Context: The Union Cabinet has approved a gravitational-wave detector project in Maharashtra costing Rs 2,600 crores, estimated to be built by 2030.
Laser Interferometer Gravitational-wave Observatory
- LIGO, or Laser Interferometer Gravitational-Wave Observatory, is an international network of laboratories meant to detect gravitational waves — ripples in space-time produced by the movement of large celestial bodies such as stars and planets.
- LIGO comprises two enormous laser interferometers located 3000 kilometres apart in Hanford, Washington and Livingston, Louisiana, the United States.
- The gravitational waves were first discovered in 2015 by two LIGOs based in the United States.
LIGO India Project
- A third gravitational-wave detection facility is being built in India as part of the LIGO-India collaboration to:
- increase the chances of detecting gravitational waves from anywhere in the observable universe.
- improve the detectors’ collective ability to pinpoint sources of gravitational waves in the sky.
- To be located in the Hingoli district of Maharashtra, LIGO-India is scheduled to begin its scientific runs in 2030.
- The Department of Atomic Energy and the Department of Science and Technology are building LIGO-India in partnership with the U.S. National Science Foundation and various national and international research institutions.
Mechanism
- The L-shaped LIGO instrument has two arms, each measuring 4 km long that constitute the most sensitive interferometers in the world. Laser pulses are fired simultaneously through both arms, bouncing off the mirrors at the ends to return to the vertex. A detector analyses whether the pulses coincide upon return. Detecting gravitational waves involves recording and analysing the slightly out-of-time pulses in the detector produced by their passage.
Need for the project
- While two LIGOs can detect gravitational waves, a third observatory is required for better triangulation of the location of a source of gravitational waves in the sky. A more ideal setup requires four observatories to record the same wave. To this end, researchers are setting up and upgrading detectors in Italy and Japan.
- Triangulation refers to analysing the results of the same study using different methods of data collection to enhance the validity, reliability, and comprehensiveness of research findings.
Significance
- The observatory will help in better understanding astronomical objects like neutron stars and black holes and for the in-depth study of gravitational waves.
- The project would have several spin-off benefits to Indian science, apart from making India an integral part of one of the most prestigious international scientific experiments.
- India could become a global site of gravitational physics research, aiding training and the handling of precision technologies and sophisticated control systems, ultimately, cementing a reputation for successfully running an experimental Big Science project.
- The starting requirement here is the timely release of funds for construction, followed by issuing the allocated resources without delay.
Gravitational Waves
- Gravitational waves are ripples in space-time caused when massive objects move with extreme accelerations (similar to ripples in a water pond).
- The waves are invisible, travel at the speed of light and squeeze and stretch anything in their path as they pass by.
- Gravitational radiation is exceedingly difficult to detect because gravity by nature is much weaker than electromagnetic radiation.
- Gravity is the weakest of the four fundamental forces of nature i.e., electromagnetic force, strong nuclear force and weak nuclear force.
- Due to the extremely low strength of gravitational waves, a high-precision instrument like LIGO is required for their detection.
- The most powerful gravitational waves are created when objects move at very high speeds. Some examples of events that could cause a gravitational wave are:
- when a star explodes asymmetrically (called a supernova)
- when two big stars orbit each other
- when two black holes orbit each other and merge.
