The Life Scientific: Brian Schmidt

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0:30Brian Schmidt:at Whole Foods Market. Don't play games with us. A vicious gang of hackers causing chaos for businesses, councils and hospitals. What if I don't finish this treatment and this cancer grows? But they didn't care. I'm dying laughing. Making outrageous demands for money. They wanted millions. It was high tech and high stakes. The country's under attack. And it was highly secretive until someone exposed it all. Cyber hack season four, The Conti Files. Listen on bbc.com or wherever you get your BBC podcasts.

1:08Today it's a bit of a dream show for me because I get to talk about physics and wine. It doesn't get much better than that. My guest is a Nobel Prize winning astronomer who threw the proverbial cat amongst the pigeons in the late 1990s when he announced that, contrary to long-held belief in cosmology, the expansion of the universe is speeding up, with everything around us moving further and further away. We'll unpack that rather isolating thought in a moment. Brian Schmidt is a distinguished professor of astrophysics at the Australian National University, known for his work on supernovae, massive explosions that take place when stars come to the ends of their lives.

1:49They're among the most energetic events in the universe and incredibly difficult to find. However, that's what his research team did, identifying enough of these rare and distant explosions to measure just how fast they were moving away from us. Their work helped pave the way for a revolution in astronomy. As if that weren't enough, Brian's gone on to discover one of the earliest stars in the universe. He's run a university and become a winemaker at his very own vineyard just outside Canberra. So it seems appropriate to say cheers and welcome, Professor Brian Schmidt, to The Life Scientific. Great to be with you.

2:26We are, of course, going to be talking about your Nobel Prize-winning discovery, that the universe is expanding at an ever-increasing speed. What did that mean for our understanding of the cosmos? Well, it kind of upended what we were thinking of the universe, thinking gravity would be slowing the universe down. And the idea was if there was a lot of stuff in the universe, if it was dense, then the universe would slow down completely in the future and reverse in direction, and then as it began in a big bang, it would end in the Gnabgib, the big bang backwards. I've not heard that one before. Well, it's a Douglas Adams, so I've stolen it from the master.

3:08So the other alternative, of course, is that the universe was light. Gravity would slow the universe down, but not enough, so the universe would coast on forever and exist forever. Now, what we discovered in that the universe was speeding up, that somehow gravity in the universe is working in reverse. And the easiest explanation is one that Einstein thought of in 1917, which is that the universe is full of energy. And, you know, just to reassure listeners, that doesn't mean we're going to stop seeing stars in the sky at night because the gravity holding our galaxy together is still strong enough to resist this expansion, this stretching of space, which is really happening in between the galaxy clusters, you know, the really empty spaces in the universe.

3:50Well, Jim, that's true in the shortness of only 100 billion years or so. But when you go to trillions upon trillions of years, all those stars are going to die. And the expanding, accelerating universe takes all the gas away. So there's no new stars. So we do end up in a dark galaxy, dark universe eventually. You know, a lot of people find that very depressing, despite the fact that, as you say, this is trillions of years into the future. I mean, we've got more immediate problems to worry about. We certainly have those. Your discovery was based on observations of a specific type of exploding star, a type 1a supernova.

4:28Why was that? So type 1A supernovae are explosions, thermonuclear detonations, so not dissimilar to an atomic bomb here on Earth, of the remnant of a white dwarf. And the beautiful thing of these explosions is they're very uniform. They're not identical. You've got to calibrate them a little bit. But to first order, we can calibrate them to roughly 4 or 5 percent. and that allows us to measure distances that are very accurate because we can look at how bright they appear and that brightness tells us how far. The further away it is, the fainter it's going to be. And they're really bright, so you can see them all the way across the universe.

5:10So, Brian, stars may be your speciality. I also mentioned in the introduction that you're a man of varied talents, including viticulture. How did you and your wife end up running a vineyard? Well, it really started on Jenny and my first date. When we went out, the wine list came out, and Jenny's Australian, and she handed me the wine list. And I didn't know what to do. I was kind of perplexed. So she grabbed it back, and she looked at me and said, if you're going to date an Australian, you're going to have to learn something about red wine. So that's how we got started. And do winemaking and astronomy have any similarities?

