Re: Twin paradox revisited ll

bill says...

According to one of my books - the Galilean Principle of relativity is
that the traveler cannot conduct any internal dynamic experiment that
would permit him to determine if he is at rest or is moving with a
uniform velocity *without reference to external information* i.e. on
the assumption that his cabin has no window however, having been
accustomed to a 'fixed firmament' whilst still on the planet our
traveler can see the stars and the planets rushing past him.

On the basis that there is no internal experiment that he can conduct
as per 'the phenomena of electrodynamics as well as of mechanics
possess no properties corresponding to the idea of absolute rest' the
traveler can only conclude, being of the opinion that he is at rest,
that it is the universe that is rushing past him.

Having experienced the force of acceleration as he takes off from the
planet the traveler, after taking his foot off the gas pedal, would be
exhibiting solipsism if he then concludes that it is the universe that
is moving - not him.

I thought I just went through this. The fact that the traveler
is the one who experienced acceleration does *not* establish
who is at rest and who is moving. It only establishes who is
*accelerating*.

Do you understand the difference between velocity and
acceleration? Acceleration is a *change* in velocity.
There is no way to establish your *absolute* velocity,
but you can establish *relative* velocities. You can
establish your velocity relative to another observer,
and you can establish your velocity now relative to
your velocity ten seconds ago.

Having experienced the force of acceleration during take off and
having thereby concluded that he is moving away from the planet

He can't conclude that. Look: suppose you are on the roof of
a moving train. You jump to the ground. After a brief period
of acceleration, you are now at rest on the ground. You are
the one who felt the acceleration, not the train. Can you
therefore conclude that you are the one who is moving, while
the train is at rest? No, of course not.

--
Daryl McCullough
Ithaca, NY

.

Relevant Pages

  • Re: Twin paradox revisited ll
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  • Re: Twin paradox revisited ll
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    (sci.physics.relativity)
  • Re: Twin paradox revisited ll
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