything returning
>>to where it was some time previously.
>
>?
>>
>>However I doubt, in a quantum mechanical world, whether a particle going
>>backwards is guaranteed to perfectly reverse all its quantum-mechanical
>>interactions.
>
>Something about weak interactions, but otherwise it's perfect
How do we know? One presumes that for a time-reversed particle,
backwards time seems precisely the same as particles see forward time.
Since the behaviour of an individual particle is not precisely
predictable in forward time, why should it be so for backwards-running
particles? Quantum behaviour is inherently unpredictable, and should be
so in both time directions.
So, if we are to have time-reversed particles then QM should break the
perfection of the past. That is, I think I am groping myself towards
believing that spacetime itself is somehow local to a body (or
particle). I don;t see how else you can generalise QM with reversed-time
particles making forward and backwards symmetrical.
The problem we have is that we have no real idea of the detail, since
(to a high degree of perfection) we live in a world entirely populated
by forward-travelling particles.
Its a bit of a mindbender, but surely someone has seriously considered
it before.
>>That hopefully being so, then a particle going past t=0 is unlikely to
>>see everything conveniently coming together in perfect unison to
>>precisely produce a singularity.
>
>I don't see why not,
Well, it breaks the unpredictability of QM. Why should QM be
unpredictable in our time direction, but predictable in a reversible
direction?
--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.
BTOPENWORLD address about to cease.
>>Use oz@farmeroz.port995.com (whitelist check on first post)<<
Charles Francis
Apr20-04, 02:34 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <c614qs\\$d1u\\$1@lfa222122.richmond.edu>, Oz\n<oz@farmeroz.port995.com> writes\n>Charles Francis <charles@clef.demon.co.uk> writes\n>>In article <c4v8t3\\$dk2\\$1@lfa222122.richmond.edu>, Oz\n>><oz@farmeroz.port995.com> writes\n>>>So perhaps better to take antiparticles as particles going backwards in\n>>>time? Or are you able to show that this has flaws too?\n>>\n>>No, it has no mathematical flaws. It\'s quite simple mathematically.\n>\n>Its an odd thing, but I find this an interesting concept.\n>\n>However, whenever I try and discuss it here there is a dearth of replies\n>as if the experts are in some way afraid of it.\n\nYes, but I don\'t really know why, except that it is the fashion to shy\naway from interpretation. They like to think the formulae are enough for\na scientific theory. I don\'t. I think we need interpretation.\n>\n>I suspect the reason may be that one of necessity seem to have to reject\n>a minkowski spacetime if you are to include QM,\n\nNo, we can do relativistic qm if we tip toe through the nasties. It\'s\ncurved space-times that cause fundamental problems.\n\n>. I am not very convinced, in fact I have\n>convinced myself of the reverse, that the worldines of \'backward\n>running\' particles do NOT see global time reversed.\n\nI don\'t see how you get that. To me that is what "backward running"\nmeans.\n\n> The trouble is that\n>this also implies that particles taking a different (relativistic) path\n>probably don\'t see all other paths taking a time-reversible (or do I\n>mean trajectory-reversible?) path either (in a curved spacetime).\n\nLet\'s stick with flat space-times here. That should be pretty good as\nspace-time is locally Minkowski and qm generally deals in local effects.\nIn this case paths are time reversible, and in time reversal particles\nget switched to antiparticles.\n>\n>In a way its just an extension of the problems of having global\n>anything-much in a curved spacetime. Does a \'global time\' in GR even\n>make sense even before you allow backward-time-running particles? I\n>suspect not.\n\nThe only "global time" in gr is cosmological time, which is really just\nproper time for particles emanating straight from the big bang. But\nreally its just a load of proper times, not a global time.\n\n\n\n\nRegards\n\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <c614qs$d1u$1@lfa222122.richmond.edu>, Oz
<oz@farmeroz.port995.com> writes
>Charles Francis <charles@clef.demon.co.uk> writes
>>In article <c4v8t3$dk2$1@lfa222122.richmond.edu>, Oz
>><oz@farmeroz.port995.com> writes
>>>So perhaps better to take antiparticles as particles going backwards in
>>>time? Or are you able to show that this has flaws too?
>>
>>No, it has no mathematical flaws. It's quite simple mathematically.
>
>Its an odd thing, but I find this an interesting concept.
>
>However, whenever I try and discuss it here there is a dearth of replies
>as if the experts are in some way afraid of it.
Yes, but I don't really know why, except that it is the fashion to shy
away from interpretation. They like to think the formulae are enough for
a scientific theory. I don't. I think we need interpretation.
>
>I suspect the reason may be that one of necessity seem to have to reject
>a minkowski spacetime if you are to include QM,
No, we can do relativistic qm if we tip toe through the nasties. It's
curved space-times that cause fundamental problems.
>. I am not very convinced, in fact I have
>convinced myself of the reverse, that the worldines of 'backward
>running' particles do NOT see global time reversed.
I don't see how you get that. To me that is what "backward running"
means.
> The trouble is that
>this also implies that particles taking a different (relativistic) path
>probably don't see all other paths taking a time-reversible (or do I
>mean trajectory-reversible?) path either (in a curved spacetime).
Let's stick with flat space-times here. That should be pretty good as
space-time is locally Minkowski and qm generally deals in local effects.
In this case paths are time reversible, and in time reversal particles
get switched to antiparticles.
>
>In a way its just an extension of the problems of having global
>anything-much in a curved spacetime. Does a 'global time' in GR even
>make sense even before you allow backward-time-running particles? I
>suspect not.
The only "global time" in gr is cosmological time, which is really just
proper time for particles emanating straight from the big bang. But
really its just a load of proper times, not a global time.
Regards
--
Charles Francis
John Baez
Apr20-04, 02:35 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <f1ac2e6e.0404121918.69e61a96@posting.google.com>, \nIgor Khavkine <k_igor_k@lycos.com> wrote:\n\n>baez@galaxy.ucr.edu (John Baez) wrote in message\n>news:<c4vns4\\$il1\\$1@glue.ucr.edu>...\ n\n>> PUZZLE:\n>>\n>> Figure out what happens if you have two planets near each\n>> other: Earth and Anti-Earth, the first with positive mass, the\n>> second with an "equal but opposite" negative mass.\n>\nGoing on what\'s written above, I think Anti-Earth will be attracted\n>to Earth, while Earth will be repelled by Anti-Earth. As a result,\n>they will both start moving, Earth running away from Anti-Earth and\n>Anti-Earth trying to catch up.\n\nRight!\n\n>This situation is rather strange since\n>the overall momentum of the system is not conserved so something\n>is fishy here.\n\nEh? Momentum is indeed conserved. In the Newtonian limit, it\'s just\nmass times velocity; the Earth and Anti-Earth have the same velocity\nbut opposite mass, so the momentum is zero!\n\nIn the Newtonian limit the kinetic energy of this funny system is also\nzero, and the potential energy doesn\'t change because the distance\nbetween Earth and anti-Earth remains constant - so energy is conserved too.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <f1ac2e6e.0404121918.69e61a96@posting.google.com>,
Igor Khavkine <k_{igor_k}@lycos.com> wrote:
>baez@galaxy.ucr.edu (John Baez) wrote in message
>news:<c4vns4$il1$1@glue.ucr.edu>...
>> PUZZLE:
>>
>> Figure out what happens if you have two planets near each
>> other: Earth and Anti-Earth, the first with positive mass, the
>> second with an "equal but opposite" negative mass.
>
Going on what's written above, I think Anti-Earth will be attracted
>to Earth, while Earth will be repelled by Anti-Earth. As a result,
>they will both start moving, Earth running away from Anti-Earth and
>Anti-Earth trying to catch up.
Right!
>This situation is rather strange since
>the overall momentum of the system is not conserved so something
>is fishy here.
Eh? Momentum is indeed conserved. In the Newtonian limit, it's just
mass times velocity; the Earth and Anti-Earth have the same velocity
but opposite mass, so the momentum is zero!
