Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/5/84; site mordor.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!bellcore!decvax!genrad!panda!talcott!harvard!seismo!ut-sally!mordor!@S1-A.ARPA,@MIT-MC.ARPA:Ghenis.pasa@Xerox.ARPA
From: @S1-A.ARPA,@MIT-MC.ARPA:Ghenis.pasa@Xerox.ARPA
Newsgroups: net.space
Subject: Closed Universe and the Twin Paradox
Message-ID: <2106@mordor.UUCP>
Date: Thu, 6-Jun-85 12:35:50 EDT
Article-I.D.: mordor.2106
Posted: Thu Jun  6 12:35:50 1985
Date-Received: Sun, 9-Jun-85 01:43:33 EDT
Sender: daemon@mordor.UUCP
Lines: 25

From: Ghenis.pasa@Xerox.ARPA

>> The key to the twin paradox is that the travelling twin goes on a
ROUND
>> TRIP, so his frame of reference is an ACCELERATED FRAME (you cannot
>> return to Earth without changing direction, and you cannot change
>> direction without acceleration) whereas the stationary twin has an
>> INERTIAL FRAME. This is what makes their frames of reference
>> non-equivalent, thereby they will experience time differently. 
>
>What if we assume that the universe is closed? Then it would be
possible to 
>return to earth without changing your accelration. What happens then?

(You mean without acceleration ...)

Interesting thought.  This would lead to a paradoxical situation when
the twins met again.  Since both would have had inertial frames of
reference, their ages should be the same (the symmetry of the thought
experiment requires this). However, each will expect the other to be
younger due to the perceived time dilation (Doppler effect).

Summary: The assumption of a closed universe leads to a contradiction. 

Does this rationale DISPROVE the notion of a closed universe?