Gravitational wave detected for 3rd time

In yet another historic moment, an international research team, including scientists from India, on Thursday announced the third detection of gravitational waves -ripples in the fabric of space and time which were first predicted by Albert Einstein more than a century ago.

The Laser Interferometer Gravitational-wave Observatory (LIGO) in the US made the detection on January 4 this year, demonstrating that a new window in astronomy has been firmly opened.

Gravitational waves pass through Earth and can be "heard" by the extremely sensitive LIGO detectors.

As was the case with the first two detections, the waves were generated when two black holes merged to form a larger black hole.

"Our handful of detections so far is revealing an intriguing black hole population we did not know existed until now," said Northwestern University's Vicky Kalogera, a senior astrophysicist with the LIGO Scientific Collaboration (LSC).

The new detection, called GW170104, occurred during the ongoing second observing run of the Advanced LIGO detectors which began on November 30 last year.

The first direct observation of gravitational waves was made in September 2015 during the first observing run.

A second detection was made in December 2015.

The third detection is described in a new paper accepted for publication in the journal Physical Review Letters.

The publication has 40 authors from 11 Indian institutions.

IIT-Madras recently joined the LSC as one of the participating institutes, under the leadership of Dr Chandra Kant Mishra.