Talk:Hafele–Keating experiment

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Link number 5 in the Link section is broken. One should either remove it or change it, right? what would be the correct link to the repeated experiment? —Preceding unsigned comment added by 194.169.250.90 (talk) 13:50, 7 April 2008 (UTC)

Contents

[edit] Time dilation

Link number 5 in the Link section is broken. One should either remove it or change it, right? what would be the correct link to the repeated experiment? —Preceding unsigned comment added by 194.169.250.90 (talk) 13:51, 7 April 2008 (UTC)

This is an obvious case of two extreme POV's. If someone has a reference ready about a more modern repeat experiment (I'm sure that there was at least one!), it would be good to add that and to rephrase (soften) some sentences. Harald88 21:29, 17 October 2005 (UTC)

An engineering discussion of the functioning of the GPS satellite system pins down all of the relevant facts and measurable values. Velocity time dilation, the sagnac effect and general relativity are all engineered into the operation of that system. Sort of a 24/7 experiment, if you will. Jok2000 22:41, 17 October 2005 (UTC)

That's right, and there are papers about that as well as, if I remember well, a special test done by the military. What is lacking now is a precise reference and referral to it with a summary here in this article. Harald88 20:10, 18 October 2005 (UTC)

BTW:, thanks Jok, your addition of GPS details is already a good improvement. Harald88 12:16, 20 October 2005 (UTC)

The UK's NPL re-did the experiment for the 25th anniversary of the original H&K version.

http://www.npl.co.uk/publications/metromnia/issue18/

It wasn't a round-the-world affair, but it was done with more precise equipment. The results are (quoting from the above website):

On return to NPL the travelling clock was predicted to have gained 39.8 ns, including an additional geometric factor. This compared remarkably well with a measured gain of 39.0 ns. We estimated the uncertainty due to clock instabilities and noise to be around ±2 ns. This short flying clock experiment therefore provided a clear demonstration of relativistic effects.

A USENET reference notes a report of this report in the 2005 Feb 26 issue of New Scientist. mdf 21:21, 20 October 2005 (UTC)

Thanks! Still, I remember that I downloaded, maybe one year ago, an original recent PDF report about such a test - likely directly from a reliable source (New Scientist, I'm sorry to say, I don't find very qualified, nor news summaries (I searched NPL's publications, but didn't find it). But if I don't find "mine" back soon, then we can cite the one you found, at least temporary. Harald88 22:17, 20 October 2005 (UTC)
I searched on the New Scientist web site and couldn't find any such article. The experiment was done as part of a BBC program commemorating the original experiment's 25th anniversary, and the program was then sold to Nova. There is a transcript of the program on Nova's web site.--24.52.254.62 01:31, 19 June 2006 (UTC)

http://www.npl.co.uk/publications/metromnia/issue18/ is a dead link. Is there another citation or reference for this experiment? --68.53.221.14 (talk) 01:46, 20 January 2008 (UTC)

[edit] GPS reference

More sources need to be cited to back up the claim that the GPS system has anything to do with time dilation effects vs redshift effects. Jeff Carr 13:33, 21 January 2006 (UTC)

How do you mean? Time dilation of a distant EM source is measured as redshift... Harald88 15:55, 21 January 2006 (UTC)

[edit] special relativity explanation

I thought that in special relativity no inertial frame is preferred. However, the explanation for why the westward clock ran fast compared to the ground(gained nanoseconds) whereas the eastward clock ran slow seems to appeal to the frame of 'the universe as a whole'. Am I misreading something? -Intangir 01:29, 8 April 2006 (UTC)

What you may have missed: the used calculations can be done for any inertial frame - in this case the earth centered inertail frame was used for convenience, and not that of "the universe". Should this be clarified perhaps? Harald88 15:58, 8 April 2006 (UTC)
Done.--24.52.254.62 01:27, 19 June 2006 (UTC)

[edit] POV war - please end it

Please don't delete published expert opinions that disagree with your POV - Wikipedia demands that significant contrary opinions are all included. In this case such a behaviour even makes no sense at all, as the results of more recent experiments are beyond doubt anyway.

