Quote:
Originally Posted by bunny
I'm afraid I don't have access to all internet sites at the work I'm at (though strangely they accepted a poker site as 'acceptable'  ) and I'm unfamiliar with this experiment.
It sounds to me though that it's a test of general relativity not special relativity - both since the clocks are presumably brought back and stood next to each other (requiring acceleration after the 'fly past' moment) but also because it is within a gravitational field. As I say though - I'm not really clear as to what happened and whether you're speaking of a real-world experiment or a thought experiment (in the real world, I dont think you'll ever really account for what we observe without using general relativity which is not so amenable to hand-wavy arguments).
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I said in an earlier post there is a gravitational effect in the experiment, but it's taken as a confirmation of SR and there is also a velocity effect.
http://en.wikipedia.org/wiki/Hafele%...ing_experiment
Hafele–Keating experiment
From Wikipedia, the free encyclopedia
The Hafele–Keating experiment was a test of the theory of relativity. In October of 1971, Joseph C. Hafele and Richard E. Keating took four cesium-beam atomic clocks aboard commercial airliners and flew twice around the world, first eastward, then westward, and compared the clocks against those of the United States Naval Observatory.
According to special relativity, the rate of a clock is greatest according to an observer who is at rest with respect to the clock. In a frame of reference in which the clock is not at rest, the clock runs slower, and the effect is proportional to the square of the velocity. In a frame of reference at rest with respect to the center of the earth, the clock aboard the plane moving eastward, in the direction of the Earth's rotation, is moving faster than a clock that remains on the ground, while the clock aboard the plane moving westward, against the Earth's rotation, is moving slower.
According to general relativity, another effect comes into play: the slight increase in gravitational potential due to altitude that speeds the clocks back up. Since the aircraft are flying at roughly the same altitude in both directions, this effect is more "constant" between the two clocks, but nevertheless it causes a difference in comparison to the clock on the ground.
The results were published in Science in 1972:[1][2]
nanoseconds gained
predicted measured
gravitational
(general relativity) kinematic
(special relativity) total
eastward 144±14 −184 ± 18 −40 ± 23 −59 ± 10
westward 179±18 96±10 275±21 273±7
The published outcome of the experiment was consistent with special relativity. The observed time gains and losses were different from zero to a high degree of confidence, and were in agreement with relativistic predictions to within the ~10% precision of the experiment. The results were verified in an improved experiment in 1976 by the University of Maryland, this time verifying the relativistic predictions to a precision of about 1%.[3] A reenactment of the original experiment took place on the 25th anniversary of the original experiment, using more precise atomic clocks, and the results were verified to a higher degree of accuracy.[4] Nowadays such relativistic effects are, for example, routinely incorporated into the calculations used for the Global Positioning System.[5]
Because the experiment was reproduced by increasingly accurate methods, there has been a consensus among physicists since at least the 1970s that the relativistic predictions of gravitational and kinematic effects on time have been conclusively verified.[6] A few authors who dispute the validity of the theory of relativity have questioned the experiment: in a 1996 paper A. G. Kelly argued that the final published outcome had to be averaged in a biased way in order to claim such a high precision,[7] and Louis Essen, the inventor of the atomic clock, published a one-page criticism of the experiment in a creationist journal in 1977,[8] and also briefly discussed the experiment in a paragraph of his 1988 article RELATIVITY - joke or swindle? where he argued that "All the experiment showed was that the clocks were not sufficiently accurate to detect the small effect predicted".[9] However, neither Kelly's monograph nor Essen's 1988 article were peer reviewed (Essen's 1977 article was in a journal peer reviewed by creationist scientists,[10] but 'creation science' is viewed as pseudoscience by the mainstream scientific community[11]), both were written by authors who hold fringe views about the theory of relativity being fundamentally flawed,[12] and neither casts doubt on the verifications of the result by more precise methods as early as 1976. The physicist Tom Roberts and Siegmar Schleif also comment on Kelly's paper in What is the experimental basis of Special Relativity?, saying:
His criticism does not stand up, as he does not understand the properties of the atomic clocks and the way the four clocks were reduced to a single “paper” clock. The simple averages he advocates are not nearly as accurate as the paper clock used in the final paper—that was the whole point of flying four clocks (they call this “correlated rate change”; this technique is used by all standards organizations today to minimize the deficiencies of atomic clocks).
Total time dilation
Τ = Δτv + Δτg + Δτs
Velocity
\Delta\tau_v = - \frac{1}{2c^2} \sum_{i=1}^{k}v_i^2 \Delta\tau_i
Gravitation
\Delta\tau_g = \frac{g}{c^2} \sum_{i=1}^{k} (h_i - h_0) \Delta\tau_i
Sagnac effect
\Delta\tau_s = - \frac{\omega}{c^2} \sum_{i=1}^{k} R_i^2 \cos^2 \phi_i \Delta\lambda_i
Where h = height, v = velocity, ω = Earth's rotation and τ represents the duration/distance of a section of the flight. The effects are summed over the entire flight, since the parameters will change with time.
[edit] References
1. ^ Hafele, J.; Keating, R. (July 14, 1972). "Around the world atomic clocks

redicted relativistic time gains". Science 177 (4044): 166–168. doi:10.1126/science.177.4044.166. PMID 17779917.
http://www.sciencemag.org/cgi/conten...t/177/4044/166. Retrieved 2006-09-18.
2. ^ Hafele, J.; Keating, R. (July 14, 1972). "Around the world atomic clocks

bserved relativistic time gains". Science 177 (4044): 168–170. doi:10.1126/science.177.4044.168. PMID 17779918.
http://www.sciencemag.org/cgi/conten...t/177/4044/168. Retrieved 2006-09-18.
3. ^ Wolfgang Rindler, Essential Relativity: Special, General, and Cosmological, Springer-Verlag, 1979, p. 45
4. ^ Metromnia Issue 18 - Spring 2005
5. ^ Deines, "Uncompensated relativity effects for a ground-based GPSA receiver", Position Location and Navigation Symposium, 1992. Record. '500 Years After Columbus - Navigation Challenges of Tomorrow'. IEEE PLANS '92.
6. ^ Wolfgang Rindler, Essential Relativity: Special, General, and Cosmological, Springer-Verlag, 1979, p. 45
7. ^ A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9
8. ^ Essen, L. (1977) "Atomic Clocks - Coming and Going", Creation Research Society Quarterly 14, p. 64.
9. ^ Louis Essen (1988) "Relativity - Joke or Swindle?", Electronics and Wireless World 94, 126 - 127
10. ^ see
http://www.creationresearch.org/crsq.html
11. ^ "Statements from Scientific and Scholarly Organizations". National Center for Science Education.
http://ncse.com/media/voices/science. Retrieved 2008-08-28.
12. ^ see this paper by A. G. Kelly where he argues that the speed of light is not independent of the source as relativity predicts, and Louis Essen's book The Special Theory of Relativity: A Critical Analysis