US – The Laser Interferometer Gravitational-Wave Observatory (LIGO) Project scientists have detected, for a second time, gravitational waves predicted by Albert Einstein a century ago. A weaker phenomenon than the first but, according to the researchers, may help in drawing a map of black holes in the universe.

The new waves were detected on December 26, 2015, more than three months after signing the historic first discovery, announced today by the University of Maryland, one of the participants in the LIGO project.

These second gravitational waves are much weaker than the first and occurred during the last moments of the merger of two black holes into a more massive one.

While the first detected waves resulted from the merger of two black holes occupying 36 and 29 times the mass of the sun, the new phenomenon was born of holes representing 8 and 14 times the mass of the star.

Gabriela Gonzalez, spokeswoman for LIGO and professor of physics and astronomy at Louisiana State University, said that it is very significant that these black holes were much less massive than those observed in the first detection.  However, it is a promising start to map populations of black holes in our universe.

Gravitational waves carry information about their origins and the nature of gravity, and are expected to allow us to observe the history of the Cosmos to remote moments, understanding how black holes are formed, how matter behaves under extreme conditions, and resulting into making new discoveries.

The new phenomenon, called GW151226, announced almost six months after its discovery and four months after LIGO unveiled that it had confirmed for the first time, the existence of gravitational waves predicted by Albert Einstein in 1916, a year after publication of his Relativity Theory.

That discovery opened a new door in Astronomy because until now scientists had made use of different forms of light (electromagnetic waves) to observe the Universe.

The two discoveries were made by LIGO, a system of two identical detectors built to detect incredibly small vibrations generated by the passage of gravitational waves, located in Livingston (Louisiana) and Hanford (Washington State), three thousand kilometers from each of the other.

Albert Lazzarini, deputy director of the laboratory of LIGO, said that with the detection of two major events in the four months of our first mission of observation, they can begin to make predictions about how often we could hear gravitational waves in the future.

In addition, one of the black holes that produced these second wave “spinning like a top,” something that did not happen in the first phenomenon and that “suggests that the object was a different story” may “absorb part of the mass of another star “before becoming a black hole, said LIGO.

The laboratory will begin a second observation mission this fall, which will have improved the sensitivity of their detectors and hope to detect more black hole collisions and even capture gravitational waves from other sources, such as binary neutron stars.