Black Holes |
Black Holes |
Dec 7 2005, 04:04 PM
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#1
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Newbie Group: Members Posts: 8 Joined: 6-December 05 Member No.: 599 |
any one wanna talk black holes. i'm not a professional or anything. i vaguely remember hearing s. hawkin revising his opinion on it saying it wasnt a "worm hole" anymore and that it just destroys all matter and worth nothing else.
i only make my observations, childlike actually, to that of what happens on earth, and why shouldnt it happen in the rest of the universe. why should anything here (goverening law of physics, etc.) be different anywhere else? just like a tornado, or water running down a drain (or that infamous lake that was drained by accident by some guys drilling and all the water drained into the salt mine, i cant remember the name now but a 6 inch hole sucked in a tanker), why wouldnt a black hole be that "event" that punched a hole into another "dimension/galaxy whatever" with less pressure. and maybe all that "dark matter" is the "reminant" of what comes out of a black hole. i dont know, just talking. my head is always "out there, out of earth..." maryalien |
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Guest_Richard Trigaux_* |
Dec 12 2005, 04:24 PM
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#2
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Guests |
An intriguing thing about black hole evaporation is as follows.
As Hawking stated, a black hole may elit a black body-like thermal electromagnetic radiation, becomming hotter and hotter when the black hole becomes smaller. But if so, what become the electric charge and the baryonic number* of the black hole? In order to decay, a black hole has to emit also protons and electrons. The same process Hawking described allows for emission of protons and electrons too, but what is said about this? A black hole with a mass LESS than allowed by its baryonic number (its equivalent mass in hydrogen) need to receive energy to emit protons, and if it emits only protons, its electric charge will become so enormous that it will mandatorily call back any emitted particle. *baryonic number is a fundamental constant of quantum physics, which is 1 for the proton and any other particle of the same family of 16 (neutron, hyperon, etc...) and -1 for the corresponding anti-particules. In any nuclear reaction, the baryonic number cannot change, and this sets the possible and impossible reactions. The baryonic number of a potato is the number of protons and neutrons it contains. In order to go to a fully rationalized metric system, grocers should price potatoes after their baryonic number rather than their mass. |
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Dec 12 2005, 05:40 PM
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#3
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Paper: astro-ph/0512211
Date: Thu, 8 Dec 2005 01:21:59 GMT (429kb) Title: On The Nature of the Compact Dark Mass at the Galactic Center Authors: Avery E. Broderick (1) and Ramesh Narayan (1,2) ((1) Institute for Theory and Computation, (2) Harvard University) Comments: 6 pages, 2 figures, submitted to ApJ Letters \\ We consider a model in which Sgr A*, the 3.5x10^6 M_sun supermassive black hole candidate at the Galactic Center, is a compact object with a surface. Given the very low quiescent luminosity of Sgr A* in the near infrared, the existence of a hard surface, even in the limit in which the radius approaches the horizon, places severe constraints upon the steady mass accretion rate in the source, requiring dM/dt < 10^-12 M_sun/yr. This limit is well below the minimum accretion rate needed to power the observed submillimeter luminosity of Sgr A*. We thus argue that Sgr A* does not have a surface, i.e., it must have an event horizon. The argument could be made more restrictive by an order of magnitude with microarcsecond resolution imaging, e.g., with submillimeter VLBI. \\ ( http://arXiv.org/abs/astro-ph/0512211 , 429kb) -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Dec 16 2005, 05:44 AM
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#4
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Paper: astro-ph/0512350
Date: Tue, 13 Dec 2005 23:58:06 GMT (110kb) Title: Supermassive Black Holes at the Center of Galaxies Authors: Christopher J. Greenwood Comments: 11 pages, 3 figures \\ This was my final paper for the AST 308 Galaxies class at Michigan State University. Using many sources I was able to compile a moderate amount of information concerning the evidence for, and the formation of Supermassive Black Holes. \\ ( http://arXiv.org/abs/astro-ph/0512350 , 110kb) -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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