Planetary Radio: Space Exploration, Astronomy and Science - A Cosmic Voyage with Astronomer Sandra Faber

Episode Date: July 5, 2017

Veteran astronomer and cosmologist Sandra Faber has just been awarded the Gruber Prize for Cosmology, honoring more than forty years of pioneering work. She talks with Mat Kaplan on this week’s show.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Wandering the Cosmos with astronomer Sandra Faber, this week on Planetary Radio. Welcome. I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. The fireworks may be over in the United States, but they'll continue forever across the farthest reaches of our universe, and maybe even beyond. We'll talk for the better part of an hour about galaxies, black holes, the multiverse, and more with the great Sandra Faber, and get her advice for young scientists. Then we'll hear what's up in the night sky and offer you a chance to win that new Planetary Radio t-shirt when Bruce Betts arrives. First, though, we welcome back the CEO of the Planetary Society, Bill Nye the Science Guy. Bill, happy Independence Day holiday. We're recording the day before that big holiday here in the U.S.

Thank you, Matt. I am a proud U.S. citizen. I'm a native, and the Fourth of July means a lot to us. So does planetary protection. Not a very good segue, but that is what we're going to talk about. Because you went to an interesting meeting last week. I think it was interesting. Well, it was more than interesting. No, it was the meeting of the committee that's part of the National Academies of Science here in the United States that's establishing, let me see if I can get this correct, the process by which the protocols will be established. They're not doing the protocols of protecting Mars from Earth microbes. They're setting up the process by which we will determine the protocol and so on and so on. But what I've told them or showed them was the Planetary Society educates,

creates, and especially advocates. We can go to the European Space Agency, National Aeronautics Space Administration, Canada Space Agency, Chinese Space Administration, Japanese Aerospace Exploration, Indian Space Research, and show them the value of protecting Mars or Europa from human microbes and the fundamental understanding that humans are going to go to Mars. There's no stopping us. People are going to show up there. So the approach is to do the search for life in parallel with whatever human exploration gets underway in the next decade and a half.

Now, Matt, I just reminded them the profound nature of their business. This is to say, this isn't just an exercise in good science, in having a control group and an experimental group, a control refuge on Mars and an experimental refuge on... No, this is about changing the course of human history. If we were to discover evidence of life on Mars, it would change the way everybody on Earth feels about being a living thing in the cosmos. The most reasonable thing, I think, speaking right now early in the 21st century,

that we would expect fossilized microbes on Mars. On Earth, you'll occasionally find stromatolites. These are rocks that have turned to stone that used to be pond scum, essentially. Stranger still would be something still alive under the sand, living on the ice or the occasional liquid water in the Martian summer. It would change the course of human history, everybody. This isn't just a nice scientific exercise. It's a big deal. So I gave them that rah-rah message. And it strikes me as an opportunity for humanity to get it right. Exactly. And that's what they want to do. But they were, my sense was, their job is bureaucratic,

and they were embracing the bureaucracy rather than the PB&J, the passion, beauty, and joy of science. But that could, as we like to say, just be me. Bill, thank you. I think you made an impression from what I hear. Thank you, Matt. That's Bill Nye. He's the CEO of the Planetary Society, getting ready to celebrate the 4th of July here in the United States. And I look forward to talking to you again. Thank you, Matt. We're going to talk now with Sandra Faber about fireworks in the distant sky, galaxies forming, big fireworks. You lucky podcast listeners are about to dive far deeper into the universe

than we have time to present in the radio version of this week's show, and I could have spent far longer listening to one of our age's greatest astronomers. Sandra Faber has been at this for over 40 years. A few days ago, she was awarded the Gruber Foundation Cosmology Prize that includes a gold medal and $500,000. It's merely the latest in a long list of accolades Sandra has earned over her career, which included discovery of something known as the Faber-Jackson relation. It led to our understanding of how galaxies are born, among other things.

