What is the effect of the twin paradoxon?

[Peter Strohmayer]

And because they were born at different places, it is not invariant, if they were born at the "same time".

When you inserted that additional "from the point of view" qualifier you redefined "same age" so that it is frame-dependent and no longer has any physical significance,

For distinct spacelike-separated events A1 and B1 ,
not all observers will regard A1 and B1 as simultaneous

This process of continually updating one's knowledge of a subject is called learning. It's the opposite of religiously adhering to an established view in the face of evidence to the contrary.

This is a frame variant concept.

τ=∫abdτ is invariant only if a and b are.

From the point of view of reference system B, event a is simultaneous with event a' and event b is simultaneous with event b'.

Does an invariant proper time elapse for a mass point B moving - from the point of view of reference system B - on a straight world line on the time axis from event a to event b?

Does no invariant proper time elapse for a mass point B' moving - from the point of view of reference system B - on a straight world line parallel to the time axis from event a' to event b'?

Does this have to do with the fact that the events a and a' and the events b and b' occur simultaneously from the point of view of the reference system B, but not from the point of view of other reference systems?

 

[Dale]

Asked and answered. This thread is closed.