Speed of Light & Time

[PrinceOfDragons]

Could someone supply links to experiments, or observable events that have been done/seen to prove time slows down faster you go?

[DJBruce]

One experiment has to do with the decay of muons as they speed through Earth's atmosphere. Here are two links that explain this.

 

http://en.wikipedia.org/wiki/Muon#Muon_decay

 

http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/muon.html

[iNow]

I wrote this post a while back. I'll recycle it here and hope you find it useful. Enjoy.

 

 

A more accurate version is known as the Hafele-Keating experiment.

 

http://en.wikipedia.org/wiki/Hafele-Keating_experiment

 

 

Here is a nice and quick video summary of that experiment:

 

 

 

 

One of the moderators here, swansont, is very well versed in the physics of time, and he is also a very good teacher. He wrote a post about this back in January, and you can learn A LOT by reading that. Here is the link:

 

http://blogs.scienceforums.net/swansont/archives/6

 

 

 

 

Here are a few studies supporting the idea:

 

Haefele and Keating, Nature 227 (1970), pg 270 (Proposal); Science Vol. 177 pg 166--170 (1972) (Experiment).

They flew atomic clocks on commercial airliners around the world in both directions, and compared the time elapsed on the airborne clocks with the time elapsed on an earthbound clock (USNO). Their eastbound clock lost 59 ns on the USNO clock; their westbound clock gained 273 ns; these agree with GR predictions to well within their experimental resolution and uncertainties (which total about 25 ns).

 

 

Vessot et al, "A Test of the Equivalence Principle Using a Space-borne Clock", Gel. Rel. Grav., 10, (1979) 181-204; "Test of Relativistic Gravitation with a Space borne Hydrogen Maser", Phys. Rev. Lett. 45 2081-2084.

They flew a hydrogen maser in a Scout rocket up into space and back (not recovered). Gravitational effects are important, as are the velocity effects of SR.

 

 

C. Alley, "Proper Time Experiments in Gravitational Fields with Atomic Clocks, Aircraft, and Laser Light Pulses," in Quantum Optics, Experimental Gravity, and Measurement Theory, eds. Pierre Meystre and Marlan O. Scully, Proceedings Conf. Bad Windsheim 1981, 1983 Plenum Press New York, ISBN 0-306-41354-X, p363-427.

They flew atomic clocks in airplanes which remained localized over Chesapeake Bay, and also which flew to Greenland and back.

 

 

Bailey et al., "Measurements of relativistic time dilatation for positive and negative muons in a circular orbit," Nature 268 (July 28, 1977) pg 301; Nuclear Physics B 150 pg 1-79 (1979).

They stored muons in a storage ring and measured their lifetime. When combined with measurements of the muon lifetime at rest this becomes a highly-relativistic twin scenario (v ~ 0.9994 c), for which the stored muons are the traveling twin and return to a given point in the lab every few microseconds.

 

 

Muon lifetime at rest:Meyer et al., Physical Review 132, pg 2693; Balandin et al. JETP 40, pg 811 (1974); Bardin et al. Physics Letters 137B, pg 135 (1984). Also a test of the clock hypotheses (below).

 

 

The Clock Hypothesis

The clock hypothesis states that the tick rate of a clock when measured in an inertial frame depends only upon its velocity relative to that frame, and is independent of its acceleration or higher derivatives. The experiment of Bailey et al referenced above stored muons in a magnetic storage ring and measured their lifetime. While being stored in the ring they were subject to a proper acceleration of approximately 1018 g (1 g = 9.8 m/s2). The observed agreement between the lifetime of the stored muons with that of muons with the same energy moving inertially confirms the clock hypothesis for accelerations of that magnitude.

 

 

Sherwin, "Some Recent Experimental Tests of the 'Clock Paradox'", Phys. Rev. 129 no. 1 (1960), p17.

He discusses some Moessbauer experiments that show that the rate of a clock is independent of acceleration (~1016 g) and depends only upon velocity.

 

 

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

 

 

 

 

 

 

And some other helpful videos:

 

 

http://youtube.com/watch?v=tpbGuuGosAY

 

http://www.youtube.com/watch?v=QTWv9WP56_s

[PrinceOfDragons]

Thank you both for the information.

[swansont]

MEASUREMENT OF THE RED SHIFT IN AN ACCELERATED SYSTEM

USING THE MOSSBAUER EFFECT IN Fe57

Phys. Rev. Lett 4, 165-166 (1960)

H. J. Hay, J. P. Schiffer, T. E. Cranshaw, and P. A. Egelstaff

 

and

 

Measurement of Relativistic Time Dilatation using the Mössbauer Effect

Nature 198, 1186 - 1187 (22 June 1963); doi:10.1038/1981186b0

D. C. Chambeney, G. R. Isaak & A. M. Khan

 

They used a centrifuge and measured the frequency shift of the target away from resonance as it spun faster

[PrinceOfDragons]

Thanks Swansont.

 

I am currently thinking of the way to put my next question Ill post back after I get it. and I found this time dilation Calculator and I was wondering is it accurate?