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Black holes are more common than previously thought, explaining why they can collide and merge, creating detectable gravitational waves:
After conducting a cosmic inventory of sorts to calculate and categorize stellar-remnant black holes, astronomers from the University of California, Irvine have concluded that there are probably tens of millions of the enigmatic, dark objects in the Milky Way – far more than expected.
"We think we've shown that there are as many as 100 million black holes in our galaxy," said UCI chair and professor of physics & astronomy James Bullock, co-author of a research paper on the subject in the current issue of Monthly Notices of the Royal Astronomical Society [open, DOI: 10.1093/mnras/stx1959] [DX].
[...] "We have a pretty good understanding of the overall population of stars in the universe and their mass distribution as they're born, so we can tell how many black holes should have formed with 100 solar masses versus 10 solar masses," Bullock said. "We were able to work out how many big black holes should exist, and it ended up being in the millions – many more than I anticipated." [...] "We show that only 0.1 to 1 percent of the black holes formed have to merge to explain what LIGO saw," [Manoj] Kaplinghat said. "Of course, the black holes have to get close enough to merge in a reasonable time, which is an open problem."
That sucks.
(Score: 5, Informative) by pTamok on Thursday August 10 2017, @04:11PM (5 children)
Nit-pick here.
Not quite exactly. They would no longer experience the solar wind [wikipedia.org], or radiation pressure [wikipedia.org], which would probably decrease the orbital radius slightly. In addition, I don't know if the Sun's magnetic field and a black hole's would be similar enough not to have different interactions with any planetary magnetic fields and peturb their orbits as well.
The effects are probably small.
(Score: 1, Insightful) by Anonymous Coward on Thursday August 10 2017, @05:06PM (3 children)
+1 Pedantic
(Score: 3, Touché) by bob_super on Thursday August 10 2017, @09:58PM (2 children)
Not quite pedantic enough. At least Mercury and Venus would also be affected by the dramatic change in surface temps, probably fractionally speeding up their rotation.
(Score: 2) by JoeMerchant on Friday August 11 2017, @03:04AM (1 child)
Rotation, or orbit? I think Mercury's rotation would remain gravitationally locked, although a change in orbit is still a change in rotation in that case.
Venus' atmosphere should condense/compress so it should start to rotate a bit faster, shorter days - if you still measure days by the stars.
But, I don't see the cooling affecting orbital speed, maybe the absence of solar wind, though I can't help but think that would be trivial compared to the shockwave that might originate from just outside the event horizon as the sun's outer layers get sucked in / compressed / detonated in heavy fusion reactions / partially slung out due to radically increased rotational velocities.
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Friday August 11 2017, @03:29AM
Another nitpick, Mercury's rotation is in resonance, but it is not locked.
(Score: 2) by inertnet on Thursday August 10 2017, @07:02PM
Ok, let's try that and make measurements to settle this argument.