View Full Version : Spooky Action At a Distance Question
<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>\nHi,\n\nThe news today of scientists teleporting an atom got me curious. So,\nI ended up reading an article on Spooky Action At a Distance. I\'m no\nphysics expert -- just an electrical engineer -- but I have a question\nfor those of you more learned than I ...\n\nTake an "ideal" rod -- a perfectly straight one that can\'t be\nstretched, compressed, or otherwise deformed -- and install one end of\nit at "point A" and the other end at "point B." Now, from point A,\nmove the rod -- either pull it or push it along its linear axis. How\nlong does it take for the rod to move at point B? Does the action at\npoint A transfer to point B instantaneously, or does it go at some\nspeed less than or equal to the speed of light? What (if any) are the\nramifications of your answer?\n\nThanks in advance for educating me a bit on quantum physics ...\n\n\nBuddy Brinkley\nwww.EngineersGuideToGod.com\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>Hi,
The news today of scientists teleporting an atom got me curious. So,
I ended up reading an article on Spooky Action At a Distance. I'm no
physics expert -- just an electrical engineer -- but I have a question
for those of you more learned than I ...
Take an "ideal" rod -- a perfectly straight one that can't be
stretched, compressed, or otherwise deformed -- and install one end of
it at "point A" and the other end at "point B." Now, from point A,
move the rod -- either pull it or push it along its linear axis. How
long does it take for the rod to move at point B? Does the action at
point A transfer to point B instantaneously, or does it go at some
speed less than or equal to the speed of light? What (if any) are the
ramifications of your answer?
Thanks in advance for educating me a bit on quantum physics ...
Buddy Brinkley
www.EngineersGuideToGod.com
Jerzy Karczmarczuk
Jun18-04, 06:03 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>Buddy wrote:\n\n> The news today of scientists teleporting an atom got me curious. So,\n> I ended up reading an article on Spooky Action At a Distance\n\n> Take an "ideal" rod -- a perfectly straight one that can\'t be\n> stretched, compressed, or otherwise deformed -- and install one end of\n> it at "point A" and the other end at "point B." Now, from point A,\n> move the rod -- either pull it or push it along its linear axis. How\n> long does it take for the rod to move at point B? Does the action at\n> point A transfer to point B instantaneously, or does it go at some\n> speed less than or equal to the speed of light? What (if any) are the\n> ramifications of your answer?\n>\n> Thanks in advance for educating me a bit on quantum physics ...\n\nThere are two distinct questions here, the transfer of quantum information\nand the problem of the rod in a relativistic context.\n\nFirst of all, no Spooky BlahBlah or other wave function collapse can\ntransmit any information faster than light, the teleporting includes the\ntransport of standard, classical piece of information using established\nphysical channels.\n\nThen, no rod is *geometrically* incompressible. A standard homework is the\nfollowing. A rocket of length L passes through a barn of length L. From the\nstatic perspective the Lorenz contraction makes it appear shorter than L, so\nwhen it is inside, both gates, front and rear are closed, and the rocket is\nconfined inside.\nBut from the pilot viewpoint, the barn is shorter than the rocket, so this\nis simply impossible. The question is not to "solve the paradox", but to\ndiscuss its *physical* implication. The "paradox is solved" by noting that\nin the rocket\'s frame the doors are closed *not* simultaneously. Now, the\nfarmer, ignoring all possible implications, refuses to reopen the doors and\nthe rocket is trapped inside forever. This means then when the nose of the\nrocket stops, e.g. by hitting the door from inside, *its rear parts MUST\nkeep moving*, the bad surprise cannot be known unless the rocket is fully\ninside... The "fake" Lorenz contraction will be converted into a physical,\nrather disastrous real contraction...\n\n\nJerzy Karczmarczuk\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>Buddy wrote:
> The news today of scientists teleporting an atom got me curious. So,
> I ended up reading an article on Spooky Action At a Distance
> Take an "ideal" rod -- a perfectly straight one that can't be
> stretched, compressed, or otherwise deformed -- and install one end of
> it at "point A" and the other end at "point B." Now, from point A,
> move the rod -- either pull it or push it along its linear axis. How
> long does it take for the rod to move at point B? Does the action at
> point A transfer to point B instantaneously, or does it go at some
> speed less than or equal to the speed of light? What (if any) are the
> ramifications of your answer?
>
> Thanks in advance for educating me a bit on quantum physics ...
There are two distinct questions here, the transfer of quantum information
and the problem of the rod in a relativistic context.
First of all, no Spooky BlahBlah or other wave function collapse can
transmit any information faster than light, the teleporting includes the
transport of standard, classical piece of information using established
physical channels.
Then, no rod is *geometrically* incompressible. A standard homework is the
following. A rocket of length L passes through a barn of length L. From the
static perspective the Lorenz contraction makes it appear shorter than L, so
when it is inside, both gates, front and rear are closed, and the rocket is
confined inside.
But from the pilot viewpoint, the barn is shorter than the rocket, so this
is simply impossible. The question is not to "solve the paradox", but to
discuss its *physical* implication. The "paradox is solved" by noting that
in the rocket's frame the doors are closed *not* simultaneously. Now, the
farmer, ignoring all possible implications, refuses to reopen the doors and
the rocket is trapped inside forever. This means then when the nose of the
rocket stops, e.g. by hitting the door from inside, *its rear parts MUST
keep moving*, the bad surprise cannot be known unless the rocket is fully
inside... The "fake" Lorenz contraction will be converted into a physical,
rather disastrous real contraction...
Jerzy Karczmarczuk
Ralph Hartley
Jun18-04, 11:27 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>Buddy wrote:\n\n> Take an "ideal" rod -- a perfectly straight one that can\'t be\n> stretched, compressed, or otherwise deformed -- and install one end of\n> it at "point A" and the other end at "point B." Now, from point A,\n> move the rod -- either pull it or push it along its linear axis. How\n> long does it take for the rod to move at point B? Does the action at\n> point A transfer to point B instantaneously, or does it go at some\n> speed less than or equal to the speed of light? What (if any) are the\n> ramifications of your answer?\n\nIt goes at the speed of *sound*, which always less, usually *much* less,\nthan the speed of light.\n\nWe don\'t normally notice this because we are not in the habit of moving\nobjects at timescales shorter than the time it takes for sound to propagate\nthrough them. Consider this (thought) experiment: place your ear against\none end of the rod, and make it move by striking the other end with a\nhammer. When do you expect to hear the impact?\n\nAn "ideal" perfectly rigid rod has an infinite speed of sound, and can\'t\nreally exist, it is just an abstraction.\n\nRelativity does not permit materials with a speed of sound grater than the\nspeed of light, but a perfectly rigid rod is inconsistent with Newtonian\nmechanics as well. To see that, calculate the force when two such rods collide.\n\nRalph Hartley\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>Buddy wrote:
> Take an "ideal" rod -- a perfectly straight one that can't be
> stretched, compressed, or otherwise deformed -- and install one end of
> it at "point A" and the other end at "point B." Now, from point A,
> move the rod -- either pull it or push it along its linear axis. How
> long does it take for the rod to move at point B? Does the action at
> point A transfer to point B instantaneously, or does it go at some
> speed less than or equal to the speed of light? What (if any) are the
> ramifications of your answer?
It goes at the speed of *sound*, which always less, usually *much* less,
than the speed of light.
We don't normally notice this because we are not in the habit of moving
objects at timescales shorter than the time it takes for sound to propagate
through them. Consider this (thought) experiment: place your ear against
one end of the rod, and make it move by striking the other end with a
hammer. When do you expect to hear the impact?
An "ideal" perfectly rigid rod has an infinite speed of sound, and can't
really exist, it is just an abstraction.
Relativity does not permit materials with a speed of sound grater than the
speed of light, but a perfectly rigid rod is inconsistent with Newtonian
mechanics as well. To see that, calculate the force when two such rods collide.
