PBS - “When I wrote this paper … I fully expected someone would come up with some reason why it definitely couldn’t be true,” says Simeon Bird, a cosmologist at the University of California, Riverside, whose article, coauthored with Kovetz and others, was the first out of the gate. Instead, LIGO continued to capture additional signals from other black holes in this immense-mass range, setting off an excited flurry of activity among theoretical physicists that has yet to abate.