She has also contributed to the creation of humanity's largest telescopes, and it was her team that figured out how to fix the Hubble Space Telescope. She recently joined me via Skype from her office at UC Santa Cruz, where she is Professor Emerita of Astronomy. Dr. Faber, Sandy, thank you so much for joining us on Planetary Radio, Dr. Faber, Sandy, thank you so much for joining us on Planetary Radio and congratulations on what is really just feel that I'm the conduit for this award because I've collaborated with so many other wonderful scientists and used telescopes supported by a large number of institutions and organizations, including, of course, most importantly, the University of California. In some sense, this is a gigantic team that I've

been working with. And I guess I've been singled out to get the prize. But I'm very quick to recognize the fact that I wouldn't have gotten this prize if I didn't have so much support and so many wonderful friends to work with. So I take it that you wouldn't mind if a lot more scientists got this sort of national and international recognition. I mean, I'm also thinking of how President Obama gave you the National Medal of Science back in 2013. Well, I certainly feel that way. I mean, getting these awards has been a great validation for me. has been a great validation for me. It's really great to feel as though your work has been noticed and it's been judged to have very high quality.

I do wish that everybody could get recognition at this level. Well, as a representative of, if not science, at least your field of astronomy, the more research I did, the more difficult it became for me to decide what we would have time to talk about, because you have done so much across your career. I want to start with the announcement just a few days ago of the discovery of a galaxy that has not one, but two supermassive black holes orbiting each other. What was your reaction to this? Well, I think this is a fantastic result. The thing that is so striking about this result is

the very close distance of these two holes with respect to one another. They're only seven parsecs apart. That's like 25 light years. So these objects are very close. They're moving within the sphere of each other's gravitational field. We understand from theory that when black holes start to orbit this way, their orbit slowly shrinks because they start to emit gravitational radiation. So these holes are going to merge pretty soon to make a bigger black hole. These orbiting black holes are predicted theoretically. That's because we know from separate observations that galaxies, big galaxies in general harbor these very massive black holes. I'm talking, you know, hundreds of millions, billions of solar masses. And when galaxies collide and merge, as they sometimes do, then the physics of the situation brings these two massive black holes from each galaxy to the center of the new remnant. And that's what we're seeing here. We're seeing the last phases of the in-spiral and soon-to-be merger of these two black holes caused by the merger of their

parent galaxies probably, oh, I don't know, I guess a few hundred million years ago. This is the end game. Talk about making waves. When these two supermassive black holes merge, I imagine that's going to be quite a gravitational event across our universe. You're absolutely right. Anytime black holes merge, they emit gravitational radiation. We've already seen that with LIGO.

But LIGO, which is on Earth, it's the Gravitational Wave Observatory, and was recently successful for the first time in detecting gravitational waves during the last year. LIGO is sensitive to lower mass merging black holes, lower mass black holes that are produced as the endpoints of stellar evolution. In contrast, these black holes that we're talking about here in this galaxy are millions to billions of times heavier than that. And that means that you need a different kind of detector. And so there's a proposal to put a gravitational wave detector named LISA out in space as a satellite observatory. And people are working on that. I don't know the exact timescale, but, you know, within a decade decade probably we'll have a different kind of gravitational wave detector out there.

And its goal is to detect these merging supermassive black holes. I did just read that funding for the LISA mission after the success of LISA Pathfinder is now in place and that we may be seeing that in the years to come. Do these developments, Lisa, LIGO, and discoveries like this, really magnificent discoveries about our universe, do they reinforce your wonder about all of this? Well, I think the observations themselves tell us that we're in an awfully interesting universe. You know, I have even more wonder. My wonder quotient is triggered actually by the ingenuity of human beings to get this information. I mean, who would have thought, first of all, that there'd be such a thing as gravitational waves? Einstein was the guy who taught us that. taught us that. But almost 100 years went by with no way of being able to detect these things. It's one of the most finely tuned, delicate experiments that's ever been done. And yet now we're seeing these minute little bobbles in the fabric of space time. You know, as an astronomer, I'm used to detecting photons. Gravitational waves are something completely new. Anyway, the whole spectrum of astronomical research, I think, inspires wonder at the universe, but also at our ability as human beings to learn about the universe.