Ralph Hartley
<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>On 18 Jun 2004 05:40:56 -0400, buddy@EngineersGuideToGod.com (Buddy)\nwrote:\n\n>\n>Hi,\n>\n>The news today of scientists teleporting an atom got me curious. So,\n>I ended up reading an article on Spooky Action At a Distance. I\'m no\n>physics expert -- just an electrical engineer -- but I have a question\n>for those of you more learned than I ...\n>\n>Take an "ideal" rod -- a perfectly straight one that can\'t be\n>stretched, compressed, or otherwise deformed -- and install one end of\n>it at "point A" and the other end at "point B." Now, from point A,\n>move the rod -- either pull it or push it along its linear axis. How\n>long does it take for the rod to move at point B? Does the action at\n>point A transfer to point B instantaneously, or does it go at some\n>speed less than or equal to the speed of light? What (if any) are the\n>ramifications of your answer?\n>\n>Thanks in advance for educating me a bit on quantum physics ...\n>\n\nFor this reason relativity theory [special?] does not admit the\nexitance of classic "rigid bodies" i.e. the elastic constant of any\nmaterial is finite, and upper bounded. See also the recent post by\nChristoph Schiller) and references therein..\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>On 18 Jun 2004 05:40:56 -0400, buddy@EngineersGuideToGod.com (Buddy)
wrote:
>
>Hi,
>
>The news today of scientists teleporting an atom got me curious. So,
>I ended up reading an article on Spooky Action At a Distance. I'm no
>physics expert -- just an electrical engineer -- but I have a question
>for those of you more learned than I ...
>
>Take an "ideal" rod -- a perfectly straight one that can't be
>stretched, compressed, or otherwise deformed -- and install one end of
>it at "point A" and the other end at "point B." Now, from point A,
>move the rod -- either pull it or push it along its linear axis. How
>long does it take for the rod to move at point B? Does the action at
>point A transfer to point B instantaneously, or does it go at some
>speed less than or equal to the speed of light? What (if any) are the
>ramifications of your answer?
>
>Thanks in advance for educating me a bit on quantum physics ...
>
For this reason relativity theory [special?] does not admit the
exitance of classic "rigid bodies" i.e. the elastic constant of any
material is finite, and upper bounded. See also the recent post by
Christoph Schiller) and references therein..
Frank Hellmann
Jun18-04, 03:20 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>> Take an "ideal" rod -- a perfectly straight one that can\'t be\n> stretched, compressed, or otherwise deformed -- and install one end of\n\nThis assumption is basically incompatible with Special Relativity, it\ncan not be formulated in terms of fields, but it\'s a nonlocal\ncondition in itself that says that the atoms on one end are always at\na constant distance from the atoms at the other end. You can use a\nNewtonian Mechanics potential to describe this but this means spooky\naction at a distance is simply in the theory.\n\nfor a relativistically covariant treatment of your situation think\nabout it this way, you accelerate the atom on the one end of the rod\nand it bumps into the next and so on, and as all atoms always are\nmoving at less then c the other end will start moving later then l/c.\nAlternatively your rod just consists of two bodies in some force\nequilibrium you move the one and the fields propagate with c to move\nthe other so your delay after moving the one end of the rod is exactly\nl/c. The truth is inbetween those extreme simplified models of course.\nPoint is, relativistic solid bodies are a lot more subtle then\nnewtonian solid bodies, and you always need a more physical/realistic\nmodel to do them.\n\nThis all has nothing to do with QM basically, however ordinary QM is\nbased in newtonian mechanics and thus inherently nonlocal.\nRelativistic QM is lorentz invariant and has a maximum speed of\naction, BUT it also has the nonlocality of the wavefunction collapse\n(Copenhagen interpretation). That is the nonlocality exploited here\nwhich is fundamentally different from the nonlocality you described,\nwhich does not actually exist in any relativistic theory.\n\n---\nfrank\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>> Take an "ideal" rod -- a perfectly straight one that can't be
> stretched, compressed, or otherwise deformed -- and install one end of
This assumption is basically incompatible with Special Relativity, it
can not be formulated in terms of fields, but it's a nonlocal
condition in itself that says that the atoms on one end are always at
a constant distance from the atoms at the other end. You can use a
Newtonian Mechanics potential to describe this but this means spooky
action at a distance is simply in the theory.
for a relativistically covariant treatment of your situation think
about it this way, you accelerate the atom on the one end of the rod
and it bumps into the next and so on, and as all atoms always are
moving at less then c the other end will start moving later then l/c.
Alternatively your rod just consists of two bodies in some force
equilibrium you move the one and the fields propagate with c to move
the other so your delay after moving the one end of the rod is exactly
l/c. The truth is inbetween those extreme simplified models of course.
Point is, relativistic solid bodies are a lot more subtle then
newtonian solid bodies, and you always need a more physical/realistic
model to do them.
This all has nothing to do with QM basically, however ordinary QM is
based in newtonian mechanics and thus inherently nonlocal.
Relativistic QM is lorentz invariant and has a maximum speed of
action, BUT it also has the nonlocality of the wavefunction collapse
(Copenhagen interpretation). That is the nonlocality exploited here
which is fundamentally different from the nonlocality you described,
which does not actually exist in any relativistic theory.
---
frank
Arkadiusz Jadczyk
Jun18-04, 04:02 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>\nOn 18 Jun 2004 05:40:56 -0400, buddy@EngineersGuideToGod.com (Buddy)\nwrote:\n\n> Does the action at\n>point A transfer to point B instantaneously, or does it go at some\n>speed less than or equal to the speed of light?\n\nI you are electrical engineer you just measure it. And you find it out.\nIf you are unhappy with your measuring technique - look for a better\none.\nTell us what you find.\n\nDifferent people find different things, depending on how they define a\n"rod", and how they define "transfer". The devil, as always, is in the\ndetails.\n\nSearch the Internet for "Hartman effect". Search it for "Zeilinger and\nMozart", or search it for tachyons, search it for "relativity" and\n"rigid body"\nYou will find all kinds of amusements!\n\nark\n--\n\nArkadiusz Jadczyk\nhttp://www.cassiopaea.org/quantum_future/homepage.htm\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>On 18 Jun 2004 05:40:56 -0400, buddy@EngineersGuideToGod.com (Buddy)
wrote:
> Does the action at
>point A transfer to point B instantaneously, or does it go at some
>speed less than or equal to the speed of light?
I you are electrical engineer you just measure it. And you find it out.
If you are unhappy with your measuring technique - look for a better
one.
Tell us what you find.
Different people find different things, depending on how they define a
"rod", and how they define "transfer". The devil, as always, is in the
details.
Search the Internet for "Hartman effect". Search it for "Zeilinger and
Mozart", or search it for tachyons, search it for "relativity" and
"rigid body"
You will find all kinds of amusements!
ark
--
Arkadiusz Jadczyk
http://www.cassiopaea.org/quantum_future/homepage.htm
--
Nicolaas Vroom
Jun22-04, 03:13 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"Buddy" <buddy@EngineersGuideToGod.com> schreef in bericht\nnews:607783e2.0406171248.1671b530@posting .google.com...\n\n> Take an "ideal" rod -- a perfectly straight one that can\'t be\n> stretched, compressed, or otherwise deformed -- and install one end of\n> it at "point A" and the other end at "point B." Now, from point A,\n> move the rod -- either pull it or push it along its linear axis. How\n> long does it take for the rod to move at point B? Does the action at\n> point A transfer to point B instantaneously, or does it go at some\n> speed less than or equal to the speed of light? What (if any) are the\n> ramifications of your answer?\n\nideal (rigit) rods that are not stretched, compressed or otherwise\ndeformed don\'t exist and as such you can not answer the question\nhow ideal rods behave.\nOne fa question is if you rotate a long rot, does the other end\nexceeds the speed of light?\nThe problem is this long rot will bent and as such you will never exceed\nthe speed of light.\nOn the other end if you take a rigid (abstract) rod the answer is different:\nYes such a rod should exceed the speed of light, but such a hypothetical\nrod does not exist, so what is the value of this answer ?\n\nA different question is if you take a rod and you either pull it from the\nfront or push it from the back how does it behave ?\nIf you push the rod it will be compressed\nand if you pull the rod it will be stretched.\nThis action transfer will propagate through the rod with less than\nthe speed of light.\nIn fact if the back end of two rods have the same speed v and one is\npushed and the other one pulled its length will be different.\nThis happens at least during acceleration.\nThe next question is will their length become the same\nwhen the speed (at the back end) becomes and stays constant ?\nMy feeling is no.\n\nNicolaas Vroom\nhttp://users.pandora.be/nicvroom/\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>"Buddy" <buddy@EngineersGuideToGod.com> schreef in bericht
news:607783e2.0406171248.1671b530@posting.google.c om...