5:47Well, there is a creative aspect to them that I think is in common. I mean, astronomy is not just rote, going, doing things. You have to be really creative about how you explore and understand the universe. The wine, you're never quite sure what the weather's going to be. You've got to learn all the little things you can do. And every year, things are a little different. So you've got to be quite creative to do your best job with each year's fruit. So different, but maybe complementary. century and I hear your parents both grew up on farms so presumably that instilled that love of the land. Yeah so my parents had me when they were very young.

6:26My mom was 19, my dad was 20 as we say in the United States where I was born a sophomore surprise and my parents as you said both grew up on farms so for most of my childhood I would go to the farms in eastern Montana and in North Dakota and be there for three months. And so I really got to participate in farm life. So it's always been something that I'm very comfortable with. But my mother, an extreme extrovert, my father, a scientist, my mother went on, studied history, and then ultimately was an office executive. My father was a fisheries biologist, and he got to take care of me a lot when I was young, because he had the time while working on a PhD when my mother actually had to go out and earn some money.

7:12So they're kind of, you know, very complimentary people. And I'm a kind of a mixture of both. Was it your father then who got you into science as a youngster? Yeah. So hanging out with my father while he was working on his PhD was something I remember very well. And I just always knew I was going to be a scientist because I loved the love that my father had for what he was doing. And it just seemed like the only thing I would be ever interested in doing. When you were a teenager, the family relocated to Alaska for your father's job. You did well in high school. You got a place to study physics and astronomy at the University of Arizona.

7:49What were your first impressions of university life? Well, showing up from Alaska, which is known for being cold and Arizona for being hot, there was some climatic adjustment to be done. But Arizona was also, especially in 1985, less so now, was really considered a party school. And it was definitely sex, drugs, and rock and roll. And I just wasn't quite prepared for that. So I don't know, I was not terribly comfortable, especially in my first year. Second year, I was able to start working at Stewart Observatory doing research. And so that kind of got me going on the path that I'm on. Well, working at the University's Stuart Observatory is something that really captured your imagination.

8:35In fact, by the end of your undergraduate degree, you were using the observatory's telescope to search for supernovae. That led to you winning a scholarship to start a PhD in astronomy at Harvard. Your thesis work involved measuring the Hubble constant. This is a number in astronomy representing how fast the universe is expanding. How did you do that? So in 1989, when I went to Harvard, the Hubble constant was a very controversial subject because there were two groups that had polarized into two numbers, and they didn't like to talk to each other because both knew each other was right. So my job was to use a method using supernovae, but not type 1a supernovae, type 2 supernovae, which for your listeners are the explosions of stars that are 10 to maybe 20 times larger than our sun.

9:30And when they explode, they're expanding balls of gas that it turns out you can measure their distance by what color they are. So it turns out the hotter you are, the brighter you are, and how fast you're expanding. And so doing that and some fancy modeling done by a postdoc, we were able to put it together and essentially measure a distance to these objects. and at the end of four years you were able to measure the Hubble constant and the number I got was quite interesting because it was 73 kilometers per second per megaparsec meaning that the universe is about 14 billion years old and I should explain why that's the case.

10:11The Hubble constant tells you how fast the universe is getting bigger and so the inverse of the Hubble constant, so you just kind of put it upside down, tells you how long it takes to get back to the Big Bang. It allows you to reverse the universe back to nothing. And so about 14 billion years was the answer that we got. And that was directly between the two opposing teams. So neither of which particularly liked my number, but turns out to be almost exactly the same number that we get in the modern day. So you managed to resolve that problem. Well, during your PhD, Brian, in the summer of 1990, you got to spend a few weeks in Europe at the famous Lesouches Physics Summer School in the French Alps.

