Gravitation of subatomic particles

vernonner3voltazim

<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>Some people seem to think that Gravitation only\nhappens between large groups of particles, and\nnot between individual particles. Have any\nexperiments actually measured gravitational\nacceleration of single particles?\n\nIf not, then how about this:\nStart with two of those special magnetic-field\ndevices that can trap neutrons. Fill one and\nplace it at altitude. Put the empty one below\nit. Turn off the upper trap. The time it\ntakes for any neutrons to end up in the lower\ntrap will depend on their initial speed (we\nknow that, right?) and gravitational\nacceleration. IF they are affected by that,\nof course. I think they will. For those\nwho think otherwise, could this experiment\nrefute them with proof?\n\nThanks!\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>Some people seem to think that Gravitation only
happens between large groups of particles, and
not between individual particles. Have any
experiments actually measured gravitational
acceleration of single particles?

If not, then how about this:
Start with two of those special magnetic-field
devices that can trap neutrons. Fill one and
place it at altitude. Put the empty one below
it. Turn off the upper trap. The time it
takes for any neutrons to end up in the lower
trap will depend on their initial speed (we
know that, right?) and gravitational
acceleration. IF they are affected by that,
of course. I think they will. For those
who think otherwise, could this experiment
refute them with proof?

Thanks!

Michael 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>"vernonner3voltazim" <vnemitz@pinn.net> wrote in message\nnews:42336979.0406250620.11b2526a@posting.google.com...\n> Some people seem to think that Gravitation only\n> happens between large groups of particles, and\n> not between individual particles. Have any\n> experiments actually measured gravitational\n> acceleration of single particles?\n>\n> If not, then how about this:\n> Start with two of those special magnetic-field\n> devices that can trap neutrons. Fill one and\n> place it at altitude. Put the empty one below\n> it. Turn off the upper trap. The time it\n> takes for any neutrons to end up in the lower\n> trap will depend on their initial speed (we\n> know that, right?) and gravitational\n> acceleration. IF they are affected by that,\n> of course. I think they will. For those\n> who think otherwise, could this experiment\n> refute them with proof?\n\nWhen proposing such an experiment, it helps to do some back of the envelope\ncalculations, and to know a bit more physics.\n\nFor the second suggestion:\nRead up on quantum mechanics and then think about the difficulty in\nmeasuring the position and velocity of the neutrons simultaneously. That is\na fundamental source of uncertainty in your measurements.\n\nFor the back of the envelope:\nNext, figure out the differential force of attraction between a neutron and\nthe earth and a neutron and a neutron plus the earth. This is not so hard\nas it sounds.\n\nTwo simple models to propose:\n\n1: f = mMG/r^2 Force between small mass m (neutron) and that of the earth\n(M).\nF = m(M+m)G/r^2 Force between small mass m (Neutron) and that of the earth\nwith an extra neutron at its center.\n\n2. Exercise left to the reader. How would you apply linear superposition\nof forces to find the relationship between the force between neutron 10\nmeters above the earth ,and the earth plus a neutron 1 meter above the\nsurface of the earth?\n\n3. Here is a subtle question: Is there an easier method of finding this\nout than what I proposed above? :-)\n\n\nNow compare the change in velocity from that force dependence and the error\nintrinsic in the quantum mechanical uncertainty principle and see which is\ngreater.\n\nThen you have to consider the technical problems. How do you make and trap\nsingle neutrons? You have to make your measurements quickly because the\nneutron has a high probability of decaying into a proton, an electron and an\nelectron-neutrino within about 15 min. How will this decay effect your\napparatus and its detectors.\n\nGoodness!\n\nOf course, this does not mean that an experiment to measure the force of\ngravity between two particles is impossible... but you have to constrain\nyour proposals within the bounds of 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>"vernonner3voltazim" <vnemitz@pinn.net> wrote in message
news:42336979.0406250620.11b2526a@posting.google.com...
> Some people seem to think that Gravitation only
> happens between large groups of particles, and
> not between individual particles. Have any
> experiments actually measured gravitational
> acceleration of single particles?
>
> If not, then how about this:
> Start with two of those special magnetic-field
> devices that can trap neutrons. Fill one and
> place it at altitude. Put the empty one below
> it. Turn off the upper trap. The time it
> takes for any neutrons to end up in the lower
> trap will depend on their initial speed (we
> know that, right?) and gravitational
> acceleration. IF they are affected by that,
> of course. I think they will. For those
> who think otherwise, could this experiment
> refute them with proof?