> Take an "ideal" rod -- a perfectly straight one that can't be
> stretched, compressed, or otherwise deformed -- and install one end of
> it at "point A" and the other end at "point B." Now, from point A,
> move the rod -- either pull it or push it along its linear axis. How
> long does it take for the rod to move at point B? Does the action at
> point A transfer to point B instantaneously, or does it go at some
> speed less than or equal to the speed of light? What (if any) are the
> ramifications of your answer?
ideal (rigit) rods that are not stretched, compressed or otherwise
deformed don't exist and as such you can not answer the question
how ideal rods behave.
One fa question is if you rotate a long rot, does the other end
exceeds the speed of light?
The problem is this long rot will bent and as such you will never exceed
the speed of light.
On the other end if you take a rigid (abstract) rod the answer is different:
Yes such a rod should exceed the speed of light, but such a hypothetical
rod does not exist, so what is the value of this answer ?
A different question is if you take a rod and you either pull it from the
front or push it from the back how does it behave ?
If you push the rod it will be compressed
and if you pull the rod it will be stretched.
This action transfer will propagate through the rod with less than
the speed of light.
In fact if the back end of two rods have the same speed v and one is
pushed and the other one pulled its length will be different.
This happens at least during acceleration.
The next question is will their length become the same
when the speed (at the back end) becomes and stays constant ?
My feeling is no.
Nicolaas Vroom
http://users.pandora.be/nicvroom/
Rob Woodside
Jun27-04, 05:57 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>Arkadiusz Jadczyk <arkREMOVETHIS@ANDTHIScassiopaea.org> wrote in message news:<mdl6d0pcl12gmdssqiir7s92meh7abo4ho@4ax.com>. ..\n> On 18 Jun 2004 05:40:56 -0400, buddy@EngineersGuideToGod.com (Buddy)\n> wrote:\n>\n> > Does the action at\n> >point A transfer to point B instantaneously, or does it go at some\n> >speed less than or equal to the speed of light?\nsnip\n\nHere\'s a gedanken experiment: A rigid body has the property that the\ndistance between any two points in the body have a fixed distance no\nmatter how it moves. Take a rigid meter stick and connect a switch\nwith a light bulb to one end and put a billiard ball next to the other\nend. Hit the end with the switch, turning on the light. Instantantly\nthe far end of the stick moves keeping the distances fixed and gives\nthe billiard ball a velocity. Instantly you have given the billiard\nball some kinetic energy and about three nanoseconds later the light\narrives.\n\nBoth Newtonian Mechanics (infinite force between colliding rigid\nbodies) and Special Relativity (gedanken experiment above) preclude\nrigid bodies. As mentioned by others energy is transmitted at the\nspeed of sound in the body. The rigid body is a useful approximation\nas long as the speed of sound inside the body can be considered\ninfinite compared to the other velocities involved.\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>Arkadiusz Jadczyk <arkREMOVETHIS@ANDTHIScassiopaea.org> wrote in message news:<mdl6d0pcl12gmdssqiir7s92meh7abo4ho@4ax.com>...
> On 18 Jun 2004 05:40:56 -0400, buddy@EngineersGuideToGod.com (Buddy)
> wrote:
>
> > Does the action at
> >point A transfer to point B instantaneously, or does it go at some
> >speed less than or equal to the speed of light?
snip
Here's a gedanken experiment: A rigid body has the property that the
distance between any two points in the body have a fixed distance no
matter how it moves. Take a rigid meter stick and connect a switch
with a light bulb to one end and put a billiard ball next to the other
end. Hit the end with the switch, turning on the light. Instantantly
the far end of the stick moves keeping the distances fixed and gives
the billiard ball a velocity. Instantly you have given the billiard
ball some kinetic energy and about three nanoseconds later the light
arrives.
Both Newtonian Mechanics (infinite force between colliding rigid
bodies) and Special Relativity (gedanken experiment above) preclude
rigid bodies. As mentioned by others energy is transmitted at the
speed of sound in the body. The rigid body is a useful approximation
as long as the speed of sound inside the body can be considered
infinite compared to the other velocities involved.
<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>That makes sense! Thanks!!!\n\nYou should be a professor somewhere!\n\nThanks also to everyone else who answered. All of your answers were\nvery helpful and much appreciated.\n\nBuddy\nwww.EngineersGuideToGod.com \n\n\nRalph Hartley <hartley@aic.nrl.navy.mil> wrote in message news:<cautr6\\$ckj\\$1@ra.nrl.navy.mil>...\n> Buddy wrote:\n>\n> > Take an "ideal" rod -- a perfectly straight one that can\'t be\n> > stretched, compressed, or otherwise deformed -- and install one end of\n> > it at "point A" and the other end at "point B." Now, from point A,\n> > move the rod -- either pull it or push it along its linear axis. How\n> > long does it take for the rod to move at point B? Does the action at\n> > point A transfer to point B instantaneously, or does it go at some\n> > speed less than or equal to the speed of light? What (if any) are the\n> > ramifications of your answer?\n>\n> It goes at the speed of *sound*, which always less, usually *much* less,\n> than the speed of light.\n>\n> We don\'t normally notice this because we are not in the habit of moving\n> objects at timescales shorter than the time it takes for sound to propagate\n> through them. Consider this (thought) experiment: place your ear against\n> one end of the rod, and make it move by striking the other end with a\n> hammer. When do you expect to hear the impact?\n>\n> An "ideal" perfectly rigid rod has an infinite speed of sound, and can\'t\n> really exist, it is just an abstraction.\n>\n> Relativity does not permit materials with a speed of sound grater than the\n> speed of light, but a perfectly rigid rod is inconsistent with Newtonian\n> mechanics as well. To see that, calculate the force when two such rods collide.\n>\n> Ralph Hartley\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>That makes sense! Thanks!!!
You should be a professor somewhere!
Thanks also to everyone else who answered. All of your answers were
very helpful and much appreciated.
Buddy
www.EngineersGuideToGod.com
Ralph Hartley <hartley@aic.nrl.navy.mil> wrote in message news:<cautr6$ckj$1@ra.nrl.navy.mil>...
> Buddy wrote:
>
> > Take an "ideal" rod -- a perfectly straight one that can't be
> > stretched, compressed, or otherwise deformed -- and install one end of
> > it at "point A" and the other end at "point B." Now, from point A,
> > move the rod -- either pull it or push it along its linear axis. How
> > long does it take for the rod to move at point B? Does the action at
> > point A transfer to point B instantaneously, or does it go at some
> > speed less than or equal to the speed of light? What (if any) are the
> > ramifications of your answer?
>
> It goes at the speed of *sound*, which always less, usually *much* less,
> than the speed of light.
>
> We don't normally notice this because we are not in the habit of moving
> objects at timescales shorter than the time it takes for sound to propagate
> through them. Consider this (thought) experiment: place your ear against
> one end of the rod, and make it move by striking the other end with a
> hammer. When do you expect to hear the impact?
>
> An "ideal" perfectly rigid rod has an infinite speed of sound, and can't
> really exist, it is just an abstraction.