10:53And one of the people you met was someone that you'd end up collaborating with later on. Yeah, Mario Humi from Chile. And Mario was starting a project to measure type 1a supernovae, which were, I guess, discussed as being things that could be used to measure distances actually, but no one had actually really done a modern experiment with them. So he and his colleagues collected the data that would be used eventually for our Nobel Prize. But I met him there and set up a lifetime of collaborations. You actually went over to Chile the following year to work with him and his team and getting extra data for your PhD.

11:38Yeah, so I was there working with Mario and Mark Phillips and Nick Sunsef mainly. and I got to learn all about what they were doing and learn to go out and have pisco sours, which is what you do in La Serena, Chile on a Saturday night. And I guess learned the art of reducing the data and making precision measurements and things. I like the fact that you mentioned it wasn't all hard work during your PhD because it was at Harvard where you met and married your wife, Jennifer. Indeed. So Jenny studied economics. We were in the residence halls together, she and the second floor, me and the first, and we found a common passion trying to organize social events in amongst all the work.

12:23So that started in 1990 and obviously has gone on ever since. After completing your PhD, Brian, in 1993, you started a postdoctoral fellowship at the Harvard-Smithsonian Center for Astrophysics. and it's worth mentioning that around this time there was something of a breakthrough in supernova studies wasn't there yeah so in about february 1994 mario hamui came up from chile with his first data from that experiment he had told me about in les ush in 1990 and he showed that they could measure the distances to the supernovae to about seven percent which was three times better than anything else at the time.

13:07And about six weeks later, Saul Perlmutter and a team at Berkeley, known as the Supernova Cosmology Project that had started in 1988 to look for exploding Type 1A supernovae, made the breakthrough that with digital detectors that were novel at the time, they could actually use these digital detectors on the largest telescopes and discover distant type 1a supernovae. And we were asked at Harvard, Bob Kirshner's group, to take a spectrum of an object. Now, we had done this many times in the past and never ended up with anything. This time, we suddenly saw that there was an object that was about three and a half billion light years away and that they clearly could find these objects.

13:55So you had those two things, and I saw that this created the amazing opportunity to measure the future of the universe, something Saul had been working on for six years. This made it clear to me you could actually do it successfully. So, you know, we tried to figure out how to work together. They're a physics group. We were an astronomy group. It was cats and dogs, and the chemistry did not work well. so in the end we decided to part our separate ways and do the experiment as cats and dogs and so that's how we ended up with two competing teams and we're going to come to the discovery later on to what you found just a few years later but the end of 1994 was a busy time for you brian because you and jennifer had your first child you also moved across the world to take up a postdoctoral fellowship at the australian national university which meant that you would be working at the Mount Stromlo Observatory, and you decided to not only seek out supernovae, but also find a way to measure from the light they give off the rate of expansion of the universe, which at that time, scientists assumed for very sensible reasons, was slowing down.

15:09So what was your plan? So the plan was to use digital detectors that were just installed at the Cerro Tololo Inter-American Observatory in Chile, and take an image, wait a couple weeks, take another image, subtract the images by doing a bunch of fancy manipulation, look for the new things, use telescopes to get spectra, so that's where you spread the light out into the colors of the rainbow. You need a really big telescope, we could use Keck telescope in Hawaii to do that. You do that a couple days later, and then afterwards you have to measure how bright the exploding star is over time. So how did it all go initially?

15:52Yeah, well, it was a bit of a disaster, actually, because it turned out the software that I had put together did not work. This was made more difficult because the internet in 1995 was very slow, and the rate of the internet was about one character per second. So that's A, B, C, D. So over a period of five or six weeks, we're just debugging and trying to get things. They sent me a bunch of data. It got lost, never arrived. And so we got to February and I'm just looking at it and saying, well, I guess this is the end of my career as an astronomer. I've just burned six nights of telescope time, nothing to show for it and then finally in march things started working and then bam suddenly an object appeared and we looked at it and uh indeed it was a supernova and it was the most distant object uh supernova ever discovered almost five billion light years in distance there you were then running the supernova searches scanning both from chile and hawaii twice a year you've got lots of data lots of work.

