From: scerir (scerir@libero.it)
Date: Sun Aug 25 2002 - 05:06:07 MDT
Alejandro
> Hasn't this kind of thing been done?
There is an essential new reference book:
"Special Relativity and its Experimental
Foundation" by Yuan Zhong Zhang, World
Scientific (1996).
XII. Time Dilatation, Clock "paradox":
Four experimental types can be distinguished:
* One way experiments
* Experiments using the Moessbauer effect
* Round trip experiments using elementary particles
* Experiments with macroscopic clocks
A: One way experiments:
1. Muons: Rossi and Hoag, Physical Review 57,
p. 461 (1940) Rossi and Hall, Physical Review
59, p. 223 (1941) Lifetime measured at rest :
Rasetti, Physical Review 60, p. 198 (1941)
(first historical experiments)
2. Pions: Durbin, Loar and Havens, Physical
Review 88, p. 179 (1952)
3. D. Frisch and J. Smith, Measurement of the
Relativistic Time Dilation Using Mesons
Am. J. Phys. 31 (1963) 342. A good
interpretation was given by : Terell, Nuovo
Cimento 16 (1960) p. 457
B: Experiment using the Moessbauer effect: Pound
Rebka, Physics Review Letters 4, p. 274
Theoretical interpretation: Josephson, Physics
Review Letters 4, p. 341
C: Round trip experiments using elementary particles:
1. Older Experiments ( lower Gamma-Factor):
Farley et al., Nuovo Cimento Vol 45, p. 281
(1966) together with Farley et al., Nature 217,
p. 17 (1968), Nuovo Cimento 9A, p. 369 (1972)
2. Bailey et al., "Measurements of relativistic
time dilatation for positive and negative muons
in a circular orbit," Nature 268 (July 28, 1977)
p. 301. More details about this experiment can
be found in: Nuclear Physics B 150 p.1-79 (1979)
Measurement of the Muon lifetime at rest: Meyer
et al., Physical Review 132, p. 2693 Balandin et
al. JETP 40, p. 811 (1974) Bardin et al. Physics
Letters 137B, p. 135 (1984)
D: Experiments with macroscopic clocks:
1. Vessot, R.F.C. and Levine, M.W. 1979, "A Test
of the Equivalence Principle Using a Space-borne
Clock," Gel. Rel. Grav., 10, 181-204. Vessot,
R.F.C et.al., 1980, "Test of Relativistic
Gravitation with a Space borne Hydrogen Maser"
Phys. Rev. Lett. 45 2081-2084.
2. Haefele-Keating Experiment: Around-the-World
Atomic Clocks Proposal: J. Haefele, Nature 227
(1970), p. 270 Experiment: Science Vol. 177
p. 166 - 170 (1972) Here are the numbers from
he Haefele-Keating experiment:
DELTA T in nanoseconds
Eastward Westward
Clock 120 -57 277
Clock 361 -74 284
Clock 408 -55 266
Clock 447 -51 266
Predicted -40 +/-23 275 +/-21
Prediction means: Sum of GR effect + SR effect
With their "fit method" ( taking into account
the clock drifts) H&K get: East : -66 nsec West
: 205 nsec This agrees well with the average
values ( second method) of East : -59 +/- 10
nsec West : 273 +/- 7 nsec
3. 273 +/- 7 nsec 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
http://science.nasa.gov/headlines/y2002/08apr_atomicclock.htm
If all goes as planned, a laser-cooled clock
named PARCS will be installed on the ISS in late
2004 or 2005. Experts expect it to be the most
stable clock ever, keeping time within 1 second
every 300 million years (1 part in 10^16).
According to Einstein's theory of gravity and
space-time -- called "general relativity" --
clocks in strong gravity tick slower than clocks
in weak gravity. Because gravity is weaker on
the ISS than at Earth's surface, PARCS should
accumulate an extra second every 10,000 years
compared to clocks ticking on the planet
below. PARCS won't be there that long, but the
clock is so stable that it will reveal this
effect in less than one year. (Strayer notes
that clocks on GPS satellites experience this
relativistic phenomenon, too, and that onboard
systems must correct for it.)
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