Talk:Kennedy–Thorndike experiment

The KT experiment is not a test of Special Relativity

The velocity between the experimenters and their experiment is always zero. Hence Special Relativity does not enter in to the experiment. Thus the experiment is totally mis-described.RFNo (talk) 13:02, 16 October 2013 (UTC) I have had no reply to my criticism so will modify the article if not challenged within 7 days.RFNo (talk) 11:11, 21 October 2013 (UTC)

You were originally not considered worth replying to, but now that you have announced your intention to add your original research to this article, I assure you that every modification you make that is not backed up by a reliable source will be reverted. You exhibit a total lack of understanding of this experiment and of special relativity in general. Original research contributions will not be tolerated. Please follow the links to discover what constitutes a "reliable source" and Wikipedia policy on "original research". Stigmatella aurantiaca (talk) 11:36, 21 October 2013 (UTC)

The reliable source that is behind my comment is Einstein's Special Theory of Relativity. An impeccable source I hope you agree. Are you denying that there was no relative velocity between the observer (the experimenter) and the observed body (the experiment). If you apply relativity where there is no relative velocity you cant expect relativity effects to occur. And please cut out the insults. If you will not accept my comments then I must ask the Relativity committee to consider them. RFNo (talk) 19:06, 21 October 2013 (UTC)

"Research that consists of collecting and organizing material from existing sources within the provisions of this and other content policies is fundamental to writing an encyclopedia. Best practice is to research the most reliable sources on the topic and summarize what they say in your own words, with each statement in the article attributable to a source that makes that statement explicitly. Source material should be carefully summarized or rephrased without changing its meaning or implication. Take care not to go beyond what is expressed in the sources, or to use them in ways inconsistent with the intention of the source, such as using material out of context. In short, stick to the sources." Stigmatella aurantiaca (talk) 23:23, 21 October 2013 (UTC)

@RFNo. As explained in plenty of sources (some of them given in the article), the Kennedy-Thorndike experiment is one of the fundamental experiments of special relativity. It tests the isotropy of the speed of light with respect to the motion of a hypothetical preferred reference frame (as Michelson-Morley), and more importantly the influence of different velocities of the Earth-bound apparatus on the speed of light during Earth's orbit around the sun. In other words: The "observer" is the KT-apparatus, and the "observed object in relative motion" is the "preferred reference frame" or "aether". Therefore such isotropy experiments are also called "aether drift experiments". In order to avoid any measured aether drift in KT-experiments, a combination of length contraction and time dilation due to the relative motion between Earth and the hypothetical "preferred frame" must be assumed. All of this is explained in plenty of sources, analyzing both Michelson-Morley and Kennedy-Thorndike experiments. Your personal opinion whether this is right or wrong is not relevant. --D.H (talk) 07:52, 22 October 2013 (UTC)

I am perfectly aware of all you have described above. But you are in a complete muddle here. The concept of the Aether is incompatible with Special Relativity. It is most novel and brave of the author of this article to employ Aether physics to explain the experiment result. But at the same time he cannot claim that it is a test of Special Relativity. Furthermore I do not know of a recognized source which predicts length contraction and time dilation as a consequence and as a function of Aether velocity and which is derived directly from the properties of the Aether. There are such sources but I do not think they are recognised as being acceptable. The hypothesis of the Aether is denied by modern physics.RFNo (talk) 10:56, 22 October 2013 (UTC)

Let me add this. I applaud both the bravery of the author and his Aether explanation of the experiment. But it is nothing to do with Special Relativity. If this article is the beginning of a return to the Aether and to Aether physics I am all for it.RFNo (talk) 11:10, 22 October 2013 (UTC)

Special relativity relies on the assumption that all frames of reference are equal, or in other words, that no preferred inertial frame exists. Therefore any refutation of such a preferred frame (or "aether") is a confirmation of special relativity and the isotropy of the speed of light ("Aether wind" is a simplified historical name for violations of the isotropy of the speed of light). See the papers by Robertson or Mansouri-Sexl (they are linked in the article) where the connection of length contraction and time dilation is discussed, in order to make all inertial frames equal in accordance with the relativity principle (connecting the experiments of Michelson-Morley, Kennedy-Thorndike, and Ives-Stilwell). --D.H (talk) 12:27, 22 October 2013 (UTC)

You are misreading the article if you believe that it supports an aether explanation. No set of experiments can disprove an aether, but for an aether to be consistent with the range of experiments that have been performed, it must possess a bizarre range of completely ad hoc properties. Special relativity is vastly preferred over aether theories because SR arrives at its conclusions starting with a completely natural set of assumptions. Modern derivations of special relativity do not even require the second postulate.

Starting with the first postulate alone, along with basic assumptions known to be required of any physical theory (e.g. a self-consistent set of transforms must form a group, etc.), one finds that there are only three theories compatible with the first postulate, the (four-dimensional) Euclidean, Galilei, and Poincare groups. Only one of these theories agrees with observations and experiment.

