Skyping with Saul

Skyping with Saul

Students in a senior physics class this spring realized every aspiring scientist’s dream: They interviewed Nobel Prize winner astrophysicist Saul Perlmutter ’77 about his groundbreaking discovery. PRODUCED BY MEG COHEN RAGAS ’85

Michael Branscom

On May 22, a section of David Williamson’s advanced physics

class engaged in a video chat with Saul Perlmutter ’77, the 2011 Nobel Prize Winner in Physics. Perlmutter won the prestigious award for discovering that the expansion of the universe is actually speeding up—not contracting, as scientists had previously believed—propelled by a mysterious force now known as “dark energy.” (Perlmutter, of the Lawrence Berkeley National Laboratory and the University of California, Berkeley, shared the Prize with two other astronomers: Brian Schmidt, of the Australian National University of Canberra and Adam Riess, of the Space Telescope Science Institute and Johns Hopkins University.) The students prepared for the interview by studying Perlmutter’s research, listening to some of his interviews and watching the video of him receiving the Nobel Prize in Stockholm last December.

“In my year-end class evaluations, a few of the students noted the

talk with Dr. Perlmutter as a highlight of the course,” says Williamson.

“It was a great opportunity for them to talk with someone on the cutting edge of cosmology. Dr. Perlmutter did a fantastic job of explaining his work, and I think the students left with a sense of wonder about the universe and a knowledge that there are still many areas of physics with important questions yet to be pursued.”

Following are excerpts from the Skype interview.

Is dark energy the only explanation for the [universe’s] accelerating rate of expansion, and if not, is there a simpler explanation that does not involve a new kind of energy? Aryeh Coburn-Soloway ’12 The term dark energy is really just a placeholder for the fact that we really don’t understand what’s going on. It could be an energy that’s pervading all of empty space, all of the vacuum, and if so, we’re

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“

“We Knew Saul When…”

Former classmates and GFS faculty share their memories of the Nobel laureate.

“What has always made Saul most special in my eyes, throughout our time together at GFS to the present, is that he possesses the highest degree of intelligence paired with the highest degree of humility—very rare indeed. At GFS, Saul was just a well-adjusted academic, musician, athlete and friend, with the ability to listen, ask questions and make us all laugh with his quick wit.

“When I first heard the news, I immediately texted Sally Solo ’77, and she responded, “We all knew it would happen one day, it was just a matter of when!” I was terribly proud and happy for Saul, his wife and daughter, his lovely parents, his entire family, and the GFS teachers who had a hand in his education.” –Jenny Harland ’77 “Saul has always been very bright and very inquisitive, so in a sense it does not surprise me that he has received the great honor of winning the Nobel Prize in Physics. It was amazing to be able to go to Stockholm with my wife and children to share in the festivities and to witness the historic event.

Saul gave a lecture on his research at a local university as is customary and he truly has a gift for making a complex topic understandable and enjoyable to his entire audience, many of whom, like me, had little prior knowledge of astrophysics.

“Saul has a knack for bringing people together and maintaining friendships as evidenced by the presence in Stockholm of friends from high school, college, grad school and his post-graduate research years as well as his family (parents, sisters, brother-in-law, parents-in-law, wife Laura and daughter Noa). Saul has always been extremely down to earth and this hasn’t changed with his recent notoriety.“ –Scott Panzer ’77 “I remember Saul wrote a paper in high school on the origin of the number zero. There was never any doubt that he was the brightest kid in the class of ’77. His unique gift was that he was/is brilliant, but he was also sociable and fun to be around.” –Bill Starrels ’77 “Saul was a relatively quiet young man, much liked by all of us and highly focused on his work. Obviously, one can have no idea about a 17- or 18-year-old in terms of his ultimate achievements in the world of science, especially at the Nobel level, but if any of us had had to guess in those days, Saul would have been among the top contenders.” –Fred Calder, former head of Germantown Friends School, 1970-86, to the Chestnut Hill Local, October 17, 2011 “He had a wonderfully gentle sense of inquiry and, I would just say, wonderment,” John Tuton, Perlmutter’s eighth-grade English teacher, to the Philadelphia Inquirer, October 5, 2011

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calling that dark energy, but we don’t know for sure and at this point, I’d say there are lots of possibilities. It could be that Einstein’s General Theory of Relativity might need a little tweaking, which would be pretty amazing if that were true, it’s possible that it’s something that we haven’t even understood yet at all. Maybe we’re actually seeing a clue that there are extra dimensions in space beyond the three dimensions and the one dimension in time that we usually see and so some theories have gravity leaking out to some other dimensions and affecting the universe expansion.

