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Do Solo Black Holes Roam the Universe?
sciencehabit writes "Two mysterious bright spots in a disheveled, distant galaxy suggest that astronomers have found the best evidence yet for a supermassive black hole being shoved out of its home. If confirmed, the finding would verify Einstein's theory of general relativity in a region of intense gravity not previously tested. The results would also suggest that some giant black holes roam the universe as invisible free floaters, flung from the galaxies in which they coalesced. Although loner black holes may be an entity that has to be reckoned with, they would still be rare."
No... the stars in a galaxy are orbiting their own collective center of gravity, not the blackhole. It just so happens that this collective center of gravity often attracts enough stars that it collapses into a super massive black hole. The most likely scenario for the blackhole to lose it's galaxy is in a collision with another galaxy (although "Collision" is a bad word since nothing actually hits anything else) The center of mass of the 2 combined galaxies would radically change rather suddenly (in galactic terms) and the Super massive blackhole would begin orbiting the new center of gravity. If it's orbit is too far out, it would get flung off. In most situations stars would get flung out with it. But rarely it could shoot off on it's own.
It makes me wonder how much of the 'missing mass' that we lump into the dark matter bucket is actually contained in bodies like this; bodies so massive that we can barely fathom their 'size'.
I'm gonna guess 'not much'. If there were a lot of them, every once in a while something would run into one, and believe me, we'd notice.
If there were lots of them then we'd also see them because of the gravitational lens effect they'd impart.
The theoretical evaporation of black holes is an incredibly slow process; a black hole the mass of the sun would only evaporate after some 10^67 years. which considering the age of the universe is 13x10^9 years (or about 6000 if you're a creationist) means it won't disappear any time soon.
Donte Alistair Anderson Roberts - hi son!
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They are finding additional %s. Brown dwarfs, extra H2 in the voids etc.
Right, but none of them have the right properties (no EM interactions, etc) to be dark matter, not to mention that their mass is trivial compared to the amount required.
Anything is possible, especially something based on 'finaglers constant' (FC=answerwant/answergot) like dark matter.
We're a little past that stage. For example, we have observed galaxies colliding in ways that separate the visible mass from the non-visible mass - i.e. the stars, gas etc, interact via EM and slow down, while the majority of the mass (inferred through gravitational lensing) continues on as if it's affected only by gravity. It's hard to ascribe that kind of behavior to dim stars or extra-galactic H2.