Washington: India and the US on Thursday signed an MoU for establishing Laser Interferometer Gravitational-Wave Observatory (LIGO) in India that will play significant role in carrying forward frontline research on various aspects of gravitational wave astronomy.
The MoU comes about a month after the Union Cabinet approved the construction of the long-awaited third LIGO interferometer.
Department of Atomic Energy Secretary Sekhar Basu and the US’ National Science Foundation (NSF) France Cordova signed the MoU in this regard in the presence of Prime Minister Narendra Modi and LIGO scientists at Washington.
The construction of the long-awaited third LIGO interferometer, expected to be functional by 2023, will significantly improve the ability of scientists to pinpoint the sources of gravitational waves and analyse the signals.
Modi, who is currently in the US to attend the two-day Nuclear Security Summit (NSS) met scientists of LIGO who recently proved gravitational waves theory. He also interacted with the Indian student scientists part of the LIGO project.
Gravitational waves — ripples in the fabric of space and time produced by dramatic events in the universe, such as merging black holes, and predicted as a consequence of Albert Einstein’s 1915 general theory of relativity — carry information about their origins and about the nature of gravity that cannot otherwise be obtained.
With their first direct detection, announced on 11 February, scientists opened a new window onto the cosmos.
The twin LIGO Observatories at Hanford, Washington, and Livingston, Louisiana, are funded by the US National Science Foundation (NSF), and were conceived, built, and are operated by Caltech and MIT.
Advanced LIGO — a major upgrade to the sensitivity of the instruments compared to the first generation LIGO detectors — began scientific operations in September 2015.
LIGO will provide Indian researchers with the components and training to build and run the new Advanced LIGO detector, which will then be operated by the Indian team, the press statement said.
In a statement, the Union cabinet had said “LIGO-India will also bring considerable opportunities in cutting edge technology for the Indian industry” which will be responsible for the construction of the new observatory’s four-kilometer-long beam tubes.
In addition, the Cabinet statement said “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.”
Indian scientists at Raja Ramanna Centre for Advanced Technology (RRCAT) Indore have designed a special testing/prototype facility for receiving Advanced LIGO parts; have been training the teams that will install and commission the detector; and are currently cross-checking the IPR vacuum-system drawings against the Advanced LIGO detector drawings, to ensure a good fit and rapid installation for the third Advanced LIGO detector.
In addition to leading the site-selection process, the Inter-University Centre for Astronomy and Astrophysics (IUCAA) scientists have been setting up a computing center for current and future data. This preparation should make it possible for India to carry the project forward rapidly, it noted. “We have built an exact copy of that instrument that can be used in the LIGO-India Observatory,” said David Shoemaker,
leader of the Advanced LIGO Project and director of the MIT LIGO Lab.
Funded in large part by the NSF, Advanced LIGO enabled a large increase in the volume of the universe probed, leading to the discovery of gravitational waves during its first observation run.
At each observatory, the four-km-long L-shaped interferometer uses laser light split into two beams that travel back and forth down the arms (four-foot diameter tubes kept under a near-perfect vacuum).
The beams are used to monitor the distance between mirrors precisely positioned at the ends of the arms.
According to Einstein’s theory, the distance between the mirrors will change by an infinitesimal amount when a gravitational wave passes by the detector.
A change in the lengths of the arms smaller than one-ten-thousandth the diameter of a proton (10-19 meter) can be detected.
According to David Reitze, executive director of LIGO and a Caltech research professor, the degree of precision achieved by Advanced LIGO is analogous to being able to measure the distance between our solar system and the sun’s nearest neighbour Alpha Centauri—about 4.4 light-years away—accurately to within a few microns, a tiny fraction of the diameter of a human hair.