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“Where did all this come from? How did it all get started?”
These are the questions that Dr. Nergis Mavalvala asks about the universe. It’s not the meaning-of-life stuff in the traditional sense, but more of how everything around us came to be. These are the questions we all have, but for Dr. Mavalvala, finding the answers is her life’s work. It’s why she became a physicist.
“I began to understand that these questions are mostly answered outside of our planet, outside of our solar system,” she explains. “It really lies in the universe. And that’s how I got interested in astrophysics.”
As dean of MIT’s School of Science, Dr. Mavalvala has her hands full with her day-to-day responsibilities, but she still has time for her first love: physics.
“When we look out into the universe, almost all the information we have gathered about the universe over millennia as humans and sentient beings is through light,” Dr. Mavalvala says. But black holes don’t give us light, she points out. That makes them hard to understand. “A black hole is a good example of something that has so much gravity that even light can’t escape its gravitational pull. And how do you study those kinds of objects?”
The answer: gravitational waves.
“About 100 years ago, Einstein gave us a clue to that, which was that there were these objects called gravitational waves, which are essentially waves that are given off by objects because of their gravity,” she explains. “Because they're really massive and they're moving, they will cause waves in the spacetime itself.”
It was these ripples in spacetime that drew Dr. Mavalvala in, both the science behind them and the technology that we’d have to build to detect them.
“If we want to answer the question of how our universe came to be and why we see the universe we do today, we have to understand things like black holes,” she says. “They’re important building blocks of the universe. If you want a complete picture of the world around us, then you need to use every messenger that nature provides. Gravitational waves are one such messenger, as is light.”
For much of Dr. Mavalvala’s career, these gravitational waves—ripples in spacetime that result from collisions between massive objects such as black holes—were theoretical.
“I got started with LIGO when I was a graduate student at MIT in the early 1990s,” Dr. Mavalvala says, referring to the Laser Interferometer Gravitational-Wave Observatory in the US. “The team of people who were working on it were seen as sort of a ragtag team of dreamers.” Her PhD adviser, Nobel laureate Dr. Rainer Weiss, was one of the founders of the project, but many of her graduate school colleagues warned her not to pursue this path. At the time, there was still some debate about whether gravitational waves even existed. “It was sort of a maverick science,” she explains. “And I have to say, in some ways, that was part of the draw, to be part of something so improbable.”
After receiving her PhD at MIT, Dr. Mavalvala went on to do her postdoctoral work at LIGO, where she continued as a research scientist, before returning to MIT as a professor. Over her illustrious career, she has won various prestigious awards and grants, including the MacArthur “genius” grant and the Lahore Technology Award, and she was named the LGBTQ Scientist of the Year in 2014.
On September 14, 2015, though, everything changed. The LIGO inferometers (which are 3,000 kilometers apart) detected their first gravitational wave. The first thing that Dr. Mavalvala felt? “Pure skepticism,” she says with a laugh. “This can’t be it!”
There were many checks the scientists had to go through before they were able to revel in their discovery and confirm that the detection was legitimate. “The euphoria and ecstasy kind of started slowly,” she says. “It wasn’t like the moment I saw the symbol on a computer screen. I was like, ‘Wow, that was a slight glimmer of what this could be,’ but the first thing was, ‘Oh my goodness, no,’ you know? ‘Let’s check.’”
As the dean of MIT’s School of Science, Dr. Mavalvala’s administrative responsibilities are considerable, but she enjoys being a part of academia. It’s young people who are the key for her. “There’s an idea that the greatest scientific discoveries are made by wiry silver-haired scientists. But it’s the work of young people that enables all of these scientific discoveries.” She wants students to know that they shouldn’t be afraid to jump in.
“I think one of the joys of being at a university, as opposed to being in any other setting, is teaching” she muses. “I get access to students because I run an active research group, but I do miss teaching.”
Dr. Mavalvala’s research has always focused on the instrumentation necessary to detect gravitational waves, and she continues that work to this day at her research group. Recently, she’s been focusing on the complications that quantum mechanics introduces into the sensitivity of gravitational wave detection. “Quantum mechanics tells us some very strange things,” she explains. “Among the very strange things about quantum mechanics is that nature does not allow us to make a very precise measurement of certain quantities. And my group’s research has really focused on how you get around that limit, how you can manipulate these limits that nature imposes.”
‘It’s been a blast,” she says with a smile.
Asking questions is at the heart of what Dr. Mavalvala does every day. “A very simple question motivates everything that we do, which is: How do we make a more sensitive gravitational wave detector?” she explains. “Every time you make a more sensitive detector, you’re able to see fainter objects that are further out, right? That’s our motivation.”
“This question has led us down many interesting technological paths,” she says. “Some of them are dead ends, and many of them are not. That’s part of the beauty of science, that not every idea pans out.”
These ideas of questioning, skepticism, and embracing failure are central to the way Dr. Mavalvala sees herself as a scientist. “I think skepticism is perhaps the most important part of that,” she explains. “That helps us ask the most important questions. Anytime you make breakthroughs, it’s because you questioned the existing world order, right? And failure is important too—who likes to fail? But it’s inevitable.”
There’s another key part of it as well. “Our journey to discovery is never complete,” she says, adding that she doesn’t mean that philosophically. “In a very concrete way, every time we make a new discovery, we’re just asking the next set of questions. If you look at LIGO, the initial discovery of those 30 solar-mass black holes colliding—after the euphoria of that discovery, reality sets in. We don’t understand how nature makes such big black holes. How do these two black holes come together to orbit each other and collide? How are they born? We saw the last subsecond of their life; what was the rest of their lives like? How did it come to be?”
“All of these questions come from one single observation,” she says. “I feel like that’s true of all the biggest discoveries, and of the everyday work.”
“It’s never complete.”