In the Newtonian limit the kinetic energy of this funny system is also
zero, and the potential energy doesn't change because the distance
between Earth and anti-Earth remains constant - so energy is conserved too.
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Charles Francis <charles@clef.demon.co.uk> writes\n>In article <c614qs\\$d1u\\$1@lfa222122.richmond.edu>, Oz\n><oz@farmeroz.port995.com> writes\n\n>>I suspect the reason may be that one of necessity seem to have to reject\n>>a minkowski spacetime if you are to include QM,\n>\n>No, we can do relativistic qm if we tip toe through the nasties. It\'s\n>curved space-times that cause fundamental problems.\n\nMinkowski spacetime allows relativistic speeds anyway, so of course.\n\nNo, its not that that is the problem. We are happy to see unpredictable\nand random effects when these are in the future, but minkowski spactime\npredicts the past perfectly (and by implication, the future). Its\nbasically newtonian in structure, that is global. QM though, ought to\npredict that a time reversed particle also show indeterminancy. That\nwould mean that the past is variable.\n\nThis brings up a whole load of very interesting problems. One thing is\nfor sure, we can\'t go back in time and repeat an experiment to see if we\nget the same result. If we did, then we might not be surprised if we got\na different result, in fact we would expect it (well, I would).\n\nhah! Actually its not really any different concept than \'predicting\'\nwhich silver ion gets to become deionised in a photographic film in a\ndiffraction pattern. The probability of any one is miniscule, but the\nprobability of one on the film is near 100%. Similarly a changed result\nof a time reversed interaction is unlikely to have more than a minute\neffect on the future, it would look like some kind of noise or low-level\nindeterminancy in the future (perhaps something like h).\n\nOne could consider the ramifications further, but I don\'t think its\nintractable. After all essentially everything locally is travelling the\nin same direction and the same speed in time so will have no effect on\n\'the local past\'.\n\n>>. I am not very convinced, in fact I have\n>>convinced myself of the reverse, that the worldines of \'backward\n>>running\' particles do NOT see global time reversed.\n>\n>I don\'t see how you get that. To me that is what "backward running"\n>means.\n\nBackward running ought to be a local phenomenon, pretty well everything\nis. It should not and need not have any relationship to any \'global\ntime\'.\n\n>>In a way its just an extension of the problems of having global\n>>anything-much in a curved spacetime. Does a \'global time\' in GR even\n>>make sense even before you allow backward-time-running particles? I\n>>suspect not.\n>\n>The only "global time" in gr is cosmological time, which is really just\n>proper time for particles emanating straight from the big bang. But\n>really its just a load of proper times, not a global time.\n\nNot really. Minkowski puts global time co-ordinates down along with\nglobal space ones. Its a fixed four dimensional co-ordinate system. No\nroom for indeterminancy.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\n\nBTOPENWORLD address about to cease. DEMON address no longer in use.\n>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Charles Francis <charles@clef.demon.co.uk> writes
>In article <c614qs$d1u$1@lfa222122.richmond.edu>, Oz
><oz@farmeroz.port995.com> writes
>>I suspect the reason may be that one of necessity seem to have to reject
>>a minkowski spacetime if you are to include QM,
>
>No, we can do relativistic qm if we tip toe through the nasties. It's
>curved space-times that cause fundamental problems.
Minkowski spacetime allows relativistic speeds anyway, so of course.
No, its not that that is the problem. We are happy to see unpredictable
and random effects when these are in the future, but minkowski spactime
predicts the past perfectly (and by implication, the future). Its
basically newtonian in structure, that is global. QM though, ought to
predict that a time reversed particle also show indeterminancy. That
would mean that the past is variable.
This brings up a whole load of very interesting problems. One thing is
for sure, we can't go back in time and repeat an experiment to see if we
get the same result. If we did, then we might not be surprised if we got
a different result, in fact we would expect it (well, I would).
hah! Actually its not really any different concept than 'predicting'
which silver ion gets to become deionised in a photographic film in a
diffraction pattern. The probability of any one is miniscule, but the
probability of one on the film is near 100%. Similarly a changed result
of a time reversed interaction is unlikely to have more than a minute
effect on the future, it would look like some kind of noise or low-level
indeterminancy in the future (perhaps something like h).
One could consider the ramifications further, but I don't think its
intractable. After all essentially everything locally is travelling the
in same direction and the same speed in time so will have no effect on
'the local past'.
>>. I am not very convinced, in fact I have
>>convinced myself of the reverse, that the worldines of 'backward
>>running' particles do NOT see global time reversed.
>
>I don't see how you get that. To me that is what "backward running"
>means.
Backward running ought to be a local phenomenon, pretty well everything
is. It should not and need not have any relationship to any 'global
time'.
>>In a way its just an extension of the problems of having global
>>anything-much in a curved spacetime. Does a 'global time' in GR even
>>make sense even before you allow backward-time-running particles? I
>>suspect not.
>
>The only "global time" in gr is cosmological time, which is really just
>proper time for particles emanating straight from the big bang. But
>really its just a load of proper times, not a global time.
Not really. Minkowski puts global time co-ordinates down along with
global space ones. Its a fixed four dimensional co-ordinate system. No
room for indeterminancy.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
BTOPENWORLD address about to cease. DEMON address no longer in use.
>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<
Dushan Mitrovich
Apr22-04, 04:25 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>baez@galaxy.ucr.edu (John Baez) wrote:\n` Igor Khavkine <k_igor_k@lycos.com> wrote:\n`\n`> baez@galaxy.ucr.edu (John Baez) wrote in message\n`\n`>> Figure out what happens if you have two planets near each\n`>> other: Earth and Anti-Earth, the first with positive mass, the\n`>> second with an "equal but opposite" negative mass.\n`>\n`> Going on what\'s written above, I think Anti-Earth will be attracted\n`> to Earth, while Earth will be repelled by Anti-Earth. As a result,\n`> they will both start moving, Earth running away from Anti-Earth and\n`> Anti-Earth trying to catch up.\n`\n` Right!\n\nSuppose there were a spherical shell of identical mass-antimass pairs,\nwith their alignments (pointing from antimass to mass) all directed at\nthe center of the sphere. It would look the same as a massive shell ac-\ncelerated inward by the gravitational field of a central mass. I don\'t\nknow what to do with this picture, but find it sort of interesting.\n\n- Dushan Mitrovich\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>baez@galaxy.ucr.edu (John Baez) wrote:
` Igor Khavkine <k_{igor_k}@lycos.com> wrote:
`
`> baez@galaxy.ucr.edu (John Baez) wrote in message
`
`>> Figure out what happens if you have two planets near each
`>> other: Earth and Anti-Earth, the first with positive mass, the
`>> second with an "equal but opposite" negative mass.
`>
`> Going on what's written above, I think Anti-Earth will be attracted
`> to Earth, while Earth will be repelled by Anti-Earth. As a result,
`> they will both start moving, Earth running away from Anti-Earth and
`> Anti-Earth trying to catch up.
`
` Right!
Suppose there were a spherical shell of identical mass-antimass pairs,
with their alignments (pointing from antimass to mass) all directed at
the center of the sphere. It would look the same as a massive shell ac-
celerated inward by the gravitational field of a central mass. I don't
know what to do with this picture, but find it sort of interesting.