17:02How did you find it? Well, it was kind of insane, actually. Working kind of 12-hour days and moved to 16-hour days, then 20-hour days to try to get everything to work. And we always just barely got across the line. And then we had to analyze the data. That's really hard. So you're writing all the software and techniques that no one has ever done before. And it was frenetic. Well, despite the chaos between 1995 and 1997, you discovered 16 distant Type 1a supernovae. And that's no mean feat because it's not just about getting the imaging right. Finding them is a bit like looking for a needle in a galactic haystack, isn't it?

17:45Indeed. So a Type 1a supernova happens in a galaxy like the Milky Way, maybe once every 250 to 400 years. You know, the last one was seen by Kepler in 1604. And there are a lot of stars in the Milky Way. Yeah, and there are 10 to 100 billion stars in the Milky Way. So when we go out and take an image of the sky, you might say, well, you're going to have to wait 400 years to see it in a galaxy. But you get around this by looking at lots of galaxies at a time. So when we take an image of the sky, we're often looking at 5 ,000 galaxies. And every 100 ,000 galaxies that you look at, you're probably going to find one of these things.

18:25So every six nights of telescope, we could find three or four. And you found enough of these exploding stars to now tackle your main goal of measuring the universe's expansion rate. How exactly do you do that? Well, the first thing we need to do is measure how bright the supernova is on each image that we take. And we do that by taking a previous image and manipulating it very carefully so that we can subtract it. Now, I think people are kind of used to doing that with programs that exist now on their phones. This was stuff we had to write from scratch. So we had to align the images really accurately.

19:05We had to make the right brightness. Then you subtract it. And then you have to go look for these tiny little glitches across what turned out to be hundreds of billions of pixels. The other thing we have to do is use a big, big telescope like Keck. Take spectra, where we spread out the colors. We measure the wavelength. So that's the color of the light coming from the supernova. We compare to what that wavelength is here on Earth. and that tells us how much the light from the supernova has been stretched by the expansion of space. So we've got sort of a velocity or a redshift from the spectrum.

19:45We've got the distance, which is the really hard bit to get from the light curve, and then we compare them. And that comparison, the ratio, gives you a measure of how fast the universe is expanding for that object. And that object is so far away, we're looking back what the universe was doing billions upon billions of years ago. Because it's taken the light so long to reach us from there. That's right. Well, in November 1997, your colleague Adam Rees sent you an email with the results of his first pass at measuring the supernovae. What did it say? He just sent me a figure, and it clearly showed that the universe was expanding slower in the past and had sped up.

20:30And he wrote, what do you think? That was all he said. So I saw it, and I'm like, oh, geez, what have we done wrong? We've been working on this for three years, and clearly there's something wrong. So I wrote him and said, okay, let's go through, and every step along the way, let's redo our things. You're going to work on it. I'm going to work on it independently. And then we're going to see, you know, where we went wrong. How long did it take you to feel confident that your data really was correct? Adam and I worked through this time, very frenetic. My wife had just had son number two. Adam was in the process of getting married.

21:09And I was on the test we could think of and could not make this result go away. The universe did seem to be speeding up. And we were, I guess, a little concerned that this might be the end of our career. And Adam and I started referring to ourselves as pawns and Fleischmann from the cold fusion fame, who disappeared without a trace. Well, that work was presented publicly in California in February 98. What was the reaction like? I mean, I have to admit, I was expecting widespread heckling and condemnation. But it turns out, it really did fix a problem in cosmology around the standard model. That is, it was really difficult to get the universe to be as old as it needed to be based on the Hubble constant that we're beginning to measure pretty accurately at this point using the Hubble Space Telescope.

22:09People were converging on that number of 14 billion years. But if the universe is slowing down, it turns out to only be 11 or something. Our measurement actually made the universe be about 14 billion years again. So it fixed that problem. It also fixed some other problems. And so the theorists around the world said, yippee this is the panacea to all of our problems and i think the other observational cosmologists were like scratching their heads and say all right guys let's wait and see this is too crazy to be true so they wanted correctly lots of proof i always say that the discovery of the accelerating expansion of the universe and dark energy is probably the most revolutionary and unexpected discovery in physics in my lifetime, something no one expected.

