Re: Astronomy in SF- Astronomical Society of the Pacific

Sea Wasp wrote:
Mike Schilling wrote:


Left foot:. The instantaneity of telepathy..
Right foot: The asymmetry of time dilation when Tom and Pat are
trying to communicate.

What's the issue here? I've heard it mentioned multiple times, but
regardless of "relativity" in the sense of "no privileged frame",
there's actual objective facts -- which insofar as relativity is
concerned, are accurately portrayed if I understand it -- which is
that the twin that goes out comes back younger than the twin that
stays, and that for the twin on board the ship when it hits
relativistic velocities one second of his perceptual time represents a
lot more distance/time for his brother.

The issue is that "velocity" is a relative term, not an absolute one. The
twin who comes home ages less because he had to accelerate (change velocity)
to do so. If there's no acceleration, say if one twin stays on Earth and
the other one travels at a constant .99c relative to Earth, the situation
remains symmetrical: each perceives the other as compressed in the direction
of relative travel, heavier, red-shifted, and time-dilated.


.

Relevant Pages

  • Re: A New Solution to the Twins Paradox, and Others
    ... I will say one thing about the ENDLESS series of posts on the twin paradox, because a lot of these guys are NOT stupid; they are absolute PROOF that something is missing, or at least extremely misleading, in the normal explanation, because the actual math is very basic and fairly straightforward. ... Furthermore, let's say that twin B accelerates in just 1 hour to a velocity of 0.866c as seen by A and B, and stays at that velocity for several years until just before he gets back, when he decelerates in an hour to zero. ... That is both false and silly, but I THINK that many people -- perhaps even a few physicists, I'm not certain -- believe that this is what relativity is all about, that "according to relativity," it really is B's velocity relative to A, and ONLY B's velocity relative to A, that determines B's age when he returns to A. ... It would be a very understandable error, because when two INERTIAL observers C and D look at each other, and remain inertial the whole time, then C really does appear to D to be slower, heavier, and shorter than normal, and vice-versa, D also appears the same to C. ...
    (sci.physics.relativity)
  • Re: SRs Basic Mistake.
    ... see if you can state the principle of relativity ... This only works in the direction that light is traveling ie no length ... The velocity of B relative to A equals the velocity of A relative to B. ... the Twin Paradox is a violation of. ...
    (sci.physics.relativity)
  • Re: Time Dilation flaw: Reciprocity is a liability not a feature.
    ... >> Relativity you can't specify a velocity to any object. ... > always measure ones velocity relative to the other twin. ... > will experience forces of acceleration. ...
    (sci.physics.relativity)
  • Re: Twin Paradox is a blasphemy to Relativity
    ... >either one's velocity without infringing on Relativity and defining an ... No one talks about acceleration vs. deceleration in the twin ...
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  • Re: Whats the beef with Einstein?
    ... Pointing out experimental evidence in support of relativity ... >>And then there is the twin paradox. ... >>distant planet that the traveling twin visited before he ...
    (sci.physics)