> 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.
Neither side was saying that they wouldn't be found.
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.
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.