Gravitational waves from a second pair of colliding black holes has validated the landmark discovery from earlier this year that confirmed Einstein's general theory of relativity. Rochester Institute of Technology scientists contributed to the initial breakthrough and to the second discovery announced today by the Laser Interferometer Gravitational-wave Observatory. The second gravitational wave was observed by the LIGO Scientific Collaboration and the Virgo Collaboration on Dec. 26, 2015, toward the end of the first science run of the Advanced LIGO detectors. The findings, which will appear in the journal Physical Review Letters, validate the new field of gravitational wave astronomy and reveal diversity of size and spin among black holes in the universe.

"This detection corroborates our previous one," said Richard O'Shaughnessy, assistant professor in RIT's School of Mathematical Sciences and a member of RIT's LIGO group. "We can now demonstrate with complete confidence that it wasn't a fluke because we saw something again. And, critically, we're going to see sources that are not just like the first sources but include a wide range."

O'Shaughnessy and several of his colleagues in RIT's Center for Computational Relativity and Gravitation are members of the LIGO Scientific Collaboration. Scientists at RIT's center simulate extreme astrophysical scenarios on supercomputers to predict and validate gravitational wave signals, analyze gravitational wave data and estimate astrophysical implications.

The landmark discovery occurred on Sept. 14, 2015, and was publicly announced on Feb. 11. The scientific breakthrough confirmed predictions in Albert Einstein's general theory of relativity and involved the merger of black holes that weighed 29 and 36 solar masses.

The binary black holes in this event weighed 14 and 8 times the mass of the sun and were one-third the size of the first pair of black holes LIGO observed. The orbiting black holes merged to form gravitational waves 1.4 billion years ago. The merger produced a single, more massive spinning black hole, weighing 21 times the mass of the sun. The impact converted the energy equivalent of the sun's mass into gravitational waves, or ripples in the fabric of space-time.