X-Message-Number: 367
From att!compuserve.com!71450.1773 Fri Jun 28 19:02:13 EDT 1991
Date: 28 Jun 91 17:39:44 EDT
From: "Steven B. Harris" <>
To: <>
Subject: Twin Paradox ala Wowk
Message-Id: <"910628213944 71450.1773 EHB56-1"@CompuServe.COM>

Dear Cryo-Science Nuts: 

    I'm a little skeptical of Brian's explanation, because it
predicts that Doppler shifts that arise when one object ac-
celerates relative to another, are dependant on the distance
between objects, and this I don't believe.  In the Mossbauer
experiments, the increased shift with radial distance was, I
believe, due only to the fact that (unlike the case on an
accelerating ship) the Earth's g field is divergent so that its
strength varies radially from point to point.  In Brian's
universe, two spaceships at different distances from Earth at the
same accelerations and velocities will NOT receive the same
frequency radio signal from an Earth station.  Huh?   Of course
they will.

   Also, as I read it, Brian's explanation demands that these
very large shifts does to acceleration be detectable even when
relative velocity is zero, and this I don't believe either.  A
ship 10 light years away from Earth, moving at zero relative
velocity, will in Brian's universe see ENORMOUS Doppler shifts
immediately on firing its jets to come home.  I say it won't see
anything until it gets going.  I don't think that there is any
"gravitational potential" Doppler shift at all on such a ship,
and that is one way you can tell the difference between being in
an accelerated ship and being on a planet.  The g field lines in
reality are not QUITE the same.

   Anyone who seriously wants to question the above should
consider what would happen otherwise to an astronaut who ac-
celerated at one g relative to all the stars a billion light
years away.  Think about the potential drop.  If Brian was right
that the Doppler shift was a function of potential drop alone
(instead of velocity and g field differences), any astronaut
foolish enough to accelerate in our universe would be fried to a
crisp by the Doppler-shifted gamma rays from distant stars.

                                      -- Steve Harris

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