>
> Relativity does not permit materials with a speed of sound grater than the
> speed of light, but a perfectly rigid rod is inconsistent with Newtonian
> mechanics as well. To see that, calculate the force when two such rods collide.
>
> Ralph Hartley
David Park
Jun27-04, 05:59 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>I\'m also a novice also trying to learn these things.\n\nOn the question of rigidity in special relativity Taylor and Wheeler have a\nwonderful exercise (L-12, p 116, paradox of the skateboard and the grid) in\ntheir Spacetime Physics text. A meter stick slides across a floor with a one\nmeter diameter hole. If the meter stick is moving at a high speed it will\nappear shortened in the frame of the hole and fall through. But from the\nperspective of the meter stick, it is the hole that is shortened and so one\nmight expect it not to fall through. But it does because \'rigidity\' is not\nan invariant concept. The meter stick \'droops\' and slips right through the\nhole. An animation of this from both viewpoints is quite dramatic and\neducational.\n\nOn the question of QM \'spooky action at a distance\', which really isn\'t\ninvolved in the question, I would like to suggest an image for popular\nvisualization. I\'m not certain how good it is - but here it is. In painting\nthere is a style called the \'pointillist\' style pioneered by Georges Seurat.\nImages are built up from a large number of points of various shades and\ncolors. These blend to give the overall image. If one looked at a very small\npiece of a painting the points would appear to be random. Spooky action at a\ndistance, say by careful measurement on an entangled painting at a distance,\nwould change the random collection of dots. But overall the painting would\nlook quite the same to the viewer and he could never tell, even by examining\nthe dots closely, what particular actions had been taken on the distant\npainting.\n\nDavid Park\ndjmp@earthlink.net\nhttp://home.earthlink.net/~djmp/\n\n"Buddy" <buddy@EngineersGuideToGod.com> wrote in message\nnews:607783e2.0406171248.1671b530@posting .google.com...\n>\n> Hi,\n>\n> The news today of scientists teleporting an atom got me curious. So,\n> I ended up reading an article on Spooky Action At a Distance. I\'m no\n> physics expert -- just an electrical engineer -- but I have a question\n> for those of you more learned than I ...\n>\n> Take an "ideal" rod -- a perfectly straight one that can\'t be\n> stretched, compressed, or otherwise deformed -- and install one end of\n> it at "point A" and the other end at "point B." Now, from point A,\n> move the rod -- either pull it or push it along its linear axis. How\n> long does it take for the rod to move at point B? Does the action at\n> point A transfer to point B instantaneously, or does it go at some\n> speed less than or equal to the speed of light? What (if any) are the\n> ramifications of your answer?\n>\n> Thanks in advance for educating me a bit on quantum physics ...\n>\n>\n> Buddy Brinkley\n> www.EngineersGuideToGod.com\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>I'm also a novice also trying to learn these things.
On the question of rigidity in special relativity Taylor and Wheeler have a
wonderful exercise (L-12, p 116, paradox of the skateboard and the grid) in
their Spacetime Physics text. A meter stick slides across a floor with a one
meter diameter hole. If the meter stick is moving at a high speed it will
appear shortened in the frame of the hole and fall through. But from the
perspective of the meter stick, it is the hole that is shortened and so one
might expect it not to fall through. But it does because 'rigidity' is not
an invariant concept. The meter stick 'droops' and slips right through the
hole. An animation of this from both viewpoints is quite dramatic and
educational.
On the question of QM 'spooky action at a distance', which really isn't
involved in the question, I would like to suggest an image for popular
visualization. I'm not certain how good it is - but here it is. In painting
there is a style called the 'pointillist' style pioneered by Georges Seurat.
Images are built up from a large number of points of various shades and
colors. These blend to give the overall image. If one looked at a very small
piece of a painting the points would appear to be random. Spooky action at a
distance, say by careful measurement on an entangled painting at a distance,
would change the random collection of dots. But overall the painting would
look quite the same to the viewer and he could never tell, even by examining
the dots closely, what particular actions had been taken on the distant
painting.
David Park
djmp@earthlink.net
http://home.earthlink.net/~djmp/
"Buddy" <buddy@EngineersGuideToGod.com> wrote in message
news:607783e2.0406171248.1671b530@posting.google.c om...
>
> Hi,
>
> The news today of scientists teleporting an atom got me curious. So,
> I ended up reading an article on Spooky Action At a Distance. I'm no
> physics expert -- just an electrical engineer -- but I have a question
> for those of you more learned than I ...
>
> Take an "ideal" rod -- a perfectly straight one that can't be
> stretched, compressed, or otherwise deformed -- and install one end of
> it at "point A" and the other end at "point B." Now, from point A,
> move the rod -- either pull it or push it along its linear axis. How
> long does it take for the rod to move at point B? Does the action at
> point A transfer to point B instantaneously, or does it go at some
> speed less than or equal to the speed of light? What (if any) are the
> ramifications of your answer?
>
> Thanks in advance for educating me a bit on quantum physics ...
>
>
> Buddy Brinkley
> www.EngineersGuideToGod.com
Doug Sweetser
Jun28-04, 12:10 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>\n\n\nHello David:\n\nThis sounds right on the mark to me:\n\n> On the question of QM \'spooky action at a distance\', which really\n> isn\'t involved in the question, I would like to suggest an image for\n> popular visualization. I\'m not certain how good it is - but here it\n> is. In painting there is a style called the \'pointillist\' style\n> pioneered by Georges Seurat. Images are built up from a large number\n> of points of various shades and colors. These blend to give the\n> overall image. If one looked at a very small piece of a painting the\n> points would appear to be random. Spooky action at a distance, say by\n> careful measurement on an entangled painting at a distance, would\n> change the random collection of dots. But overall the painting would\n> look quite the same to the viewer and he could never tell, even by\n> examining the dots closely, what particular actions had been taken on\n> the distant painting.\n\nI actually created my own artwork devoted to this idea, titled "Groups\nof coherent photons behave like waves and particles", a 26"x43" IRIS\nprint that hangs in my livingroom. In every dual slit experiment or\nspooky type experiment, the source of the particles must be coherent,\neither in time, space, or both for a laser. Look at any small volume\nof spacetime, and there will be (to make up numbers), say 0, 3, 5, or\n10 photons. Consistently sample the same volume of spacetime. If the\nsource is coherent, a pattern will emerge. If the source in\nincoherent, the pattern will be random.\n\nHere is a link to the artwork:\n\nhttp://world.std.com/%7Esweetser/PopScience/photons/photons.html\n\nYou might also enjoy the textual explanation that goes along with it.\n\n\ndoug\nquaternions.com\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>Hello David:
This sounds right on the mark to me:
> On the question of QM 'spooky action at a distance', which really
> isn't involved in the question, I would like to suggest an image for
> popular visualization. I'm not certain how good it is - but here it
> is. In painting there is a style called the 'pointillist' style
> pioneered by Georges Seurat. Images are built up from a large number
> of points of various shades and colors. These blend to give the
> overall image. If one looked at a very small piece of a painting the
> points would appear to be random. Spooky action at a distance, say by
> careful measurement on an entangled painting at a distance, would
> change the random collection of dots. But overall the painting would
> look quite the same to the viewer and he could never tell, even by
> examining the dots closely, what particular actions had been taken on
> the distant painting.
I actually created my own artwork devoted to this idea, titled "Groups
of coherent photons behave like waves and particles", a 26"x43" IRIS
print that hangs in my livingroom. In every dual slit experiment or
spooky type experiment, the source of the particles must be coherent,
either in time, space, or both for a laser. Look at any small volume
of spacetime, and there will be (to make up numbers), say 0, 3, 5, or
10 photons. Consistently sample the same volume of spacetime. If the
source is coherent, a pattern will emerge. If the source in
incoherent, the pattern will be random.
