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]<mailto:[email protected]>> wrote: On Wed, Feb 19, 2014 at 3:25 PM, H Veeder <[email protected]<mailto:[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
