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It was less "should not exist" and more "should only form when black holes merge," and apparently the "black hole mergers fill the mass gap" hypothesis is now s

It was less "should not exist" and more "should only form when black holes merge," and apparently the "black hole mergers fill the mass gap" hypothesis is now supported by evidence. Nobody was claiming that there is some physical reason black holes of such mass could not exist, only that the best understood process of black hole formation should not allow for such masses (but other processes can).

cgriswald 6y ago
The title is bad, but... > Chris Belczynski, an astrophysicist at Warsaw University, previously felt so sure that such a large specimen wouldn’t be seen that in 2017 he placed a bet with colleagues. “I think we are about to lose the bet,” Belczynski said, “and for the good of science!” LIGO has existed for decades and by 2017 had already detected a merger. My guess is he considered black holes in this range rare enough that we were unlikely to detect any. If he believed they were impossible the article certainly doesn’t elucidate on that fact.
- deleted 6y ago
  [deleted]
- 3JPLW 6y ago
  This was a key feature of the bet. It's within the first 100 gravitational wave detections. They're betting against an unknown distribution. Neither side was saying that they wouldn't be found.
  - gizmo686 6y ago
    Is there a sampling bias involved? I presume that different masses of black holes result in different frequency waves, and that LIGO is not uniformly sensitive to all frequencies. Depending on the actual numbers, this would make these intermediate sized mergers either over or under represented in our data.
enkid 6y ago
Would there be a reason we wouldn't expect these mergers to happen very often? I mean, LIGO doesn't detect black holes that often considering how much space it is surveying. Would there be time for the small black holes to accumulate into a large black hole?
- imglorp 6y ago
  LIGO only detects mergers, and then only in a certain low mass range. The article hints that these are most likely to happen in a star-dense area (duh, right?) like a nebula.
  - deleted 6y ago
    [deleted]
imglorp 6y ago
Yeah I think the key words in the bet, were "astrophysical" black hole coming from a star, as opposed to "dynamical" ones coming from mergers. It seems the party doubting dynamical ones thought space was big and they would be unlikely to find each other. As evidence is showing, all kinds of mergers are happening.
hinkley 6y ago
Somehow black hole videos have ended up at the top of my youtube recommendations lately, and it seems like the binary star system is a somewhat common path to supernovae or black holes. And we know about some trinary and double binary systems out there. I would think after supernova, the companion star(s) would end up in a modified orbit that would result in more destructive gravitational interactions (collisions, mass transfer, feeding or creating a black hole). To the layperson it feels like a matter of 'when', not 'if'. Perhaps it's that I'm thinking that in a universe of a billion billion distinct examples of orbital mechanics, surely we are going to spot a lot of exceedingly lucky/unlucky events out there. Especially if we are doing any kind of observation that filters for those events. After all, a one-in-a-billion probability event on earth happens to about eight people. If you know how to find them, it's a good human interest story.

cgriswald 6y ago

The title is bad, but... > Chris Belczynski, an astrophysicist at Warsaw University, previously felt so sure that such a large specimen wouldn’t be seen that in 2017 he placed a bet with colleagues. “I think we are about to lose the bet,” Belczynski said, “and for the good of science!” LIGO has existed for decades and by 2017 had already detected a merger. My guess is he considered black holes in this range rare enough that we were unlikely to detect any. If he believed they were impossible the article certainly doesn’t elucidate on that fact.

deleted 6y ago
[deleted]
3JPLW 6y ago
This was a key feature of the bet. It's within the first 100 gravitational wave detections. They're betting against an unknown distribution. Neither side was saying that they wouldn't be found.
- gizmo686 6y ago
  Is there a sampling bias involved? I presume that different masses of black holes result in different frequency waves, and that LIGO is not uniformly sensitive to all frequencies. Depending on the actual numbers, this would make these intermediate sized mergers either over or under represented in our data.

enkid 6y ago

Would there be a reason we wouldn't expect these mergers to happen very often? I mean, LIGO doesn't detect black holes that often considering how much space it is surveying. Would there be time for the small black holes to accumulate into a large black hole?

imglorp 6y ago
LIGO only detects mergers, and then only in a certain low mass range. The article hints that these are most likely to happen in a star-dense area (duh, right?) like a nebula.
- deleted 6y ago
  [deleted]

imglorp 6y ago

Yeah I think the key words in the bet, were "astrophysical" black hole coming from a star, as opposed to "dynamical" ones coming from mergers. It seems the party doubting dynamical ones thought space was big and they would be unlikely to find each other. As evidence is showing, all kinds of mergers are happening.

hinkley 6y ago

Somehow black hole videos have ended up at the top of my youtube recommendations lately, and it seems like the binary star system is a somewhat common path to supernovae or black holes. And we know about some trinary and double binary systems out there. I would think after supernova, the companion star(s) would end up in a modified orbit that would result in more destructive gravitational interactions (collisions, mass transfer, feeding or creating a black hole). To the layperson it feels like a matter of 'when', not 'if'. Perhaps it's that I'm thinking that in a universe of a billion billion distinct examples of orbital mechanics, surely we are going to spot a lot of exceedingly lucky/unlucky events out there. Especially if we are doing any kind of observation that filters for those events. After all, a one-in-a-billion probability event on earth happens to about eight people. If you know how to find them, it's a good human interest story.