Thus I'll reinsert the deleted published POV's, and harmonize the text accordingly. Harald88 19:15, 20 June 2006 (UTC)

PS I'm not sure if Kelly's research has been published other than by his university (his papers were kindly sent to me by them); and I don't know if university papers are accepted as "source" for Wikipedia. Harald88 19:45, 20 June 2006 (UTC)

Hi -- The current version, with your latest edit, seems fine to me. I suppose the issue is what would count as a "significant contrary opinions." I don't think there are any significant opinions that are against the validity of special relativity, but I suppose my definition of "significant" might differ from yours. The current version accurately explains that although there some people tried to challenge the validity of the experiment, they were later proved wrong. NPOV doesn't mean that we have to give equal credence to people who say the Earth is flat, or that the periodic table is a hoax.--24.52.254.62 00:09, 21 June 2006 (UTC)
Hi we seem to agree, except perhaps about the validity of experiments: an experiment's validity doesn't depend on the correctness of the theory that is tested, instead it depends on the quality of the equipment and the skills of the experimenter. But perhaps it was a slip of the pen, and you meant that some people continued to doubt the validity of the theory. Note also that at that time relativity theory was by far not as established as for example the spherical Earth today. Hafele-Keating was really a milestone as it was the first realisation of Einstein's 1905 proposal for a time dilation experiment. Harald88 21:57, 21 June 2006 (UTC)

[edit] the Kelly paper

Kelly's paper is "notable" because it created a flurry of interest when it was published, and because AFAIK, nobody has been able to fault his analysis. I no longer have my files, but as far as I recall, Kelly's paper essentially said that the large degree of intermittent error in the HK test meant that the results should probably have been discarded as worthless regardless of whether they happened to support SR or not. The clock with the largest error was also the clock that contributed most of the desired result: if that clock had been taken out of the experiment (as later USNO guidelines would suggest), then most of the reported effect disappeared.

This isn't to say that the prediction itself is wrong ... only that the experiment that set out to verify it, judged according to more modern quality criteria, was arguably too unreliable to be counted as a proper verification of the effect.

The apparent shortcomings of the H-K experiment don't amount to a criticism of special relativity (if the experiment is invalid it doesn't count one way or the other), but some people may take the SR community's enthusiasm for this experiment (without subjecting it to the proper sceptical scientific analysis) as an indication of "cultural problems" in this part of the physics community that seem to be preventing proper scientific standards from being maintained. We should have been told about these problems immediately by the mainstream community itself, we shouldn't have had to wait 25 years for an "outsider" to do their job for them, and that outsider shouldn't have been subjected to the character assassination that happened, for apparently just telling the truth. When an experiment is done for the very first time, sometimes it isn't quite as good as the experimenters think ... the equipment is often being used in unusual ways, and in extreme conditions, and potential problems may not emerge until some time later, by which time everyone's become more familiar with the techniques involved. This is just something that happens from time to time.

IMO we shouldn't be especially critical of H&K either -- they had a cool idea for a relatively inexpensive experiment, they went out and did it, and they tried to report the results that they obtained. Good for them. It perhaps wasn't their fault if the technology wasn't quite good enough at the time for their results to be quite as significant as some SR proponents made them out to be. That's the thing about famous experiments ... they are/were experimental, and the more famous an experiment, the more "experimental" it's likely to have been. Sometimes they work well, sometimes they don't. The most famous ones often turn out with hindsight to be a bit dodgy, because they tend to be pushing the experimental "envelope" further than anyone's been able to go before. The thing is to be honest about it. ErkDemon 14:04, 7 May 2007 (UTC)

[edit] GPS section needs citations

An anonymous user whose IP address keeps changing keeps removing {{fact}} tags and not citing any sources. The whole section is heavily biased too. This week I'll try to do some research and get to the bottom of this, but in the meantime, qualifying everything with "seems to" is not an improvement. —Keenan Pepper 05:50, 22 August 2006 (UTC)


Just google for GPS and time dilation. You will be able to find the equations. Jok2000 20:24, 22 August 2006 (UTC)

The equations aren't the issue, because everyone agrees on them. The issue is whether the effects they represent are negligible. Are Our job is to present the different views from a neutral point of view and with appropriate citations so readers know who's whose views they are. —Keenan Pepper 01:38, 23 August 2006 (UTC)

This is the "anonymous user whose IP address keeps changing" (whew, you caught yourself a real Internet bandit, Mister! Try google for 'dynamic IP'). Now, let’s cut to the chase: besides watching too many episodes of Star Track (you are a teen, aren't you), what exactly qualifies you in this subject matter, to insist on the ridiculous notion that GPS could not survive without GR or SR?

