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Electrodynamics paradox

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by , 06-11-2011 at 06:49 PM (2605 Views)
This is a question about general relativity and classical electrodynamics. Consider an electron freely falling under the influence of gravity. In it's own frame of reference it feels no acceleration and should not radiate (principle of equivalence). But in the frame of the body exerting the gravitational force it is accelerating, so it should radiate. How can it radiate in one frame of reference and not in another?

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  1. Neverfly's Avatar
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    One thing to remember is that everything is relative. So, although the thought experiment can place certain assumptions, they are relative to the observation of the OP.
    The thought experiment presents a special presentation of a classic situation.
    The thought experiment as placed HERE assumes too much- it states that the electron will not radiate at all from its own reference frame.
    The very short answer is that from any reference point the electron will radiate. The difference is in how much can be measured depending on the change of momentum within each reference frame.
    The measured radiation is proportional to the charge squared and inversely proportional to the mass squared.
    signal2noise likes this.
  2. rainbow's Avatar
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    IMO you would not expect an unaccelerated electron to radiate, even a little bit. It should just sit there. For one thing, it would have to get the energy from some where. Or am I missing something?
  3. profmesmus1's Avatar
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    It will not radiate in the gravitational well either, because, under the circumstances its apparent movement is a result of the curvature of space itself rather than a standard field effect with what one would see with electromagnetism. If it radiated the same in either circumstance, then you would have a truly unified field.