Lauren Gatta

When Yale physics professor Jack Harris was a postdoctoral associate at Harvard, renowned physicist Nergis Mavalvala showed him around the Massachusetts Institute of Technology’s facilities, explaining some of the instruments that she used and the great scientific questions she was attempting to answer.

On Monday afternoon, Harris introduced Mavalvala to speak at the Leigh Page Prize Award Lectures at Yale.

Nergis Mavalvala, a professor of astrophysics at MIT and a recipient of the MacArthur “genius” grant, presented a talk titled “The Warped Universe: the one hundred year quest to discover Einstein’s gravitational waves,” to a nearly packed lecture hall at Sloane Physics Laboratory, as part of the 40th anniversary of the Leigh Page Prize lectures. The talk touched on the history of gravitational wave observation, black hole collisions and LIGO technology, which involves a large-scale observatory that uses lasers to detect cosmic gravitational waves.

In his introduction, Harris lauded Mavalvala’s great contributions to LIGO technology.

“In my opinion, LIGO’s scientific results are the most inspiring results in the physical sciences in my life,” Harris said. “And I think that the only equivalent or historical parallel is the inventions of Galileo pointing his optical telescope up at the skies.”

MIT professor Rainer Weiss and California Institute of Technology professors Kip Thorne and Barry Banish designed the LIGO system, for which they won the 2017 Nobel Prize in Physics. The actual design of the LIGO system is two four-kilometer long detectors, set perpendicular to one another, with mirrors near the intersection. Weiss crucially proposed the size of the mechanism, as previous researchers had always attempted to measure gravitational waves on a smaller scale. Mavalvala played an important role in this research, as a member of the team that first measured gravitational waves in February 2016.

Mavalvala began her talk with a brief history of early and modern experimentation and observation in the field of gravitational waves. She began with Newton’s dilemmas, quickly working her way to Einstein’s theories and issues, such as dealing with the theoretical concept of black holes, which occur when a gravitational field is so intense that no matter can escape it.

Mavalvala then touched specifically on gravitational waves, explaining what they do, what cause them and how they are measured. Mavalvala said the most important way to detect gravitational waves is by understanding how they compress and stretch spacetime.

“We know that they are ripples of space-time and they travel at the speed of light,” Mavalvala said. “We also know that they compress and stretch space-time as they travel.”

The greatest difficulty in measuring these waves is how much they stretch and compress: The magnitude of this effect is smaller than the size of a single proton, according to Mavalvala.

This is where LIGO technology comes in. While the size of wavelengths is measured at 10E-18, LIGO technology can detect wavelengths as small as 5*10E-22. This allows LIGO to detect astrological events such as the merging of two black holes and the collision of neutron stars.

Mavalvala highlighted the progress scientists and engineers have made in astrophysical observations.

“Since then, we’ve built hundred-inch telescopes here on earth, we’ve put hundred-inch telescopes in space,” Mavalvala said. “We’re now building with 20-by-20 meter glass. We’ve also added all different wavelengths of light to our observation. And this was all before I got here, since Galileo gave us a kick in the pants.”

Her talk was followed by a meet-and-greet on the third floor of Sloane Physics Lab. Samir Abbas ’20, who attended the lecture, said he was most fascinated to hear about the effects of space-time ripples.

“It’s also super cool that you can think about ripples in space-time being the factor that causes things to move towards each other,” Abbas said. “And then as a direct consequence of this, you can start start confirming Einstein’s theories as well, which I found super cool, surreal.”

The Leigh Page Prize lecture series is awarded to a distinguished physicist in the memory of Leigh Page, class of 1913, a Yale physics professor who directed the Sloane Physics Laboratory. Mavalvala will present her second lecture, “Future directions in gravitational wave detection,” on Tuesday.

The most recent collision of two black holes occurred on Aug. 17, 2017. Known as kilonova, the collision occurred in the southern constellation of Hydra, 130 million light years away.

Nick Tabio | nick.tabio@yale.edu

NICK TABIO