Friday, September 30, 2016

Black Holes Second Collision Reported: More Gravitational Waves Detected

Black Holes Second Collision Reported: More Gravitational Waves Detected

S. Ossokine and A. Buonanno, Max Planck Institute for Gravitational Physics, and the Simulating eXtreme Spacetime (SXS) project. Scientific Visualization: T. Dietrich and R. Haas, Max Planck Institute for Gravitational Physics.


An international team of scientists and engineers detected gravitational waves for the second time, according to a statement announced on June 15 during the American Astronomical Society (AAS) meeting in San Diego, USA. These gravitational waves were created during the violent final moments of two black holes merging together on Dec. 26, 2015 at 03:38:53 UTC (Coordinated Universal Time).

The merging black holes were estimated to have 14 and 8 solar masses respectively. These two produced one huge spinning black hole that has 21 times the mass of our sun. The findings will be published in the journal Physical Review Letters.

The cosmic event was recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors in the US. Unlike the first detection, the latest gravitational waves released provided longer signal and more data.

Gravitational waves can shed light on the origins of gravity. They used to be only a part of Albert Einstein’s 1915 general theory of relativity but they were proven to exist back on Sept. 14, 2015, also made possible by LIGO.

The first detection was created by two massive black holes merging. In comparison, the black holes in the first one had 36 and 29 times solar masses. They merged to create a black hole that is said to have 62 times the mass of the sun.

“It is very significant that these black holes were much less massive than those in the first detection,” says Louisiana State University physicist and astronomy professor Gabriela Gonzalez, the spokesperson of the LIGO Scientific Collaboration. “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.”

This discovery adds to the growing knowledge about black holes. Once scientists have all the data they need, they can finally provide a clearer and more accurate analysis of the universe.

“We expect black holes with a range of masses, which we now are seeing, showing us that black holes form ubiquitously in the universe,” says LIGO member Vicky Kalogera, also the director of Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). “This second detection also proves the first was not a fluke — the gravitational waves truly came from cosmic sources. Multiple events are exactly what we needed to be convinced beyond any doubt.”