Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Kryptid on 26/04/2008 03:33:45

Title: Is there any way to tell if a black hole has charge?
Post by: Kryptid on 26/04/2008 03:33:45

If a black hole possesses charge, how would you know? The electric field wouldn't be detectable, would it? I meant the virtual photons that make up the electric field shouldn't be able to get out of the black hole. Does possessing electric charge change some observable property of a black hole? Also, I've heard that black holes cannot have magnetic fields. Why is this? Can't you generate a magnetic field by moving an electric charge, in this case, the electrically-charged black hole? Or could the magnetic field lines simply not get through the event horizon?

Title: Is there any way to tell if a black hole has charge?
Post by: graham.d on 26/04/2008 09:37:15

If a black hole has charge you would indeed see the electric field resulting from this (as far as I know). You may be right about the lack of a magnetic field from a perfect black hole, though I am not sure (no time to research this). But, more practically, a black hole usually has a whole gamut of stuff, incuding charged particles, falling into it from decaying orbits. These would be expected to have an associated magnetic field. Rotating neutron stars can certainly have a magnetic field associated with them as this is though to be the reason for the pulses from pulsars.