When proposing such an experiment, it helps to do some back of the envelope
calculations, and to know a bit more physics.

For the second suggestion:
Read up on quantum mechanics and then think about the difficulty in
measuring the position and velocity of the neutrons simultaneously. That is
a fundamental source of uncertainty in your measurements.

For the back of the envelope:
Next, figure out the differential force of attraction between a neutron and
the earth and a neutron and a neutron plus the earth. This is not so hard
as it sounds.

Two simple models to propose:

1: [itex]f = mMG/r^2[/itex] Force between small mass m (neutron) and that of the earth
(M).
[itex]F = m(M+m)G/r^2[/itex] Force between small mass m (Neutron) and that of the earth
with an extra neutron at its center.

2. Exercise left to the reader. How would you apply linear superposition
of forces to find the relationship between the force between neutron 10
meters above the earth ,and the earth plus a neutron 1 meter above the
surface of the earth?

3. Here is a subtle question: Is there an easier method of finding this
out than what I proposed above? :-)

Now compare the change in velocity from that force dependence and the error
intrinsic in the quantum mechanical uncertainty principle and see which is
greater.

Then you have to consider the technical problems. How do you make and trap
single neutrons? You have to make your measurements quickly because the
neutron has a high probability of decaying into a proton, an electron and an
electron-neutrino within about 15 min. How will this decay effect your
apparatus and its detectors.

Goodness!

Of course, this does not mean that an experiment to measure the force of
gravity between two particles is impossible... but you have to constrain
your proposals within the bounds of physics.

Patrick Van Esch

<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>vnemitz@pinn.net (vernonner3voltazim) wrote in message news:<42336979.0406250620.11b2526a@posting.google.com>...\n> Some people seem to think that Gravitation only\n> happens between large groups of particles, and\n> not between individual particles. Have any\n> experiments actually measured gravitational\n> acceleration of single particles?\n\nHave a look at:\n\nNesvizhevsky V.V., Boerner H.G., Petukhov A.K., Abele H.,\nBaessler S., Ruess F.J., Stoeferle T., Westphal A., Gagarski A.M.,\nPetrov G.A., Strelkov A.V. - Quantum states of neutrons in the\nearth\'s gravitational field\nNature Vol. 415 pp. 297-299, 2002\nCode Number: ILL02NE146\nSubject: NUCLEAR AND PARTICLE PHYSICS\nInstrument used at the ILL: PN3 gamma-ray spectrometer\n\ncheers,\nPatrick.\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>vnemitz@pinn.net (vernonner3voltazim) wrote in message news:<42336979.0406250620.11b2526a@p...google.com>...
> Some people seem to think that Gravitation only
> happens between large groups of particles, and
> not between individual particles. Have any
> experiments actually measured gravitational
> acceleration of single particles?

Have a look at:

Nesvizhevsky V.V., Boerner H.G., Petukhov A.K., Abele H.,
Baessler S., Ruess F.J., Stoeferle T., Westphal A., Gagarski A.M.,
Petrov G.A., Strelkov A.V. - Quantum states of neutrons in the
earth's gravitational field
Nature Vol. 415 pp[itex]. 297-299,[/itex] 2002
Code Number: ILL02NE146
Subject: NUCLEAR AND PARTICLE PHYSICS
Instrument used at the ILL: PN3 [itex]\gamma-ray[/itex] spectrometer

cheers,
Patrick.

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