- Dushan Mitrovich
Charles Francis
Apr27-04, 02:56 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In message <c697gh\\$gqb\\$1@lfa222122.richmond.edu>, Oz\n<oz@farmeroz.port995.com> writes\n>Charles Francis <charles@clef.demon.co.uk> writes\n>>In article <c614qs\\$d1u\\$1@lfa222122.richmond.edu>, Oz\n>><oz@farmeroz.port995.com> writes\n>\n>>>I suspect the reason may be that one of necessity seem to have to reject\n>>>a minkowski spacetime if you are to include QM,\n>>\n>>No, we can do relativistic qm if we tip toe through the nasties. It\'s\n>>curved space-times that cause fundamental problems.\n>\n>Minkowski spacetime allows relativistic speeds anyway, so of course.\n>\n>No, its not that that is the problem. We are happy to see unpredictable\n>and random effects when these are in the future, but minkowski spactime\n>predicts the past perfectly (and by implication, the future). Its\n>basically newtonian in structure, that is global. QM though, ought to\n>predict that a time reversed particle also show indeterminancy. That\n>would mean that the past is variable.\n\nIt only means that what we can know of the present does not determine\nthe past. Maybe that is what you meant.\n>\n>This brings up a whole load of very interesting problems. One thing is\n>for sure, we can\'t go back in time and repeat an experiment to see if we\n>get the same result. If we did, then we might not be surprised if we got\n>a different result, in fact we would expect it (well, I would).\n\nThe universe can\'t be two different things at the same time so if we\ncould go back we must get the same result. But certainly we should never\nhave been be surprised if we repeat an experiment and get a different\nresult at different time.\n>\n>hah! Actually its not really any different concept than \'predicting\'\n>which silver ion gets to become deionised in a photographic film in a\n>diffraction pattern.\n\nYes, its just the same. Laws of motion are time reversible - although\ncollapse takes place at a different stage of the motion (i.e. the end,\nwhether you are going forwards or backwards)\n\n>>>. I am not very convinced, in fact I have\n>>>convinced myself of the reverse, that the worldines of \'backward\n>>>running\' particles do NOT see global time reversed.\n>>\n>>I don\'t see how you get that. To me that is what "backward running"\n>>means.\n>\n>Backward running ought to be a local phenomenon, pretty well everything\n>is. It should not and need not have any relationship to any \'global\n>time\'.\n\nGlobal time is a local phenomenon. It is just a set of proper times for\nparticles on particular world lines from the big bang. By backward\nrunning we mean backward running wrt other local matter. This other\nmatter has been on a roughly ok world line from the big bang, so can be\nsynchronised with global time.\n\n>>>In a way its just an extension of the problems of having global\n>>>anything-much in a curved spacetime. Does a \'global time\' in GR even\n>>>make sense even before you allow backward-time-running particles? I\n>>>suspect not.\n>>\n>>The only "global time" in gr is cosmological time, which is really just\n>>proper time for particles emanating straight from the big bang. But\n>>really its just a load of proper times, not a global time.\n>\n>Not really. Minkowski puts global time co-ordinates down along with\n>global space ones.\n\nThat is taking Minkowski too far. He only applies locally, and does not\napply at all at a singularity like the big bang.\n\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In message <c697gh$gqb$1@lfa222122.richmond.edu>, Oz
<oz@farmeroz.port995.com> writes
>Charles Francis <charles@clef.demon.co.uk> writes
>>In article <c614qs$d1u$1@lfa222122.richmond.edu>, Oz
>><oz@farmeroz.port995.com> writes
>
>>>I suspect the reason may be that one of necessity seem to have to reject
>>>a minkowski spacetime if you are to include QM,
>>
>>No, we can do relativistic qm if we tip toe through the nasties. It's
>>curved space-times that cause fundamental problems.
>
>Minkowski spacetime allows relativistic speeds anyway, so of course.
>
>No, its not that that is the problem. We are happy to see unpredictable
>and random effects when these are in the future, but minkowski spactime
>predicts the past perfectly (and by implication, the future). Its
>basically newtonian in structure, that is global. QM though, ought to
>predict that a time reversed particle also show indeterminancy. That
>would mean that the past is variable.
It only means that what we can know of the present does not determine
the past. Maybe that is what you meant.
>
>This brings up a whole load of very interesting problems. One thing is
>for sure, we can't go back in time and repeat an experiment to see if we
>get the same result. If we did, then we might not be surprised if we got
>a different result, in fact we would expect it (well, I would).
The universe can't be two different things at the same time so if we
could go back we must get the same result. But certainly we should never
have been be surprised if we repeat an experiment and get a different
result at different time.
>
>hah! Actually its not really any different concept than 'predicting'
>which silver ion gets to become deionised in a photographic film in a
>diffraction pattern.
Yes, its just the same. Laws of motion are time reversible - although
collapse takes place at a different stage of the motion (i.e. the end,
whether you are going forwards or backwards)
>>>. I am not very convinced, in fact I have
>>>convinced myself of the reverse, that the worldines of 'backward
>>>running' particles do NOT see global time reversed.
>>
>>I don't see how you get that. To me that is what "backward running"
>>means.
>
>Backward running ought to be a local phenomenon, pretty well everything
>is. It should not and need not have any relationship to any 'global
>time'.
Global time is a local phenomenon. It is just a set of proper times for
particles on particular world lines from the big bang. By backward
running we mean backward running wrt other local matter. This other
matter has been on a roughly ok world line from the big bang, so can be
synchronised with global time.
>>>In a way its just an extension of the problems of having global
>>>anything-much in a curved spacetime. Does a 'global time' in GR even
>>>make sense even before you allow backward-time-running particles? I
>>>suspect not.
>>
>>The only "global time" in gr is cosmological time, which is really just
>>proper time for particles emanating straight from the big bang. But
>>really its just a load of proper times, not a global time.
>
>Not really. Minkowski puts global time co-ordinates down along with
>global space ones.
That is taking Minkowski too far. He only applies locally, and does not
apply at all at a singularity like the big bang.
--
Charles Francis
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Charles Francis <charles@clef.demon.co.uk> writes\n> In message <c697gh\\$gqb\\$1@lfa222122.richmond.edu>, Oz\n><oz@farmeroz.port995.com> writes\n>>Charles Francis <charles@clef.demon.co.uk> writes\n>>>In article <c614qs\\$d1u\\$1@lfa222122.richmond.edu>, Oz\n>>><oz@farmeroz.port995.com> writes\n>>\n>>>>I suspect the reason may be that one of necessity seem to have to reject\n>>>>a minkowski spacetime if you are to include QM,\n>>>\n>>>No, we can do relativistic qm if we tip toe through the nasties. It\'s\n>>>curved space-times that cause fundamental problems.\n>>\n>>Minkowski spacetime allows relativistic speeds anyway, so of course.\n>>\n>>No, its not that that is the problem. We are happy to see unpredictable\n>>and random effects when these are in the future, but minkowski spactime\n>>predicts the past perfectly (and by implication, the future). Its\n>>basically newtonian in structure, that is global. QM though, ought to\n>>predict that a time reversed particle also show indeterminancy. That\n>>would mean that the past is variable.\n>\n>It only means that what we can know of the present does not determine\n>the past. Maybe that is what you meant.\n\nPossibly, I was being more explicit.\n\n>>This brings up a whole load of very interesting problems. One thing is\n>>for sure, we can\'t go back in time and repeat an experiment to see if we\n>>get the same result. If we did, then we might not be surprised if we got\n>>a different result, in fact we would expect it (well, I would).\n>\n>The universe can\'t be two different things at the same time so if we\n>could go back we must get the same result.\n\nWhy? If we repeated \'going back and doing the same experiment\' many\ntimes, I think we would end up with the standard probabilistic result.\nHowever individual events would differ. I can\'t see why, from the\nviewpoint of a reversed-time particle, the past should not look as we\nsee the future, that is to some degree undetermined.\n\nIn general I doubt this matters much, since the macroscopic view is one\nborn of an immense multitude of interactions where the average result is\nin practice \'reality\'. It really doesn\'t bother \'the future\' precisely\nwhich pattern of dots, in which order, produced that diffraction\npattern, only that a diffraction pattern was produced.\n\nFurthermore its clear that anything happening before the universe was at\nt=0 can never affect us. Any changes can never propagate to the present.