Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site noao.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!hplabs!hao!noao!sharp From: sharp@noao.UUCP (Nigel Sharp) Newsgroups: net.physics Subject: Re: Re: "big bang" a big bust? Message-ID: <444@aquila.noao.UUCP> Date: Wed, 5-Dec-84 12:01:39 EST Article-I.D.: aquila.444 Posted: Wed Dec 5 12:01:39 1984 Date-Received: Sun, 9-Dec-84 03:26:32 EST References: <127@sdcc12.UUCP> <17266@lanl.ARPA> Organization: Natl. Optical Astronomy Observatories, Tucson, AZ USA Lines: 37 > Information does NOT escape from a black hole. Correct. The information was always there, locally. As the state of the object changes towards being a black hole, changes in the locally obtained information about that state propagate outwards at the speed of light. (Incidentally, the available parameters are mass, angular momentum, charge and [mathematically acceptable] magnetic monopole moment.) > Note also that light DOES escape from a black hole. A black hole radiates > like a blackbody whose temperature ..... NO NO NO NO NO NO NO NO NO NO NO NO NO NO NO NO NO This is precisely the sort of remark which confuses people. The quantum mechanical effect by which a black hole radiates energy as a black body, and therefore loses mass, eventually disappearing in a puff whose properties noone has adequately calculated, is NOT THE ESCAPE OF LIGHT FROM THE HOLE. Using the word `escape' implies that something inside gets to the outside, whereas what is happening is very difficult to explain - energy transfer is happening by the addition of energy to external states and the removal of energy from internal states - in fact, the addition of negative energy states. I'm not explaining this very well: I have still to come up with an adequate way. The mathematics seems to make sense, and the radiated spectrum is black body, but there is no possibility of anything moving from the inside to the outside. The black body nature is a reflection of the destruction of information. > ................ but no information > about the internal structure of the black hole (if any) is carried by this > radiation. The original poster (post-person ? post-being ? :-) ) probably knows what he's talking about, and this is correct, but I have been trying for some time to persuade people to be very careful about their language when explaining any of a black hole's effects. It is difficult to translate mathematics, and we have more trouble explaining why, when x said y, he really didn't mean it, than we do explaining the phenomena. (`But Carl said ....' `Yes, but what he meant was ...' `Then why did he say ...' Sigh.) -- Nigel Sharp [noao!sharp National Optical Astronomy Observatories]