An Indian observatory to detect Einstein’s gravitational waves
When you throw a heavy object such as a rock into a water body, ripples are formed. Similarly, when celestial bodies such as stars and planets orbit one another, gravitational waves are generated. This was proposed by world-renowned scientist Albert Einstein in the early 20th century.
However, it took more than a century to directly observe the theory in September 2015 when US-based physicists detected the waves using two Laser Interferometer Gravitational-Wave Observatory or LIGO in Washington and Louisiana respectively.
But nevertheless, more such observatories are required to be built worldwide to analyse the gravitational waves in further details. This has recently motivated the Narendra Modi-led Union Cabinet to approve the development of such a project in India. In fact, they have set up a budget of INR 2600 crore to build the nation’s first Laser Interferometer Gravitational-Wave Observatory or LIGO-India in Hingoli region of Maharashtra. The project is scheduled to begin mid-2023 and wrap up by 2030. It will be constructed by the Department of Atomic Energy in collaboration with the Department of Science and Technology and the US-based National Science Foundation.
In fact, this will be the world’s fifth LIGO and is aimed at building a larger international network of gravitational wave detectors. The other two LIGOs are located in Italy and Japan. They are named Virgo and KAGRA respectively. Each of these LIGO detectors consists of dual arms, each 4 kilometres in length, and having 1.2-metre-wide steel vacuum tubes arranged in an L-shape. They are also each covered by 10 feet wide and 12 feet tall concrete shelter that saves the tubes from the external environmental factors.
As of now, all the four detectors can only confirm and measure the gravitational waves but are far from effectively locating the source or understand about the waves’ actual polarisation. With another one added to the global network of gravitational wave detector, scientists around the world are hopeful that better information can be extracted from the gravitational waves, including their location, as well as other theories surrounding gravity, space, time, astrophysics, and cosmology. In fact, at least four compatible detectors need to be functioning together to localise the source, as recently revealed by a team of NASA physicists.
Now for those unaware, gravitational wave theory was part of Einstein’s bigger Theory of General Relativity. In fact, he defined it as “ripples in space-time.” If better put, it refers to the fluctuation in space-time caused by accelerating masses of two objects orbiting each other, that propagates as waves at the speed of light.
Okay, but why is the study of gravitational waves so important? Well, it is because it helps researchers understand a few of the most basic laws in physics, including, evolution of galaxies, birth and death of the universe (Big Bang), black holes and of course black matter.