Union Cabinet Approves LIGO-India Project: RS.2600Crore Gravitational Wave Observatory

Gravitational waves are ripples in space-time caused by massive objects moving at high speeds.

In 1916, Einstein predicted in his general theory of relativity that massively accelerating objects would disrupt space-time, causing waves of sinuous space-time to propagate in all directions^[1].

For a long time, scientists relied on EM (Electromagnetic) waves to study the observable universe, but gravitational waves interact with matter relatively less, giving us a clear view of the universe, whereas EM waves interact with matter and can be modified by the interaction.

The gravitational waves LIGO detects are some of the energetic cosmic events, such as colliding Black holes, merging neutron stars, supernovae, and even the birth of the universe itself.

For detecting gravitational waves LIGO (Laser Interferometer Gravitational-wave Observatories) was first built at Livingston (Louisiana) and Hanford (Washington) which detected Gravitational waves from 2 supermassive black holes, 1.3 billion light years away from the Earth.

LIGO has unveiled the mysteries of the universe and opened new possibilities for exciting research in Astronomy.

LIGO-India is a new collaboration between Caltech and MIT (LIGO labs) and three institutions of India namely, Raja Ramanna Center for Advanced Technology, Institute for Plasma Research, and the Inter-University Center for Astronomy and Astrophysics^[2].

The Union Cabinet approved LIGO-India, a 2600Crore (26 billion) INR Project (317,612,880 in US Dollars) on Thursday, the observatory will be built in Maharashtra and the facility’s construction is expected to be completed by the year 2030.

What is LIGO?

LIGO or the Laser Interferometer Gravitational-wave Observatories consists of 2 interferometers, arranged in the shape of “L“.

LIGO uses the physical properties of light and space to detect and understand the sources of gravitational waves (GW).

LIGO, unlike optical or radio telescopes, cannot detect electromagnetic radiation. (e.g., visible light, radio waves, microwaves), because gravitational waves are not part of the electromagnetic spectrum.

Although in some cases, we do expect to see some form of EM radiation coming from GW sources, they are different phenomena.

Indeed, electromagnetic radiation is so insignificant to LIGO that its detection components are totally segregated and shielded from the outer environment.

LIGO does not need to be spherical or dish-shaped like optical telescope mirrors or radio telescope dishes, which both require such structures to focus electromagnetic radiation onto a detector. 

Each LIGO detector is made up of two arms, each 4km (2.5 miles) long, with 1.2 meter-wide steel vacuum tubes organized in an “L” form and protected from the elements by a 10-foot wide, 12-foot tall concrete shelter.

LIGO is also capable of detecting gravitational waves originating from any direction, even the GW waves coming from underneath.

LIGO-India’s Future Developmental Journey

The primary motivation for developing a third LIGO interferometer is to expand the global network of gravitational wave detectors.

To extract the most information from gravitational waves, a global network of widely spaced facilities is required.

Adding more detectors to the network, in particular, improves our ability to discover sources, test theories of gravity, space, and time, and provide significant answers to astrophysics and cosmology puzzles.

The ultimate goal is to pinpoint a source of gravitational waves anywhere in the sky and to accomplish this, four equivalent detectors must be operational at the same time all around the world. 

Of course, given the complexity of gravitational wave detectors, more than four detectors in a network are required to improve the likelihood that four detectors are operational at the same time.

And indeed a fourth detector, Kagra, is set to be online in Japan within the next year. 

LIGO-India will be the crucial fifth member, once operational, which will considerably increase the possibility that four detectors are operational at any given time.

LIGO-India’s construction would be done on 174 acres of land in the Hingoli district, the government had already approved the project in 2016, but finding a flat, seismic disturbance-free region took a little longer than expected ((LIGO India, ‘Ligo India‘, “LIGO-India received the Indian Government’s in-principle approval in February 2016.”, https://www.ligo-india.in/))

The observatory will be built by the Department of Atomic Energy and The Department of Science and Technology with help of several International Research Institutions.

The Key components for the lab worth 560 Crores INR (about 6,84,16,096 in US Dollars) will be provided by the US.

References

1. LigoCaltech, ‘What are Gravitational Waves?‘, “Gravitational waves are ‘ripples’ in space-time caused by some of the most violent and energetic processes in the Universe. Albert Einstein predicted the existence of gravitational waves in 1916 in his General Theory of Relativity.”, https://www.ligo.caltech.edu/page/what-are-gw[↩]
2. LigoCaltech, ‘LIGO-India: A Planned Joint India-US Detector‘, https://www.ligo.caltech.edu/page/ligo-india[↩]