Here is a link to the artwork:
http://world.std.com/%7Esweetser/PopScience/photons/photons.html
You might also enjoy the textual explanation that goes along with it.
doug
quaternions.com
Arkadiusz Jadczyk
Jun29-04, 05:46 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>On Sun, 27 Jun 2004 22:57:06 +0000 (UTC), rwmw@telus.net (Rob Woodside)\nwrote:\n\n>Both Newtonian Mechanics (infinite force between colliding rigid\n>bodies) and Special Relativity (gedanken experiment above) preclude\n>rigid bodies. As mentioned by others energy is transmitted at the\n>speed of sound in the body. The rigid body is a useful approximation\n>as long as the speed of sound inside the body can be considered\n>infinite compared to the other velocities involved.\n\n\nIndeed,\nThe devil is always in the details. You say that Newtonian Mechanics\npreclude rigid bodies. You can say, similarly, that it precludes point\nparticles, right? Infinite density! And yet the concept of a point\nparticle is useful and manageable. Similarly a point charge (Dirac\ndelta) is a useful concept - we will get finite answers provided we ask\nthe right questions, we will get nonsensical answers for some other\nquestions.\n\nark\n--\n\nArkadiusz Jadczyk\nhttp://www.cassiopaea.org/quantum_future/homepage.htm\n\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>On Sun, 27 Jun 2004 22:57:06 +0000 (UTC), rwmw@telus.net (Rob Woodside)
wrote:
>Both Newtonian Mechanics (infinite force between colliding rigid
>bodies) and Special Relativity (gedanken experiment above) preclude
>rigid bodies. As mentioned by others energy is transmitted at the
>speed of sound in the body. The rigid body is a useful approximation
>as long as the speed of sound inside the body can be considered
>infinite compared to the other velocities involved.
Indeed,
The devil is always in the details. You say that Newtonian Mechanics
preclude rigid bodies. You can say, similarly, that it precludes point
particles, right? Infinite density! And yet the concept of a point
particle is useful and manageable. Similarly a point charge (Dirac
\delta) is a useful concept - we will get finite answers provided we ask
the right questions, we will get nonsensical answers for some other
questions.
ark
--
Arkadiusz Jadczyk
http://www.cassiopaea.org/quantum_future/homepage.htm
--
Nicolaas Vroom
Jun30-04, 05:41 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>"Arkadiusz Jadczyk" <arkREMOVETHIS@ANDTHIScassiopaea.org> schreef in bericht\nnews:k350e01lu0b2h72gvdrh9cusls397c7t2f@4 ax.com...\n> On Sun, 27 Jun 2004 22:57:06 +0000 (UTC), rwmw@telus.net (Rob Woodside)\n> wrote:\n\n> You say that Newtonian Mechanics preclude rigid bodies.\nEvery theory should preclude rigid bodies.\nEvery theory should warn the reader that rigid bodies are considerd.\n\n> You can say, similarly, that it precludes point particles, right?\nI assume you mean point masses.\nIf that is the case, that is correct.\nEvery theory should warn the reader that point masses are considerd.\n\nHowever the implications are completely different.\nYou can consider each mass as a point mass as long as the distance\nbetween the two masses is greater than r1+r2.\n(r1 and r2 being the distance between the two masses involved)\n\nTo consider a mass as a rigid body is physical wrong, at least\nmasses are stretched or compressed when pulled or pushed.\nWhat are the benefits for considering a mass as a rigid body ?\nIs this required in order to understand SR ? or GR ?\nand if yes what happened if normal masses are considered.\n\n> Infinite density!\nInfinite density is no issue as long as the distance\nbetween the two masses is greater than r1+r2.\nThe same for singularity.\n\n> And yet the concept of a point\n> particle is useful and manageable. Similarly a point charge (Dirac\n> delta) is a useful concept - we will get finite answers provided we ask\n> the right questions, we will get nonsensical answers for some other\n> questions.\n\nWe can only expect clear answers if we ask clear questions\n(And in many cases the answer should be: we do not know)\n\nNicolaas Vroom\nhttp://users.pandora.be/nicvroom/\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>"Arkadiusz Jadczyk" <arkREMOVETHIS@ANDTHIScassiopaea.org> schreef in bericht
news:k350e01lu0b2h72gvdrh9cusls397c7t2f@4ax.com...
> On Sun, 27 Jun 2004 22:57:06 +0000 (UTC), rwmw@telus.net (Rob Woodside)
> wrote:
> You say that Newtonian Mechanics preclude rigid bodies.
Every theory should preclude rigid bodies.
Every theory should warn the reader that rigid bodies are considerd.
> You can say, similarly, that it precludes point particles, right?
I assume you mean point masses.
If that is the case, that is correct.
Every theory should warn the reader that point masses are considerd.
However the implications are completely different.
You can consider each mass as a point mass as long as the distance
between the two masses is greater than r1+r2.
(r1 and r2 being the distance between the two masses involved)
To consider a mass as a rigid body is physical wrong, at least
masses are stretched or compressed when pulled or pushed.
What are the benefits for considering a mass as a rigid body ?
Is this required in order to understand SR ? or GR ?
and if yes what happened if normal masses are considered.
> Infinite density!
Infinite density is no issue as long as the distance
between the two masses is greater than r1+r2.
The same for singularity.
> And yet the concept of a point
> particle is useful and manageable. Similarly a point charge (Dirac
> \delta) is a useful concept - we will get finite answers provided we ask
> the right questions, we will get nonsensical answers for some other
> questions.
We can only expect clear answers if we ask clear questions
(And in many cases the answer should be: we do not know)
Nicolaas Vroom
http://users.pandora.be/nicvroom/
Frank Hellmann
Jul2-04, 04:32 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\n> Every theory should warn the reader that point masses are considerd.\n>\n\nWhy?\nInfinities are not inherently unphysical. Especially in the case of\npoint masses. SR requires the fundamental constituents of a system to\nbe point like.\n\nThe infinite self energy of a charged point particle is renormalized\naway as unphysical, the singularity of a black hole is considered\nphysical.\n\nInfinities and singularities are not inherently unphysical, but they\noften disagree with experiment (infinite self energy of point charge\nis a prime example of the. We experimentally observe the rest energy\nof a particle to be finite).\n\nRigid bodies in Newtonian mechanics are of course perfectly consistent\nfor the most part. An abstraction and idealization supported by the\nframework of newtonian mechanics (as opposed to SR, where you can\'t\ndefine a rigid bodie within it\'s framework but have to make up a more\nrealistic model straight away).\nIf some infinities drop out of it this does not invalidate the whole\nin any way.\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>Every theory should warn the reader that point masses are considerd.
>
Why?
Infinities are not inherently unphysical. Especially in the case of
point masses. SR requires the fundamental constituents of a system to
be point like.
The infinite self energy of a charged point particle is renormalized
away as unphysical, the singularity of a black hole is considered
physical.
Infinities and singularities are not inherently unphysical, but they
often disagree with experiment (infinite self energy of point charge
is a prime example of the. We experimentally observe the rest energy
of a particle to be finite).
Rigid bodies in Newtonian mechanics are of course perfectly consistent
for the most part. An abstraction and idealization supported by the
framework of newtonian mechanics (as opposed to SR, where you can't
define a rigid bodie within it's framework but have to make up a more
realistic model straight away).
If some infinities drop out of it this does not invalidate the whole
in any way.
