Experimental support for SR & GR

[Chi Meson]

I would like to create (with everyone's help) a list of experiments etc that support SR and GR.

These should be reproducable experiments, or profound predictions that have been upheld, as well as objects/systems that use SR/GR calculations on an everyday basis.

I would predict that such a list could get lengthy, so hopefully just a description of the "experiment" and maybe a web page that shows data would be most appreciated.

If this thread takes off, I'll be maintaining the list starting with the second post.

 

[Simon666]

No doubt the perihelion shift of Mercurius will get named, but a German schoolteacher named Paul Gerber reached the same result years before Einstein using Newtonian physics and the assumption the propagation speed of gravity is not infinite. Just a note.

 

[quartodeciman]

some older resources online:

Relativity FAQ - What is the experimental basis of the Special Relativity Theory? --->
http://www.weburbia.demon.co.uk/physics/experiments.html

Living Review: The Confrontation between General Relativity and Experiment --->
http://relativity.livingreviews.org/Articles/lrr-2001-4/

 

[russ_watters]

Can't forget my personal favorite: http://www-astronomy.mps.ohio-state.edu/~pogge/Ast162/Unit5/gps.html .

Relativity is not just some abstract mathematical theory: understanding it is absolutely essential for our global navigation system to work properly!

Besides being a device that depends on Relativity, experiments can be conducted using it as a tool.

 

[turin]

Particle accelerators come to mind.

No doubt the perihelion shift of Mercurius will get named, but a German schoolteacher named Paul Gerber reached the same result years before Einstein using Newtonian physics and the assumption the propagation speed of gravity is not infinite. Just a note.

I would like to read about this. Do you have a reference or webpage?

 

[robphy]

I would like to read about this. Do you have a reference or webpage?

By Googling, I found this on Gerber
"Gerber's Gravity" (Kevin Brown)
http://www.mathpages.com/home/kmath527/kmath527.htm
and
(if you have access)
"A simple approach to the experimental consequences of general relativity"
(Peter Rowlands) Phys. Educ. 32 (January 1997) 49-55
http://www.iop.org/EJ/abstract/0031-9120/32/1/020
[which cites
Roseveare N T 1982 Mercury’s Perihelion from
Le Verrier to Einstein (Oxford: Clarendon) pp 137–44]

I haven't read any of these carefully yet.

 

[robphy]

More resources
http://www.itp.ucsb.edu/online/colloq/damour1/
http://wugrav.wustl.edu/people/CMW/tegp.html
http://xxx.lanl.gov/abs/astro-ph/9701032
http://xxx.lanl.gov/abs/gr-qc/9612039
http://xxx.lanl.gov/abs/gr-qc/9508043
http://archive.ncsa.uiuc.edu/Cyberia/NumRel/EinsteinTest.html
http://einstein.stanford.edu/
http://www.npl.washington.edu/eotwash/
http://www.ift.unesp.br/users/matsas/p41.html
http://relativity.livingreviews.org/Articles/lrr-2003-1/

 

[chroot]

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

 

[Simon666]

I would like to read about this. Do you have a reference or webpage?

http://www.energyscience.co.uk/le/le02app.htm

 

[Janitor]

If Thomas precession was not already included above-

http://www.mathpages.com/rr/s2-11/2-11.htm

 

[Chronos]

question: what propagation speed of gravity explains the perhelion shift of mercury? and how does it compare to the speed of light? this could be important.

 

[Chi Meson]

Thanks everyone so far. So far it's been mostly a list of many lists, but I am going through the sites one by one. I'm compiling a nice reference list which I will post here when it's in a coherent form.

So far, the effect I like the most is the "transverse Doppler effect." This is mentioned in the site offered by Chroot.

Do keep them coming folks. Thanks again.

 

[Chi Meson]

OK. I'm looking for a website reference that has data/discussion about the increase of the B-field required to hold a relativistic proton in a circular path (e.g. as required at CERN). I've tried a few googles, but I'm getting overwhelmed by articles that are a little too arcane/advanced. Anyone got something on this?

 

[ZapperZ]

Actually, do you only want references with complete web access, or are you also collecting journal citations?

Zz.

 

[Chi Meson]

Journals are fine, but the level of difficulty should be so that a BS physicist could follow, so some PhD level papers are "too much." I don't need each and every support of SR/GR. This list was originally intended as a starting point for my AP student's final projects (and the project is to be "paperless").

Ideally, what I'm putting together will be a list in which:

...a brief paragraph description of prediction/result/experiment that supports SR and/or GR, followed by one or two websites that contains some or most of the specific results from that experiment. It does not have to contain all of the data, but should contain a deeper description of the set-up, and significant, conclusive data.

