In the Hafele-keating experiment, the atomic clock is used to detect the relativistic time effect. We know, the atomic clock is the very accurate device. A little action by the surroundings, such as that a person is walking to it, can disturb this atomic clock. As an atomic clock in an airplane, this airplane is vibrating, shaking and jittering. Why the atomic clock in the airplane in the Hafele-keating experiment was not disturbed?
well a person walking by an atomic clock kept in a lab will have an effect on the clock reading as the lab is stationary environment and thus, even a little disturbance will change that environment. Now inside the plane, the plane is already moving, therefore relatively the vibrations, shaking, jittering might have a very little effect on the clock reading as the whole system is in motion now. Hence we can say that the results given by Hafele-Keating experiment are legit and credible.
Hope it helps.
A more complex and precise experiment of this kind was performed by a research group of the University of Maryland between September 1975 and January 1976. Three atomic clocks were taken to an altitude of 10 km. Special containers protected the clocks from external influences such as vibrations, magnetic fields, or temperature variations. The overall difference agreed with the relativistic predictions to a precision of +/- 1.6%.
If similar care was taken during the Hafale-Keating experiment, we can rely on the results.
"Tthe experiment had been a total failure due to the erratic behavior of the clocks...
The upshot is that the 'data' presented by Hafele and Keating are an embarrassment for science." ...
http://thescientificworldview.blogspot.com/2011/02/time-dilation-and-hafele-and-keating.html
The experiment is credible since the same results are obtained every day with atomic clocks which nowadays can detect heights of 10 cm in a gravitational potential.
Dear Dr. Stefano Quattrini,
It is noted that there are two different questions:
First: Is the Hafele-keating experiment credible?
Second: Are there some kinds of gravitational effect on an atomic clock.
No one doubts that there are some kinds of gravitational effect on an atomic clock.
But, some of these gravitational effects are being argued. Please see:
Hohensee M A, Chu S, Peters A, et al. Comment on:‘Does an atom interferometer test the gravitational redshift at the Compton frequency?’，Classical and Quantum Gravity, 2012, 29(4): 048001.
The link mentioned by Radwan M Kassir is a ``popularisation'' link and shows basic ignorance of the most elementary tenets of relativity. Thus the author does not even understand why the eastound flight shows clocks running slow and the westbound flight shows them running fast. Until I see a criticism made by someone who understands the issues, I shall believe the Hafele Keating experiment. The fact that other experiments, especially with optical clocks, could obtain the relativistic results for small speeds gives additional confidence.
The following link provides criticism that seems to comprise the “skipped” details in the previous one:
http://debunkingrelativity.com/twin-flight-experiment/
Reading the Hafele-Keating article provides some answers to your question: 4 clocks were carried in each flight, both westward and eastward. If random effects caused by someone walking by, por by vibration, had had any effect, we would expect the four clocks at the end of the flight to show readings which siginificantly differed from each other. Also, the clock readings were initially and finally compared with standard time. If the airplane vibration, say, had affected the clock readings, major differences would be expected when one compares the clock reading with standard time at the end of the flight. This is not the case. To be specific, the only variation observed was of the magnitude and qualitative nature expected from relativity.
It is important to realize, however, that the Hafele-keating experiment is by no means the only test of time-dilation. Its remarkable beauty comes from being done at ``normal'' velocities. The Wikipedia article on time dilation will show that there are a large number of similar experiments with results consistent with relativity. An extremely striking one involves highly accurate optical clocks, which detect the time dilation caused by motions with velocities of the order of 10 m/sec.
Finally, one should emphasize that there is no single experiment a ``relativity debunker'' can attack. There are, over all, I would guess, hundreds. Further, no one so far has made a reproducible experiment that actually would conflict with relativity, and would confirm what some people might call ``common sense''. So physicists should presumably leave the debunkers to their metaphysics, and stick to their job, which is describing reality as it is.
You can find a detailed analysis of the Hafele-Keating experiment (on the Phys. graduate and senior undergrad. level) in my book "Special Relativity and How It Works", Wiley-VCH, 2008 (Sec. 8.2 (Ch.8)). Of course, the atomic clocks, as any measuring device, even with all precautions made, are subjected to experimental errors. The final conclusions can be made only with the account taken of these errors, after their appropriate statistical treatment (taking the average of many trials, evaluating the standard deviation etc.) In the given case, the small random disturbances such as vibrations etc., affect statistically equally all the clocks involved, and can be accounted for. The final results distilled of all possible errors reflect relativity of time (time dilation in a moving system, gravitational red shift etc.) and show good agreement with theoretical predictions.
Worth reading:
http://www.conspiracyoflight.com/Hafele/HafeleKeating.html
Ladies and gentlemen,
Please return to my question:Is the Hafele-keating experiment credible?