Well, as somebody who has great respect for technological developments, you've been a part of some of the most significant ones. significant ones. Before we get on to your actual astronomical work, I wonder if maybe you could tell us a little bit about your key role in development of what are still the most powerful telescopes on our planet, certainly the largest on our planet or anywhere in the universe that we know about. Tell us about your involvement with the Keck telescopes. Well, I come from a line of engineers. My grandfather and my father were both civil engineers, and I think I've inherited some of their love for large structures. They built high-tension electrical towers. They built dams. They built mines. And and I am just really inspired by being able to build a big telescope like Keck, which is 10 meters across, that's 33 feet across,

and yet every part of the mirror, it's in segments, you probably know that, they have to be polished perfectly, they have to be held in perfect alignment to much, much better than the width of a human hair. So this is one of the great mechanical engineering challenges of all time. And there certainly was some professional self-interest in this because you've been able to use these great instruments right in your work. Yeah. I have an expression, which is you cannot intuit the nature of the universe from the inside of a closet. You know, we're constantly being surprised. So you have to go out there and look. And the history of astronomy has been constantly over and over again, we see that new detective abilities, probings of new parts of phase space, energy, wavelength, faintness,

parts of phase space, energy, wavelength, faintness, angular resolution. Every time we get advances in that way, we discover something new. So this is the history of our field. And when an astronomer named Joe Wampler at my institution, Santa Cruz, proposed in 1977 that he thought we could build a telescope that was twice as big in diameter as Mount Palomar. Palomar is five meters. He was proposing 10 meters. Wow, my interest was really piqued. And so I immediately went off in the next couple weeks or so and learned about how a big telescope could see fainter. I'd never learned that in graduate school. And I quickly realized that the increase of a factor of four in area of the mirror would really just be the very beginning, because at that time, 1977, we were discovering even better astronomical sites on the ground that made tighter, finer, more strongly condensed images

on the ground, a quick calculation showed me that that by itself, if we just built in a better site with better seeing, we could see fainter. And then I began to think about how we could build more powerful instrumentation. You know, the telescope's just a light bucket that makes images. You have to detect those images or you have to take spectra of the objects that you've found. And I realized that we could probably, instead of taking one spectrum at a time, we could take 100 or maybe even 1,000. And so before I knew it, within two weeks' time, I thought we could exploit the new Keck telescopes, if built in Hawaii, to gain a factor of almost 100,000 in speed over existing telescopes. This was staggering.

There's another technical miracle that I thought you might want to comment on, especially when I saw that your office, or at least your old office, was in the Center for Adaptive Optics up there at Santa Cruz. What about that development and what it has meant for astronomy? Yeah, I'm sitting in the Center for Adaptive Optics right now, Dr. D. Well, I alluded before to the importance of having sharp images, and there are really two reasons for this. First of all, if you're looking at point sources like stars, why don't we see even fainter? Well, it turns out that the sky at night is not completely black, it's bright. And if you have bad seeing and bad images in the telescope that are fuzzy, what you're doing is you're taking the light of a faint star and spreading it out over a larger area, and it's harder to detect against the bright night sky.

So if you can make an image in which those stars are as sharp as possible, then you can actually see fainter just for that reason. Twinkle, twinkle little star. Nice, nice tune for kids, but not so great for astronomers. Not so great for astronomers, right. And of course, then the second reason why we want sharper images is lots of things are not point sources. They're extended. And if we have better detail, we can see all the fine structure in them. Witness all those amazing pictures from the Hubble Space Telescope. I'm so glad you went in that direction because that is still the Hubble, still the largest telescope we have in space, at least for another year or so, assuming the James Webb Space Telescope works as promised.