One thing is to learn how to read and then be proud of it, like in your case of a Star Trackie boy scout. It’s a totally different ballgame to be able to actually read scientific papers in an area of interest. Now, go tell your science advisor you are unable to do this. Perhaps you will, in a few decades from now, but just not yet. OK? So kid, do us a favour and go have a cup of milk. Oh, and please try hard to not pollute the Internet with Dart Wader wormhole misfit realities. Hope you really are going to do "more research on this", although, in all honesty, I am not certain how you plan on accomplishing that in such a brief time. Oh, don't tell us, you own a paper-copy of the Hawking's "Brief..." too! —The preceding unsigned comment was added by 80.65.175.63 (talk • contribs) .

I'm trying to ignore your personal attacks, so there's not much left to reply to. I'm not insting that "GPS could not survive without GR or SR", in fact personally I believe your point of view is closer to the truth. But it doesn't matter what I believe, because, as you put it, I'm just a "Star Trackie boy scout". People don't care what you or I think, they care what experts think and what's published in reputable journals. That's why WP:V and WP:CITE are so important. —Keenan Pepper 01:38, 23 August 2006 (UTC)

[edit] Message to 80.65.175.*

I'm not going to put this on 256 talk pages so I'll put it here. Stop vandalizing this talk page or I'll ask permission to do a range block. It's not funny anymore, so just quit it. —Keenan Pepper 04:14, 25 August 2006 (UTC)

- When you post a GPS ownership title in your name for all to see, you will be most welcome to start "turning us in". Until then, besides teenagers like you, Wikipedia remains open to all, I believe? —The preceding unsigned comment was added by 80.65.175.42 (talk • contribs) .

I don't understand what you mean by "post a GPS ownership title in your name". Wikipedia has always been open to everyone, regardless of age. Why do you keep adding links to Wikipedia:Sign your posts on talk pages with the text "...signatures on Wikipedia are not intended to indicate ownership or authorship of any Wikipedia article"? I never put my signature on the article itself, and I never implied that my signature indicated ownership of the article, so I don't know what your point is. Please spell it out for me so that my feeble teenage mind can understand, rather than using cryptic vandalism. —Keenan Pepper 21:43, 25 August 2006 (UTC)

Stop policing me while polluting Wikipedia with your Star Track fantasies about GPS being a proof of relativity theories. I have contributed to Wiki in several areas over the years, always as an anonymous user, and I intend to do just that in the years to come. 99% of my posts stood the test of time, but I have never encountered such a ridiculous figure like you.—The preceding unsigned comment was added by 213.249.155.239 (talk • contribs) .

[edit] Civility

A general comment to all users. Do not modify other users' talk page comment and remain WP:CIVIL. Also please do not use personal attacks. JoshuaZ 16:36, 26 August 2006 (UTC)

[edit] GPS continued

First of all, how many people think the GPS section even belongs in this article? It doesn't seem to have much to do with the experiment performed by Hafele and Keating.

Second of all, [1] doesn't even mention relativity. It's mostly about the combination of inertial navigation systems with GPS. The only other source is the book GPS satellite surveying, which I'm going to check out from my university's library right now. I doubt it really says all this stuff the article currently implies it says, but I could be wrong. We'll see. —Keenan Pepper 16:00, 8 September 2006 (UTC)

Let's start with: "Why do you believe that the functioning GPS's system time dilation is unrelated to the time dilation expected by Haefel & Keating, which they also seem to have measured?". After that, we can then argue as to why the theory (that is to say, the equations) behind both cannot be used in the article. Then when we're done that, we may ask the question, why are some users so dedicated in to making Wikipedia worse? (i.e. that insulting dude continually deleting the equations?). Then after that, we can ponder why there are so many cranks trying to mess up "time dilation", "twin paradox" and "Haefele Keating" all at the same time. Hm, and now I notice, also "GPS" with that innaccurate quote about GR&SR being unimportant (thus the importance of the equations). Jok2000 20:51, 8 September 2006 (UTC)

I have Leick's book right here and on page 68 it says: Relativistic effects are important in GPS surveying, but fortunately can be accurately computed. The atomic frequency standards in the satellites are affected by both special relativity (the satellite's velocity) and general relativity (the difference in the gravitational potential at the satellite's position relative to the potential at the earth's surface. That's very satisying to me. —Keenan Pepper 23:35, 8 September 2006 (UTC)
Good - then that is settled. Harald88 13:28, 9 September 2006 (UTC)
Not even close to being settled: since when are 'important' and 'critical' synonyms? What a lack of focus! Where does it say in the Leick's book that GR/SR are critical to GPS, so much to claim the GPS as a proof of the two theories as the present style of your writing implies (avoiding conditionals)? Can you show it, please? I didn't think so... —Preceding unsigned comment added by Unknewthat (talk • contribs) 01:51, 10 September 2006


