From: utzoo!decvax!harpo!eagle!mhuxt!mhuxj!mhuxi!aluxz!ltn
Newsgroups: net.physics
Title: Re: General Relativity Paradox (?)
Article-I.D.: aluxz.1107
Posted: Thu Feb 17 08:54:25 1983
Received: Mon Feb 21 20:50:59 1983
References: sri-arpa.453

Paradox:  General relativity says that an observer in a box cannot tell if he is
   undergoing uniform acceleration, or is sitting in a gravitational field.  A
   charge carried in the box would radiate if accelerated.  But if the box and
   charge are in a gravitational field, then either:
   A)  The charge radiates, in which case, where does the energy come from?
   B)  The charge doesn't radiate, in which case there is a difference between
       a gravitational field and uniform acceleration.

Resolution:  The charge in the gravitational field does *not* radiate.
   However, the observer in the box undergoing uniform acceleration (with the
   charge that *does* radiate) will *not* see any radiation.  This is because
   he remains at rest with respect to the charge.  A magnetic field is generated
   by a moving electric field; since he is at rest, there is no motion, hence
   no magnetic field and no radiation  (in the observer's frame).
   (Maxwell's equations are relativistically correct, despite having been 
   developed 40 years before Einstein came along.)
   Thus in either case, the observer sees no radiation from the charge, and thus
   cannot tell if he is undergoing acceleration or is sitting in a magnetic
   field.  An outside observer, can of course, tell which is the case.

Les Niles, Bell Labs  Murray Hill  (aluxz!ltn)