\nI have a gut feel, well it would be interesting to think carefully\nabout, that a reversed particle interacting differently in the past\nwould result in a change propagating forward in time which may not\nprecisely reach us in the present. This would be much more a viewpoint\nthat makes \'many worlds\' a viable process to examine.\n\n>But certainly we should never\n>have been be surprised if we repeat an experiment and get a different\n>result at different time.\n\nI can see no reason why this should not be true of an experiment\nperformed in the past, as it is one performed in the future. That is\nboth should be random.\n\n>>hah! Actually its not really any different concept than \'predicting\'\n>>which silver ion gets to become deionised in a photographic film in a\n>>diffraction pattern.\n>\n>Yes, its just the same. Laws of motion are time reversible - although\n>collapse takes place at a different stage of the motion (i.e. the end,\n>whether you are going forwards or backwards)\n\nThe laws of motion are reversible, absolutely.\nFrom this we get very many irreversible laws for bulk matter (we are\nbulk matter). If we lived in an antimatter-time-reversed universe we\ncould not know, the laws of physics would remain the same.\n\nAs a matter of fact, we live in a universe where antiparticles have\ntremendously short lifetimes and are hugely rare. Are you sure the\nirreversibility of time is not an assumption born of the fact that\neverything we see is travelling (fast) in the same time direction?\n\n>>>>. I am not very convinced, in fact I have\n>>>>convinced myself of the reverse, that the worldines of \'backward\n>>>>running\' particles do NOT see global time reversed.\n>>>\n>>>I don\'t see how you get that. To me that is what "backward running"\n>>>means.\n>>\n>>Backward running ought to be a local phenomenon, pretty well everything\n>>is. It should not and need not have any relationship to any \'global\n>>time\'.\n>\n>Global time is a local phenomenon. It is just a set of proper times for\n>particles on particular world lines from the big bang. By backward\n>running we mean backward running wrt other local matter. This other\n>matter has been on a roughly ok world line from the big bang, so can be\n>synchronised with global time.\n\nThis is certainly so for matter travelling +vely in time.\nNone of it can go backwards. This need not be so of reversed-time\nparticles.\n\n>>>>In a way its just an extension of the problems of having global\n>>>>anything-much in a curved spacetime. Does a \'global time\' in GR even\n>>>>make sense even before you allow backward-time-running particles? I\n>>>>suspect not.\n>>>\n>>>The only "global time" in gr is cosmological time, which is really just\n>>>proper time for particles emanating straight from the big bang. But\n>>>really its just a load of proper times, not a global time.\n>>\n>>Not really. Minkowski puts global time co-ordinates down along with\n>>global space ones.\n>\n>That is taking Minkowski too far. He only applies locally, and does not\n>apply at all at a singularity like the big bang.\n\nYes, a good point. A backwards-running particle should, as in the other\nthread, see black holes as white holes. This rather screws up ted\'s\nstatement that you can\'t tell if a film is being run backwards or\nforwards. For a black hole, you most certainly can.\n\nWe thus, delightfully, run into an impasse.\n\nHang on tho, its a bit more subtle than this. [Gosh this is fun].\n\nThroughout I have assumed an antiparticle in this viewpoint has +ve\nmass, at least in the sense that it bends spacetime the same as a\nparticle. That, at least, seems to be OK experimentally.\n\nSo there is no difference between an \'antiparticle\' black hole and a\n\'particle\' black hole, except they evolve in opposite time directions.\nIf you don\'t accept this difference then you will run into an internal\ncontradiction. Doubtless this separation is completely anathema to GR,\nbut lets stick with it for a while.\n\nFirstly its easy to tell you have an antiparticle black hole, its one\nemitting lots of particles (or absorbing lots of antiparticles) as it\nevolves backwards. Since I am accepting backwards-travelling particles\nthen of course I have to accept backwards-travelling black holes, so\nthis is not a problem. In an antimatter universe, where everything\ntravels backwards, of course they look like \'ordinary\' black holes to\nthe denizens there.\n\nSecondly the hawking radiation modelled as a particle-antiparticle pair\nproduction where the antiparticle is absorbed, allowing the particle to\nbe emitted looks slightly more reasonable. We just have to be careful\nnot to start invoking negative mass, at least in an unphysical way.\n\nProbably I should stop at this point....\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\n\nBTOPENWORLD address about to cease. DEMON address no longer in use.\n>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Charles Francis <charles@clef.demon.co.uk> writes
> In message <c697gh$gqb$1@lfa222122.richmond.edu>, Oz
><oz@farmeroz.port995.com> writes
>>Charles Francis <charles@clef.demon.co.uk> writes
>>>In article <c614qs$d1u$1@lfa222122.richmond.edu>, Oz
>>><oz@farmeroz.port995.com> writes
>>
>>>>I suspect the reason may be that one of necessity seem to have to reject
>>>>a minkowski spacetime if you are to include QM,
>>>
>>>No, we can do relativistic qm if we tip toe through the nasties. It's
>>>curved space-times that cause fundamental problems.
>>
>>Minkowski spacetime allows relativistic speeds anyway, so of course.
>>
>>No, its not that that is the problem. We are happy to see unpredictable
>>and random effects when these are in the future, but minkowski spactime
>>predicts the past perfectly (and by implication, the future). Its
>>basically newtonian in structure, that is global. QM though, ought to
>>predict that a time reversed particle also show indeterminancy. That
>>would mean that the past is variable.
>
>It only means that what we can know of the present does not determine
>the past. Maybe that is what you meant.
Possibly, I was being more explicit.
>>This brings up a whole load of very interesting problems. One thing is
>>for sure, we can't go back in time and repeat an experiment to see if we
>>get the same result. If we did, then we might not be surprised if we got
>>a different result, in fact we would expect it (well, I would).
>
>The universe can't be two different things at the same time so if we
>could go back we must get the same result.
Why? If we repeated 'going back and doing the same experiment' many
times, I think we would end up with the standard probabilistic result.
However individual events would differ. I can't see why, from the
viewpoint of a reversed-time particle, the past should not look as we
see the future, that is to some degree undetermined.
In general I doubt this matters much, since the macroscopic view is one
born of an immense multitude of interactions where the average result is
in practice 'reality'. It really doesn't bother 'the future' precisely
which pattern of dots, in which order, produced that diffraction
pattern, only that a diffraction pattern was produced.
Furthermore its clear that anything happening before the universe was at
t=0 can never affect us. Any changes can never propagate to the present.
I have a gut feel, well it would be interesting to think carefully
about, that a reversed particle interacting differently in the past
would result in a change propagating forward in time which may not
precisely reach us in the present. This would be much more a viewpoint
that makes 'many worlds' a viable process to examine.
>But certainly we should never
>have been be surprised if we repeat an experiment and get a different
>result at different time.
I can see no reason why this should not be true of an experiment
performed in the past, as it is one performed in the future. That is
both should be random.
>>hah! Actually its not really any different concept than 'predicting'
>>which silver ion gets to become deionised in a photographic film in a
>>diffraction pattern.
>
>Yes, its just the same. Laws of motion are time reversible - although
>collapse takes place at a different stage of the motion (i.e. the end,
>whether you are going forwards or backwards)
The laws of motion are reversible, absolutely.
From this we get very many irreversible laws for bulk matter (we are
bulk matter). If we lived in an antimatter-time-reversed universe we
could not know, the laws of physics would remain the same.
As a matter of fact, we live in a universe where antiparticles have
tremendously short lifetimes and are hugely rare. Are you sure the
irreversibility of time is not an assumption born of the fact that
everything we see is travelling (fast) in the same time direction?
>>>>. I am not very convinced, in fact I have
>>>>convinced myself of the reverse, that the worldines of 'backward
>>>>running' particles do NOT see global time reversed.
>>>
>>>I don't see how you get that. To me that is what "backward running"
>>>means.
>>
>>Backward running ought to be a local phenomenon, pretty well everything
>>is. It should not and need not have any relationship to any 'global
>>time'.
>
>Global time is a local phenomenon. It is just a set of proper times for
>particles on particular world lines from the big bang. By backward
>running we mean backward running wrt other local matter. This other
>matter has been on a roughly ok world line from the big bang, so can be
>synchronised with global time.
This is certainly so for matter travelling +vely in time.
