PM lays foundation stone of world's final gravitational wave observatory

Seven years after the “in-principle” approval, Prime Minister Narendra Modi on Thursday finally kick started the Rs 2,600 core LIGO India programme as he laid the foundation stone to set up the world's final gravitational wave observatory in Maharashtra for capturing the elusive cosmic waves whose existence was predicted by Albert Einstein more than a century ago.

The observatory is one of the Rs 5,800 crore worth of projects by the Department of Atomic Energy that the Prime Minister rolled out to celebrate the 25th anniversary of Pokhran-II nuclear test.

Describing LIGO-India as one one of the foremost science and technology initiatives, Modi said the observatory would bring new opportunities for research for the students and scientists.

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Coming up at Hingoli in the Marathwada region, the L-shaped observatory will have two 4-km long vacuum tunnels that will house sophisticated and highly sensitive sensors to pick up the feeble signals emanating from violent cosmic events like merger of black holes and neutron stars taking place in distant universe.

Last month’s cabinet nod for LIGO (Laser Interferometer Gravitational wave Observatory) India came seven years after the Modi government gave an in-principle approval to the programme soon after the maiden detection of such waves in 2015 by a group of scientists who announced it in 2016. The estimated project cost at that time was Rs 1,260 crore.

LIGO-India was one of the mega-science projects proposed by the Planning Commission in 2011. A year later, the National Science Board in the USA gave its nod for shifting one of the US gravitational wave detectors to an Indian site.

The green signal from NSB came after the National Science Foundation, which funds the US detectors, asked the board to look at the Indian proposal.

At the Indian end, however, the project gathered dust for several years till the news of the first detection of the gravitational wave took the world by storm, following which the Centre gave an “in-principle” approval in 2016. Three of the pioneers received the Nobel Prize a year later.

But subsequent red tapes and Covid-19 pandemic once again delayed the final approval and the cost shot up to Rs 2,600 crore. Also there are now four observatories – two in the USA, one in Italy and one in Japan. The Indian observatory will be the last one in this class.

“LIGO-India is designed to achieve the same sensitivity as the two observatories in the USA. At this time LIGO-US observatories have achieved much higher sensitivity than the ones in Europe and Japan,” one of Indian scientists associated with the LIGO-India project told DH. The scientists hope to commission the observatory by 2030 when the “first joint scientific run” can be achieved.

The Indian observatory will possibly be the last of the 4 km sized ones in a global network of such instruments. There are already proposals for larger and more sensitive observatories on 10, 20 and 40 km lengths. But a big challenge would be to find sites to house such observatories..