LIGO experiment Current Affairs
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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.
Scientist for the first time have discovered Gravitational Waves (GW) that were hypothesised by Albert Einstein in 1916.
These waves were detected by the scientists working at two LIGO (Laser Interferometer Gravitational-wave Observatory) facilities in United States.
- LIGO scientists have detected these gravitational waves produced by collision of two black holes located 1.3 billion light years away from earth.
- Process of Discovery: The LIGO experiment has 4km long L-shaped tunnels and uses lasers to measures changes in the distance between two ends.
- When the GW enters into LIGO, it stretches space and direction, and disperses space in another direction i.e. these waves disturb the light emitted lasers.
- Scientists by measuring the interference (disturbances) of lasers light map the disturbed space which has been compressed or stretched.
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.
- 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.
Previous evidences: Earlier in 1974, Russel Hulse and Joseph Taylor had disovered indirect evidence for the existence of gravitational waves emitted from the decaying orbital period of objects called binary pulsars. Both of them for their discovery were awarded the Nobel Prize in Physics in 1993.
- This discovery opens new window in studying cosmos and unlock secrets about the early universe and mysterious objects like black holes and neutron stars.
- Confirms a key prediction of Albert Einstein’s General Theory of Relativity.
- Gravitational waves may be useful for studying black holes and other dark objects.
- As these waves do not interact with matter, gravitational waves coming to Earth may be carrying undistorted information about its origin.
- It may also improve methods for estimating the distances to other galaxies. It may also help in mapping the abundance of black holes and frequency of their mergers.