Gravitational Waves Detected

00 hours 07 mins

The transcript

400 years after Galileo's first telescope we are on the verge of new way of looking at space, which will open new frontiers in Astronomy. This will be achieved through the observations of Gravitational-waves, predicted by one of the most revolutionary theories in physical sciences, Einstein’s General theory of Relativity, proposed 100 years ago. In this film, we will introduce the basic idea, current developments and highlight the contributions made by Indian scientists. In March, 1944 Einstein had humorously quipped, “Why is it that nobody understands me, yet everybody likes me?”. The domain of General Relativity is complex and esoteric however this has become so pedantic that it literally in the hands of 2.6 billion people in form of smart phones. 

Now if you throw a lighter ball at a fast speed, it will roll around the heavier ball due to the curvature in the fabric that the latter induced. And this is exactly why the earth goes around the sun. The stretched sheet is 4-dimensional space time fabric of the universe and gravity as the curvature of space-time. 

If two black holes collide or large twin stars circle around each other? Then they would radiate GW which are strong enough to be measured. And by measuring these waves we could see what no man or woman has seen before. Even these stronger gravitational waves would require extremely sophisticated instruments to be able to measure deflections about 10-18m much smaller than the size of atomic nucleus. The deflection data generated by these instruments is very feeble and hence contains a lots of noise. Seismic noise, Airplanes flying by, traffic noise, even the school band playing nearby can corrupt the data. So to detect and extract just the gravitational wave from the deflection data generated by these sophisticated instruments, we also need really smart algorithms or methods which can extract the pure Gravitational Wave from noisy data. This is where Indian scientists figure in. The method to detect and extract GR was developed by a team of scientists at IUCAA and is now used universally across the world. Extraction process requires very accurate phase information of the wave which was done by scientists at Raman Research Institute.
Indian scientists have made many other significant contributions in gravitational wave research like

1 Developing an understanding of Black Holes, 
2 strategies to look for unknown sources
3 identifying and mitigating instrumental glitches 
4 following up potential GW events with electromagnetic telescopes.

We have not yet detected a GW but we are very close with the help of laser based detectors called LIGO. Two of these have been constructed in US 2000 miles apart. But the Holy Grail in Gravitational waves is to detect one and also locate the source of the wave in the sky. Now to exactly locate the source of the wave, in the space, we need to have another facility much much farther away. By getting the data of the same wave from three detectors far away we can triangulate and exactly locate the source of Gravitational Wave in the sky. And hence can follow up the source using other telescopes. 
India is on the other side of the two LIGO detectors based in US. And so if we build a LIGO in India we will be able to improve our accuracy of finding the source of Gravitational Waves ten times. 
We are at a very interesting phase in Astronomy where India can play a major role. With some of the most fundamental research in Gravitational Waves, General Relativity supporting us and geographical advantage of being farthest from current detectors we take a lead and pave way for many fundamental discoveries in our understanding of cosmos and testing basic scientific theories. We hope to get started soon on this massive LIGO project in India which when completed by 2020 will provide a platform for many scientists and youngsters to collaborate together in our quest for beyond. Thank You.

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