None of it can go backwards. This need not be so of reversed-time
particles.
>>>>In a way its just an extension of the problems of having global
>>>>anything-much in a curved spacetime. Does a 'global time' in GR even
>>>>make sense even before you allow backward-time-running particles? I
>>>>suspect not.
>>>
>>>The only "global time" in gr is cosmological time, which is really just
>>>proper time for particles emanating straight from the big bang. But
>>>really its just a load of proper times, not a global time.
>>
>>Not really. Minkowski puts global time co-ordinates down along with
>>global space ones.
>
>That is taking Minkowski too far. He only applies locally, and does not
>apply at all at a singularity like the big bang.
Yes, a good point. A backwards-running particle should, as in the other
thread, see black holes as white holes. This rather screws up ted's
statement that you can't tell if a film is being run backwards or
forwards. For a black hole, you most certainly can.
We thus, delightfully, run into an impasse.
Hang on tho, its a bit more subtle than this. [Gosh this is fun].
Throughout I have assumed an antiparticle in this viewpoint has +ve
mass, at least in the sense that it bends spacetime the same as a
particle. That, at least, seems to be OK experimentally.
So there is no difference between an 'antiparticle' black hole and a
'particle' black hole, except they evolve in opposite time directions.
If you don't accept this difference then you will run into an internal
contradiction. Doubtless this separation is completely anathema to GR,
but lets stick with it for a while.
Firstly its easy to tell you have an antiparticle black hole, its one
emitting lots of particles (or absorbing lots of antiparticles) as it
evolves backwards. Since I am accepting backwards-travelling particles
then of course I have to accept backwards-travelling black holes, so
this is not a problem. In an antimatter universe, where everything
travels backwards, of course they look like 'ordinary' black holes to
the denizens there.
Secondly the hawking radiation modelled as a particle-antiparticle pair
production where the antiparticle is absorbed, allowing the particle to
be emitted looks slightly more reasonable. We just have to be careful
not to start invoking negative mass, at least in an unphysical way.
Probably I should stop at this point....
--
Oz
This post is worth absolutely nothing and is probably fallacious.
BTOPENWORLD address about to cease. DEMON address no longer in use.
>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<
Charles Francis
May3-04, 05:52 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\nIn message <SnP7R0F4N1jAFwS1@farmeroz.port995.com>, Oz\n<oz@farmeroz.port995.com> writes\n>Charles Francis <charles@clef.demon.co.uk> writes\n>> In message <c697gh\\$gqb\\$1@lfa222122.richmond.edu>, Oz\n>><oz@farmeroz.port995.com> writes\n>\n>>>This brings up a whole load of very interesting problems. One thing is\n>>>for sure, we can\'t go back in time and repeat an experiment to see if we\n>>>get the same result. If we did, then we might not be surprised if we got\n>>>a different result, in fact we would expect it (well, I would).\n>>\n>>The universe can\'t be two different things at the same time so if we\n>>could go back we must get the same result.\n>\n>Why? If we repeated \'going back and doing the same experiment\' many\n>times, I think we would end up with the standard probabilistic result.\n>However individual events would differ.\n\nPerhaps it is a confusion over words. Surely the only way I understand\nto go back in time is to reoccupy the same consciousness and redo the\nsae experiment. It is then only one experiment, seen again. Otherwise it\nwould be a different experiment, at the same time but a different place.\nIn this case the result need not be the same.\n\n> I can\'t see why, from the\n>viewpoint of a reversed-time particle, the past should not look as we\n>see the future, that is to some degree undetermined.\n\nIt does.\n>\n>In general I doubt this matters much, since the macroscopic view is one\n>born of an immense multitude of interactions where the average result is\n>in practice \'reality\'. It really doesn\'t bother \'the future\' precisely\n>which pattern of dots, in which order, produced that diffraction\n>pattern, only that a diffraction pattern was produced.\n>\n>Furthermore its clear that anything happening before the universe was at\n>t=0 can never affect us. Any changes can never propagate to the present.\n>I have a gut feel, well it would be interesting to think carefully\n>about, that a reversed particle interacting differently in the past\n>would result in a change propagating forward in time which may not\n>precisely reach us in the present. This would be much more a viewpoint\n>that makes \'many worlds\' a viable process to examine.\n\nI think it is a version of the idea discussed on uba, that at the big\nbang the universe could split into disconnected regions, conceivable but\nuntestable at the present time. Mind you there is no good reason for\ncalling one of these disconnected regions t<0, since there is no way to\ncompare time between one region and another, and there is no way to say\nthat only two such regions exist. One may as well call the regions red,\nblue yellow, or anything else.\n>\n>\n>The laws of motion are reversible, absolutely.\n>From this we get very many irreversible laws for bulk matter (we are\n>bulk matter).\n\nThat is mostly down to thermodynamics. Even entropy would be reversible\nif you could know a final condition, and know that the prior state was\nnot determined in anyway.\n\n> If we lived in an antimatter-time-reversed universe we\n>could not know, the laws of physics would remain the same.\n>\n>As a matter of fact, we live in a universe where antiparticles have\n>tremendously short lifetimes and are hugely rare.\n\nPositrons can be kept in storage rings almost indefinitely.\n\n>Are you sure the\n>irreversibility of time is not an assumption born of the fact that\n>everything we see is travelling (fast) in the same time direction?\n\nYes. It is something we can prove from statistical mechanics. It is down\nto knowledge of initial conditions, not matter or antimatter. If the\nuniverse is fated for final collapse I would expect entropy to be\nreversed during the dying phase.\n>\n>>>>>. I am not very convinced, in fact I have\n>>>>>convinced myself of the reverse, that the worldines of \'backward\n>>>>>running\' particles do NOT see global time reversed.\n>>>>\n>>>>I don\'t see how you get that. To me that is what "backward running"\n>>>>means.\n>>>\n>>>Backward running ought to be a local phenomenon, pretty well everything\n>>>is. It should not and need not have any relationship to any \'global\n>>>time\'.\n>>\n>>Global time is a local phenomenon. It is just a set of proper times for\n>>particles on particular world lines from the big bang. By backward\n>>running we mean backward running wrt other local matter. This other\n>>matter has been on a roughly ok world line from the big bang, so can be\n>>synchronised with global time.\n>\n>This is certainly so for matter travelling +vely in time.\n>None of it can go backwards. This need not be so of reversed-time\n>particles.\n\nIt would be the same. Remember a backward running electron appears to us\nexactly like a forward running positron, so proper time for time\nreversed particles behaves just as for forward running particles..\n\n>Yes, a good point. A backwards-running particle should, as in the other\n>thread, see black holes as white holes.\n\nWhich other thread? Gravity looks just the same under time reversal, so\na black hole remains a black hole.\n\n>This rather screws up ted\'s\n>statement that you can\'t tell if a film is being run backwards or\n>forwards. For a black hole, you most certainly can.\n\nI don\'t think so.\n\n>Throughout I have assumed an antiparticle in this viewpoint has +ve\n>mass, at least in the sense that it bends spacetime the same as a\n>particle. That, at least, seems to be OK experimentally.\n>\n>So there is no difference between an \'antiparticle\' black hole and a\n>\'particle\' black hole, except they evolve in opposite time directions.\n>If you don\'t accept this difference then you will run into an internal\n>contradiction. Doubtless this separation is completely anathema to GR,\n>but lets stick with it for a while.\n>\n>Firstly its easy to tell you have an antiparticle black hole, its one\n>emitting lots of particles (or absorbing lots of antiparticles) as it\n>evolves backwards.\n\nThat\'s the wrong way about. I believe an antiparticle black hole will\nemit antiparticles by Hawking radiation.\n\n>Secondly the hawking radiation modelled as a particle-antiparticle pair\n>production where the antiparticle is absorbed, allowing the particle to\n>be emitted looks slightly more reasonable. We just have to be careful\n>not to start invoking negative mass, at least in an unphysical way.\n>\nThe only reason the antiparticle is absorbed is if it is a particle\nblack hole. It is the negative energy particle which is absorbed,\nallowing that negative energy particles can exist in qft for very short\ntime durations.\n\n\n\n\n\n\nRegards\n\n--\nCharles Francis\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In message <SnP7R0F4N1jAFwS1@farmeroz.port995.com>, Oz
<oz@farmeroz.port995.com> writes
>Charles Francis <charles@clef.demon.co.uk> writes
>> In message <c697gh$gqb$1@lfa222122.richmond.edu>, Oz
>><oz@farmeroz.port995.com> writes
>
>>>This brings up a whole load of very interesting problems. One thing is
>>>for sure, we can't go back in time and repeat an experiment to see if we
>>>get the same result. If we did, then we might not be surprised if we got
>>>a different result, in fact we would expect it (well, I would).