FOr example, I've got two good sites for the Sagnac effect:
http://citebase.eprints.org/cgi-bin/citations?id=oai:arXiv.org:gr-qc/0305084
http://www.mathpages.com/rr/s2-07/2-07.htm

I'm right now looking for a site that deals with the Haefele-Keating (atomic Clocks) experiment. There are lots of sites that mention it, and some that provide the final "delta t's", but I can't get one that goes into specifics of the equations used and preditictions made.

BTW, I'm not expecting you folks to write the paragraphs; I'm just hoping to get tuned into experiments I hadn't heard of. So far It's going well. I'll attach a draft here probably next week.

 

[meteor]

I'd like to add the COW experiment, performed in 1975; it demonstrates the equivalence of inertial mass and gravitational mass at the quantum level.

 

[Chi Meson]

Could I have more information on this experiment? I googled "COW experiment" and the closest thing I got was a Cesium/barium radioactivity college lab outline.

 

[Chi Meson]

Here's how it looks so far. I've attached the document as an MS Word file. Our system has up-to-the-minute virus protection, so you shouldn't have to worry about any bugs, but play it safe anyway.

 

[turin]

I don't follow what you mean by "COW," (is that an acronym?). If you mean the word "cow," then the column of Cs resin in the radioactivity experiment is called a "cow" and the extraction of the metastable Ba (into which the Cs decays) is called "milking the cow." The extraction is performed by titrating an ionic solution that reacts with Ba but not with Cs. My experience with this experiment is that the solution does not do its job (i.e. you get excessive amounts of Cs in your sample).

 

[Creator]

Chi Meson and Turin. The "COW" experiment is short for Collela, Overhauser and Werner, who were the authors of a notable experiment (in the 1970's I believe). However, it wasn't about proving equivalence principle.

It was a neutron diffraction experiment that showed conclusively that the relative phase of the neutron wavefunction is altered by the presence of a gravitational field.
It was the first indication of how gravity affects a particle on a quantum level.

Creator

 

[Chi Meson]

Thank you Creator.

BTW, good job with trees and stuff (or was that you?)

 

[Creator]

Thank you Creator.

BTW, good job with trees and stuff (or was that you?)

Yep, ... trees, animals, people,...the whole ball of wax.
Glad you like it...

 

[Nereid]

question: what propagation speed of gravity explains the perhelion shift of mercury? and how does it compare to the speed of light? this could be important.

I think 'the speed of gravity' is 'c' in GR (hard-coded, not an input parameter), so any experimental result consistent with GR is also support for 'speed of gravity = c'. Putting aside GR, how would you go about testing the difference between the speed of gravity and c, even in principle?

 

[loseyourname]

One example that routinely comes up in particle accelerators is the increased half-life of particles moving near c. Take the \mu-meson, which has a resting half-life of 1.87 x 10^-6s. At a speed of 0.95c, the half-life is measured at 6.00 x 10^-6s. This is in accordance with the Lorentz transformation for time dilation,
\Delta t' = \frac{\Delta t_{0}}{\sqrt{1 - (v^2/c^2)}},
confirming that aspect of SR. A little like the GPS, I don't think this was ever done as an experiment with the intent to confirm SR, but the measured quantities do behave in accordance with the theory.

 

[zefram_c]

Don't forget all the high precision measurements in Quantum Electrodynamics, which incorporates SR as a building block.

 

[DW]

Don't forget all the high precision measurements in Quantum Electrodynamics, which incorporates SR as a building block.

I think its spelled Zephram. Don't you think, Mr. Cochrane?

 

[zefram_c]

You know, I've seen both spellings. There seems to be some disagreement within the community as to whether the spelling is invariant in all reference frames, or whether it is permitted to depend on the book/episode/movie you choose to refer to.

 

[DW]

You know, I've seen both spellings. There seems to be some disagreement within the community as to whether the spelling is invariant in all reference frames, or whether it is permitted to depend on the book/episode/movie you choose to refer to.

I guess so. In a google search I get 1650 hits for "zephram cochrane", 415 for "zephram cochran", 482 for "zefram cochran", and 6540 for "zefram cochrane" so I guess your spelling is the most common.

 

[zefram_c]

Wow. Only that few (<10,000 total) ? Somehow I expected more. In any event, my main concern was to bring this thread back to plain sight... it seems its usefulness has not yet expired.

In fact, there is an even better experimental support, and once again it comes from QFT (ie SR+QM+fields). This involves the test of the CPT theorem, which requires that particles and antiparticles have the same mass. This can be measured to very high precision in the neutral kaon system with CP violation. The current experimental status restricts any mass difference between the K₀ and its antiparticle, normalized to the K₀ mass, to less than one part in 10¹⁸... if that's not convincing enough I don't know what is.