Scientists for the second time have successfully detected gravitational waves created by the collision of two black holes 1.4 billion light years away.
These waves were detected using the twin Laser Interferometer Gravitational-wave Observatory (LIGO) interferometers in the US.
This second detection of gravitational waves once again confirms Einstein’s theory of general relativity and successfully tested LIGO’s ability to detect incredibly subtle gravitational signals.
- The detection was made by the LIGO’s twin detectors in Louisiana and Washington on 26 December 2015 when the waves hit the observatory.
- The second detection lasted for about a full second and was 5 times longer than the first one announced in February 2016.
- Using advanced data analysis techniques, the team of researchers determined the waveform signalled a gravitational wave.
- They also calculated that the gravitational wave arose from the collision of two black holes, 14.2 and 7.5 times the mass of the Sun.
- The first detection reported on February 11, 2016 had lasted for 1.1 milliseconds and was very faint signal amid the surrounding noise. It had produced a clear peak in the data.
- The second detection was far subtler, generating a shallower waveform that was almost buried in the data.
What are Gravitational Waves?
In physics, gravitational waves are ripples in the curvature of spacetime which propagate as waves, travelling outward from the source at the speed of light. They were first predicted in 1916 by Albert Einstein on the basis of his Theory of General Relativity. Gravitational waves transport energy as gravitational radiation and pass through matter without interacting with it.