>>
>>The universe can't be two different things at the same time so if we
>>could go back we must get the same result.
>
>Why? If we repeated 'going back and doing the same experiment' many
>times, I think we would end up with the standard probabilistic result.
>However individual events would differ.
Perhaps it is a confusion over words. Surely the only way I understand
to go back in time is to reoccupy the same consciousness and redo the
sae experiment. It is then only one experiment, seen again. Otherwise it
would be a different experiment, at the same time but a different place.
In this case the result need not be the same.
> I can't see why, from the
>viewpoint of a reversed-time particle, the past should not look as we
>see the future, that is to some degree undetermined.
It does.
>
>In general I doubt this matters much, since the macroscopic view is one
>born of an immense multitude of interactions where the average result is
>in practice 'reality'. It really doesn't bother 'the future' precisely
>which pattern of dots, in which order, produced that diffraction
>pattern, only that a diffraction pattern was produced.
>
>Furthermore its clear that anything happening before the universe was at
>t=0 can never affect us. Any changes can never propagate to the present.
>I have a gut feel, well it would be interesting to think carefully
>about, that a reversed particle interacting differently in the past
>would result in a change propagating forward in time which may not
>precisely reach us in the present. This would be much more a viewpoint
>that makes 'many worlds' a viable process to examine.
I think it is a version of the idea discussed on uba, that at the big
bang the universe could split into disconnected regions, conceivable but
untestable at the present time. Mind you there is no good reason for
calling one of these disconnected regions t<0, since there is no way to
compare time between one region and another, and there is no way to say
that only two such regions exist. One may as well call the regions red,
blue yellow, or anything else.
>
>
>The laws of motion are reversible, absolutely.
>From this we get very many irreversible laws for bulk matter (we are
>bulk matter).
That is mostly down to thermodynamics. Even entropy would be reversible
if you could know a final condition, and know that the prior state was
not determined in anyway.
> If we lived in an antimatter-time-reversed universe we
>could not know, the laws of physics would remain the same.
>
>As a matter of fact, we live in a universe where antiparticles have
>tremendously short lifetimes and are hugely rare.
Positrons can be kept in storage rings almost indefinitely.
>Are you sure the
>irreversibility of time is not an assumption born of the fact that
>everything we see is travelling (fast) in the same time direction?
Yes. It is something we can prove from statistical mechanics. It is down
to knowledge of initial conditions, not matter or antimatter. If the
universe is fated for final collapse I would expect entropy to be
reversed during the dying phase.
>
>>>>>. I am not very convinced, in fact I have
>>>>>convinced myself of the reverse, that the worldines of 'backward
>>>>>running' particles do NOT see global time reversed.
>>>>
>>>>I don't see how you get that. To me that is what "backward running"
>>>>means.
>>>
>>>Backward running ought to be a local phenomenon, pretty well everything
>>>is. It should not and need not have any relationship to any 'global
>>>time'.
>>
>>Global time is a local phenomenon. It is just a set of proper times for
>>particles on particular world lines from the big bang. By backward
>>running we mean backward running wrt other local matter. This other
>>matter has been on a roughly ok world line from the big bang, so can be
>>synchronised with global time.
>
>This is certainly so for matter travelling +vely in time.
>None of it can go backwards. This need not be so of reversed-time
>particles.
It would be the same. Remember a backward running electron appears to us
exactly like a forward running positron, so proper time for time
reversed particles behaves just as for forward running particles..
>Yes, a good point. A backwards-running particle should, as in the other
>thread, see black holes as white holes.
Which other thread? Gravity looks just the same under time reversal, so
a black hole remains a black hole.
>This rather screws up ted's
>statement that you can't tell if a film is being run backwards or
>forwards. For a black hole, you most certainly can.
I don't think so.
>Throughout I have assumed an antiparticle in this viewpoint has +ve
>mass, at least in the sense that it bends spacetime the same as a
>particle. That, at least, seems to be OK experimentally.
>
>So there is no difference between an 'antiparticle' black hole and a
>'particle' black hole, except they evolve in opposite time directions.
>If you don't accept this difference then you will run into an internal
>contradiction. Doubtless this separation is completely anathema to GR,
>but lets stick with it for a while.
>
>Firstly its easy to tell you have an antiparticle black hole, its one
>emitting lots of particles (or absorbing lots of antiparticles) as it
>evolves backwards.
That's the wrong way about. I believe an antiparticle black hole will
emit antiparticles by Hawking radiation.
>Secondly the hawking radiation modelled as a particle-antiparticle pair
>production where the antiparticle is absorbed, allowing the particle to
>be emitted looks slightly more reasonable. We just have to be careful
>not to start invoking negative mass, at least in an unphysical way.
>
The only reason the antiparticle is absorbed is if it is a particle
black hole. It is the negative energy particle which is absorbed,
allowing that negative energy particles can exist in qft for very short
time durations.
Regards
--
Charles Francis
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Charles Francis <charles@clef.demon.co.uk> writes\n>\n><oz@farmeroz.port995.com> writes\n>>\n>>Why? If we repeated \'going back and doing the same experiment\' many\n>>times, I think we would end up with the standard probabilistic result.\n>>However individual events would differ.\n>\n>Perhaps it is a confusion over words. Surely the only way I understand\n>to go back in time is to reoccupy the same consciousness and redo the\n>sae experiment. It is then only one experiment, seen again. Otherwise it\n>would be a different experiment, at the same time but a different place.\n>In this case the result need not be the same.\n\nBut what if you do the same experiment at the same time and place?\nIs there any reason to expect the precise same result?\nGR says yes, QM says no.\nThe interaction of individual particles is a QM event, so I say no.\n\n>> I can\'t see why, from the\n>>viewpoint of a reversed-time particle, the past should not look as we\n>>see the future, that is to some degree undetermined.\n>\n>It does.\n\nIt cannot be determined by our viewpoint but undetermined from an\nantiparticles\'. Hmm, maybe it can, but philosophically treacherous.\n\n>I think it is a version of the idea discussed on uba, that at the big\n>bang the universe could split into disconnected regions, conceivable but\n>untestable at the present time. Mind you there is no good reason for\n>calling one of these disconnected regions t<0, since there is no way to\n>compare time between one region and another, and there is no way to say\n>that only two such regions exist. One may as well call the regions red,\n>blue yellow, or anything else.\n\nOf course.\n\n>>The laws of motion are reversible, absolutely.\n>>From this we get very many irreversible laws for bulk matter (we are\n>>bulk matter).\n>\n>That is mostly down to thermodynamics. Even entropy would be reversible\n>if you could know a final condition, and know that the prior state was\n>not determined in anyway.\n\nQue? In QM I don\'t think its so that knowing the final states precisely\nallows you to state the initial states precisely. You can only do it to\nsome level of accuracy.\n\n>> If we lived in an antimatter-time-reversed universe we\n>>could not know, the laws of physics would remain the same.\n>>\n>>As a matter of fact, we live in a universe where antiparticles have\n>>tremendously short lifetimes and are hugely rare.\n>\n>Positrons can be kept in storage rings almost indefinitely.\n\nBut only by isolating them from our universe.\nThis is a terribly rare situation.\n\n>>Are you sure the\n>>irreversibility of time is not an assumption born of the fact that\n>>everything we see is travelling (fast) in the same time direction?\n>\n>Yes. It is something we can prove from statistical mechanics. It is down\n>to knowledge of initial conditions, not matter or antimatter. If the\n>universe is fated for final collapse I would expect entropy to be\n>reversed during the dying phase.\n\nSee my comment on \'antimatter black holes\'.\n\n>>This is certainly so for matter travelling +vely in time.\n>>None of it can go backwards. This need not be so of reversed-time\n>>particles.\n>\n>It would be the same. Remember a backward running electron appears to us\n>exactly like a forward running positron, so proper time for time\n>reversed particles behaves just as for forward running particles..\n\nHmm. Good point. I need to ponder this again.\nSo what that means is a backwards-running universe looks like a forward-\nrunning anti-universe.\n\nOK, my whole argument shot down in flames......\n\nThere is one implication though. That is that time is something a\nparticle carries.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\n\nBTOPENWORLD address about to cease. DEMON address no longer in use.\n>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Charles Francis <charles@clef.demon.co.uk> writes
>
><oz@farmeroz.port995.com> writes
>>
>>Why? If we repeated 'going back and doing the same experiment' many
>>times, I think we would end up with the standard probabilistic result.
