Talk:Transverse Doppler effect

message: Hi the classical Doppler prediction is not "no effect at all", but an effect that depends on one's speed relative to he ether. I hope I don't need to explain that, and that that error was just due to oversight. Harald88 09:56, 31 October 2005 (UTC)
thread_title:  little error on classical prediction 

message: The explanation about the "why"of the effect is very incomplete: the main point to include but that is lacking is time dilation.
About the recent edits by Scienceapologist: No, IMO it certainly may NOT also be referred to as aberration redshift! And neither did I ever see such an idea in peer reviewed literature. As this may cause a lot of confusion, as well as the other related material, I reverted it.
Please provide first a peer reviewed reference according to which this is so. Harald88 05:03, 17 December 2005 (UTC)
replies: text: No problem. Apart of that, the sources are in the time dilation article as well as in most text books on SRT. Harald88 19:54, 19 December 2005 (UTC)
thread_title:  the mess seems to be increasing 

message: Should these two articles not be merged? Harald88 18:02, 24 December 2005 (UTC)
thread_title:  [[Relativistic Doppler effect]], in particular: [[transverse Doppler effect]] and '[[time dilation]]' 

message: The classical forerunner of SRT is the discipline of "Optics of moving bodies", compare, e.g., A. I. Miller's historical account of SRT. This theory which is based on Bradley's aberration theorem  does, of course, also predict the so-called transverse Doppler effect. Velocity aberration brings about that the apparent direction of the light source observed never coincides with its true geometrical direction. Thus, if the apparent direction of the light source makes a right angle  with respect to the observer's line of motion (which is the condition under which the "transverse Dopper effect" is measured), its true direction deviates from the axis of the telescope by a small angle, the aberration angle. This discrepancy between apparent and true directions gives rise to the transverse Doppler effect, a redshift of second order. But at that time, little attention was focused on effects of second order. In his original paper of 1842, C. Doppler simply approximated Bradley's theorem with the help of a cosine function. If this crude approximation is made, the transverse Doppler effect is suppressed. 
Apart from this, the classical transverse Doppler effect does also exist in acoustics, where also the aberration law has to be observed; compare, e.g., the corresponding section in the book Theoretical Physics" by Georg Joos.84.153.104.56 14:31, 12 September 2006 (UTC)
thread_title:  Assertions found on the classical transverse Doppler effect in textbooks on SRT are indeed misleading 

message: The "political" problem we have here is that differences in nomenclature, and differences in the unambiguous physical outcomes of experiments (say, the number that will be shown on a particular frequency-meter), have become all mixed up together into an ugly confused mess. That mess doesn't originate here in the article and discussion page, or with us, it originates out there in the research community. They fouled things up, and the confusion here is an accurate representation of the mess they those guys created, and never got around to cleaning up. 
Some SR sources insist that the term "transverse redshift" ought properly to be reserved for effects under special relativity, because that's the common usage. We might be able to get away with that if everyone realised that the literal meaning of the term then isn't quite the same as how it is used. If we accepted this, then when other theories predicted similar or indistinguishable effects in the same experimental setup, then even though those shifts would be "transverse" and "red", they couldn't be referred to as "transverse redshifts", because their conceptual basis and explanation would be different to that of the SR effect.   
But SR sources also say that we can test SR by carrying out experimental verifications of the transverse redshift effect. You see the problem. There are two slightly different understood "standard" meanings here, and they clash: One says that this effect doesn't ever appear in other theories by definition, and the other treats it as the simple uninterpreted physical outcome of an experiment that can be used to assess the relative worth of different theories. 
Fuse these two different meanings together and you can get the sort of "junk logic" that sometimes appears in SR texts, where they say that SR predicts the effect, we find the effect, the effect is known to be unique to SR, and therefore ... the experimental result can only be explained by SR. It's an invalid conclusion assembled from reasonable smaller component arguments that shift the meaning of a term part-way through a chain of logic. It's a bit like saying saying that the immature fruits of the orange tree outside your window are green, apples are also green, and therefore apples are coloured "orange". One word, two meanings that overlap but aren't entirely interchangeable. 
The way out of this mess would seem to be to allow the term to mean what it says without specifying a single theory (words meaning what they say -- there's a novel concept) or, as a compromise, to allow talk of "classical" transverse effects (or some other similar qualified phrase), so that SR could be allowed its default ownership of the term "transverse redshift" for historical reasons, but we would still have a way of acknowledging the existence of physically-similar predictions under other theories. There have been objections to each of these options. I do understand why some SR enthusiasts may like things exactly the way they are right now, but for things to go on as they are now is not really in the interests of the subject, or the theory. It's not good for a theory's reputation if it seems that the theory is being partly supported by a manipulation of language that makes it impossible for people to mention the existence of similar effects in previous theories. ErkDemon 06:25, 26 February 2007 (UTC)
thread_title:  Experimental success - based on numbers or language ? 

message: If the subscript s means source and o observer, then the equation is backwards.  The transverse Doppler shift increases the observed frequency,
making the light bluer. Clem137 20:43, 10 April 2007 (UTC)
thread_title:  Source & observer wrong. 

message: Would the addition of a diagram help of just confuse?  RJFJR (talk) 16:22, 18 March 2009 (UTC)
thread_title: Would a diagram be useful?