We know, the Newtonian gravitational force has an effect on the atomic clock: The variation of the altitude at the level less than 10cm can be detected with the atomic clock. This effect is much larger than the Einstein’s gravitational effect on the atomic clock.
Why the Newtonian gravitational effect on the atomic clock has not been observed in the Hafele-keating experiment?
Dear Yin Zhu: there seems to be a misunderstanding. Newtonian gravity has no effect whatever on atomic clocks. These work by monitoring the behaviour of an atomic hyperfine transition, which is quite unaffected by gravity, except to the extent that gravity affects space-time, which is the Einsteinian effect. Whoever said that variations in altitude of 10 cm were detected by atomic clocks, meant the *Einsteinian effect*. In the Hafele-Keating experiment, both time dilation and the Einsteinian gravity effect are measured. Reading the Hafele-Keating paper might resolve some of your doubts.
Dear F. Leyvraz,
It is noted that, first, variations in altitude of 10 cm cannot be detected with the *Einsteinian effect*. Second, the atomic interferometer was used to detect the Newtonian universal gravitational constant, G. In it the gravitational force F=GMm/R^2 between an atom and a mass of 500kg can be detected.
http://www.alternativephysics.org/book/GPSmythology.htm
"The presence of Special and General Relativity effects has no bearing on the accuracy of GPS operation. In summary, it wouldn’t matter whether clocks aboard GPS satellites ran faster or slower than Earth’s clocks or even changed their speed each day. Just so long as the satellites’ clocks remained synchronised with each other and the time-difference relative Earth’s clocks didn’t become too large, GPS receivers would continue to calculate their correct position.
The GPS is certainly an excellent navigational aid. But from an operational viewpoint at least, it doesn’t serve as a test for Relativity. Scientists should stop calling it that."
If we ignore the time effect of change in gravity potential (let us assume for a moment that the journeys and clock comparisons are done at constant potential), then the H&K result is a gain in clock time going westward 96 ns, and a contraction in clock time going eastward -184 ns.
Then why this gain in time going westward compared to the frame of rest (centre of earth) which was used as the inertial frame.
The spurious explanation is that going westward is slower speed because of the Earth’s rotation, but why does this matter? Speed is relative in Relativity Theory. The H&K experiment is about the “locked in” time dilation test, not time dilation per se.
For the “locked in” time dilation, the distinction is between A an inertial frame, and B a travelling frame subject to start/stop accelerations. Hence there should not be any gain in clock time for the travelling frame B. https://www.researchgate.net/publication/304582871_Unwinding_the_Relativistic_Time_-_print
Deleted research item The research item mentioned here has been deleted
@ Andersen: The problem is that neither the Earthbound frame nor the airplane frames are inertial. Hence the need to compare everything to an inertial frame, namely the frame that follows Earth but does not rotate with it. There is thus nothing spurious about this justification. It is what relativity predicts and experiment confirms.
The comment by Robert Low explains it all in greater detail.
@Leyvraz: Thanks for reply. I admit that I need to understand a bit more about the exact details of H&K. I'm surprised that H&K don't refer their results to an assumed inertial frame. Relativistic time dilation and the Theory of Relativity is reality; this is not the issue. But the interesting question is how it works and what it predicts. For my research, I try to distinguish between local time dilation (which is symmetric BTW) and "locked-in" time dilation (asymmetric), as e.g. the twin paradox. How nice it would be if H&K had referred their results directly to the assumed inertial frame.
@ Andersen: read the paper (the first one, in which they make the predictions: Science,New Series, Vol. 177, No. 4044 (Jul. 14, 1972), pp. 166-168). They do refer immediately to an inertial frame, namely the frame which rotates around the sun with the Earth, but moves with the Earth's center. This is, of course, not quite an inertial frame, but the deviations are insignificant, since the experiments only took a few days, which is a small part of one year. Further, this frame is in free fall, so in fact the General Theory of Relativity guarantees that we may neglect non-inertiality.
The results of Hafele-Keating experiment are completely credible. Moreover, they show that GR is applicable for studies of the structure of time. As follows from the theory of physically observed values, the temp of the observed time (T) depends on the gravitational potential (w) and the 3-velocity (vi) of rotation of the reference body: dT = (1 - w/c2)dt - viui/c2, t is the ideal time (flows uniformly). The results of H-F were proved in USSR during 1980 and later: it was shown that the dates of transporting (flying) and resting clocks are different. Calculations of corrections by means of the formula for dT show that theoretical and experimental dates coincide completely. Moreover, calculations show that the corrections, which are due to the rotation of the Earth, depend not only on the time of travel but and on the direction of airplane (to or against of the axial rotation of the Earth). The value of this correction is exactly 208 ns: it is positive (added if airplane flies in the axial direction) and is negative by the opposite direction. The H-K exeriments can be the initial point of applying of GR as the theory of the time. It is necessary to accept as the fact: GR can be not only the theory of small corrections. It is applicable for studies of strong gravitational fields (w = c2) as at the surface of non-rotating black hole) and in the case of the rotation with the sub-light (and light) velocity.