Nicolaas Vroom
Jul2-04, 12:54 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>\n"David Park" <djmp@earthlink.net> schreef in bericht\nnews:oYXBc.9823\\$bs4.1308@newsread3.news .atl.earthlink.net...\n> I\'m also a novice also trying to learn these things.\n>\n> On the question of rigidity in special relativity Taylor and Wheeler have\na\n> wonderful exercise (L-12, p 116, paradox of the skateboard and the grid)\nin\n> their Spacetime Physics text. A meter stick slides across a floor with a\none\n> meter diameter hole. If the meter stick is moving at a high speed it will\n> appear shortened in the frame of the hole and fall through. But from the\n> perspective of the meter stick, it is the hole that is shortened and so\none\n> might expect it not to fall through. But it does because \'rigidity\' is not\n> an invariant concept. The meter stick \'droops\' and slips right through the\n> hole.\n\nIs this the outcome of a real experiment ?\nIf No than this whole discussion has no "value" i.e.\ndoes not make sense\nIf Yes what has rigidity to do with this experiment because\nwhy considering the meter stick (rod) rigid\nwhen in reality a rod is not rigid ?\n\nIf the meter stick drops through the hole as the result of an experiment\n(In reality there should be a small bar at the middle of the hole, other\nwise\na rod which is almost twice as large as the hole with a small speed\nmoving left to right over the hole will drop through the hole)\nthen there are two points of view,\none from the frame of hole (and fall through)\nand one from meter stick (and not fall through).\nIf the meter stick drops through the hole as the result of an experiment\nthan the second point of view is just wrong.\nand not "because \'rigidity\' is not an invariant concept"\n\n> On the question of QM \'spooky action at a distance\', which really isn\'t\n> involved in the question, I would like to suggest an image for popular\n> visualization. I\'m not certain how good it is - but here it is. In\npainting\n> there is a style called the \'pointillist\' style pioneered by Georges\nSeurat.\n> Images are built up from a large number of points of various shades and\n> colors. These blend to give the overall image. If one looked at a very\nsmall\n> piece of a painting the points would appear to be random. Spooky action\n> at a distance, say by careful measurement on an entangled painting at a\n> distance, would change the random collection of dots.\n> But overall the painting would look quite the same to the viewer\n> and he could never tell, even by examining the dots closely,\n> what particular actions had been taken on the distant painting.\n\nWhat has spooky action at a distance (if it exists) and entanglement\nto do with the paintings of for example Rembrandt and van Gogh ?\nIMO nothing.\n\nNicolaas Vroom\nhttp://users.pandora.be/nicvroom/\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>"David Park" <djmp@earthlink.net> schreef in bericht
news:oYXBc.9823$bs4.1308@newsread3.news.atl.earthl ink.net...
> I'm also a novice also trying to learn these things.
>
> On the question of rigidity in special relativity Taylor and Wheeler have
a
> wonderful exercise (L-12, p 116, paradox of the skateboard and the grid)
in
> their Spacetime Physics text. A meter stick slides across a floor with a
one
> meter diameter hole. If the meter stick is moving at a high speed it will
> appear shortened in the frame of the hole and fall through. But from the
> perspective of the meter stick, it is the hole that is shortened and so
one
> might expect it not to fall through. But it does because 'rigidity' is not
> an invariant concept. The meter stick 'droops' and slips right through the
> hole.
Is this the outcome of a real experiment ?
If No than this whole discussion has no "value" i.e.
does not make sense
If Yes what has rigidity to do with this experiment because
why considering the meter stick (rod) rigid
when in reality a rod is not rigid ?
If the meter stick drops through the hole as the result of an experiment
(In reality there should be a small bar at the middle of the hole, other
wise
a rod which is almost twice as large as the hole with a small speed
moving left to right over the hole will drop through the hole)
then there are two points of view,
one from the frame of hole (and fall through)
and one from meter stick (and not fall through).
If the meter stick drops through the hole as the result of an experiment
than the second point of view is just wrong.
and not "because 'rigidity' is not an invariant concept"
> On the question of QM 'spooky action at a distance', which really isn't
> involved in the question, I would like to suggest an image for popular
> visualization. I'm not certain how good it is - but here it is. In
painting
> there is a style called the 'pointillist' style pioneered by Georges
Seurat.
> Images are built up from a large number of points of various shades and
> colors. These blend to give the overall image. If one looked at a very
small
> piece of a painting the points would appear to be random. Spooky action
> at a distance, say by careful measurement on an entangled painting at a
> distance, would change the random collection of dots.
> But overall the painting would look quite the same to the viewer
> and he could never tell, even by examining the dots closely,
> what particular actions had been taken on the distant painting.
What has spooky action at a distance (if it exists) and entanglement
to do with the paintings of for example Rembrandt and van Gogh ?
IMO nothing.
Nicolaas Vroom
http://users.pandora.be/nicvroom/
Peter Shor
Jul9-04, 03:49 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\n"Nicolaas Vroom" <nicolaas.vroom@pandora.be> wrote in message news:<DdhFc.172371\\$iL3.8637564@phobos.telenet-ops.be>...\n> "David Park" <djmp@earthlink.net> schreef in bericht\n> news:oYXBc.9823\\$bs4.1308@newsread3.news.atl.eart hlink.net...\n> > I\'m also a novice also trying to learn these things.\n> >\n> > On the question of rigidity in special relativity Taylor and Wheeler have\n> a\n> > wonderful exercise (L-12, p 116, paradox of the skateboard and the grid)\n> in\n> > their Spacetime Physics text. A meter stick slides across a floor with a\n> one\n> > meter diameter hole. If the meter stick is moving at a high speed it will\n> > appear shortened in the frame of the hole and fall through. But from the\n> > perspective of the meter stick, it is the hole that is shortened and so\n> one\n> > might expect it not to fall through. But it does because \'rigidity\' is not\n> > an invariant concept. The meter stick \'droops\' and slips right through the\n> > hole.\n>\n> Is this the outcome of a real experiment ?\n> If No than this whole discussion has no "value" i.e.\n> does not make sense\n> If Yes what has rigidity to do with this experiment because\n> why considering the meter stick (rod) rigid\n> when in reality a rod is not rigid ?\n\nThis is a thought experiment, and the object of this thought\nexperiment should be to convince you that special relativity\npredicts there\'s no such thing as a rigid meter stick.\n\n> If the meter stick drops through the hole as the result of an experiment\n> (In reality there should be a small bar at the middle of the hole, other\n> wise\n> a rod which is almost twice as large as the hole with a small speed\n> moving left to right over the hole will drop through the hole)\n> then there are two points of view,\n> one from the frame of hole (and fall through)\n> and one from meter stick (and not fall through).\n> If the meter stick drops through the hole as the result of an experiment\n> than the second point of view is just wrong.\n> and not "because \'rigidity\' is not an invariant concept"\n\n> Nicolaas Vroom\n> http://users.pandora.be/nicvroom/\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>"Nicolaas Vroom" <nicolaas.vroom@pandora.be> wrote in message news:<DdhFc.172371$iL3.8637564@phobos.telenet-ops.be>...
> "David Park" <djmp@earthlink.net> schreef in bericht
> news:oYXBc.9823$bs4.1308@newsread3.news.atl.earthl ink.net...
> > I'm also a novice also trying to learn these things.
> >
> > On the question of rigidity in special relativity Taylor and Wheeler have
> a
> > wonderful exercise (L-12, p 116, paradox of the skateboard and the grid)
> in
> > their Spacetime Physics text. A meter stick slides across a floor with a
> one
> > meter diameter hole. If the meter stick is moving at a high speed it will
> > appear shortened in the frame of the hole and fall through. But from the
> > perspective of the meter stick, it is the hole that is shortened and so
> one
> > might expect it not to fall through. But it does because 'rigidity' is not
> > an invariant concept. The meter stick 'droops' and slips right through the
> > hole.
>
> Is this the outcome of a real experiment ?
> If No than this whole discussion has no "value" i.e.
> does not make sense
> If Yes what has rigidity to do with this experiment because
> why considering the meter stick (rod) rigid
> when in reality a rod is not rigid ?
This is a thought experiment, and the object of this thought
experiment should be to convince you that special relativity
predicts there's no such thing as a rigid meter stick.
> If the meter stick drops through the hole as the result of an experiment
> (In reality there should be a small bar at the middle of the hole, other
> wise
> a rod which is almost twice as large as the hole with a small speed
> moving left to right over the hole will drop through the hole)
> then there are two points of view,
> one from the frame of hole (and fall through)
> and one from meter stick (and not fall through).
