Scientists have successfully detected gravitational waves for fourth time coming from merger of two massive black holes. It was for first time, these waves were simultaneously detected by US-based Laser Interferometer Gravitational-wave Observatory (LIGO) and Italy-based Virgo detectors. The first two detection were made in September and December 2015 in quick succession and for third time it was detected in January 2017.
The recently detected gravitational waves were emitted during final moments of merger of two black holes located about 1.8 billion light-years away with masses about 31 and 25 times mass of Sun. The newly produced spinning black hole has about 53 times mass of our sun i.e. about 3 solar masses were converted into gravitational-wave energy during merger.
Gravitational waves are ripples curvature of spacetime which propagate as waves, travelling outward from source at the speed of light. They transport energy as gravitational radiation and pass through matter without interacting with it. Gravitational waves were first predicted in 1916 by Albert Einstein on the basis of his Theory of General Relativity. Strongest sources of gravitational waves are among enigmatic objects in our universe like black holes, supernova, neutron stars and Big Bang. Information extracted by these transmitted waves may help to address unsolved questions and mysteries of physics and astronomy.
Note: Russel Hulse and Joseph Taylor had discovered indirect evidence for existence of gravitational waves emitted from decaying orbital period of objects called binary pulsars in 1974,. Both of them for their discovery were awarded the Nobel Prize in Physics in 1993.