>>However individual events would differ.
>
>Perhaps it is a confusion over words. Surely the only way I understand
>to go back in time is to reoccupy the same consciousness and redo the
>sae experiment. It is then only one experiment, seen again. Otherwise it
>would be a different experiment, at the same time but a different place.
>In this case the result need not be the same.
But what if you do the same experiment at the same time and place?
Is there any reason to expect the precise same result?
GR says yes, QM says no.
The interaction of individual particles is a QM event, so I say no.
>> I can't see why, from the
>>viewpoint of a reversed-time particle, the past should not look as we
>>see the future, that is to some degree undetermined.
>
>It does.
It cannot be determined by our viewpoint but undetermined from an
antiparticles'. Hmm, maybe it can, but philosophically treacherous.
>I think it is a version of the idea discussed on uba, that at the big
>bang the universe could split into disconnected regions, conceivable but
>untestable at the present time. Mind you there is no good reason for
>calling one of these disconnected regions t<0, since there is no way to
>compare time between one region and another, and there is no way to say
>that only two such regions exist. One may as well call the regions red,
>blue yellow, or anything else.
Of course.
>>The laws of motion are reversible, absolutely.
>>From this we get very many irreversible laws for bulk matter (we are
>>bulk matter).
>
>That is mostly down to thermodynamics. Even entropy would be reversible
>if you could know a final condition, and know that the prior state was
>not determined in anyway.
Que? In QM I don't think its so that knowing the final states precisely
allows you to state the initial states precisely. You can only do it to
some level of accuracy.
>> If we lived in an antimatter-time-reversed universe we
>>could not know, the laws of physics would remain the same.
>>
>>As a matter of fact, we live in a universe where antiparticles have
>>tremendously short lifetimes and are hugely rare.
>
>Positrons can be kept in storage rings almost indefinitely.
But only by isolating them from our universe.
This is a terribly rare situation.
>>Are you sure the
>>irreversibility of time is not an assumption born of the fact that
>>everything we see is travelling (fast) in the same time direction?
>
>Yes. It is something we can prove from statistical mechanics. It is down
>to knowledge of initial conditions, not matter or antimatter. If the
>universe is fated for final collapse I would expect entropy to be
>reversed during the dying phase.
See my comment on 'antimatter black holes'.
>>This is certainly so for matter travelling +vely in time.
>>None of it can go backwards. This need not be so of reversed-time
>>particles.
>
>It would be the same. Remember a backward running electron appears to us
>exactly like a forward running positron, so proper time for time
>reversed particles behaves just as for forward running particles..
Hmm. Good point. I need to ponder this again.
So what that means is a backwards-running universe looks like a forward-
running anti-universe.
OK, my whole argument shot down in flames......
There is one implication though. That is that time is something a
particle carries.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
BTOPENWORLD address about to cease. DEMON address no longer in use.
>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<
Charles Francis
May3-04, 06:52 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In message <vhbUQJBx\\$ilAFwVk@farmeroz.port995.com>, Oz\n<oz@farmeroz.port995.com> writes\n>Charles Francis <charles@clef.demon.co.uk> writes\n>>\n>><oz@farmeroz.port995.com> writes\n>>>\n>>>Why? If we repeated \'going back and doing the same experiment\' many\n>>>times, I think we would end up with the standard probabilistic result.\n>>>However individual events would differ.\n>>\n>>Perhaps it is a confusion over words. Surely the only way I understand\n>>to go back in time is to reoccupy the same consciousness and redo the\n>>sae experiment. It is then only one experiment, seen again. Otherwise it\n>>would be a different experiment, at the same time but a different place.\n>>In this case the result need not be the same.\n>\n>But what if you do the same experiment at the same time and place?\n>Is there any reason to expect the precise same result?\n>GR says yes, QM says no.\n\nHistory says yes. QM has no bearing on that.\n\n>>> I can\'t see why, from the\n>>>viewpoint of a reversed-time particle, the past should not look as we\n>>>see the future, that is to some degree undetermined.\n>>\n>>It does.\n>\n>It cannot be determined by our viewpoint but undetermined from an\n>antiparticles\'. Hmm, maybe it can, but philosophically treacherous.\n\nYes.\n>\n>>I think it is a version of the idea discussed on uba, that at the big\n>>bang the universe could split into disconnected regions, conceivable but\n>>untestable at the present time. Mind you there is no good reason for\n>>calling one of these disconnected regions t<0, since there is no way to\n>>compare time between one region and another, and there is no way to say\n>>that only two such regions exist. One may as well call the regions red,\n>>blue yellow, or anything else.\n>\n>Of course.\n>\n>>>The laws of motion are reversible, absolutely.\n>>>From this we get very many irreversible laws for bulk matter (we are\n>>>bulk matter).\n>>\n>>That is mostly down to thermodynamics. Even entropy would be reversible\n>>if you could know a final condition, and know that the prior state was\n>>not determined in anyway.\n>\n>Que? In QM I don\'t think its so that knowing the final states precisely\n>allows you to state the initial states precisely. You can only do it to\n>some level of accuracy.\n\nYou can only do it to the same extent as vice versa, probabilistically.\n>\n>>>This is certainly so for matter travelling +vely in time.\n>>>None of it can go backwards. This need not be so of reversed-time\n>>>particles.\n>>\n>>It would be the same. Remember a backward running electron appears to us\n>>exactly like a forward running positron, so proper time for time\n>>reversed particles behaves just as for forward running particles..\n>\n>Hmm. Good point. I need to ponder this again.\n>So what that means is a backwards-running universe looks like a forward-\n>running anti-universe.\n\nPrecisely.\n>\n>OK, my whole argument shot down in flames......\n>\n>There is one implication though. That is that time is something a\n>particle carries.\n>\nThat is something of which I am quite convinced. It ties together a lot\nof ideas that people have thought about for some time, "many fingered\ntime", the importance of proper time. But I think it becomes clear when\nput like that, that time is a property of matter, matter does not exist\nin time.\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In message <vhbUQJBx$ilAFwVk@farmeroz.port995.com>, Oz
<oz@farmeroz.port995.com> writes
>Charles Francis <charles@clef.demon.co.uk> writes
>>
>><oz@farmeroz.port995.com> writes
>>>
>>>Why? If we repeated 'going back and doing the same experiment' many
>>>times, I think we would end up with the standard probabilistic result.
>>>However individual events would differ.
>>
>>Perhaps it is a confusion over words. Surely the only way I understand
>>to go back in time is to reoccupy the same consciousness and redo the
>>sae experiment. It is then only one experiment, seen again. Otherwise it
>>would be a different experiment, at the same time but a different place.
>>In this case the result need not be the same.
>
>But what if you do the same experiment at the same time and place?
