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Black Holes Grow By Eating Quantum Foam
An anonymous reader writes "The discovery that even the most distant galaxies have supermassive black holes at their cores is a puzzle for astrophysicists. These objects must have formed relatively soon after the Big Bang. But if a galaxy is only a billion years old and contains a black hole that is a billion times more massive than the Sun, how did it get so big, so quickly? Now one cosmologist says he has the answer: black holes feed off the quantum foam that makes up the fabric of spacetime. This foam is 'nourishing' because it contains quantum black holes that can contribute to the black hole's growth. This idea leads to a prediction: that the supermassive black hole at the center of the Milky Way must also be growing in this way and at a rate that we should be able to measure. Just watch out for the burps."
No, it's actually close to the exact opposite, though both are quantum effects. In loose terms, Hawking's argument is that if you generate a pair of particles just outside of the black hole (which is allowed by the energy/time uncertainty principle so long as their lifetime - before they recollide - is short enough), and one falls through the event horizon and the other escapes, then they can *never* recombine -- and then you're left with a net negative energy. That negative energy has to come from somewhere, and it comes from the black hole. Which means that the black hole radiates energy -- Hawking radiation -- and eventually will evaporate.
The argument here is quite different, although it's still a quantum effect; instead of virtual pairs here, we simply have a black hole gobbling up unimaginably small black holes that foam in and out of existence. There is no net energy loss with these, and rather than losing mass/energy, the black hole *gains* it. I'd be interested in a study seeing whether these two effects would ever balance -- I'd imagine they probably would, somewhere near the Planck scale, but that's nothing more than a speculative assumption.
In astronomy, all that matters is being within a factor of 10. :P
I read TFA and all I got was this lousy cookie