The 2017 Nobel Physics Prize was awarded “for decisive contributions to the LIGO detector and the observation of gravitational waves”. What is Gravitational Wave and how are they detected? How does India’s association in LIGO-India project matters? Examine in the context of gain which India aspires. (250Words/15Marks)



Model Answer:


  • The Laser Interferometer Gravitational-Wave Observatory is a large-scale physics experiment aiming to directly detect gravitational waves. It comprises two enormous laser interferometers located thousands of kilometers apart. ‎ The Interferometers used in LIGO work by merging two or more sources of light to create interference pattern, which can be measured and analyzed.


Gravitational Waves:

  • “These are ripples in the fabric of space-time that are produced, when black holes collide and stars explode”, gravitational waves are produced when objects accelerate.
  • Gravitational waves were first proposed, 100 years ago by Albert Einstein, as part of the Theory of Relativity.
  • Strongest sources of gravitational waves are among produced by catastrophic events such as colliding black holes, supernovas etc.
  • These waves are detected using two large laser instruments in the United States, known together as the Laser Interferometer Gravitational-Wave Observatory (LIGO), as well as another in Italy.
  • The twin LIGO installations are located roughly 3,000 km apart, is a way to sift out terrestrial rumblings, such as traffic and earthquakes, from the faint ripples of space itself.
  • When a gravitational waves passes by earth, it squeezes and stretches space. LIGO can detect this squeezing and stretching. Each LIGO observatory has two arms that are more than 4 kms long.
  • A passing GW causes the length of the arms to change slightly. The observatory uses lasers, mirrors and extremely sensitive instruments to detect these tiny changes.
  • The waves detected by the 2017 Nobel laureates came from the collision of two black holes some 1.3 billion light years away. A light year is about 9.5 trillion km.

Gravitational waves matter to us because:

  • Gravitational wave astronomy is a way of mapping out some of the most violent processes in the universe such as black hole or neutron star mergers that cannot be detected with light or the conventional methods.
  • Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation.
  • Newton’s law of universal gravitation, part of classical mechanics, does not provide for their existence, since that law is predicated on the assumption that physical interactions propagate instantaneously (at infinite speed).
  • Gravitational waves can penetrate regions of space that electromagnetic waves cannot.
  • They are able to allow the observation of the merger of black holes and possibly other exotic objects in the distant Universe.

Benefits for India by the LIGO-India project:

  • The impact of LIGO-India is multi-faceted and would push the frontiers along each direction-
  • IndIGO, the Indian Initiative in Gravitational-wave Observations, is an initiative to set up advanced experimental facilities, for a multi-institutional Indian national project in gravitational-wave astronomy.
  • Since 2009, the IndIGO Consortium has been involved in constructing the Indian road-map for Gravitational Wave Astronomy and a strategy towards Indian participation in realising the crucial gravitational-wave observatory in the Asia-Pacific region.
  • The project will bring unprecedented opportunities for scientists and engineers to dig deeper into the realm of gravitational wave and take global leadership in this new astronomical frontier.
  • The LIGO-India project has the potential to impact precision experiments and cutting-edge technology in the country. The project has interfaces with quantum metrology, laser physics and technology, vacuum technologies, optical engineering, sensor technologies,
  • LIGO can act as platform to unravel the mysteries of universe and India’s association with it is going to help us in the future.
  • Scientists have long believed that measurement of gravitational waves can help us better understand the structure of neutron stars, the location and distribution of black holes in space and the physical processes that occurred during the Big Bang.
  • The project will motivate Indian students and young scientists to explore newer frontiers of knowledge, and will add further impetus to scientific research in the country.
  • Setting up of the LIGO-India observatory will require the involvement of top Indian technology and infrastructure industries across large-scale fabrication, precision engineering, intricate electronics and big data science.
  • Successful construction and operation of LIGO-India could spark off a re-definition of ethics and work culture in science and technology in India, and build strong bridges across disparate disciples of S&T in academia and the industry.


  • LIGO-India brings forth a real possibility of Indian scientists and technologists stepping forward, with strong international cooperation, into the frontier of an emergent area of high visibility and promise presented by the recent gravitational wave detections and the high promise of a new window of gravitational-wave astronomy to probe the universe.