- LIGO India project is coming up in Maharashtra, near Aundha in Hingoli district.
- This article explain about the LIGO projects across the world, their significance and India’s part in the global LIGO project.
- In September 2015, LIGO’s US detectors made the first discovery of gravitational waves travelling outwards from a point 1.3 billion light years away from the earth.
- At this point, two massive black holes with masses 29 and 36 times
that of the sun had merged to give off gravitational wave disturbances.
This discovery led to the confirmation of Einsteins’ prediction and
launched a new way of studying the Universe.
- Black holes are exotic objects that have immense gravitational pull and they trap even the fastest object in the world, which is light.
- When objects with such an immense gravity merge, the disturbance is felt by the very fabric of space time and travels outward from the merger, Thus, gravitational waves have been described as “ripples in the fabric of space time”.
- LIGO stands for Laser Interferometer Gravitational-Wave Observatory. It consists of a pair of huge interferometers, each having two arms which are 4 km long.
- LIGO, unlike usual telescopes, does not “see” the incoming ripples in spacetime because gravitational waves are not a part of electromagnetic spectrum or light.
- They are not light waves but a different phenomenon altogether — a stretching of spacetime due to immense gravity.
Detection of gravitational waves:
- Remarkable precision is needed to detect a signal as faint as a gravitational wave, and the two LIGO detectors work as one unit to ensure this.
- This requires weeding out noise very carefully, for when such a faint signal is being detected, even a slight human presence near the detector could derail the experiment by drowning out the signal.
- A single LIGO detector cannot confidently detect this disturbance on its own and at least two detectors are needed. This is because the signal is so weak that even a random noise could give out a signal that can mislead one into thinking a genuine gravitational wave has been detected.
- It is because two detectors detect the faint signal in coincidence that leads to the certainty of it being read as a genuine reading and not noise.
Other LIGO detectors
- Following the 2015 detection, which later won the Physics Nobel (2017), the two LIGO detectors detected seven such binary black hole merger events before they were joined by the European Virgo detector in 2017. The two facilities have now detected 10 events.
- The Japanese detector, KAGRA, or Kamioka Gravitational-wave Detector, is expected to join the international network soon.
- In the meantime, in a collaboration with LIGO, a gravitational wave detector is being set up in India.
- The LIGO India project is expected to join the international network in a first science run in 2025.
Sources of Gravitational Waves
- Mergers of black holes or neutron stars, rapidly rotating neutron stars, supernova explosions and the remnants of the disturbance caused by the formation of the universe and the Big Bang, are the strongest sources.
- There can be many other sources, but these are likely to be too weak to detect.
Significance of Gravitational Waves
- The data collected by LIGO, may have far-reaching effects on many areas of physics including gravitation, relativity, astrophysics, cosmology, particle physics, and nuclear physics.
- It has opened a completely new window with which scientists are starting to probe hitherto unexplored phenomena such as the formation of black holes, exploding neutron stars and witnessing the birth of the Universe.
- It enriches multi-messenger astronomy complementing the conventional means of observing and studying the Universe with telescopes using light.
- As more detectors would be in place, the study would also offer a new way to map out the universe, using gravitational-wave astronomy. Perhaps one day with highly accurate detection facilities, signatures of gravitational waves bouncing off celestial objects will help in detecting and mapping them.
- LIGO India will come up in Maharashtra, near Aundha in Hingoli district. The observatory will cost 12.6 billion rupees (US$177 million) and is scheduled for completion in 2024.
- Like the LIGO detectors, the one at LIGO India will also have two arms of 4 km length. But while there are similarities there will be differences too.
- Being an ultra-high precision large-scale apparatus, LIGO India is expected to show a unique “temperament” determined by the local site characteristics.
- The LIGO Laboratory — which is operated by the California Institute of Technology (Caltech) in Pasadena and the Massachusetts Institute of Technology (MIT) in Cambridge — will provide the hardware for a complete LIGO interferometer in India, technical data on its design, as well as training and assistance with installation and commissioning for the supporting infrastructure.
- India will provide the site, the vacuum system and other infrastructure required to house and operate the interferometer — as well as all labour, materials and supplies for installation.
- The LIGO-India project will be built by by the Department of Atomic Energy (DAE) and the Department of Science and Technology (DST), Government of India, with a Memorandum of Understanding (MoU) with the National Science Foundation (NSF), USA, signed in 2016, along with several national and international research and academic institutions.
Significance of LIGO India
- It will dramatically increase the sensitivity with which gravitational events will be detected.
- It will allow accurate calculation of sizes of black holes.
- Help to better understand the Universe’s rate of expansion.
- Detection of gravitational waves: With the current number of detectors in the world, there is huge uncertainty in determining where in the sky the disturbance came from. Observations from a new detector in a far-off position will help locate the source of the gravitational waves five to ten times more accurately than current efforts allow.
- Development of Astronomy: India is conventionally strong in theoretical astronomy. It will help Indian astronomers partner with the global community and bring new insights into this vibrant area.
- Careers in Science: Presence of such a world-leading facility in India will inspire and attract generations of students to pursue challenging careers in science, technology and innovation.