Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!decvax!harpo!seismo!hao!hplabs!sri-unix!gwyn@brl-vld From: gwyn%brl-vld@sri-unix.UUCP Newsgroups: net.physics Subject: Re: Another Thought(less) Experiment - (nf) Message-ID: <13497@sri-arpa.UUCP> Date: Wed, 9-Nov-83 21:59:05 EST Article-I.D.: sri-arpa.13497 Posted: Wed Nov 9 21:59:05 1983 Date-Received: Sat, 12-Nov-83 14:15:10 EST Lines: 14 From: Doug Gwyn (VLD/VMB) No, the situation is not symmetrical. In fact the "paradox" of the twins is not the time dilation for a moving twin, it is precisely the argument you were giving, namely, that each observer could consider himself at rest and the other as the one undergoing time dilation, apparently leading to two differing predictions as to the relative ages of the observers when the journey is over. The correct answer is that the moving twin is younger than the stationary one (according to their bodies' internal clocks) at the end of the journey. If you plot out the hypothetical trip on a space-time diagram, including the clock pulses, you can see what is happening.