In this scenario one friend doesn't go anywhere. The other friend does the travelling.
harry On Fri, Feb 21, 2014 at 2:19 PM, Roarty, Francis X < [email protected]> wrote: > I don't see why the "direction" of the 2 friends matter, dialation is an > effect of the velocity wrt C ... no vector is involved, just a trigonmetric > relationship of the spatial plane to another dimensional axis. Bothfriends > slow down the same amount regardless of direction and the only dilation is > between themselves and the outside stationary world they are passing thru > if they have the same velocity.. when they meet up they should however find > their time quite different from that read on a clock at their stationary > meeting place. > > > > *From:* H Veeder [mailto:[email protected]] > *Sent:* Friday, February 21, 2014 2:06 PM > *To:* [email protected] > *Subject:* EXTERNAL: Re: [Vo]:Time Dilation impossibility > > > > > > > > On Wed, Feb 19, 2014 at 9:50 PM, Eric Walker <[email protected]> > wrote: > > On Wed, Feb 19, 2014 at 3:25 PM, H Veeder <[email protected]> wrote: > > > > Imagine two friends with synchronized watches. One friend boards a train > and zips away for a time at near c and then gets off and walks back to his > friend > > so that they can compare the time on their watches. Which watch is ahead? > > > > Using the principles of SR I can come up with contradictory answers. > > > > I'm curious what the two scenarios are. > > > > Eric > > > > > > > > Each friend should see the other's watch tick more slowly according to > special relativity. Therefore when they meet up again, both watches should > record the same elapsed time, but what happened to the time-dilation effect > on the passage time? SR ends in contradiction when watches are compared > after the travelling. > > > > Dave mentions that acceleration might play role in resolving the > contradiction. I have heard that reason too, but it strikes me as hand > waving. Even if acceleration has to be factored in, the ratio of time spent > accelerating to the time spent travelling at uniform speed near c can be > assumed to be arbrarily small so that the acceleration becomes irrelevant. > > > > Harry > > > >
