Talk:Hafele–Keating experiment

message: 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)
thread_title: Broken link

message: 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)
replies: text: 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)

text: 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)

text: Here is the NPL pub 18http://resource.npl.co.uk/docs/publications/newsletters/metromnia/issue18_einstein.pdf 71.120.142.163 (talk) 15:06, 12 March 2024 (UTC)
thread_title: Time dilation

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

message: 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)
replies: text: 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)
replies: text:  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)
thread_title:  POV war - please end it 

message: 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)
thread_title: the Kelly paper

message: An anonymous user whose IP address keeps changing keeps removing  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)
replies: text: 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)

text: 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)
thread_title:  GPS section needs citations 

message: 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)
replies: text: 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)
thread_title:  Message to 80.65.175.* 

message: 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)
thread_title:  Civility 

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

message: I notice that Mpatel chose   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)
replies: text: Yes. Pfalstad 11:46, 4 October 2006 (UTC)

text: 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)
thread_title: References format

message: 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)
replies: text: 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)
replies: text: 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)
replies: text: ?  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)
replies: text:  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)
thread_title:  Why is GPS mentioned 

message: 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)
replies: text: 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)
thread_title: photo

message: I'm confused by the equations section in this article. What is k? Vectro (talk) 14:34, 8 December 2008 (UTC)
thread_title:  Equations section 

message: I have moved this link to what seems to be a personal webpage from the article to here:
* Tom Tushey:Theoretical fundamentals for the H-K experiment
http://www.tushey.fw.hu/en/hk_eng.htm
Why is this supposed to be a reliable source??
Cardamon (talk) 20:01, 30 January 2009 (UTC)
thread_title:  Tushey webpage 

message: An experiment along similar lines was shown on the BBC's Bang Goes The Theory programme. More info is available at http://www3.open.ac.uk/media/fullstory.aspx?id=19636. Adambro (talk) 12:52, 10 September 2010 (UTC)
thread_title:  [[Bang Goes The Theory]] 

message: How does this Experiment justify its results knowing that gravity just bends space/time?  If we are on a curved path through gravity, and that gravity is detectable by moving clocks, wouldn't that tend to show that the MM experiment results were due to the "ether" and not necessarily space dilation?  After all, the atoms in the atomic clock would only be effected by the curvature of space/time, not what the earth was doing; unless there was sufficient frame dragging for them to be effected by it - and that means the MM results were due to the "ether"/frame dragging.
All in all this experiment seems to produce contradictory results and cannot be used to differentiate between "ether" and relativity.  And when considered as a whole based on the comments made throughout this discussion, it would tend to show that there is something else besides relativity causing the clocks to vary their timing.
And as far as the "doesn't work for non-inertial frames" group, please show how the rotating frame causes the clocks to detect the motion.
BWilliams2010 (talk) 20:36, 25 September 2010 (UTC)
replies: text: This article talk page is not really the place for this. This is where we duscuss the article, not the subject or part of it -- see wp:TPG. You might try to put this question at wp:reference desk/science. Good luck. DVdm (talk) 20:58, 25 September 2010 (UTC)
thread_title:  Curved Space 

message: The article spends almost as much time debunking anti-relativity kooks as it does discussing the experiment itself. This clearly violates WP's rule about not giving undue weight: http://en.wikipedia.org/wiki/Wikipedia:Reliable_sources_and_undue_weight I am going to greatly shorten all the text starting from "A few authors..." down to the end of the Overview section.--75.83.69.196 (talk) 01:44, 15 November 2010 (UTC)
thread_title: Undue weight given to kooks

message: Some of the notation in the Equations section is never defined. I'm guessing that R is the radius of the earth (but then why the subscript i?), phi is the latitude, and lambda is the longitude.--75.83.69.196 (talk) 03:48, 16 November 2010 (UTC)
thread_title: Undefined notation

message: I'v included a description and a link to the 2010 repetition of the experiment (see here), and the original link to the 1996 repetition (see here). --D.H (talk) 16:25, 19 June 2011 (UTC)
thread_title:  Repetitions 

message: I came across the following reference, which describes the proposed experiment in future tense: Hafele, American Journal of Physics 40 (1972) 81, http://ajp.aapt.org/resource/1/ajpias/v40/i1/p81_s1 --75.83.64.6 (talk) 00:18, 16 September 2012 (UTC)
thread_title: AJP reference

message: Why does the Hafele Keating experiment article mention Herbert Dingle and Mendel Sachs at all? Their opinion is not notable. The dissent of Herbert Dingle and Mendel Sachs is not indicative of any doubt in the scientific community.
It is well known that Herbert Dingle never understood the first thing about relativistic physics. His objections came from deep misunderstanding.
In august 2011 Mendel Sachs wrote on his website about the Twin paradox:
I have recently been asked if I still believe what I said in my 1971 paper, "Resolution of the Clock paradox" (Physics today, 24, 23 (1971)), [...] my main claim: that the letter 't' in the formulas from special relativity, [...] is not a physical process, such as the physical aging of a human being or the unwinding of the spring of a clock! Rather, 't' represents an abstract measure of time, such as the reading of the hands of a clock, not the physical unwinding of the spring behind the face of the clock. [...]
Please read the entire blog entry to make sure you understand what he is saying.
It's unclear whether Mendel Sachs ever took notice of the results of the Hafele Keating experiment. (Unfortunately it's no longer possible to ask him, he died may 5th, 2012) 
Whatever the case, the evidence is clear that Mendel Sachs disagreed with the scientific community on a fundamental point, and that his point of view was incompatible with many different experimental results.
I suggest that the mention of Herbert Dingle and Mendel Sachs is removed from the article.
--Cleonis | Talk 11:12, 28 April 2013 (UTC)
replies: text: I removed the phrase. --D.H (talk) 11:27, 29 April 2013 (UTC)
thread_title:  About Mendel Sachs 

message: Not all the variables in the equations (section) are labelled - without them, the equations are useless, unless you happen to be already familiar with the equations - which defeats the purpose of Wikipedia, surely. Missing are i, R, h0 and phi. Also, the variables should appear in the same font and italic style in the labels as they do in the equations, to remove any possibility of confusion. A worked example using the results/predictions from the one of the described experiments would also remove doubt.--Quitequick (talk) 08:13, 29 October 2013 (UTC)
replies: text: Indeed. It would also be nice to have a direct reference to the book or article from which these equations were pulled. I tagged the section. - DVdm (talk) 08:19, 29 October 2013 (UTC)
thread_title:  Equation variables not all labelled 

message: You're very welcome.  I figured that with the Wired article, the PTTI presentation (establishing professional respect; he's not WP:FRINGE) and the TV show, we've established WP:Notability.  And, although self-published, his own web site is a good source for the practical details of carrying out the experiment. 71.41.210.146 (talk) 16:16, 31 March 2017 (UTC)
thread_title:  Tom van Baak's replication 

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thread_title:  External links modified 

message: Per lack of wp:reliable sources, wp:FRINGE and wp:UNDUE I have removed () the fringy, badly sourced section about the challenge of the test results. Cited sources were this (as a subpage of this) which is someone's personal opinion on their private website, and this which is just an obituary of Kelly, a mechanical engineer, not even a physicist. Comments welcome. - DVdm (talk) 11:49, 1 November 2020 (UTC)
thread_title:  Removed badly sourced challenge section