Talk:Time dilation/Archive 2019

Some suggestions ... again.
As I expected you made no use of the suggestions I presented on 2nd November 2017. I hope to be more lucky this time ! I think you are fully aware that good quality clocks, and at least atomic clocks , are not sensitive to displacement. And if the clocks are moving at constant speed, that is predicted by the very first postulate of special relativity !

Unfortunately Einstein and his followers never used vectors, and so never spoke of units of time. That was a consequence of the railway examples then currently used. Later on they switched to tensor calculations, again without vectors. So if I try to find direct sources, I find none ! Nobody tells us that the clock of the train controller has the same rhythm than the clock of the station master !

But that is true !!

Please take a look at following statements :

I/ Between two time unit vectors we have :

$$1/ \qquad e_0 \cdot f_0= \gamma=\cosh{\alpha}$$

where $$\alpha$$ is the hyperbolic "angle" between $$e_0 $$ and $$f_0$$. In geometric algebra we write :

$$2/ \qquad f_0=exp^{i \alpha}e_0=(\cosh{\alpha}+i \sinh{\alpha})e_0=\cosh{\alpha} e_0+\sinh{\alpha} e_1$$

$$3/ \qquad i=e_1 e_0=f_1 f_0=e_1 \wedge e_0=f_1 \wedge f_0$$

It is crystal clear that (1) explains completely traditional velocity time dilations and reciprocity !

II/ Taylor and Wheeler introduce wristwatch time for curved time paths. Thus they admitted silently that their watches were not sensitive to displacement !

III/ Finally abstract space time could not exist if there were no units of time and of space !

Thus we may conclude that in the present article there are too much hidden truths. Introduction of chrono-geometry could perhaps be a possible smooth solution ? Cordially. --Chessfan (talk) 18:56, 2 March 2019 (UTC)

Gravitational time dilation
The article repeatedly uses wording that suggests that dilation is related to the strength of the gravitational field. This is somewhat misleading. It should be relatively simple to improve this, as the relevant parameter is the local depth of the gravitational potential well. PhysicistQuery (talk) 00:14, 19 July 2019 (UTC)
 * But according to the literature, time dilation is related to the strength of the gravitational field. - DVdm (talk) 10:01, 19 July 2019 (UTC)
 * I'll look at this when I have a chance. Depth within the gravitational potential well is correct. If the article says that strength of the gravitational field is the relevant parameter, the article is wrong, or at least, worded in a misleading fashion. Prokaryotic Caspase Homolog (talk) 10:34, 21 July 2019 (UTC)
 * Yuck. I had never looked at the article as a whole before; my only previous contribution had had been to add the figure File:Time_Dilation_vs_Orbital_Height.png to replace Time.dilation.to.orbital.height.svg, which was completely messed up and which I requested to be deleted. This article needs a major revamp, but lots of it will have to be done by somebody other than me. I'm OK with the SR parts, but I would not consider myself any sort of expert in GR. Prokaryotic Caspase Homolog (talk) 10:47, 21 July 2019 (UTC)
 * Corrected the egregious errors, but the article as a whole is too much a mishmash for me to tackle. There are more important articles to work on, for instance Special relativity, whose section on dynamics is completely inadequate. Prokaryotic Caspase Homolog (talk) 06:22, 22 July 2019 (UTC)
 * Good action, this. IMO it just needed a little change - DVdm (talk) 06:28, 22 July 2019 (UTC)
 * Thanks! Prokaryotic Caspase Homolog (talk) 06:40, 22 July 2019 (UTC)

Summary
Time dilation is a Galilean transformation calculation, of simple geometry, with the speed of light c being calculated as constant, between two visual light observers of which one is moving and yields the same time for both observers (used correctly). The same equation provides correction for an observer who, by visual perception, has mis-measured time by assuming c2==c1+v, which it does not. Which observer moves matters for doppler, but not for dilation. c is limited to remaining c in space thus there is no second inertial frame it can be in. The observers must observe v by the simple Galilean transform. If light is not used in measurement the equation is completely invalid. — Preceding unsigned comment added by 2601:143:400:547B:94F6:2347:9F50:AC34 (talk) 00:23, 28 August 2019 (UTC)
 * That's overly technical and also unclear. And also unsourced. Try to convey the physical interpretation, while making sure it is attributed to a reliable source. El_C 00:29, 28 August 2019 (UTC)