In the last 12 years there’s been a theoretical paper trying to explain what’s going on every 24 hours, on average, so I can’t possibly keep up with all of these papers. I think if you ask theorists whether they believe their particular theory, they’d say, “Oh, no, no, I’m just trying to expand the range of possibilities.” So in that sense, dark energy really is just a placeholder for this range of theories we’re trying to explore in an attempt to figure out what’s going on.

You mentioned how theoretical physics interacts with experimental physics. Can you expand on how you’re working with the more theoretical findings? Bryce Low ’12 In physics, in certain fields, we’ve ended up really dividing into theorists and experimentalists, and that happened, for example, in the field of fundamental particle physics. It’s not quite as much in every sub-area of physics, but in most areas there are the theorists and the experimentalists, and they have this fun, combative relationship.

Of course, I’m on the experimentalist side, and in the very early days when we were first doing the measurement that led to this amazing result, the theorists were always saying, “Well, we’re glad you’re doing the measurement but we already know what the answer is,” and I thought, “Well, we really should make this measurement, it seems kind of important to know what the fate of the universe is and if the universe is infinite or not. I’m not going to trust any theorist.”

The upside was, not only was I surprised [by the finding], everyone was surprised, it wasn’t what anyone expected. And of course that doesn’t always happen, a lot of the time the theorists are right, and that is very disappointing for us experimentalists.

Are you doing any additional research to refine the results of your work, particularly in the area of the exact rate of the accelerating universe? Peter Lee ’12 The only way to tell apart these thousands of theories right now is to really get at this stuff. One way we’re doing this is by going back and doing the same supernova measurement that we used before, but this time we’re trying to make the measurement much more precise, which means we have to understand the supernova better if we’re going to use it as the standard measuring tool. So we’ve developed a new space telescope concept, and we’ve been trying to push that through.

The funny thing there is that we actually got it approved and the Department of Energy, which funds fundamental physics, was about to build the satellite and fly it and then NASA complained, “Wait, we do the space stuff, why don’t we get to do this one?” So the whole thing stopped so that the Department of Energy and NASA could get a chance to do it together, and then they started arguing about who got to do what, and that went on for several years. By now it’s gone through three or four committees, and each time they agree to do the satellite— it’s gotten funded several times—the agencies start squabbling with each other, and so we still haven’t managed to fly the satellite. So I’d say even harder than solving fundamental mysteries of how the universe works is solving fundamental mysteries of how the government works.

If you hadn’t discovered the universe was expanding

The First Nobel

Before Saul Perlmutter, GFS claimed another Nobel Prize winner among its alumni: Owen Chamberlain ’37 received the distinguished award (also, coincidentally, in physics) in 1959 for his discovery of an antiproton, a subatomic particle that is the antimatter equivalent of a proton. His research, conducted at the University of California at Berkeley with his partner, Emilio Segre, opened new areas in the field of physics, led to the discovery of other antiparticles and expanded scientists’ understanding of the composition of the universe.

While at GFS, Chamberlain enjoyed his physics class, but was often bored by other subjects. A math teacher recognized his need for more advanced work and allowed him to go to the library to teach himself calculus—because none of the GFS faculty taught it at the time. Chamberlain went on to study at Dartmouth College, earned a Ph.D. at the University of Chicago and joined the faculty at the University of California, Berkeley, in 1948.

Chamberlain worked on the Manhattan Project—a top-secret group of scientists organized by the government to develop

the first atomic bomb for the military to use to end WW II—from 1942-1946, and later apologized to the Japanese for the nuclear attacks during that war. Afterward, he became involved in progressive political causes, including the ’60s Free Speech Movement at Berkeley, and a proponent of Owen Chamberlain ’37 nuclear disarmament.