You were very involved with that as well, at least with one instrument on the Hubble, right? That's right. I was a member of the original Wide Field Camera team, and it fell to members of this team to diagnose what was wrong with the original Hubble. Remember, Hubble had an optical flaw and didn't work. Trouble with Hubble. I remember those awful cartoons, Hubble sees double. Yeah, now we can laugh about it. Right. Yeah, it was our team that diagnosed what was wrong with Hubble, and that permitted people to go off and fix it, which they did brilliantly. So I would say that Hubble is still the reigning instrument as far as taking beautiful, sharp pictures of the universe is concerned. But this adaptive optics method has a great future ahead. Let me say briefly what it

is, if I may. Sure. As we've said, light comes down through the atmosphere. The atmosphere is the bad guy here. There are little temperature fluctuations, and they cause the beam of light to divert and go in different directions. It's very turbulent, and so the directions are constantly changing, like a thousand times a second. And so when we take a picture through a big telescope, we have beams on one side of the primary mirror that were diverted in one direction and beams on the other side that were diverted in another direction. And so the beams are all spread out. That's what we call seeing or bad seeing. Now, supposing we put in some new optics and we could measure

instantaneously a thousand times a second what all of those beam diversions were. And now let's put a flexible mirror, a deformable mirror in the light path that is able to bend or redirect every one of those incoming rays to cancel out the bad effects of the atmosphere. Then when we take a picture, we get an image that's as sharp as the telescope can possibly make. That's called the diffraction limit. And bigger telescopes can make sharper images. Something like the Keck telescope, that is quick calculation, mental arithmetic, I think, four times larger in diameter than Hubble. So Keck working at the diffraction limit can take images that are four times sharper than Hubble. Well, that's only the beginning, because now we're talking about making

telescopes that are 20, 30, 40 meters in diameter. The 30-meter telescope that is being put together by the University of California, Caltech, and international partners, that is, if memory serves, something like 12 times bigger than Hubble, and will make images that are 12 times sharper. So stay tuned. Adaptive optics has a way to go in terms of development. But we're going to see spectacular pictures that just are actually at the moment impossible in space because the biggest telescopes can be built on the ground. Your work continues, right? I read about a new, is it a spectrograph, spectrometer, Deimos that you're part of? Well, Demos was built for the Keck telescopes. It was one of the major spectrographs out at Keck.

It was commissioned in 2001. But the 30-meter telescope needs a spectrograph like Demos. A while ago, I said we should be taking spectra of as many objects as possible. Demos typically takes 150 spectra at a time. We're trying to build an instrument like that for the 30 meter. It's called WFOS, and it's let out of Santa Cruz here. So my colleagues and I are thinking about that. We report regularly on the development of this new generation of telescopes that is fast approaching the 30 meter telescope, the giant Magellan telescope,

and some of the European efforts. Without getting into the current political and cultural difficulties that the 30-meter telescope has run into, there is, of course, now this possibility that it may lose its terrific site high on the mountain in Hawaii. What does that mean, in your opinion, to astronomy, that this may not be built there, may have to be built in a less ideal site? Two things about that. First, the more we learn about Mauna Kea, which is this volcano on the big island in Hawaii, 14,000 feet high, the more we learn about it in comparison to other sites. I've been working on this recently, actually, with the help of colleagues here at Santa Cruz. The more we learn about it in comparison to other sites, I've been working on this recently, actually, with the help of colleagues here at Santa Cruz.

The more we learn about Mauna Kea, the more exceptional it seems to be. It's exceptional in particular for adaptive optics because the turbulence profile as a function of height at Mauna Kea is unique. Most of the turbulence is at the ground. The upper atmosphere has little turbulence. Therefore, it turns out that we can put something called ground-layer adaptive optics on telescopes at Mauna Kea that can correct a very wide field quite well

simply by taking out that ground-layer turbulence. And there's no other site in the world as far as we can see that has that wonderful property. So it would be very sad if Mauna Kea is closed off not only to the 30 meter, but it's really the goal of the native Hawaiians to shut down all the telescopes there, let the ones that are there age over time, not replace them, and return the site to a pristine site which would not have any telescopes in the future. That's really a very sad thing for astronomy. Yeah, well, without getting into the arguments made by the native Hawaiians, it certainly would be a tragedy for science and for astronomy. Let's turn now to your contributions to astronomy. And I want to go way back to what

