Hawking also described how he discovered that particles could slowly leak out of black holes and release energy. A miniature black hole of the mass of a mountain could generate enough power to supply the world’s energy needs. However, the energy would be difficult to harness as the power could not be maintained in a power station. It would drop through the floor and end up at the center of the Earth.
Read more at:
http://phys.org/news156450506.html#jCp
slowly leak out of black holes and release energy
Hawking radiation is black body radiation that is predicted to be emitted by black holes, due to quantum effects near the event horizon. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974,[1] and sometimes also after Jacob Bekenstein, who predicted that black holes should have a finite, non-zero temperature and entropy.[2] Hawking's work followed his visit to Moscow in 1973 where the Soviet scientists Yakov Zeldovich and Alexei Starobinsky showed him that according to the quantum mechanical uncertainty principle, rotating black holes should create and emit particles.[3] Hawking radiation reduces the mass and the energy of the black hole and is therefore also known as black hole evaporation. Because of this, black holes that lose more mass than they gain through other means are expected to shrink and ultimately vanish. Micro black holes (MBHs) are predicted to be larger net emitters of radiation than larger black holes and should shrink and dissipate faster.
emitted by black holes
In 1975 Hawking published a shocking result: if one takes quantum theory into account, it seems that black holes are not quite black! Instead, they should glow slightly with "Hawking radiation", consisting of photons, neutrinos, and to a lesser extent all sorts of massive particles. This has never been observed, since the only black holes we have evidence for are those with lots of hot gas falling into them, whose radiation would completely swamp this tiny effect. Indeed, if the mass of a black hole is M solar masses, Hawking predicted it should glow like a blackbody of temperature
6 × 10-8/M kelvins,
so only for very small black holes would this radiation be significant. Still, the effect is theoretically very interesting, and folks working on understanding how quantum theory and gravity fit together have spent a lot of energy trying to understand it and its consequences. The most drastic consequence is that a black hole, left alone and unfed, should radiate away its mass, slowly at first but then faster and faster as it shrinks, finally dying in a blaze of glory like a hydrogen bomb. However, the total lifetime of a black hole of M solar masses works out to be
1071 M3 seconds
so don't wait around for a big one to give up the ghost. (People have looked for the death of small ones that could have formed in the big bang, but they haven't seen any.)
How does this work? Well, you'll find Hawking radiation explained this way in a lot of "pop-science" treatments:
Virtual particle pairs are constantly being created near the horizon of the black hole, as they are everywhere. Normally, they are created as a particle-antiparticle pair and they quickly annihilate each other. But near the horizon of a black hole, it's possible for one to fall in before the annihilation can happen, in which case the other one escapes as Hawking radiation.
To summarise black holes are neither black or inescapable
Jb
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