crummer@AEROSPACE.ARPA (06/18/85)
From: Charlie Crummer <crummer@AEROSPACE.ARPA> > Received: by sri-unix.ARPA (4.12/4.16) > id AA26679; Sat, 15 Jun 85 00:04:41 pdt > Message-Id: <8506150704.AA26679@sri-unix.ARPA> > Date: Wed, 12-Jun-85 06:17:56 PDT > To: physics@sri-unix > From: merrill%raja.DEC@DECWRL.ARPA (Rick - Font Mgr. for Hardcopy Engineering) > Subject: One Quick Question > Article-I.D.: <2627@decwrl.UUCP> > >Path: decwrl!dec-rhea!dec-kirk!williams > >Subject: Two quick answers > > > > The time traveler travels close to the speed of light in > >relation to the inertial frame. He travels into the future. > >... John Williams > One thing I'd like cleared up: does the traveler moving at CONSTANT > VELOCITY move FURTHER into the future the longer he travels, or > did he move into the future by Accellerating To Speed? > Rick Merrill At any speed < c there is no time travel. To achieve a speed >= c requires infinite force since the relativistic mass increases without bound as c is approached. Cosmic rays travel very close to c (as do particles in any large accelerator) and they do not travel backwards in time. (See Feynman's books for the description of a positron as an electron travelling backwards in time. Since CPT is conserved, it seems, C amounts to T where P is conserved. C, P, T, are charge conjugation, parity, and time-reversal.) --Charlie