Scientists at the Advanced Laser Interferometer Gravitational Waves Observatory (LIGO) have announced that they detected gravitational waves for the second time – on December 25th last year.
Earlier in February, LIGO scientists had announced first detection of a large space-time ripple at LIGO labs in Livingston, Louisiana and Hanford, Washington. This ripple was detected on September 14th, 2015, and according to scientists, it had originated from the final stages of two merging black holes, weighing 29 and 36 solar masses and located about 1.3 billion light years from Earth.
Gravitational waves are the ripples in the fabric of space-time that are produced by violent events in the Universe, such as merging of black holes and neutron stars. Waves produced by accelerating masses are believed to propagate at the speed of light.
The waves detected on Boxing Day emanated from the spinning dance of a binary black hole pair – weighing 8 and 14 solar masses – and on the brink of merging. They were located about 1.4 billion light years from Earth, and their merger created another black hole 21 times the mass of the sun, with rest of the mass transforming into a gravitational energy. This energy was sensed by the laser interferometers of the LIGO labs in Livingston, Louisiana, and Hanford, Washington State on 25 December (03:38 GMT, 26 Dec; Boxing Day in Europe).
“It shows the first event wasn’t just a fluke. It shows that the Universe is filled with black holes spiraling in together and merging and giving off these huge bursts of gravitational waves quite regularly. It’s a violent Universe,” UK collaboration member Prof Bernard Schutz of Cardiff University told BBC News.
Since the first detection of gravitational waves, key LIGO pioneers have been honored with lots of prizes.
“One of the black holes was spinning with the dimensionless number of 0.2,” Prof Gabriela González from Louisiana State University, US, told reporters.
“We measure between zero (not spinning) and one (maximally spinning). We can also measure the spin of the final black hole but we expect that black hole to have a spin (because of the merger); we don’t know about the original black holes and that’s astrophysical information that informs the scenarios for how black holes form.”
The latest announcement on detection of gravitational waves has come a week after the European Space Agency stated that it is now possible to fly a gravitational wave observatory in orbit. Scientists believe an observatory in space would allow sensing of gravitational waves of different frequencies to those detected on Earth.
The detailed findings of the study have been accepted for publication in Physical Review Letters.
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