Dear Dr. Larissa,
The question is: in a shocking and vbrating plane, what can be measured with a accruate and precise atomic clock? If nothing cannot be measured under such condition, why the Hafele-Keating experiment is credible?
Please note: " A little action by the surroundings, such as that a person is walking to it, can disturb this atomic clock. "
In addition, do you know what is the effect that the gravity on the atoms in an atomic clock?
@Zhu: 'Please note: " A little action by the surroundings, such as that a person is walking to it, can disturb this atomic clock. "'
I think this is simply wrong. Otherwise atomic clocks could not serve their purpose of high-precision measurement of time. The engineers that build them are not stupid.
But even if there are disturbances on the order of the measured time intervals for sufficiently short times (i.e. in the nanosecond range), these would average out, in a longer time measurement, because they would run in both directions. There is no reason for them to behave differently in the westbound airplane from the eastbound one. So the time difference measured between these two cannot be explained away by disturbances.
Dear Dr. K. Kassner,
The Hafele-Keating experiment is invalid in both theory and experiment. Please see:
https://www.researchgate.net/publication/292970880_A_comparison_between_Newtonian_gravitational_time_effect_and_Einstein%27s_gravitational_time_dilation?ev=prf_pub
Here, the reason that I only mentioned that " A little action by the surroundings, such as that a person is walking to it, can disturb this atomic clock." is that this is a very clear fact.
Data A comparison between Newtonian gravitational time effect and...
And what is your authority for the remarkable statement ``A little action...''? In my opinion, it is merely something you made up.
Hafele and Keating state that the reason why they attempted the experiment was the remarkable robustness of the clocks. More to the point, they carried four different clocks on each trip, so that footsteps, vibrations and the like, if they had had any influence, would easily have been noticed, as all clocks would have been affected differently and thus have shown different times at the end of the trip. Deviations did occur, but they were well within the range of experimental error and do not affect the result's validity.
As to the Newtonian gravitational effect you claim, it is inexistent, and your claims in this respect show a total lack of understanding of what a clock is and how it operates.
which is why, without any reference to authority, I just take pains to explain to you what Hafele and Keating did. They state the clocks are robust. I see no reason to doubt them, certainly not on *your* authority. They took 4 clocks. It is entirely obvious that the external influences you refer to would affect all clocks differently.
I am honest, indeed. You are not: you make things up out of thin air, do not listen and do not think, whether for yourself or otherwise. Pitiful.
just start dividing everything by c squared and shazam: PROOF!
do you believe in transubstantiation?
Dear Dr. Peter Jackson presented a very valued data on https://www.researchgate.net/publication/313350339_Does_an_intrinsic_time_dilatation_really_exist?focusedCommentId=5950ca311042bfede160bf1e
I copy it here:
I researched H&K quite deeply.
Hafele's NY speech before submission of the paper was telling, clearly stating the results were not consistent with the theory. The draft was unfortunately rejected, even initially by their professor, and they were forced to change it against their will to get it published.
Adrian
That's all your misguided comments can achieve. Professors and editors won't tolerate any advancement of understanding if it appears to conflict with older 'established' theory.
Article Does an intrinsic time dilatation really exist?
The setup for H&K was not really suitable since that had to make considerable corrections, already assuming GTR. However, this H&K has apparently been repeated by NPL in 1996, so what is going on? Are they right for the wrong reason, or wrong for the right reason? I have written a paper for examining a projective view which restores the symmetry betwen the twins by a mathematically consistent solution. "Unwinding the Relativistic Time". But I will always keep an open mind.
According to STR, the time dilation is symmetric since the speeds are "relative" and the effect includes a quatric term v^2, hence the same for both. But OK, one is accelerated more than the other, but then STR is at least half wrong. Something doesn't add up.
Dear Dr. Johannes Harder Andersen,
Thank you for your answers.
Very unfortunately, not only Einstein’s theory of relativity is just a faked story or pseudoscience, but also the so-called Standard Model should result in pseudoscience if we cannot rightly treat it. May you see:
https://www.researchgate.net/publication/317014509_Anti-ethics_and_pseudoscience_On_Albert_Einstein%27s_theory_of_relativity
I am spreading this article. If anyone should help to this spreading, I should thank him/her very much.
Data Anti-ethics and pseudoscience: On Albert Einstein's theory o...
