The world’s third Laser Interferometer Gravitational Observatory (LIGO), a gigantic instrument to detect stellar gravitational waves that will be set up in India, is more than a file waiting to get cabinet approval.
Over the past four years, scientists from four Indian institutes have completed the “legwork” needed for the ground-based observatory — a century after Albert Einstein predicted the existence of gravitational waves and scientists recently experienced one.
“We may be waiting for the final approval for years now but the legwork had been done and therefore LIGO-US and the National Science Foundation have continued to support us,” said Tarun Souradeep, project coordinator, LIGO-INDIA, Inter University Centre for Astronomy and Astrophysics. “So it’s not as if we’ve lost a lot of time.”
India has a geographical advantage and the detector here will form a triangulate along with the two US-based instruments that will help locate the source of the event that caused a gravitational wave.
The US detectors cover an area of the sky equivalent to 2,500 moons. With the India detector, the area will become 100 times smaller and that, according to scientists, will make a difference.
Seismic and terrain analysis has found 22 potential sites in central India’s Deccan plateau running through Maharashtra, Madhya Pradesh and Karnataka. This area has low seismic activity and low background noise levels, and is away from the coast too.
“Seismometres were placed at the shortlisted sites for two to three weeks each and we compared it to LIGO at Hanford which is the gold standard for its low seismic levels and hard terrain. The shortlisted sites are doing better,” said physics professor Rajesh Nayak at the Indian Institute of Science Education and Research, Kolkata.
There will be long duration experiments at the final site.
The Institute of Plasma Research (IPR), Gandhinagar, has completed drawings of infrastructure.
The 4 km arms of the detector will hold one million litres of vacuum.
“We’ve been assigned 90% work in terms of development of infrastructure, fabrication of ultra high vacuum systems and global supervisory control system. Table-top experiment has been set up,” said Ziauddin Khan of IPR and project manager, LIGO-INDIA preparatory group.
The Raja Ramana Centre for Advanced Technology, Indore, will develop extreme state of the art laser and optics.