Scientists detect gravitational waves, pair of colliding black holes for 2nd time in history

Zee Media Bureau

New Delhi: An international team of scientists for the second time in history has detected gravitational waves-- ripples in the fabric of space-time -- and a pair of colliding black holes.

Using the twin, US-based Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, the second detection occurred on December 26 last year and is named as the "Boxing Day event" (after the holiday celebrated in Britain).

LIGO's first detection of gravitational waves and merging black holes occurred on September 14, 2015 -- an event that made headlines worldwide, confirming a major prediction of Albert Einstein's 1915 general theory of relativity.

"Scientifically, these black holes are important because it shows binary black holes exist as a population, with a range of masses, forming from a range of different stars," said Vicky Kalogera, director of Northwestern University's centre for interdisciplinary exploration and research in astrophysics (CIERA).

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 eight times the mass of the sun -- to produce a single, more massive spinning black hole 21 times the mass of the sun.

This time, the gravitational waves released by the violent black hole merger resulted in a longer signal, or chirp, providing more data.

(With IANS inputs)