Chamberlain had a long career conducting research, inspiring students with his lively teaching style and advocating for nuclear peace, all the while staying active as a GFS alumnus. He passed away on February 28, 2006, at the age of 85. –Laura Jamieson

at an accelerated rate, do you think you still would have won the Nobel Prize? Tyler Altenhofen ’12 No, I don’t think so. I mean, you have to take these Nobel Prizes with a grain of salt because it could be the same project, the same people doing the same thing, and you don’t necessarily get a Prize every time. In this case, it was going to be a fun project, it was the most exciting project I could imagine working on anyway, and that was because we were going to be measuring the fate of the universe.

We were finding out if the universe was going to be slowing in its expansion, coming to a halt and then collapsing, so we could have discovered if the universe was coming to an end some day or not. At the time, we also thought that it would tell us if the universe curved in on itself in this kind of weird way that Einstein’s General Theory of Relativity allows, so that would mean that there’s not an infinite amount of real estate out there—eventually, if you travel far enough in one direction you’ll end up back somewhere you were before.

I thought it would be amazing to see if that were true, and I thought it was going to be a wonderful project, no matter what the answer. I was very excited about it, and it turns out now, with this result, I still can’t tell you the fate of the universe and we still don’t really know if the universe is curved in or not, although at the moment we think it’s probably not. So in the end, we weren’t able to do what we set out to do in the first place, but instead we won a Nobel Prize.

What are your plans with your fame from the Nobel Prize, and what doors have opened for you? Will Hannah ’12 To be honest, I don’t really know yet because it’s only been a few months, and you know how busy these few months have been. But in general, almost everyone I know who’s working on big projects of different kinds, everybody’s just frantically busy all the time, and so you go through these waves of being overly busy and traveling too much.

That’s been happening for over the past ten years, but it’s happening a lot more now because I’m getting all of these invitations. I have an eight-year-old daughter at home, so I’m not dying to be traveling all of the time, so in general, it just feels like a really, really busy period in my ordinary life and a few extra people want to talk to me.

What I don’t know is if that’s going to go on forever, or if things

will begin to calm down at the end of the year. The other aspect that I’m trying to take a little bit seriously is that it feels like, at various points in your life, you should be asking yourself if you’re working on the things that you want to be working on and is this a good moment to switch your focus from one thing to another. Over the years, I’ve stopped at various points and asked myself that question, and it feels like if you’re ever going to ask yourself that question you should do it at a moment when you’ve just won a major prize because it’s a time when a few more people might want to hear what you have to say.

How was your transition from GFS to the Harvard physics program? Do you think you had a good knowledge base? Peter Lee ’12 I had a physics professor, Harry Saffren, who was great, we all really enjoyed him, and basically the one bit of physics I had [at GFS] was that one course. If I remember correctly, [physics] was not yet calculus-based at that time. And I remember during that period, the number of people in the physics course was much smaller, generally. At that time, GFS had a really strong focus on writing and on history; the humanities and the social sciences were where people put most of their efforts. We did get a biology course, a physics course and a chemistry course, so it wasn’t like we learned nothing about science, but it wasn’t as much of a focus. For me, at the time, I thought I was going to go into science later, so I wasn’t worried because I also wanted to have a strong background in writing and reading and other things.

Was there more competition or collaboration between you and the other group working on the research? Aryeh Coburn-Soloway ’12 There were two groups that were making this measurement. The other group was more traditional astronomers and my group had more physicists with some astronomers. What’s interesting is that even though these are two fields that are so close to each other and share so many of the same questions and techniques, the cultures are slightly different.

It was a fierce rivalry for many years partly because when we started working in this field, there was a little bit of feeling on the part of the astronomers, “Who are these physicists coming in and poaching our territory, applying to use the same telescopes as us?,” (Continued on page 20)

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(Continued from page 14) and so we had a hard time getting to use the telescopes originally. The other group started later [than us], but they were already well into the astronomy world, so they had a head start in a different way.

There was a period of about three or four years when we’d be applying to use the same telescopes and we’d be in these situations where we would be flying to Chile to use the telescope there or to Hawaii to use the telescope there or to Tucson to use the one there, on back-to-back nights, so we’d pass the other team in the airport, as we were flying in or they were flying out, and so actually it was this very tough-fought rivalry. But even in its fiercest stage, we were also the only people who understood what the other was going through.