> If the meter stick drops through the hole as the result of an experiment
> than the second point of view is just wrong.
> and not "because 'rigidity' is not an invariant concept"
> Nicolaas Vroom
> http://users.pandora.be/nicvroom/
Tom Trotter
Jul11-04, 02:57 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\n\n\nbuddy@EngineersGuideToGod.com (Buddy) wrote in message news:<607783e2.0406171248.1671b530@posting.google. com>...\n> Hi,\n>\n> The news today of scientists teleporting an atom got me curious. So,\n> I ended up reading an article on Spooky Action At a Distance. I\'m no\n> physics expert -- just an electrical engineer -- but I have a question\n> for those of you more learned than I ...\n>\n> Take an "ideal" rod -- a perfectly straight one that can\'t be\n> stretched, compressed, or otherwise deformed -- and install one end of\n> it at "point A" and the other end at "point B." Now, from point A,\n> move the rod -- either pull it or push it along its linear axis. How\n> long does it take for the rod to move at point B? Does the action at\n> point A transfer to point B instantaneously, or does it go at some\n> speed less than or equal to the speed of light? What (if any) are the\n> ramifications of your answer?\n>\n> Thanks in advance for educating me a bit on quantum physics ...\n>\n>\n> Buddy Brinkley\n> www.EngineersGuideToGod.com\n\nThe way this relates to entanglement is this: if you mark two\npoints on the rod, A and B, then set the rod in motion, any motion,\nthen A\'s motion will be correlated with B\'s motion even though\nthere\'s no signal, no communication between A and B to facilitate\nthis correlation. This is one type of entanglement.\n\nAnother type of entanglement is where objects that have interacted\nor have a common origin share a motional property because of their\ncommon history. If you detect some aspect of that shared property\nwrt one of the objects, then, barring any intervening influences\non the other object, you can deduce something about an eventual\ndetection of the other object wrt the shared property.\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>buddy@EngineersGuideToGod.com (Buddy) wrote in message news:<607783e2.0406171248.1671b530@posting.google.com>...
> Hi,
>
> The news today of scientists teleporting an atom got me curious. So,
> I ended up reading an article on Spooky Action At a Distance. I'm no
> physics expert -- just an electrical engineer -- but I have a question
> for those of you more learned than I ...
>
> Take an "ideal" rod -- a perfectly straight one that can't be
> stretched, compressed, or otherwise deformed -- and install one end of
> it at "point A" and the other end at "point B." Now, from point A,
> move the rod -- either pull it or push it along its linear axis. How
> long does it take for the rod to move at point B? Does the action at
> point A transfer to point B instantaneously, or does it go at some
> speed less than or equal to the speed of light? What (if any) are the
> ramifications of your answer?
>
> Thanks in advance for educating me a bit on quantum physics ...
>
>
> Buddy Brinkley
> www.EngineersGuideToGod.com
The way this relates to entanglement is this: if you mark two
points on the rod, A and B, then set the rod in motion, any motion,
then A's motion will be correlated with B's motion even though
there's no signal, no communication between A and B to facilitate
this correlation. This is one type of entanglement.
Another type of entanglement is where objects that have interacted
or have a common origin share a motional property because of their
common history. If you detect some aspect of that shared property
wrt one of the objects, then, barring any intervening influences
on the other object, you can deduce something about an eventual
detection of the other object wrt the shared property.
Nicolaas Vroom
Jul12-04, 01:46 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>\n"Peter Shor" <peterwshor@aol.com> schreef in bericht\nnews:9b2e17b4.0407071422.16bf537b@posting .google.com...\n>\n>\n> "Nicolaas Vroom" <nicolaas.vroom@pandora.be> wrote in message\nnews:<DdhFc.172371\\$iL3.8637564@phobos.t elenet-ops.be>...\n> > "David Park" <djmp@earthlink.net> schreef in bericht\n> > news:oYXBc.9823\\$bs4.1308@newsread3.news.atl.eart hlink.net...\n> > >\n> > > On the question of rigidity in special relativity Taylor\n> > > and Wheeler have a wonderful exercise in their\n> > > Spacetime Physics text. A meter stick slides across\n> > > a floor with a one meter diameter hole.\nSNIP\n> >\n> > Is this the outcome of a real experiment ?\n> > If No than this whole discussion has no "value" i.e.\n> > does not make sense\n> > If Yes what has rigidity to do with this experiment because\n> > why considering the meter stick (rod) rigid\n> > when in reality a rod is not rigid ?\n>\n> This is a thought experiment, and the object of this thought\n> experiment should be to convince you that special relativity\n> predicts there\'s no such thing as a rigid meter stick.\n\nExactly how ?\nLet me try to summarize.\nConsider a one "rigid meter stick"\nand a floor with a one meter hole\nThe meter stick slides over the floor.\nAccordingly to SR.\nIn the frame of the floor the meter stick is shortened\nand the meter stick will fall through.\nIn the frame of meter stick the hole is shortened\nand the meter stick will not fall through.\nThis is a paradox (or a contradiction ?)\nSolution: "rigid meter sticks" do not exist.\nAll accordingly to SR.\n\nDoes this thought experiment imply that SR is correct ?\n\nThe problem is rigid meter sticks do not exist.\nThat means your starting point is already false.\n(And I have problems to understand and accept that you\ncan THAN use any form of logic to predict the outcome\nof any thought experiment)\n\nSuppose you start with a "non rigid meter stick".\nDoes this not lead to the same paradox ?\nAnd is than the solution that "non rigid meter sticks"\ndo not exist ?\n\n\nNicolaas Vroom\nhttp://users.pandora.be/nicvroom/\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>"Peter Shor" <peterwshor@aol.com> schreef in bericht
news:9b2e17b4.0407071422.16bf537b@posting.google.c om...
>
>
> "Nicolaas Vroom" <nicolaas.vroom@pandora.be> wrote in message
news:<DdhFc.172371$iL3.8637564@phobos.telenet-ops.be>...
> > "David Park" <djmp@earthlink.net> schreef in bericht
> > news:oYXBc.9823$bs4.1308@newsread3.news.atl.earthl ink.net...
> > >
> > > On the question of rigidity in special relativity Taylor
> > > and Wheeler have a wonderful exercise in their
> > > Spacetime Physics text. A meter stick slides across
> > > a floor with a one meter diameter hole.
SNIP
> >
> > Is this the outcome of a real experiment ?
> > If No than this whole discussion has no "value" i.e.
> > does not make sense
> > If Yes what has rigidity to do with this experiment because
> > why considering the meter stick (rod) rigid
> > when in reality a rod is not rigid ?
>
> This is a thought experiment, and the object of this thought
> experiment should be to convince you that special relativity
> predicts there's no such thing as a rigid meter stick.
Exactly how ?
Let me try to summarize.
Consider a one "rigid meter stick"
and a floor with a one meter hole
The meter stick slides over the floor.
Accordingly to SR.
In the frame of the floor the meter stick is shortened
and the meter stick will fall through.
In the frame of meter stick the hole is shortened
and the meter stick will not fall through.
This is a paradox (or a contradiction ?)
Solution: "rigid meter sticks" do not exist.
All accordingly to SR.
Does this thought experiment imply that SR is correct ?
The problem is rigid meter sticks do not exist.
That means your starting point is already false.
(And I have problems to understand and accept that you
can THAN use any form of logic to predict the outcome
of any thought experiment)
Suppose you start with a "non rigid meter stick".
Does this not lead to the same paradox ?
And is than the solution that "non rigid meter sticks"
do not exist ?