>Is there any reason to expect the precise same result?
>GR says yes, QM says no.
History says yes. QM has no bearing on that.
>>> I can't see why, from the
>>>viewpoint of a reversed-time particle, the past should not look as we
>>>see the future, that is to some degree undetermined.
>>
>>It does.
>
>It cannot be determined by our viewpoint but undetermined from an
>antiparticles'. Hmm, maybe it can, but philosophically treacherous.
Yes.
>
>>I think it is a version of the idea discussed on uba, that at the big
>>bang the universe could split into disconnected regions, conceivable but
>>untestable at the present time. Mind you there is no good reason for
>>calling one of these disconnected regions t<0, since there is no way to
>>compare time between one region and another, and there is no way to say
>>that only two such regions exist. One may as well call the regions red,
>>blue yellow, or anything else.
>
>Of course.
>
>>>The laws of motion are reversible, absolutely.
>>>From this we get very many irreversible laws for bulk matter (we are
>>>bulk matter).
>>
>>That is mostly down to thermodynamics. Even entropy would be reversible
>>if you could know a final condition, and know that the prior state was
>>not determined in anyway.
>
>Que? In QM I don't think its so that knowing the final states precisely
>allows you to state the initial states precisely. You can only do it to
>some level of accuracy.
You can only do it to the same extent as vice versa, probabilistically.
>
>>>This is certainly so for matter travelling +vely in time.
>>>None of it can go backwards. This need not be so of reversed-time
>>>particles.
>>
>>It would be the same. Remember a backward running electron appears to us
>>exactly like a forward running positron, so proper time for time
>>reversed particles behaves just as for forward running particles..
>
>Hmm. Good point. I need to ponder this again.
>So what that means is a backwards-running universe looks like a forward-
>running anti-universe.
Precisely.
>
>OK, my whole argument shot down in flames......
>
>There is one implication though. That is that time is something a
>particle carries.
>
That is something of which I am quite convinced. It ties together a lot
of ideas that people have thought about for some time, "many fingered
time", the importance of proper time. But I think it becomes clear when
put like that, that time is a property of matter, matter does not exist
in time.
--
Charles Francis
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Charles Francis <charles@lluestfarmpoultry.co.uk> writes\n>In message <vhbUQJBx\\$ilAFwVk@farmeroz.port995.com>, Oz\n><oz@farmeroz.port995.com> writes\n\n>>But what if you do the same experiment at the same time and place?\n>>Is there any reason to expect the precise same result?\n>>GR says yes, QM says no.\n>\n>History says yes. QM has no bearing on that.\n\nHistory is by definition macroscopic and gr-like.\n\n>>>It would be the same. Remember a backward running electron appears to us\n>>>exactly like a forward running positron, so proper time for time\n>>>reversed particles behaves just as for forward running particles..\n>>\n>>Hmm. Good point. I need to ponder this again.\n>>So what that means is a backwards-running universe looks like a forward-\n>>running anti-universe.\n>\n>Precisely.\n>>\n>>OK, my whole argument shot down in flames......\n>>\n>>There is one implication though. That is that time is something a\n>>particle carries.\n>>\n>That is something of which I am quite convinced. It ties together a lot\n>of ideas that people have thought about for some time, "many fingered\n>time", the importance of proper time. But I think it becomes clear when\n>put like that, that time is a property of matter, matter does not exist\n>in time.\n\nI am much tempted by this idea, it seems to fit.\nBut then you have to consider that space is also a property of matter.\nGod only knows what *that* would do to my crank index.\n\nOh, well, at least I have a better grasp of time and antiparticles, so\nthe thread has not been wasted.\n\n--\nOz\nThis post is worth absolutely nothing and is probably fallacious.\n\nBTOPENWORLD address about to cease. DEMON address no longer in use.\n>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Charles Francis <charles@lluestfarmpoultry.co.uk> writes
>In message <vhbUQJBx$ilAFwVk@farmeroz.port995.com>, Oz
><oz@farmeroz.port995.com> writes
>>But what if you do the same experiment at the same time and place?
>>Is there any reason to expect the precise same result?
>>GR says yes, QM says no.
>
>History says yes. QM has no bearing on that.
History is by definition macroscopic and gr-like.
>>>It would be the same. Remember a backward running electron appears to us
>>>exactly like a forward running positron, so proper time for time
>>>reversed particles behaves just as for forward running particles..
>>
>>Hmm. Good point. I need to ponder this again.
>>So what that means is a backwards-running universe looks like a forward-
>>running anti-universe.
>
>Precisely.
>>
>>OK, my whole argument shot down in flames......
>>
>>There is one implication though. That is that time is something a
>>particle carries.
>>
>That is something of which I am quite convinced. It ties together a lot
>of ideas that people have thought about for some time, "many fingered
>time", the importance of proper time. But I think it becomes clear when
>put like that, that time is a property of matter, matter does not exist
>in time.
I am much tempted by this idea, it seems to fit.
But then you have to consider that space is also a property of matter.
God only knows what *that* would do to my crank index.
Oh, well, at least I have a better grasp of time and antiparticles, so
the thread has not been wasted.
--
Oz
This post is worth absolutely nothing and is probably fallacious.
BTOPENWORLD address about to cease. DEMON address no longer in use.
>>Use oz@farmeroz.port995.com (whitelist check on first posting)<<
Charles Francis
May6-04, 01:17 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In message <KhKdAxD00ylAFwx0@farmeroz.port995.com>, Oz\n<oz@farmeroz.port995.com> writes\n>Charles Francis <charles@lluestfarmpoultry.co.uk> writes\n>>In message <vhbUQJBx\\$ilAFwVk@farmeroz.port995.com>, Oz\n>><oz@farmeroz.port995.com> writes\n>\n>>>But what if you do the same experiment at the same time and place?\n>>>Is there any reason to expect the precise same result?\n>>>GR says yes, QM says no.\n>>\n>>History says yes. QM has no bearing on that.\n>\n>History is by definition macroscopic and gr-like.\n\nHistory is that which happened. That which happened, happened,\nirrespective of the physical laws underlying it.\n\n>>>There is one implication though. That is that time is something a\n>>>particle carries.\n>>>\n>>That is something of which I am quite convinced. It ties together a lot\n>>of ideas that people have thought about for some time, "many fingered\n>>time", the importance of proper time. But I think it becomes clear when\n>>put like that, that time is a property of matter, matter does not exist\n>>in time.\n>\n>I am much tempted by this idea, it seems to fit.\n>But then you have to consider that space is also a property of matter.\n\nIndeed. But whereas time is an elemental property, pertaining to each\nindividual particle, distance is emergent, requiring a system of\ninteractions between several particles.\n\n\n\nRegards\n\n--\nCharles Francis\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In message <KhKdAxD00ylAFwx0@farmeroz.port995.com>, Oz
<oz@farmeroz.port995.com> writes
>Charles Francis <charles@lluestfarmpoultry.co.uk> writes
>>In message <vhbUQJBx$ilAFwVk@farmeroz.port995.com>, Oz
>><oz@farmeroz.port995.com> writes
>
>>>But what if you do the same experiment at the same time and place?
>>>Is there any reason to expect the precise same result?
>>>GR says yes, QM says no.
>>
>>History says yes. QM has no bearing on that.
>
>History is by definition macroscopic and gr-like.
History is that which happened. That which happened, happened,
irrespective of the physical laws underlying it.
>>>There is one implication though. That is that time is something a
>>>particle carries.
>>>
>>That is something of which I am quite convinced. It ties together a lot
>>of ideas that people have thought about for some time, "many fingered
>>time", the importance of proper time. But I think it becomes clear when
>>put like that, that time is a property of matter, matter does not exist
>>in time.
>
>I am much tempted by this idea, it seems to fit.
>But then you have to consider that space is also a property of matter.
Indeed. But whereas time is an elemental property, pertaining to each
individual particle, distance is emergent, requiring a system of
interactions between several particles.
Regards
--
Charles Francis
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