Gravitational waves carry information about the origins of black holes and about the nature of gravity that cannot otherwise be obtained. Physicists have concluded that these gravitational waves were produced during the final moments of the merger of two black holes — 14 and 8 times the mass of the sun — to produce a single, more massive spinning black hole 21 times the mass of the sun (In comparison, the black holes detected Sept. 14, 2015, were 36 and 29 times the sun’s mass, merging into a black hole of 62 solar masses.)
This time, the gravitational waves released by the violent black hole merger resulted in a longer signal, or chirp, providing more data. The December chirp lasted one second; the September chirp lasted just one-fifth of a second. The higher-frequency gravitational waves from the lower-mass black holes better spread across the LIGO detectors’ sweet spot of sensitivity.
“It is very significant that these black holes were much less massive than those in the first detection,” said Gabriela Gonzalez, spokesperson of the LIGO Scientific Collaboration and professor of physics and astronomy at Louisiana State University.
Scientists now have a small population of black holes from which to learn more about the universe.
“Because of their lighter mass, they spent more time — about one second — in the sensitive band of the detectors. It is a promising start to mapping the populations of black holes in our universe,” she said.
Gravitational waves are not sound waves, but researchers have converted the gravitational wave’s oscillation and frequency to a sound wave with the same frequency, producing a “chirp” people can hear.