is now known across the field as the Faber-Jackson relationship. I'm hoping that you can explain to me, because this is absolutely fascinating, but I'm still puzzled, why would a galaxy's brightness and spectra, the color of the light, be related to the movement of the stars that are making all that light? And you may want to say something, provide a little bit of history to this as well. Well, you've asked me about the importance of the Faber-Jackson relation and a little bit about the history of that relation and similar relations. What do we mean by a relation? Let's pause there. Let's say we have a piece of graph paper in front of us. We've measured two things about a galaxy. In my case, the one thing was

how big the galaxy was, which I used luminosity to indicate that. And then the y-coordinate, if you will, is the speed of orbital motion of the stars. When I and my graduate student, Jackson, Robert Jackson, made that plot, we found a correlation. It wasn't perfect. There was scatter. But nevertheless, you could tell very strongly that when the galaxies were bigger, the stars in them moved faster. Why was that important? Because actually correlations are the lifeblood of astronomy. This is the single most important observation, in my opinion, that you can make in astronomy that will tell you something about where objects came from, how they formed, and how they evolved. So my analogy there is something called the main sequence of stellar evolution, which

your listeners might have heard about. It was arguably the first correlation ever discovered in astronomy. And what is it? If you plot on the x-axis the temperature of a star, and on the y-axis the brightness of a star, you see a very narrow relation. And we call that the star form, the main sequence of stellar evolution. Oh, maybe 30 years went by before it was explained. But the explanation was profound.

It could only be explained by understanding nuclear reactions inside stars. The explanation, in other words, was to make models of stars take their power from nuclear reactions, hydrogen combining with other hydrogen to make helium and heavier elements, releasing energy. This is how you make a hydrogen bomb. That's what stars are. They're controlled, confined hydrogen bombs. What I'm trying to say is understanding that simple plot, A, took a long time, and B, revealed something profound about the nature of stars. This happens over and over again in astronomy. So back to the Faber-Jackson relation, that was the first scaling law, the first relation

ever discovered for galaxies. And even though I could not understand it at the time, since I knew about scaling laws and since I knew about the main sequence of star formation, I intuited that I was onto something really important here. And indeed, that turned out to be the case. Decades again went by. We did not have the tools back in 1976 when I first published that paper. But we have now learned that that scaling law and other related scaling laws, which were gradually discovered over time, they are explained by galaxy formation in a dark matter-dominated universe. Okay, I think there are two interesting things about the dark matter-dominated universe. First of all, there is the fact that it is dark matter-dominated.

And that was another thing that I worked hard on, along with a lot of other people, showing in the late 70s that the mass in the universe is about five, six composed of something that to this day we don't know what it is. But the best guess is that it's some kind of massive weakly interacting particle, a particle like a neutrino that can go through light years of lead and not bounce off anything else or stop, but nevertheless much more massive than a neutrino, maybe 100 times more massive than a proton, for example. So people are trying to find this dark matter particle. They're trying to make it at the CERN Large Hadron Collider, so far without success. But we need that particle in the universe in order to account for galaxies and clusters of galaxies. So astronomers are very

confident that that particle exists, even if our physicist friends have not been able to produce it yet. But they're on the hunt, fortunately. They are. If it weren't for dark matter, would our universe contain the billions of galaxies that it does? How would it be different? universe contain the billions of galaxies that it does? How would it be different? Well, it's a combination of the dark matter together with something else. And that is this amazing concept, which came straight out of physics, the concept of inflation. When we look at our current theories of particles in physics, by a particle I mean an electron or a quark, a muon, things like this that you hear about being produced in particle accelerators or coming down in cosmic rays. There's a whole theory of these things called the standard model that accounts pretty much for their masses, their charges, and how they fit together. And when you take that picture and you ask yourself, hmm, how does this family

