# Talk:Ives–Stilwell experiment

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## why 3 and not 4?

It's known (but not sufficently well known?) that that the first prediction of SRT by Lorentz and Einstein was the dynamic behaviour of accelerated electrons - they correctly predicted the factor gamma. That makes 4, not 3. Harald88 22:43, 28 October 2006 (UTC)

## other references needed

As Ives specifically referred his experiment to Lorentz and Larmor, it's pertinent to include reference to the most relevant papers by them. For Lorentz we should probably refer to his 1904 paper; and Ives referred specifically (in a 1937 paper) to Larmor's paper "Aether and Matter, 1900" Harald88 22:55, 21 November 2006 (UTC)

## Transverse Doppler effect wrong

It is a mistake to say the Ives Stilwell experiment is based on the transverse Doppler effect of Einstein. It is not. It is based on Ives own theory of relativity different from Einstein's. There was no measurement of transverse Doppler effect, simply a measurement of time dilation due to motion. There was no transverse measurement of the Doppler in this experiment. You guys need to get facts right. Wikipedia is a source of misinformation and this article is a good example of that.71.251.183.186 (talk) 14:53, 30 July 2008 (UTC)

The article had contradicted itself on this point. The lead said it was a measurement of the transverse Doppler effect, while the body said, correctly, that it was longitudinal. I've corrected the lead. Re "It is based on Ives own theory of relativity...," please provide a reference to support this assertion. Note that even if part of Ives' motivation was that he had his own theory, the results were consistent with Einstein's theory.--75.83.64.6 (talk) 03:32, 18 March 2013 (UTC)
The term "transverse Doppler effect" is correct, even if it is observed with the particles moving longitudinally. Stigmatella aurantiaca (talk) 04:31, 18 March 2013 (UTC)
No, the transverse Doppler effect is the Doppler effect observed with the motion in the transverse direction. Your version of the first sentence of the lead simply misstates what was done in the experiment. It's true that the relativistic longitudinal Doppler effect (LDE) differs from the classical longitudinal Doppler effect (LDE) by a factor of gamma, and that gamma is also the relativistic TDE factor. Therefore, Ives and Stilwell's longitudinal observations differed from the classical theory by a factor of gamma, which is the same as the relativistic TDE factor; but it is still completely incorrect to say that what they observed was the TDE. Nobody succeeded in doing a decent measurement of the TDE until much later, because it's much harder. --75.83.64.6 (talk) 21:51, 18 March 2013 (UTC)
I am not sure what you consider to be the problem. The bisected positions of the advancing and receding longitudinally Doppler-shifted lines was compared with the position of the non-Doppler-shifted line. For v<<c, that measurement provides a result identical to that of a transverse-Doppler-shifted line. Stigmatella aurantiaca (talk) 01:32, 19 March 2013 (UTC)
All three figures in this article are my work. Please refer to the large figure in the middle. In the center column, the transverse-Doppler-shifted line is listed as having a wavelength of 4861.06 Å. In the right column, the computed average of the blueshifted line and its redshifted reflection is 4861.06 Å, which is numerically identical to the transverse-Doppler-shifted line. An undisplaced line also shows up in the spectrum due to the glow of ions not in the accelerated beam; these unaccelerated ions are represented as black dots in the figure. Do you have any objection to how I put together this figure? If you have no objection to how I put together this figure, then the first line of the article is correct as it currently stands, i.e. Ives and Stilwell performed a measurement of the TDE. Stigmatella aurantiaca (talk) 09:45, 19 March 2013 (UTC)
Depends on whether one connects the TDE formula $f_o =f_s /\gamma$ generally to the specific time dilation effect in the Doppler shift formula, or specifically to measurements conducted at right angles. Many authors, including Born (1964), use both definitions when they refer to TDE und the experiments of Ives-Stilwell and Otting. Whatever, I've tried to reformulate the intro to meet both views. --D.H (talk) 10:12, 19 March 2013 (UTC)
Nice rewording! Thanks! Stigmatella aurantiaca (talk) 10:18, 19 March 2013 (UTC)

## No reference To A Primary Source For Ives Papers

This article does not refer the reader to the primary reference source on Ives work. The Einstein Myth and the Ives Papers, available for \$39.95 from Hope Publishing House. You guys are really lazy.71.251.183.186 (talk) 14:57, 30 July 2008 (UTC)

I've added a reference to the original papers. I don't know if you're familiar with how Wikipedia works, but there was nothing stopping you from adding the appropriate reference yourself. I don't see any reason, however, to add a reference to a reprint that is part of an expensive book.--75.83.64.6 (talk) 03:38, 18 March 2013 (UTC)
The references already existed in the article. I changed the ones that you added to point to the ones already present in the article. Stigmatella aurantiaca (talk) 04:32, 18 March 2013 (UTC)

## The Kündig experiment (1963)

D.H - Could you check my figures in the caption? I misplaced my copy of the paper (I had it just last week), and recalculated based on memory, but my calculated figures don't necessarily match what Kündig actually measured. Thanks! Stigmatella aurantiaca (talk) 06:31, 10 July 2012 (UTC)

Thanks for double-checking. I had previously forgotten the factor of two in calculating the circumference of a circle from a radius, and initially wrote 48 microns per second. Embarrassing... :-( Stigmatella aurantiaca (talk) 12:16, 10 July 2012 (UTC)
Thank YOU for your excellent images and contributions. --D.H (talk) 15:30, 10 July 2012 (UTC)

## What were the initial conditions of the ELECTRONS in the experiment?

Totally new here - is this where I make suggestions? I've never been able to find the answer to this question - maybe someone on here knows the answer and could add it to this article? What were the initial conditions of the ELECTRONS in the experiment?

There seems to be the implicit assumption that only the positive ions' state of motion has an effect on the photons being emitted. I recognize that the ions are orders of magnitude more massive than the electrons, and thus their trajectories would be essentially unaffected. But aren't the photons emitted by the JOINT actions of both positive and negative charges? And how did the electrons get past the accelerating grid into the recombination chamber?

Could the answer be that the initial conditions of the electrons are "random". And thus the "net" directed activity be that of the positive ions? Ben.brenneman (talk) 20:49, 10 December 2013 (UTC) Ben.brenneman (talk) 20:49, 10 December 2013 (UTC)

I don't have their paper in front of me (my old computer died with many of my pdf archives, those that I didn't move to the cloud), but Ives and Stilwell observed an entire spectrum of lines from their experiment, choosing one which was strong and well-separated from the others. The wavelengths of the emitted photons depended, of course, on internal energy level transitions in the H2 and H3 ions. The relative speed of the ions and the ambient media would have affected the spectral distribution (i.e. the relative strengths of the lines at different wavelengths) but not the wavelengths of the emitted lines themselves (that is, in the frame of the ions). I do not know what form of electronic transition the 4861 Angstrom line represented, but it did not necessarily represent recombination of an ion and an electron. I recollect that one of the images in their paper showed quite dramatic changes in the spectra at different voltages, but you should take my my recollections with a grain of salt. I'll see if I can get to the university library in the next few days to verify what I remember of the paper. Good questions! Stigmatella aurantiaca (talk) 11:28, 11 December 2013 (UTC)
The article on Canal rays should answer many of your questions. Stigmatella aurantiaca (talk) 12:40, 11 December 2013 (UTC)