I had the impression that the disagreement was about if "GPS section even belongs in this article", based on the erroneous argument that GPS experiments had nothing to do with the Hafele-Keating experiment. Phrasing is a different issue altogether. Harald88 08:27, 10 September 2006 (UTC)
Uknewthat: I have rv'd for the following reasons: 1) I think the equations for the various effects are an important part of this article and should not be deleted. Physics does involve the use of mathematics. 2) The section on GPS seems argumentative to me. That is, it appears to be pushing a point of view. 3) I suspect that the point of view being pushed lies outside the scientific mainstream. Cardamon 12:57, 16 September 2006 (UTC)
No. Keenan is an Einstein's teenage groupie who takes equations and quotes by researchers out of context and uses them to impose his own (a teenager's, mind you) view of what complex notions mean. Leick clearly stated in the same book (see the GPS section) that relativity corrections are not needed to achieve even the mm accuracy with GPS. Likewise, Einstein's equations taken out of context and placed next to a phoney experiment claims is nothing else but a hoax meant to impress the uninitiated. —The preceding unsigned comment was added by Uknewthat (talk • contribs) .

I am starting an RFC on User:Uknewthat: Wikipedia:Requests for comment/Uknewthat. If you have anything to say about this user, please say it there. —Keenan Pepper 19:41, 16 September 2006 (UTC)

This person(s) now goes 'inquisition style'. A note to the serious readers/users of Wiki: I do not intend to discuss anything with an 18 year old Einstein's groupie, let alone sophisticated science. Have your milk Keenan, and then go to bed. You'll do the world a big favour. —The preceding unsigned comment was added by Uknewthat (talk • contribs) .

[edit] 3RR

I have filed a report about this page at WP:AN/3RR. Dual Freq 15:14, 17 September 2006 (UTC)

[edit] References format

I notice that Mpatel chose [2] without discussion to move 2 of the 4 references to footnotes. Actually, moving to that format is not such a bad idea. What do people say to the idea of putting all the references in this article into that format? Cardamon 10:58, 4 October 2006 (UTC)

Yes. Pfalstad 11:46, 4 October 2006 (UTC)
Agree, general refs are hard for the reader to follow unless it's done like Harvard refs. --Dual Freq 23:24, 4 October 2006 (UTC)

If the A. G. Kelly ref recently added applies to the fact tag that was removed I believe it should be used with a citation tag so that future readers will know that that item is referenced. --Dual Freq 23:24, 4 October 2006 (UTC)

[edit] Page protection

I've protected the page because Uknewthat seems to be engaged in a slow revert war against consensus. Please try to reach some kind of agreement here, or if you're unable to, let me know. SlimVirgin (talk) 01:07, 5 October 2006 (UTC)

Why did you revert the last change? That seemed like a good compromise -- leave the stuff what this chap writes about his grandfather's experiment, but ADD what I put about the GPS not being a definitive proof of GR/SR theories. What is the problem with that? Why revert that? Why lock without including what the other side has to say? —Preceding unsigned comment added by Uknewthat (talk • contribs) 12:54, 5 October 2006
This page is about "his grandfather's experiment", but doesn't really have anything to do with the GPS. So we discuss the first, and not the second. Ben Standeven 14:41, 5 October 2006 (UTC)
There may be a misapprehension here. It is true that Buddhist Monk Wannabe left messages [3] [4]on Uknewthat's talk page indicating that "Joe Hafele" was his or her grandfather. However, User:Buddhist Monk Wannabe seems to have never edited the Hafele-Keating experiment article. (In his first message to Unknewthat, Buddhist Monk Wannabe apparently thought that Unkewthat had written the material on the experiment.) So, to "leave the stuff what this chap writes about his grandfather's experiment" would be to leave nothing. Cardamon 21:37, 5 October 2006 (UTC)
What are you talking about? The H-K experiment page implies H-K has major GPS relevance by the concluding sentence. Besides, the last link is to "GPS Time Dilation". Very sneaky indeed! As for the whose-grandpa-did-what and all that: good thing my grandpas had only fought Hitler so they never had a chance to do any foul science; sorry if I didn't recognize the grandboy as the author of the sneaky page. Einstein troll puppets all look the same to me, as indeed they should. —Preceding unsigned comment added by Unknewthat (talk • contribs) 23:53, 7 October 2006
Hi, Uknewthat. I'd like to repeat that there is no evidence that any part of the H-K experiment page was ever even edited by User:Buddhist Monk Wannabe. I would like to ask you to consider that people may disagree with you without being either puppet or trolls. In other words, please assume good faith. Also, repeatedly calling someone a puppet or a troll can be considered a personal attack. Finally, could you please start signing and dating your comments?. Doing this makes it clear who said what, and when. This helps a lot in keeping a talk page easy to understand. It isn't hard. Just put four tilde's (~'s) in a row at the end of your statement, and Wikipedia will do the rest. Cardamon 06:56, 10 October 2006 (UTC)
Actually, I don't think that sentence and link belong either; but in any event it is better to have one sentence and a link than a whole section of the article on something only tangentially related. Ben Standeven 16:27, 10 October 2006 (UTC)

