Re: relativity of simultaneity - real or perceived?


"Curious" <anthonyroseuk-curious@xxxxxxxxxxx> wrote in message news:1116036993.415902.212980@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Does 'relativity of simultaneity' mean that an event which is
> simultaneous in one frame of reference, need not be simultaneous in
> another frame?

*Two* events can be simultaneous in some frame.
Simultaneous means "having the same time coordinate as".
So, obviously a event is always simultaneous *with itself*.

> Or do the two frames just APPEAR to have a different
> timing of events?
>
> In the common example of a fast train struck by lightning at both ends,
> simultaneously from the point of view of the embankment, and an
> observer on the train sees the lightning at different times, is that
> not merely a result of his *perception* of the events?

No. Seeing has nothing to do with anything.
The time of a coordinate is usually calculated from having seen
something. If I see a lightning flash when my clock says T, then
the time of the flash is T minus something.

> If he were a
> scientist, could he not calculate the time taken for the light to
> travel and realise that the lightning did indeed strike at the same
> time?

Yes, that is the idea.

>
> If two photons pass opposite ends of a box at the same time as measured
> by an observer at rest wrt to the box, could they ever be correctly
> calculated to be in the same positions at some point in time to any
> observer at any speed? Or would they be correctly calculated to pass
> the ends of the box at different times by that other observer?

I have tried to explain how this stuff works when answering
your previous question. You can go back and specify what
you didn't understand.
If you are really curious, that is.

Dirk Vdm


.

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