23:02Your discovery was eventually recognised with a share of the 2011 Nobel Prize in Physics, which you received jointly with Adam Rees and Saul Perlmutter. Is it true that when you went to Sweden for the prize ceremony, you presented King Carl Gustav with a bottle of wine from your vineyard? I did. I sent it in advance through diplomatic channels, as one does. And so if you ever see the video of me shaking his hand and getting the Nobel Prize, what he said to me is, thank you very much for the bottle of wine. It was delicious. Now, I kind of expected him to maybe hold on to it for a little bit, but he had already drunk it.

23:39So that was great. That's a good sign. Since then, Brian, you've taken on various projects, including stepping up to vice chancellor and president of the Australian National University from 2016 to 2023. You You also oversaw the SkyMapper program, which came about in the wake of the catastrophic bushfires around Canberra in the early 2000s that destroyed the Mount Stromlo Observatory. Tell me about that. So 2003, January 20th, a huge bushfire came through and this telescope, the 50 inch Great Melbourne Telescope, sent me a text onto my phone because that's how it communicated to us saying, temperature out of bounds 73 degrees celsius now the instrument was supposed to be like minus 100 degrees celsius so i knew things were bad so the telescope burned to the ground the whole observatory burned to the ground and in the aftermath we decided to build a replacement located up at siding springs a much darker site and uh yeah it's hard to build a big telescope and make it work So a lot of work went into SkyMapper, but it's one of the things we did post-fire.

24:53And it led to the discovery of very early stars in the universe. In fact, discovery in 2014 of the first star that doesn't contain any iron, which has some interesting implications. Yeah, so when supernovae explode, they create most of the elements that you and I are made out of, the Earth's made out of, beyond helium. When the first stars were created after the Big Bang, they were made out of hydrogen and helium. That's it. So the idea was to look for those first stars. And we found this particular star. It has no iron, but it does have calcium. It's a magnesium. So it's not a first star. It's a second star.

25:36But we can kind of diagnose what that first star was like. Probably 10 to 50 times bigger than our sun. and rather than exploding, it probably created a black hole and only a little bit of the star was liberated. It didn't really explode as a supernova. So that is a really interesting thing and it turns out it is to this day the only star ever found where iron is undetectable. Well, Brian, coming back to your discovery of the accelerating universe, that was a leap forward. But the fact remains we understand comparatively little about this cosmic acceleration, the dark energy that's driving it.

26:14What's the next big question you think we need to answer? So with respect to dark energy, I really think we need theory. I think we need someone to have a big idea that makes sense of what we're seeing. So how does gravity and quantum mechanics really come together, the theory of everything, so to speak? Like maybe something will emerge from string theory or some other version of quantum gravity explorations. I doubt that I will live to see a satisfactory explanation of dark energy. But you never know. Science works in mysterious ways. Absolutely. Well, I have to ask you this final question, Brian.

26:54Nowadays, what gives you the bigger thrill, identifying a new object in another galaxy or sampling the first batch of your latest wine? oh geez no i i don't i don't have favorites i just like many many things and i am an optimist i'm a glass half full person even though i'm a little concerned more than normal right now for the state of the universe or at least state of our part of the universe i remain optimistic and so i like both i do both and that's the beautiful thing brian schmidt thank you very much for sharing your life scientific thank you very much And thank you for listening. I'm Jamal Khalili and my producer is Lucy Taylor.

27:37Don't play games with us. A vicious gang of hackers causing chaos for businesses, councils and hospitals. What if I don't finish this treatment and this cancer grows? But they didn't care. I'm dying laughing. Making outrageous demands for money. They wanted millions. It was high tech and high stakes. The country's under attack. and it was highly secretive until someone exposed it all. Cyberhack, Season 4, The Conti Files. Listen on bbc.com or wherever you get your BBC podcasts.