SR paradox - help!

From: DavidBowman (dt041054_at_yahoo.com)
Date: 02/06/05 

Date: 5 Feb 2005 18:15:13 -0800

This question was inspired by a single sentence in a post by Kenseto to
prove his aether theory. He got the tongue-lashing he deserved... but
the problem still haunts me.

So I want to expand and instantiate it, and present it as a legitimate
paradox that I can't resolve -- but hopefully you can, if you would be
so very kind.

======

The Bureau of Standards sets up two identical beacons. The one on
earth fires an omnidirectional radio pulse. When that energy reaches
the moon one second later, it's twin beacon on the moon detects it and
fires another omnidirectional burst.

One second after that, the radio pulse from the moon reaches earth and
is detected by the earth beacon which fires another omnidirectional
blast ...and so on.

Each beacon is triggered by the other, and alternately fires a radio
pulse every two seconds. So a guy on Mars hears a "click" on his radio
reciever at one-second intervals.

So far, so good.

BUT:
A guy in a spaceship moving .999c must also hear the same clicks at
one-second intervals, since we all agree that the earth-moon distance
is one light-second, and c is the same for everybody.

The problem is that this gizmo can be used as a universal time standard
-- literally. Everyone in the universe can listen to the master clock
ticking away once per second, no matter how fast they're moving --
including the two guys in the twin paradox.

The only way out I can see is if time dialation causes the guy in the
spaceship to observe a light pulse travel from the earth to the moon in
an arbitrarily short time, limited only by how fast his rocket can go.

But if that's the case, you can get superluminal communication,
because:

1) you can make radio travel from the earth to the moon in an
arbitrarily short time, and

2) the space ship is a finite number of earth-moon distances away.

=========

"Well Hal, I'm damned if I can find anything wrong with it!"
     -- David Bowman to HAL9000 in the pod bay

=[ d

Relevant Pages

  • Re: SR paradox - help!
    ... > earth fires an omnidirectional radio pulse. ... > the moon one second later, it's twin beacon on the moon detects it and ... > A guy in a spaceship moving .999c must also hear the same clicks at ...
    (sci.physics.relativity)
  • Re: Barnacles on writers other than Heinlein
    ... Radio in space was considered a hard problem ... contact with a ship in flight. ... Moon_, there was again no radio contact until the intrepid crew had ... returned to Earth. ...
    (rec.arts.sf.written)
  • Re: Barnacles on writers other than Heinlein
    ... Michael Stemper wrote: ... Radio in space was considered a hard problem ... Moon_, there was again no radio contact until the intrepid crew had ... returned to Earth. ...
    (rec.arts.sf.written)
  • Re: Missed It By That Much
    ... Aboard for the Moon", Amazing Stories, April, 1947. ... radio set which beams radio waves of such high frequency that we are ... in conjunction with the television apparatus ... project back to earth the actual scenes as we are witnessing them. ...
    (rec.arts.sf.written)
  • Re: YASID: Pyramids in Space?
    ... Moon, other planets, and even the stars seemed just decades away, ... Possibly a spaceship might carry a *huge* radio transmitter ... Earth; but the individual spacesuit radios? ...
    (rec.arts.sf.written)