There’s two main formation pathways for black holes: ongoing stellar collapse and galaxy collapse in the early universe. The former makes stellar-mass black holes. The latter makes enormous million-stellar mass black holes or larger. That’s 5-6 orders of magnitude difference.
What’s interesting is that we can measure/infer the mass of a black hole from these gravitational waves and we are finding a lot of ~1000x stellar mass black holes. Too big to be stellar collapse, too small to be galaxy centers. Where do these come from?
The number for how many there should be is very close to zero. Presumably you’d only get one from a stellar black hole gobbling up enough mass to get that big, but 10 doublings is too much to have happened except by freak accident, and these are regularly occurring.
The current best theory is that they formed in the early universe before or during galaxy formation by some process that we don’t yet understand.
What’s interesting is that we can measure/infer the mass of a black hole from these gravitational waves and we are finding a lot of ~1000x stellar mass black holes. Too big to be stellar collapse, too small to be galaxy centers. Where do these come from?
The number for how many there should be is very close to zero. Presumably you’d only get one from a stellar black hole gobbling up enough mass to get that big, but 10 doublings is too much to have happened except by freak accident, and these are regularly occurring.
The current best theory is that they formed in the early universe before or during galaxy formation by some process that we don’t yet understand.