It was really hard to get the whole thing to work: If you got just one bad night of weather, a whole semester’s worth of activity could be ruined. There was one time, for example, they got clouded out on the key night they needed to measure the identity of the supernova and they were using the biggest telescope in the world on Hawaii, and we were on just a night or two later, on the same telescope, and we took some observations for them. And similarly, there was one night when we got clouded out right in the middle of our search for the supernova and the head of the other group traded a night with me.

So it was a funny kind of rivalry because we really understood each other’s problems but we were also trying to beat each other. It actually worked well in terms of the science, though, because the calculations were often really tricky to do and it was really good to have another team trying to prove you wrong because if they couldn’t find anything wrong, then you knew it had to be right.

What do you think are the best areas of physics for physics majors to go into? Isabella Di Dio ’12 It changes all the time. From one period to the next, there are new discoveries, new directions, to pursue and, depending on what looks exciting and hot, you end up slightly changing the direction you go in. For me, I happen to be interested in those topics that feel very fundamental and philosophical and so that tends to draw me more towards projects that have to do with fundamental particle physics, fundamental cosmology, areas that have been very fertile and my guess is will continue to be for the next decade. It’s going to be an exciting time for cosmology, so I still recommend it as a direction to work in, but it’s also been a very exciting period for other new areas like bio physics, where people are just now starting to use physics to get at fundamental biological questions, or there are these fascinating discoveries of materials that allow you to do all sorts of amazing tricks, and you can catch the universe in the act of doing weird things in studying them. It’s really a question of what appeals to you, what gets you excited and makes you feel like it’s going to be fun to go to work in the morning.

How did you feel when you found out you’d won the Nobel Prize? Did you expect it? Shimpei Kurokawa ’12 It’s a funny kind of business because when you have a result that everyone’s very excited about, like the accelerated expansion of the universe, of course people constantly debate the possibility that there could be a Nobel Prize. But then what starts happening is the University and the National Lab I work at, they have press offices, and so every year, for the past five years or so, they started calling me up and asking, “Where are you going to be next Tuesday?,” and this is some time in the end of September, and I’d say, “In Berkeley, why do you ask?” And they’d say, “Oh, just in case there’s a phone call in the

middle of the night,” and I’d say, “Oh, right, yeah.”

So you start having this problem that every year someone’s reminding you that you may not win a Nobel Prize that year. So for your mental health, you basically try to ignore it every year, and this year was the same—we went to bed, I tried to ignore it—and then in the middle of the night, the phone rings and I pick it up, and the person on the other end goes, “Hi, is this Perlmutter?,” and I said, “Yes,” and he said, “How do you feel?” And I said, “Fine, thanks, why do you ask?” And then he said, “About the Prize?” And I said, “What Prize?”

The Nobel Prize Committee had been trying to reach me, they’d already announced it in Stockholm, and were supposed to have called me before the announcement, so now it was a reporter calling me to hear my response. And of course I hadn’t heard about it yet officially, so I wasn’t sure if it was a hoax. My wife had an iPad by the bed and picked it up and showed me, “Look, it’s real, you actually won the Prize!”

So at that point you wake up and you realize it’s 2:45 a.m., and the phone’s been ringing constantly, and I look at my wife and say, “So now what do we do?” Sure enough, within 45 minutes, the TV vans are showing up with the bright lights and the generators in front of our house and they want to do interviews.

That first day is very exciting, you have no sleep and you’re rushed from press conferences to celebration receptions. I asked that we get all of the members of the team who were in Berkeley to come together to give their impressions. We did this panel and the students at Berkeley were asking questions about what it was like to work on the team for the past ten years, so it was a fun celebration for the whole group.

What’s written on the board behind you? It looks pretty complicated. Peter Lee ’12 This board has become somewhat of an historic artifact because anytime we would be discussing anything and trying to decide, “Okay, what are we going to do next?,” we’d write down some equations or a calendar to try and figure out what days we’d be able to observe the supernova, and people would just be writing things on the white board all the time. At one point, the furniture got rearranged and we couldn’t get to the board for awhile and so it got frozen. After we received the Prize everyone said, “Wait, that board shows everything we were doing for those ten years, don’t take it down!” So we just left it.

Michael Branscom

Skyping with Saul

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