Nicolaas Vroom
http://users.pandora.be/nicvroom/
jason cooper
Jul16-04, 08:20 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\nNicolaas Vroom (nicolaas.vroom@pandora.be) wrote:\n\n: Consider a one "rigid meter stick"\n: and a floor with a one meter hole\n: The meter stick slides over the floor.\n: Accordingly to SR.\n: In the frame of the floor the meter stick is shortened\n: and the meter stick will fall through.\n: In the frame of meter stick the hole is shortened\n: and the meter stick will not fall through.\n\nI\'ll take a crack at this.\n\nA common example (but not the same) is a meterstick and two gates\nset a little less than a meter apart. We move the meterstick,\nlengthwise, past these gates. In the frame of the gates, the\nmeterstick fits entirely between them at some point -- we close\nthe gates momentarily at that time. The "paradox" is that in its\nown frame, the stick is never entirely between the gates, so this\ncan\'t happen.\n\nThe resolution, there, is that in the frame of the stick, the\ngates close at different times (recall that space and time are\nmixed) so that the stick sees the front gate close, then open,\nthen as the back of the stick clears the rear gate, the rear gate\ncloses. No paradox.\n\nYour example involves gravity, which I\'m going to suppose\ncomplicates things. But as an equivalent example, suppose we\nhave a surface with a hole in it, moving at a constant speed\nperpendicular to the path of the stick (ie, the "floor" is moving\nat a constant speed up, but no gravity). In the frame of the\nfloor, things are pretty straightforward -- the stick manages to\n"fall" through the hole.\n\nIn the frame of the stick, I would suggest that we would see the\nfloor as being at some angle to the path of the stick (again,\nmixing of space and time), so that the stick moves through the\nhole "at an angle", in effect. I would further suggest that, if\nwe used gravity instead of a moving floor, we would see a similar\neffect.\n\n-----------------------------------------------------------------\n. . . Except when they don\'t,\nBecause sometimes they won\'t. - Dr. Seuss\n-----------------------------------------------------------------\nJason Cooper jcooper@acs.ucalgary.ca\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>Nicolaas Vroom (nicolaas.vroom@pandora.be) wrote:
: Consider a one "rigid meter stick"
: and a floor with a one meter hole
: The meter stick slides over the floor.
: Accordingly to SR.
: In the frame of the floor the meter stick is shortened
: and the meter stick will fall through.
: In the frame of meter stick the hole is shortened
: and the meter stick will not fall through.
I'll take a crack at this.
A common example (but not the same) is a meterstick and two gates
set a little less than a meter apart. We move the meterstick,
lengthwise, past these gates. In the frame of the gates, the
meterstick fits entirely between them at some point -- we close
the gates momentarily at that time. The "paradox" is that in its
own frame, the stick is never entirely between the gates, so this
can't happen.
The resolution, there, is that in the frame of the stick, the
gates close at different times (recall that space and time are
mixed) so that the stick sees the front gate close, then open,
then as the back of the stick clears the rear gate, the rear gate
closes. No paradox.
Your example involves gravity, which I'm going to suppose
complicates things. But as an equivalent example, suppose we
have a surface with a hole in it, moving at a constant speed
perpendicular to the path of the stick (ie, the "floor" is moving
at a constant speed up, but no gravity). In the frame of the
floor, things are pretty straightforward -- the stick manages to
"fall" through the hole.
In the frame of the stick, I would suggest that we would see the
floor as being at some angle to the path of the stick (again,
mixing of space and time), so that the stick moves through the
hole "at an angle", in effect. I would further suggest that, if
we used gravity instead of a moving floor, we would see a similar
effect.
-----------------------------------------------------------------
. . . Except when they don't,
Because sometimes they won't. - Dr. Seuss
-----------------------------------------------------------------
Jason Cooper jcooper@acs.ucalgary.ca
Nicolaas Vroom
Aug12-04, 08:30 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\n\n"jason cooper" <jcooper@acs4.acs.ucalgary.ca>\nschreef in bericht news:cd6qv6\\$k0l\\$1@news.ucalgary.ca...\n>\n>\n> Nicolaas Vroom (nicolaas.vroom@pandora.be) wrote:\n>\n> : Consider a one "rigid meter stick"\n> : and a floor with a one meter hole\n>\n> I\'ll take a crack at this.\n>\n> A common example (but not the same) is a meterstick and two gates\n> set a little less than a meter apart. We move the meterstick,\n> lengthwise, past these gates. In the frame of the gates, the\n> meterstick fits entirely between them at some point -- we close\n> the gates momentarily at that time. The "paradox" is that in its\n> own frame, the stick is never entirely between the gates, so this\n> can\'t happen.\n\nThat is not the "paradox" that is the question.\nThe question is if you close the gates simultaneous does the stick\nentirely fit within the gates.\nTo state it slightly different does the moving stick bump against\na closed gate ?\nAll within the rest frame i.e. the frame of the gates.\nIf length contraction is involved (assuming a large enough speed\nbecause the two gates are set a LITTLE LESS than a meter apart)\nIMO the answer is Yes.\nThe problem is how you perform this experiment.\nHow do you close the two gates simultaneous in the rest frame ?\n\nA much easier situation arises if near the gates there\nare two contacts and lamps and an observer at the middle\nbetween the two gates.\nAssume that the gates are one meter appart.\nThe only question you have two ask to the observer:\ndid you see two simultaneous signals Yes or Not\nwhen the back passed the back gate\nand the front passed the front gate.\nIf length contraction is involved IMO the answer is NO.\n\nYou can use that same observer to close the two gates\nsimultaneous, with some extra clocks all in the rest frame\nto perform the closing gates experiment (and if you know\nthe speed v of the back of the meterstick)\n\nHowever the moving barn gates paradox is here not so much\nthe issue,\nThe issue is can you use physical objects with non existing\nphysical properties in order to describe the physical reality\n(in order to find the laws of physics)\nIn this case can you use a RIGID meter stick,\nSee the original question raised by David Park 28/6/04\nIMO the answer is NO for rigid meter sticks.\n\nI do not know if this is true in general but if you do\nyou have to be very carefull.\n\nNicolaas Vroom\nhttp://users.pandora.be/nicvroom/\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>"jason cooper" <jcooper@acs4.acs.ucalgary.ca>
schreef in bericht news:cd6qv6$k0l$1@news.ucalgary.ca...
>
>
> Nicolaas Vroom (nicolaas.vroom@pandora.be) wrote:
>
> : Consider a one "rigid meter stick"
> : and a floor with a one meter hole
>
> I'll take a crack at this.
>
> A common example (but not the same) is a meterstick and two gates
> set a little less than a meter apart. We move the meterstick,
> lengthwise, past these gates. In the frame of the gates, the
> meterstick fits entirely between them at some point -- we close
> the gates momentarily at that time. The "paradox" is that in its
> own frame, the stick is never entirely between the gates, so this
> can't happen.
That is not the "paradox" that is the question.
The question is if you close the gates simultaneous does the stick
entirely fit within the gates.
To state it slightly different does the moving stick bump against
a closed gate ?
All within the rest frame i.e. the frame of the gates.
If length contraction is involved (assuming a large enough speed
because the two gates are set a LITTLE LESS than a meter apart)
IMO the answer is Yes.
The problem is how you perform this experiment.
How do you close the two gates simultaneous in the rest frame ?
A much easier situation arises if near the gates there
are two contacts and lamps and an observer at the middle
between the two gates.
Assume that the gates are one meter appart.
The only question you have two ask to the observer:
did you see two simultaneous signals Yes or Not
when the back passed the back gate
and the front passed the front gate.
If length contraction is involved IMO the answer is NO.
You can use that same observer to close the two gates
simultaneous, with some extra clocks all in the rest frame
to perform the closing gates experiment (and if you know
the speed v of the back of the meterstick)
However the moving barn gates paradox is here not so much
the issue,
The issue is can you use physical objects with non existing
physical properties in order to describe the physical reality
(in order to find the laws of physics)
In this case can you use a RIGID meter stick,
See the original question raised by David Park 28/6/04
IMO the answer is NO for rigid meter sticks.
I do not know if this is true in general but if you do
you have to be very carefull.
Nicolaas Vroom
http://users.pandora.be/nicvroom/
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