Re: relativity of simultaneity - real or perceived?

Dear Curious:

"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?

Yes.

> Or do the two frames just APPEAR to have
> a different timing of events?

A distinction without a difference.

> 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?

"Measurement", rather than "perception".

> 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?

Using... relativity perhaps? If you accept the postulates of SR
or LET, this allows you to make this determination. Without it,
you would expect a measureable variance.

> If two photons pass opposite ends of a
> box at the same time as measured by an
> observer at rest wrt to the box,

Rather "light signals", than "photons". Photons are quantum
objects, and individually have neither "path" nor "position".

> could they ever be correctly
> calculated to be in the same positions at
> some point in time to any observer at any
> speed?

No.

> Or would they be correctly calculated to pass
> the ends of the box at different times by that
> other observer?

You have some underlying belief in "truth" or "absolute". Any
measurement is as "correct" as any other. SR (and LET) simply
allows us to calculate what another frame would measure. Neither
is "correct", or both are "correct".

It is much like calculating what your speed actually is if you
put taller or shorter tires on your car. The speedometer
actually only measures drive axle rpm (for most cars), the tire
size and rear axle gear ratio are calibrated into its display of
speed.

David A. Smith


.

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