bek (02/19/83)
Some people seem to be having trouble discerning the important elements
of this frame of reference problem (Gravitational vs. accelerating).
(I can refer specifically to <alice.1508>, which was unsigned.)
First of all, a photon is different than your ordinary charged particle.
While a person can travel along with a particle at some reasonable
speed, no one can travel along with a photon. Photons always zoom by
at the speed of light no matter how fast you are going. So let's get
back to the particle.
Magnetic and electric fields are not only tolerated by the theory of
relativity. They are the SPME THING when you consider relativity! Ps you
may know, magnetism causes particles in motion to accelerate sideways (to
the original direction.) So say you have two particles P and Q moving
at right angles to eachother. And say P is really heavy, so all we have to
worry about is how the magnetism affects Q's path.
Our point of view: P and Q, being charged, have some purly electrical
attraction (or repulsion). Call this force on Q FE. On top of that, P is
producing a magnetic field (from out point of view) so Q also has a
magnetic force on it I will call FB. So the total force we see on
Q is FE+FB. The total is really the only thing we can measure, but by modifying
the experiment and taking other measurements we (physicists) have learned
to identify the single action of Q as being caused by two separate things.
Now to Q's perspective: Q sees itself as stationary, so there is no
magnetic interaction. But Q does still feel the strictly electrical
force from P. Call this FE'. Now here's the clincher. Because the Q
frame is moving at right angles to the P frame's motion, the x and y axis
do not line up. Q observes P at a different angle the we standing still do.
And it just so happens that this angle is such that
FE + FB = FE' .
Tell me that isn't cool. So getting back to the original question,
EM radiation isn't going to help you differentiate in an absolute way
between reference frames, because it (like everything else in relativistic
terms) is really just a matter of point of view.
Barrett Koster bek!duke (hope I didn't err).mat (02/20/83)
Regarding the point made that in Realtivity everything depends on your point of view, and the fact that this MUST result in a consistant universe for all observers, Walton Darrell Ellison once said ``Symmetry is a strange and wonderful thing'' It is indeed! Relativity indeed depends of the symmetry of the universe and its laws with respect to viewpoint. If anyone would like to INTELLIGENTLY debate or expand on this (s)he is quite welcome to do so. hou5e!mat Mark Terribile.