Guest ymir Posted October 13, 2003 Posted October 13, 2003 New research published in the IOP's journal of Classical and Quantum Gravity shows that primordial black holes did not die out - they formed stable gravitational bound states called Holeums in the aftermath of the Big Bang - which form haloes around galaxies today, and are an important constituent of dark matter. An isolated black hole is subject to the evaporation of its mass due to the Hawking radiation caused by the vacuum fluctuations in its vicinity. This would seem to rule out the possibility of formation of bound states of primordial black holes. There are two conditions which need to be satisfied for a black hole to evaporate due to Hawking radiation: (a) The black hole should be isolated. (b) It sould be in field-free space. Primordial (microscopic) black holes were produced in vast quantities in the immediate aftermath of the Big Bang. The conditions prevalent in that era were very different from those present today. (1) Matter was highly compressed - all matter was closely packed together, and expanding at a high rate. This violates the condition of isolation of black holes necessary for the Hawking radiation. (2) Near the unification temperature, of the order of 10 exp 16 GeV, all the four fundamental interactions of nature are expected to have the same strength. In particular, the gravitational interaction would have a strength far greater than it has now. This violates another condition for the Hawking radiation, namely, a field-free space. This also means that the rate of gravitational interactions among the black holes would correspondingly be higher - and they would form stable, bound states. In other words, extremely high number density, vastly stronger gravity and an enormously larger rate of interactions are likely to lead to the formation of stable bound states of primordial black holes. This is analogous to what happened with neutrons - although a free neutron decays, neutrons in the nucleosynthesis era of the early universe finding themselves in high number densities and subject to the strong interaction formed stable nuclei and never decay except those neutrons that are in heavy nuclei containing a large number of protons. These stable bound states of PBHs would still be around and would form a significant constituent of dark matter. This should give LIGO something to look for! The papers can be seen online at: http://arxiv.org/ftp/gr-qc/papers/0308/0308054.pdf http://arxiv.org/ftp/gr-qc/papers/0309/0309044.pdf
Skye Posted October 13, 2003 Posted October 13, 2003 Holeum moleum Batman, it's a non-radiating black hole!
YT2095 Posted October 15, 2003 Posted October 15, 2003 for what it`s worth, this may provide a breif but interesting read; http://www.discoverychannel.co.uk/newscientist/article02.shtml (I don`t know how long the URL`s valid for though)
alt_f13 Posted October 16, 2003 Posted October 16, 2003 Some galaxies have no dark matter. That's odd. I wonder if when galaxies collide, much of the dark matter in them also collides and destroys itself. "a huge stock of WIMPs could have built up in the Sun's core. Occasionally these trapped WIMPs would collide with each other and be destroyed, producing high-energy neutrinos that would zip out into space." So might WIMPs have a strange form of attraction towards eachother and colide with oncoming WIMPs?
jrd261 Posted October 26, 2005 Posted October 26, 2005 I am not a quantum theorist but it does not seem anyone in quantum gravity has latched on to this idea. Does anyone know of any rebuttles to the papers? The theory does work well to explain dark matter and perhaps one of the legs of the cosmic ray spectra. I fully suggest anyone to check these papers out. Some have claimed the time scale of evaporation is far to short (less then the plank time), but what is the timescale of it becoming QM bound?
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