Re: What is "local time"?

On Mon, 14 Oct 2024 11:28:45 +0000, Richard Hachel wrote:

What is "local time" in relativity?

So long as we can cut out the e=mcc crap we can talk about relativity.
Local time is what your watch or clocktower says provided they function
properly.
Local time will be different a millimetre away between time zones.
So it is arbitrary as to where timezones are constructed. Then there is
such an arbitrary thing as daylight saving.
These days we believe that the world turns round and round continuously,
instead of staying put with the sun, stars and moon going around us in
fixed crystal spheres.
Part of the reason we don't think so has to do with astronomy. The
angular position of distant stars varied with time, becoming exact after
a little over 365 days.
That period forms the calendar which has leap years inbuilt to account
for the little extra time for a complete revolution.
All days are said to have the exact same time and here the word time has
relation to one revolution on one hand and about 365 rotations on the
other.
The key event interval then for the measurement of time related to the
alignment of stars. Which is absolute and not arbitrary.
Time as seen by the watch varies from place to place. That is because we
want it so. We could in theory have one standard time everywhere, never
put our clocks front or back. That is confusing from the practical point
of view when people travel. So timezones have to exist.

>
1. Is it the chronotropy of the local frame of reference?
>
2. Is it the time noted on the watch of a given observer?
>
This is obviously not AT ALL the same thing, and I suspect that many
physicists speak without knowing what they are talking about.
>
Perhaps I could be more precise here.
>
What are we talking about?
>
R.H.