The black holes that produced the first detected gravitational waves may have exotic origins in the early universe.
When the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO, glimpsed gravitational waves from two merging black holes, scientists were surprised at how large the black holes were — about 30 times the mass of the sun (SN: 3/5/16, p. 6). Inspired by this unusual finding, two papers published in Physical Review Letters propose that the hefty black holes were born in the universe’s infancy.