About Hafele & Keating. Since they had so many atomic clocks, why didn't they repeat the experiment with the clocks swapped around?
Dear Dr. Johannes Harder Andersen,
Please consider that what is the Newtonian gravitational force on an atomic clock.
The effect of Newtonian gravitational force on an atomic clock is much larger than that of Einstein's general relativity. But, The effect of Newtonian gravitational force on an atomic clock has never been considered in the H-K experiment.
Johannes> What is it?
I am sure Yin Zhu has hourglasses in mind. You know, sand is made of atoms too! ;=D
We clearly know, a hourglasses, a mechanical clock and an atomic cklock are always acted by the Newtonian gravity.
But, in all the experiments to "have proven" Einstein's theory of relativity, the Newtonian gravitational effect has never been considered. And, in these experiments, Einstein's theory were "rightly" proven. Why? Because these experiments are all faked. So, in the Hafele-keating experiment, the time on the acurate of nanosecond was measured in a shocking and vibrating plane. In any standard, this is such an experiment that is too irresponsible for science.
I'm sure they did a proper experiemnt, the H&K experiment has also been repeated by NPL with the same result. The question I (and other people) have is the interpretation of the data. Obviously, the atomic clocks were affected by the travel; that was the whole point of the experiment. But did the atomic clocks measure the *time*. The experiment was crude in some sense by only comparing the overall difference; not instant time differences to see when it happened. Why was this not done?
Dear Dr. Johannes Harder Andersen,
You posted the same arguments again and again. But, you have never considered the arguments that others and I presented.
Please consider a question: the Newtonian gravity has an effect on an atomic clock. And, the Newtonian effect is much larger than Einstein’s gravitational tine effect. Why have not the Newtonian effect been measured in the Hafele-keating experiment?
Before you have not answered this problem, please not repost your argument again.
I'm very pleased that this argument has now losts its purpose. Have a nice day.
Yin Zhu> the Newtonian gravity has an effect on an atomic clock. And, the Newtonian effect is much larger than Einstein’s gravitational tine effect.
There is absolutely no evidence that this is true.
Yin Zhu> ... the same arguments again and again.
You post the same balderdash statements again and again, not even providing arguments.
Kåre Olaussen>
This is my reply on Data A comparison between Newtonian gravitational time effect and...
in Eq.(2), T=f(g). What kind of explanation you needed?
For an atomic clock, the gravitational acceleration g can make the speed of atoms in this clock varied. It results in the phase of the frequency of the atoms to shift. also, What kind of explanation you needed? Why have you not see these explanations?
What happened to you?
I quite agree that the kinematic time dilation suffers from symmetry failure, as so many have already noticed and called out. The gravitatinal time dilation doesn't have that same symmetry problem. https://www.gsjournal.net/Science-Journals/Research%20Papers-Relativity%20Theory/Download/6682
I think Kassner answered this question sufficiently. But if we are just taking the general question: "Is the Hafele-keating experiment credible?" then I would have to say no, it isn't. Others have pointed out the extremely poor documentation of the experiment. While it was done a long time ago; considering how wide-ranging and impactful an experiment it was, you would expect much more care taken when gathering the data.The lack of good data makes it difficult to judge whether or not the experiment was properly conducted in the first place and whether its conclusions should be taken seriously, therefore.
One of the experiment's major detractors comes in the form of another experiment called 'The Sagnac Effect'. For some reason, this experiment is often cited (if it is cited at all) as proof of Relativity, but it would appear to be a major thorn in the heal of the Hafele-Keating experiment. In fact, the problem with it is so rudimentary and fundamental that one wonders how it could have been missed in the first place, or if it was missed intentionally. Then again, most people have never heard of this effect and fewer still have put the pieces together, as Doug Marett did in this article:
http://www.conspiracyoflight.com/SagnacRel/TheSagnacEffect.pdf
Perhaps if it was repeated using better equipment we could sort this all out. Then again, if there's a problem with this experiment, it could be that it is based upon flawed assumptions from previous experiments, like the Michelson Morley Experiment, for example. If so, it would mean that a control version of the MM experiment be done, preferably on the Moon or Mars, or failing that LEO.
Is the Hafele-keating experiment credible?
I just came across the H & K experiment and thought today it should be easy to re-calculate their results given 1971. But it cost time as usual.
What you should take into account
8900m for 41.2h keeping constant quite good is possible
9400m for 48.6h keeping constant quite good is possible
So the GR experimental time dilation should be in good agreement with any calculation within the range of ns but hidden behind the SR time dilation accompanied. I tried to compare GR effect (upper limits) with and without sun-metric influence.
The main problem ist to get the speed under control. Here is born the biggest mistake if there is one. (Data are missing) But I am satisfied anyhow.
Presentation Hafele Keating kurz
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