1 8th August 22:52 dlzc External User   Posts: 1 Charge and black holes Roughly speaking, there are no geodesics that extend from "inside" the event horizon into the Universe at large. If I selectively drop 10^30 electrons into a black hole, and somehow keep an attendant number of protons from doing a similar dive, does the hole end up with a net charge? If so, where does the Universe perceive this charge to reside? David A. Smith

 2 8th August 22:54 starblade13 External User   Posts: 1 Charge and black holes It resides in the electrons right before they fall into a black hole. What we should be asking is what happens to the color charges if a nucleon if it falls into a black hole, at least, the color charges at the event horizon. The same could be asked of the weak charges of neutrinos or antineutrinos. (...Starblade Riven Darksquall...)
 3 9th August 15:41 dlzc External User   Posts: 1 Charge and black holes Dear Starblade Darksquall: news:... I have heard people discuss how objects appear to always be stuck at the event horizon (like klingons), and they just get dimmer and dimmer. I wonder what "dimmer" means to a charge? David A. Smith
 4 10th August 14:47 dubious External User   Posts: 1 Charge and black holes dlzc@aol.com $$formerly$$: Yes, but there is a limit to the charge a black hole can have which depends upon its mass and total angular momentum. I assume that it "resides" in the the same place the mass "resides" - the singularity. I don't think the word "resides" makes a lot of sense when referring to the singularity, though. Personally, my inclination would be to give the singularity the bare charge on the electrons and take the charge of the black hole outside the horizon to be the charge as measured once one includes the vacuum polarization.
 5 10th August 14:47 zed External User   Posts: 1 Charge and black holes Do charge potentials propagate ? Why would they be confined by an event horizon ?
 6 12th August 00:10 dlzc External User   Posts: 1 Charge and black holes Dear Bilge: Thanks. I was just wondering if the E-field of a charge was written into the Universe way back when, and the particle entered the hole, how its virtual photon(s) could express outside (as in the Universe side of) the event horizon. Mixed metaphors I guess... Answers accepted as I'll understand your answers about the same time as we actually get to visit the neighborhood of a black hole. David A. Smith
 7 13th August 12:12 clade External User   Posts: 1 Charge and black holes Hello, You´re right: they *appear*. An electric charge does not become "dimmer". You will end up with a black hole that carries the sum of the charges of the electrons you have dropped in (because electric charge is conserved). You can measure this charge by measuring the black hole´s electric field. regards, Jürgen
 8 24th August 07:36 dubious External User   Posts: 1 Charge and black holes Starblade Darksquall: Nucleons are colorless, so an infalling nucleon has a net color charge of zero. Ditto for mesons. The only way to give a black hole a net color charge is with a quark or gluon. It's pretty hard to come up with an example of how to do that. This isn't as hard to address. The charge Q is related to the weak hypercharge (current) through the relation: Q = T_3 + Y/2 For a neutrino, T_3 = 1/2 and Y = -1, so T_3 + Y/2 is also 0. In other words, the electric charge and weak charge are different manifestations of the same thing. It might be more interesting to ask if a black hole could beta decay. If all neutrinos are massive, then I think it's not possible. If one of the neutrinos is massless, then it might be possible.
 9 24th August 17:22 dlzc External User   Posts: 1 Charge and black holes Dear Bilge: Not sure what you mean by "beta decay". If no geodesics extend from inside to the Universe side, I am assuming you don't mean an electron would be ejected from inside the event horizon... David A. Smith
 10 31st August 05:36 dubious External User   Posts: 1 Charge and black holes dlzc@aol.com $$formerly$$: No. I was imagining something like the following. Hawking radiation results involves photons from vacuum fluctuations at the horizon. When a virtual photon pair is produced, if one of the pair is absorbed by the black hole, and satisfies the "on mass shell[1]" condition (i.e., becomes real and propagates inside the horizon), then the second photon must go "on mass-shell" and propagate as well. If it's trajectory doesn't take it inside the horizon, then it escapes as hawking radiation. Now, instead of photons, picture the fluctuation of a W+/W- pair, such that the W+ ends up propagating inside the horizon and satisfies the on mass-shell condition. The W- must then go on mass shell and propagate. Assuming it decays before its trajectory takes it inside the horizon, the decay looks like this: e-, \mu- or \tau- / W- ----> \ - - - \nu_e, \nu_mu, or \nu_tau If one on the neutrinos is massless, I would assume it could escape, just as a photon does. The lepton would fall back into the hole. This is all pretty much a guess and doing the actual calculation to see how probable such a process might be, would be difficult (for me, at least).