B Twin paradox explained for laymen

[FactChecker]

Flat spacetime = SR
Curved spacetime = GR

I think there was some argument in the early days about which label to apply to non-inertial frames in flat spacetime. But ultimately there's no physics in non-inertial frames that isn't in inertial frames - just the maths is harder. There is new physics in curved spacetime. So it makes sense to draw the dividing line there.

I think that I am finally getting to the bottom reason for my stubbornness on this issue. I had the very definition of SR and GR wrong. Sorry. I think I owe an apology to many people.

 

[PeterDonis]

I had the very definition of SR and GR wrong.

As I commented earlier, so does the Gron paper that was referenced. There are other sources in the literature that also get this wrong; a big reason for that is that it took a fair amount of time after relativity was first discovered for physicists to get clear about this, because of the issue @Ibix mentioned with regard to non-inertial frames. Even Einstein wasn't entirely clear about it in all of his writings.

 

[Dale]

Does it have to do with the curvature of the space?

Yes. Flat spacetime is SR and curved spacetime is GR

 

[vanhees71]

"True gravity", i.e. the gravitational interaction is within GR covariantly characterized by curvature. If there's no gravitational interaction (or rather can be neglected as in particle physics) then SR is valid.

 

[PeterDonis]

I am pointing out that time is is also affected by energy in space. An energytime.

This is personal theory, which is off limits here. You have now been banned from further posting in this thread.