What if the black holes LIGO sees are the results of a merger? I mean, we see mergers, but maybe those are second-generation ones, and the two merging black holes come from first-generation mergers. Or (more likely…) stellar mass black holes form from stars and only merge once…
Davide Gerosa, Emanuele Berti.
Physical Review D 95 (2017) 124046.
Selected as PRD Editors’ Suggestion.
Other press coverage: Ars Technica.