‘Gravity new way to discover universe’

LAHORE: Prof Nergis Mavalvala, the Pakistani-American Professor of Physics and Dean of the School of Science at the Massachusetts Institute of Technology (MIT) gave the keynote at the Afkar-e-Taza ThinkFest Online 2021 on Thursday evening.

According to a press release, she spoke on “Opening a New Window into the Universe,” in conversation with Prof Pervez Hoodbhoy. In an extremely engaging talk, Prof Mavalvala, discussed her path breaking work on gravitational waves where members of her team won the 2017 Nobel Prize in physics. She noted: “The old way of looking into the universe was light, but now we can use gravity to learn more about the universe.

“Light does not reflect off dark objects, and so we could not understand several things beforehand.” Explaining what gravitational waves are Prof Mavalvala said: “Gravitational waves literally jitter us up; they are waves emitted when two stars or black holes collide in space time.”

“Now we can use gravity instead of light to discover the universe,”’ she underscored. Einstein gave the theory of gravitational waves in 1916, but he dismissed them as he said they were nearly impossible to detect. However, in the 1960s and 70s two professors --- Kip Thorne and Rainer Weiss --- started to work on them and in 1975 collaborated to make large detectors in the United States. She noted that there are four kilometers long detectors in the US, a three-kilometer one in Europe and several others being planned.

It was through these detectors that in 2015 a massive discovery was made, Prof Mavalvala noted. “We detected gravitational waves from the collision of two black holes 1.3 billion years ago,” she exclaimed. “This was the first time we were able to detect the creation of a new black hole by the collision of two black holes and were able to even detect their distance, mass and other properties,’ she said.

Prof Mavalvala then talked about the next discovery which was made on Aug 17, 2017, when the collision of two neutron stars was observed. “We were even able to detect gamma rays which enabled our astronomer friends to actually see this spectacular firework in the southern hemisphere,” she said.

“We have too much gold on earth,” Prof Mavalvala exclaimed. Explaining her assertion she noted that for a long time we did not know how some of our heavier elements were formed, but that now we know that gold is probably formed by neutron star dust. This is also a great discovery, she pointed out.

In answer to Prof Hoodboy’s on the effect of her discovery on Einstein’s theory of general relatively, she said that until now it was not possible to prove that space time can ripple, this was only possible with the discovery of gravitational waves. “Because of the growing precision of our systems, other theories are growing weaker and weaker,” she emphasised.