By Nadia Drake
Hiding in a clump of stars 10,000 light-years away are two small black holes, slowly sipping their stellar prey.
But the black holes shouldn’t be there — at least, not both of them. The snacking pair disobeys prevailing theories that predict the survival of only one black hole in M22, a globular cluster of stars. And, like cockroaches and rats, observing two means the cluster could contain many, many more small black holes — perhaps as many as 100, a team of astronomers reports in the Oct. 4 Nature.