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Friday, October 16, 2020

An Alternative Source

Ghez giving a presentation to the Harvard-Westlake Parents’ STEAM Club

UCLA has put out various items on Nobelist Andrea Ghez. Below is Harvard-Westlake School's write-up: [From an emailed newsletter]

Written in the Stars: An HW mom on black holes, the Nobel Prize, and getting it right 

On October 6, astronomer and UCLA professor Andrea Ghez P’19 ’24 was awarded the Nobel Prize in physics. She shares half the prize with Reinhard Genzel, Director of the Max Planck Institute for Extraterrestrial Physics, “for the discovery of a supermassive compact object at the center of our galaxy.” The other half of the prize goes to Roger Penrose, mathematics professor emeritus at the University of Oxford, “for the discovery that black hole formation is a robust prediction of the general theory of relativity.” Only the fourth woman to win the Nobel Prize in physics, Ghez has spent more than 20 years doing the research that has now made her a Nobel Laureate.

What was it like to find out you won?

I got the news at 2 a.m., so I was fast asleep. The tradition is the committee makes their decision and then calls the recipients right away. I actually once visited the Royal Swedish Academy of Sciences, and there’s a phone booth with the specific phone that they call the Nobel Laureates on. You get to speak to the head of the Royal Swedish Academy of Sciences and the head of the committee for physics, who asked me to prepare a few remarks for their press conference an hour later. I hung up with a combination of shock, disbelief, giddiness—I kept thinking I must be dreaming—and made myself a cup of coffee. Luckily, I’m an astrophysicist, so I’m used to being up in the middle of the night.

Did you have any idea you were being considered?

People will tell you they think you’re in the running. But the minute you get wrapped up in “this might help you win a prize” or “this might help you be first,” you move away from getting the science right. This award recognizes my work and the work of a group I’ve been competing with for the past two decades. Sometimes I’ve been first, sometimes they’ve been first, sometimes it’s incredibly close. But there was a moment 10 years in, when I started having kids, that I decided consciously to give up on the concept of being first and really focus on getting it right. I was trying to figure out how to manage being at the forefront of a very competitive world and being a mom. When my oldest was really little, I remember going to my first conference, where I talked about my latest results, and my competitor scooped me because I hadn’t published them yet; I wasn’t in any shape to publish fast. There was a moment of being destroyed and then a moment of realization that first isn’t everything; take the time and get it right. I just decided to lean into that strength of being careful instead. And the work became more creative after that.

What if your teams worked together instead of competing?

There have been many overtures over the years for the two teams to join forces, and I’ve explicitly resisted that. A lot of these measurements are hard to get right. Once you join forces, it’s kind of like a mind meld; you have to agree how to approach the problem. Over the years, we’ve had different approaches and gotten different results. My competitor and I definitely learn from each other as we publish, but there’s a lot to be said for the independence and space to do the analysis in a different way. I’m also much younger than he, so I was more aware of the danger of being subsumed. There is benefit to collaboration, but it’s kind of like when companies become a monopoly. There’s something useful in competition.

What is a supermassive black hole, and how can you tell there’s one in the center of our galaxy?

Supermassive black holes are black holes that are a million to a billion times the mass of the sun. And if you want to prove that these black holes exist at the center of galaxies, our galaxy is the best one to study because it’s the closest example; the next galaxy center is 100 times further away. While you can’t directly see black holes themselves, you can see energetic phenomena associated with things just outside the event horizon, which is the last point that light can escape. Why is all this important? Black holes represent the breakdown of our laws of physics. They’re a giant red arrow saying “work more here.” You can’t describe a black hole, because it’s an object whose mass is contained in zero volume. So that means the density goes to infinity, which in physics we call a singularity. It also means that black holes create gravitational effects that mix space and time, which makes them very intriguing subjects for lots of good science-fiction movies.

How did you do your research? 

My work is all done with Keck telescopes, the largest telescopes in the world. Big telescopes allow you to see fine detail, but the Earth’s atmosphere blurs these images. I’ve spent a lot of my career working on techniques to correct that blurring effect. By getting that technique to work, we’ve been able to get the sharpest images of the center of the galaxy, discover stars at the heart of the galaxy, and then measure their motions. By detecting how they move, you’re tracking the gravitational influence of whatever’s inside their orbit. One of the quickest stars goes around every 16 years. Its orbit tells you that there’s four million times the mass of the sun inside a region the size of our solar system, which demonstrates the existence of a black hole at the center of its orbit. This has increased the evidence for the existence of supermassive black holes by a factor of 10 millions, which has moved the idea of the existence of these objects from a possibility to a certainty. And it’s been so much fun—these images have allowed us to not only discover the black hole, but also to understand that the region around the black hole is unlike anything we expected. It defies almost all our predictions about how galaxies should interact with their host galaxies. That’s another part of this project that I’ve enjoyed immensely. Not only has it allowed us to answer the questions we’ve posed, but we’ve also opened up more questions than we’ve answered.

You’ve said that your high school chemistry teacher was an inspiration for you. How did she influence you?

My chemistry teacher was the first female science teacher I had. She taught me all sorts of things, but her most important lesson came when I was applying to college. I wanted to apply to MIT early, and someone told me they don’t take girls. I went to her upset, and she said, “What’s the worst thing they could do, say no?” [Editor’s note: She got in.] Don’t be afraid of trying, even if people don’t think it’s possible. If you believe in yourself, just do it.

Do you think of yourself more as a scientist or a teacher?

When I was in high school and college, public speaking terrified me. I was one of those kids, if you were in a group and you went around to introduce yourself, my heart would beat fast just to say my name. But I really cared about encouraging women in science, so in grad school I asked to be a teaching assistant for introductory physics, which at Caltech, only the professors teach. So I had to convince them. It’s funny, because I was so terrified of teaching, but they didn’t have any women professors in the physics department at the time, and I thought it was so important. I ended up loving it. At first it was connected to convincing both the young women and the young men that women could be scientists by just being visible. Today I do all my teaching at the undergrad level, the very first introductory classes, because that’s where the role model piece has the biggest impact. I still see myself first and foremost as a scientist, but I’ve come to appreciate the power of teaching now more than ever because we rely on the next generation to think independently and have hard, complex discussions.

I understand that you wanted to be an astronaut when you were a kid. Why do you think you ended up exploring space in a different way?

The early moon landings inspired me, that’s true. It got me thinking about the scale of the universe and the concept of infinity. But quite frankly I had no idea what I wanted to do. There was a stage I wanted to be a dancer. I went to college thinking I wanted to be a math major. It’s important for kids to realize that not everyone knows what they want to do in the beginning. So many kids feel the pressure to understand where they’re going. For some, it is really clear, but for others it’s a random walk, and it’s continually evolving. It’s almost like asking a scientist, what’s your next research question going to be? I have no idea. You just keep pursuing and trying to figure out what you enjoy doing and how you’re going to put all these pieces together. But it's so important to keep trying new things because you never know what you’re going to enjoy.

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