• After Chandrayaan and Aditya L1, the next big thing happening in India to reveal deep mysteries of space is the Laser Interferometer Gravitational Wave Observatory project or LIGO-India.
• Gravitational waves are ripples in the fabric of space-time, caused by moving celestial objects.
• A spherical body like Earth, when squeezed from one side tends to elongate in the other side, just like a rubber ball would behave when squeezed. It is this behaviour that LIGO uses to detect gravitational waves.

ABOUT LIGO-INDIA

• It is coming up in Maharashtra’s Hingoli district.
  • The area is part of the underdeveloped Marathwada region of Maharashtra.
• LIGO-India will be the third node of the LIGO Laboratory in the US, which has observatories in Hanford (Washington) and Livingston (Louisiana).
• The design is exactly the same as that of the two existing LIGO facilities in the United States.
  • The observatory will have a Corner Station and two 4-km long arms, essentially vacuum chambers, each with a diameter of 1.2 metres and in a piped casing that stretch out in an L-formation.
• Once completed, LIGO-India will join a global network of gravitational-wave observatories that includes Virgo in Italy and KAGRA in Japan.
• The LIGO observatory is expected to commence operations by 2030 with an expected life of 30 years.
• It will be built by Department of Atomic Energy and Department of Science and Technology.

THEORY

• Albert Einstein predicted gravitational waves , in 1915, in his General Theory of Relativity.
• He proposed that open space, or rather space-time, wasn’t something that was fixed, inert or transparent, but was affected by the presence, and movement, of celestial bodies like planets and stars.

DETECTION

• At the end of the two vacuum chambers are placed highly-reflective mirrors. Light rays released into both the vacuum chambers hit the mirrors, get reflected and are captured back.
  • In normal circumstances, the light rays in both the chambers would return simultaneously.
  • But when a gravitational wave arrives, one of the chambers gets a little elongated, while the other one gets squished a bit.
  • In this case, light rays do not return simultaneously and there is a phase difference. The presence of a phase difference marks the detection of a gravitational wave.

APPLICATION

• A large part of the universe is known to be completely ‘dark’, with no electromagnetic radiation coming from these areas. These areas remain invisible to human beings.
• Gravitational waves offer scientists a completely new window for looking at the universe.