I'd like to add that User:Jok2000 added the See also GPS item here. I believe it was added to placate certain anonymous users repeatedly adding POV GPS related non-sense to this article. It appears to me that it was a (failed) attempt to compromise with the anonymous users. Funny thing is, the anons kept adding the very same GPS POV section that Uknewthat keeps adding. (and also was unable or unwilling to sign posts.) --Dual Freq 23:49, 10 October 2006 (UTC)

I'm wondering whether it would be okay to unprotect the page now. Let me know, please. Cheers, SlimVirgin (talk) 20:01, 12 October 2006 (UTC)

EVERYONE: Please note that, in an agreement with SlimVirgin, I have only added a paragraph to the H-K page, without doing any edits to the rest of the page. The added paragraph is based in part on the discussion that can be found on the GPS page. Uknewthat 01:25, 15 October 2006 (UTC)

[edit] Why is GPS mentioned

Does anyone know why GPS is relevant here at all? Relativity is related to GPS, but why this experiment? It seems that an earlier version of this article claimed that the equations shown were used in the GPS system. Is there a source for this? Unless this experiment has some specific relevance to GPS, we should remove the references.. Hopefully that will help keep the cranks away too. Pfalstad 15:25, 15 October 2006 (UTC)

Only inderectly relevant. The atomic clocks in the GPS satellites are corrected for SR/GR relativistic effects, using the same equations as teh HK-experiment. But I think it is enough to mention GPS time delation as a "see also", as it is done right now.Mossig 16:53, 15 October 2006 (UTC)
I agree with Pfalstad. HK seems to be here only as a distraction. The author can always start his or her own Web site to expand on an experiment as obscure as this one. 1freerider 20:32, 3 November 2006 (UTC)
? I wasn't saying that the HK experiment had no relevance.. I just wondered why the GPS material was present in this article. Pfalstad 21:47, 3 November 2006 (UTC)
Easy: the GPS was brought up as alternative verification of the same laws as HK tested for--similar as set forth in GPS#Relativity-- but that part was edited out by someone. Consequently the line of logic got lost. Harald88 21:52, 3 November 2006 (UTC)

[edit] photo

In Hartle's Gravity: An Introduction to Einstein's General Relativity, there's a nice photo of Hafele and Keating getting on the plane with the clock. The photo credit is to the US Naval Observatory, which makes me think that it might be PD. Anyone know anything about this? A Google Images search doesn't turn it up.--76.81.164.27 05:31, 10 April 2007 (UTC)

Another interesting image: http://www.usno.navy.mil/library/photo/clk6c.html . This would appear to be from the same type of experiment, but the date is from the year before. Maybe the Lloyd-Percival experiment failed, and then Hafele-Keating got it to work the next year? Googling on Lloyd and Percival yields nothing of interest that I can find.--76.81.164.27 03:40, 11 April 2007 (UTC)


[edit] Hafele-Keating Experiment Disproves Rather Than Confirms Special Relativity

It is apparent that the claim that this experiment confirms relativity is false. Special relativity demands symmetrical time dilation. This means that each clock runs slow relative to the other clock. Since the experiment does not verify this result, but shows that one distinct clock, the airplane clock, runs slower than the ground clock, then the symmetric prediction of special relativity is refuted by observation. Hence the claim that this experiment verifies special relativity is false. 71.251.176.71 13:10, 12 September 2007 (UTC)

Which reliable source are you citing here? Harald88 19:38, 12 September 2007 (UTC)
The anonymous writer is technically correct: the experiment confirms the general relativity theory. (Special relativity does not include accelerated frames of reference.) Mossig 21:07, 12 September 2007 (UTC)
You mean SRT does not include gravitation effects on time dilation - indeed.
However, the term "Relativity" usually includes gravitation. Harald88 20:46, 15 September 2007 (UTC)