Particle Lifetime in Gravity: Experimental Evidence?

[Xilor]

Hello, I was wondering if the particle lifetimes as measured by observers increases in gravitational heavier areas. Relativity seems to suggest this, and there seems to be little criticism of this concept but I couldn't find any experimental evidence supporting this. Has this ever been shown? Or are the differences simply too small?

 

[PatrickPowers]

Hello, I was wondering if the particle lifetimes as measured by observers increases in gravitational heavier areas. Relativity seems to suggest this, and there seems to be little criticism of this concept but I couldn't find any experimental evidence supporting this. Has this ever been shown? Or are the differences simply too small?

It has been shown with the muon, which at rest has a decay time of a little over two microseconds. This was extended by a large factor, four or something like that.

 

[Xilor]

It has been shown with the muon, which at rest has a decay time of a little over two microseconds. This was extended by a large factor, four or something like that.

As far as I'm aware this has only been concluded based on the difference in time dillations from special relativity between moving muons and muons at rest. Not a difference due to gravitational time dilation as predicted by general relativity.

 

[jtbell]

I don't remember reading of any experiments that show different particle lifetimes in different gravitational potentials, but there are experiments that show gravitational time dilation by other means, e.g. the classic Pound-Rebka experiment:

http://en.wikipedia.org/wiki/Pound–Rebka_experiment

 

[Xilor]

Alright, thank you. What about gravitational length contraction? Has that been tested directly somehow? Or has it just been derived from c being the same for observers within different areas of gravitational potential?

 

[Dale]

I don't think that gravitational length contraction is even a well-defined or commonly-accepted term.

 

[Xilor]

I don't think that gravitational length contraction is even a well-defined or commonly-accepted term.

Well that would then explain why that never made made too much sense to me.. Is there anything that can be said about it, what it actually means and if it's predicted? I assumed it would be some side effect of the warping of spacetime, as warps occur increasing the lengths of paths, so would apparent lengths of objects contract because their sizes as compared to distances within the area are smaller.

 

[Dale]

Is there anything that can be said about it, what it actually means and if it's predicted?

Well, what it actually means (or in other words, a definition of gravitational length contraction) would have to be the first step. Once it was defined clearly then you could check if it were predicted and propose experiments to test it. I don't know of any rigorous definition.