On Tue, Sep 9, 2025 at 1:38 PM Alan Grayson <[email protected]> wrote:
> > > *> I'm not sure the impossibility of absolute simultaneity solves the > problem,* > > > *Watch the video! If you follow what he does step-by-step you will see > that he is right. It's not difficult. * > > > *I wish I was taught the Twin's Paradox this way! > <https://www.youtube.com/watch?v=GsMqCHCV5Xc&t=2s>* > > > > *I'll definitely watch it, very soon, but a-priori the impossibility of > absolute simultaneity can't solve the paradox because it's not its cause. > Can you succinctly state the cause of the paradox?* > > > *Yes, i**t's impossible for all observers to agree that two events are > simultaneous unless they happen at the same place. But I'm sure that is a > little too succinct to convince you, that's why you need to watch the > video, it's only a little longer. And neither acceleration nor General > Relativity is the key to resolving the twin "paradox", as far as this > matter is concerned you'd do best to forget about them. * > > > *The twins ARE at the same place when the thought experiment begins, and > since they're juxtaposed when the thought experiment begins, their clocks > are synchronized without anything to do with absolute simultaneity! And > second, using a spacetime diagram, the paths are unequal, and that's > because only one path represents the accelerating twin who is traveling. If > you don't believe me, look at (ds)^2 for each twin to confirm my claim. > Take notice of the second order differentials. AG * > > > *CORRECTION: The spacetime path lengths are INVARIANT, but along the path > of the stationary twin, the second order differentials are zero since that > twin is NOT accelerating, but those second order differentials for the > traveling twin are NON-ZERO since he's accelerating. Now look at the proper > times along both paths and you'll see that it's greater for stationary twin > because the path lengths are invariant. Hence, stationary twin ages more > than traveling twin! Note also that this analysis uses SR. If the video is > using a simultaneity argument, then the video is wrong. AG* > *In the time it took you to write all that you could have just watched the video. * * John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>s* > *ffff* -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAJPayv3gNzMcVDCbiXe3k9j-%3D2Smyjk_vTQxf4iRG%2BoNUwTgHw%40mail.gmail.com.