As D.H has explained, the KT experiment is one of the core experiments supporting special relativity, since it shows that length contraction alone provides an insufficient explanation for the observed experimental results. Stigmatella aurantiaca (talk) 13:04, 22 October 2013 (UTC)

In addition, WP policies have already been explained to @RFNo here:

Talk:Twin_paradox#New_preliminary_section.

Any discussion based on original research cannot improve the article. --D.H (talk) 13:38, 22 October 2013 (UTC)

The conclusions that the author reaches are unwarranted.Applying Special Relativity gives a zero relative velocity between the observer (the experimenter) and the observed body (the experiment). Thus no relative velocity effects are predicted and were not observed. A null result for zero relative velocity cannot be proof of Special Relativity as you claim. Aether physics looks at the KT experiment differently. It assumes the experiment is moving through the Aether but that length contraction and time dilation (as functions of Aether velocity) operate such that they give the observed null result. Thus two different and incompatible theories both predict the same result. It is not possible that the operation of Aether physics goes any way to proving Special Relativity or indeed any other theory. The author of this article is in a total muddle.RFNo (talk) 15:34, 23 October 2013 (UTC)

Who, within Wikipedia, is responsible for allowing the publication of the false conclusions that I describe? I am told that if I were to correct them my corrections would be removed. I wish to know who is in control here.80.41.159.132 (talk) 13:35, 3 November 2013 (UTC)

A consensus of responsible editors guard against introduction of your poorly thought-out original research. Aether physics substitutes a complex, ad hoc explanation for a simple explanation that, in modern derivations (improved and streamlined over Einstein's original derivation by over a century of close study) is easily derived from the first postulate along with a handful of basic assumptions known to be required of any physical theory. Hence, Occam's razor clearly favors relativity. Aether theory is a theory of light alone. Lorentz invariance, on the other hand, forms a fundamental aspect of all modern physical theories. Aether theories have no such record of success or applicability. Stigmatella aurantiaca (talk) 15:14, 3 November 2013 (UTC)

I return to my previous post in which I state that the author of this article is in a total muddle. Wiki requires a neutral position to be held by the article. Other posters want to make the KT experiment evidence to support Special Relativity when it does nothing of the sort.I have previously explained my reasons. This attitude is totally contrary to Wiki's principles. RFNo (talk) 10:16, 14 February 2014 (UTC)

I feel the need to repeat my main point. The relative velocity between experimenter and his experiment is zero. Hence the observed relativistic effects are none. A null result is not evidence of Special Relativity (or indeed any of other theory) as is claimed within the article. This false conclusion makes the article unworthy of the experiment.RFNo (talk) 11:05, 14 February 2014 (UTC)

It is not possible to know absolute matter length

In the section 'Importance to Relativity' it is assumed that absolute matter length can be known. This is not possible as we do not have access to a standard against which absolute length can be ascertained. RFNo (talk) 09:26, 7 February 2014 (UTC)

I take it by the silence that no-one disagrees with my comment.RFNo (talk) 10:28, 13 February 2014 (UTC)

The silence could also mean that no-one agrees, or sufficiently cares to respond. - DVdm (talk) 11:14, 13 February 2014 (UTC)

On the contrary, by our silence, we were hoping that you'd just shut up and disappear. It was evident from previous discussions with you that you have no understanding of relativity or the theory behind the Kennedy–Thorndike experiment. Stigmatella aurantiaca (talk) 11:21, 13 February 2014 (UTC)

Stigmatella, that was not very pleasant. As you disagree with my criticism then I expect you to point out where we can find this length standard by which we may determine absolute distance. Substance rather than insults, please. RFNo (talk) 09:55, 14 February 2014 (UTC)

Another possibility is that "in the section 'Importance to Relativity' it is" not "assumed that absolute matter length can be known," in which case your second sentence is moot. Indeed nowhere does the section say that "absolute matter length can be known", so your comment is not about the article but about the subject, or about your personal (mis)understanding of it. Alas, that is—per wp:talk page guidelines—off-topic. That is of course part of the reason why no-one replied. - DVdm (talk) 10:13, 14 February 2014 (UTC)

DVdm. As 'absolute' length cannot be known then there is no point whatever in having a paragraph which directly or indirectly refers to it. This can only be denied by pointing out the absolute standard. I am concerned and disappointed with the replies that I am getting. Both you and others seem to have the object to support the theory of Special Relativity even when there is no relevance or when it is entirely wrong to do so, when the object should be to give a NEUTRAL description of this experiment. In this you are denying the rules of Wiki.RFNo (talk) 10:39, 14 February 2014 (UTC)

"'Absolute' length" is not mentioned, and even if it was mentioned, your objections to it would be off topic. - DVdm (talk) 11:00, 14 February 2014 (UTC)