The announcement of the discovery of gravitational waves earlier this week has opened up a whole new vista for astronomers worldwide. Prof Sanjeev Dhurandar, who spearheaded the research on gravitational waves at Pune’s Inter-University Centre for Astronomy and Astrophysics (IUCAA), puts it even more succinctly when he says that they have opened a new window to the Universe.
“We can now actually detect black holes and other astronomical objects that were only theoretical constructs, by directly using the information coded in the gravitational waves they emit,” says the 64-year-old physicist.
He should know. Dhurandar has been scanning the skies in search of these elusive waves since the early 80s when no one was looking for them. “Till now we have only surmised the presence of black holes, now we can actually feel their impact. Every object emits a distinct kind of gravitational wave; if I move my arm, it too will generate a signature wave carrying information about the arm, its origin and its movements. But it would be too weak a signal to detect. When black holes move and collide they emit very strong waves. That is why we are able to see them so far away in time and space. In this way we can now directly observe space time events,” says Dhurandar.
This has become possible with the advancements in laser, vacuum and signal technologies. The current discovery was made when the change in the length of a 4-km LIGO arm by a ten thousandth of the width of a proton was detected and attributed to a ripple in space time caused by the collision of two black holes almost a billion years ago.
Dhurandar became interested in gravitational waves “because here was an opportunity actually to do some experimental work on what until now has been a theoretical assumption. Research in gravitational field in the `80s was just getting interesting and we were beginning to develop the technologies that would one day make it possible for us to experience the Universe directly. Especially signal technologies that enable us to hear the minutest noises or pick out different signals from noise that emanates from space,” says he.
Having proved what he set out to prove, where does he go from here? “Back to work; with LIGO coming to India, everything here has started anew. I still have 30 more years of work left in me!”
With the central government on Wednesday giving an in-principle clearance to a proposal to establish a gravitational wave observatory in India in collaboration with the Laser Interferometer Gravitational-wave Observatory (LIGO) in the US, Indian astrophysicists can now hope for a greater share of the gravitational research pie. The discovery is already being heralded as the discovery of the century. In addition, the extension of the LIGO project to India will mean that Indian industry will be able to absorb and implement cutting-edge technology in the construction of the 8 km-long beam tube at ultra-high vacuum on a levelled terrain required for the laboratory.