of particles behave at higher temperatures, which means back in time because the universe is cooling off, it was hot in the beginning. When you reach this magic temperature of 10 to the 28th degrees Kelvin, you find that physics is radically different. The particles as we know them do not exist yet. Instead, there is some mother of all particles called a scalar field. And the energy in that scalar field is going to give rise to the energy density of the universe and the particles that we see today. But the interesting thing about the scalar field, which is completely counterintuitive, is that as the universe expanded then, and we're talking early times, 10 to the minus 35 seconds after the Big Bang in the standard picture, remarkably, the energy expands today, the galaxies are getting farther apart. The whole thing is getting more dilute, except for something we'll come back to in a minute. equations which describe the dynamics of the universe, you get absolutely bizarre result. And that is that instead of slowing down due to attractive gravity, this scalar field generates a repulsive gravity and causes the universe to accelerate. And in fact, the universe accelerates

so fast, it speeds up and a particle right next to you zips away. It's pushed away from you and it actually disappears because it's going to move faster than the speed of light with respect to you. Are we now getting into not dark matter, but dark energy? Yes, we are. That's right. Why don't we save that for a moment? Because the term dark energy really has never been used to apply to this early scalar field. As I said, caveat a few seconds ago, something interesting and different is happening in our universe right now. That's dark energy. But let's postpone that, because I haven't had a chance to tell you the main important thing about the early scalar field.

I've said that scalar fields cause acceleration, unlimited acceleration. Things expand faster than the speed of light. And when they do that, quantum fluctuations are frozen in, quantum fluctuations from natural fluctuations from Heisenberg uncertainty principle that we know and love today, they get frozen in. They can't disappear because the universe is being ripped apart under their very feet. And these fluctuations, we have a hard time calculating the amplitude, but empirically we know about a part in 100,000 from point to point, not large, but big enough to act as the seeds for attractive gravity, which is going to enter shortly as the temperature cools off. And those seeds, the positive fluctuations, act as attractive points drawing in matter around them. And voila,

believe it or not, those are the galaxies that we live in today. Wow. Before I start getting email from listeners who say, what are you talking about? Things can't go faster than light. Well, what you're really talking about is space itself expanding, right? Yes, that would be the right way to think about it. You know, things don't go faster than the speed of light when they're right next together. But you can use the acceleration of the universe to take two particles that are separated by some distance, and as you say, have space stretch in between them. And then when you do that, you can go faster than the speed of

light. Let me give you another example of going faster than the speed of light. And that is when particles fall into black holes. As a particle falls into a black hole, as it passes through the event horizon, that's the point at which it acquires the speed of light with respect to you, the stationary observer outside, and it continues to accelerate as it falls in. The interesting thing about this going faster than the speed of light is both in the black hole in the universe, the particles are moving away from you. They're going faster and faster away. That means they're going more and more redshifted.

And so you never actually see them go faster than the speed of light. They are, but as you watch them, their light redshifts infinitely. At some point, you see the last photon from them, and as far as you're concerned, they have disappeared, even though they're still there going faster than the speed of light. Absolutely fascinating. Don't we now, as you get past that event horizon, enter into this realm where relativity breaks down? Are we any closer to understanding what's really going on with the black hole? Well, I think you've got the wrong person on the program at this point. You know, I'm encouraging you to have another interviewee who can discuss the bowels of black holes, singularities, this accelerating universe is really just

a black hole turned inside out. And instead of accelerating inward, the universe is accelerating outward. The nice thing about that is that I don't have to worry about what happens at very high densities and small dimensions because the universe is getting bigger, not smaller. Astronomer and cosmologist Sandra Faber. Stick around as we switch gears and talk to her about how she came to be one of the greatest living astronomers. This is Planetary Radio.

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Our mission is to give you the power to advance space science and exploration. With your support, we sponsor innovative space technologies, inspire curious minds, and advocate for our future in space. We are the Planetary Society. Join us. Welcome back to Planetary Radio. Join us. Welcome back to Planetary Radio. I'm Matt Kaplan, back with University of California astronomer and UC Santa Cruz professor emerita, Sandra Faber. My admiration for Sandra only increased

as I learned more about her and her accomplishments in cosmology. As with most of the great scientists and others we host, I wondered how she had gotten into this field. It was back when there were very few women she could call colleagues. I read that very early on, you had to make a decision between the very small, the infinitesimal, and the very large. And you obviously went in the direction of the very large, as in galaxies. What led you to that decision? Well, I think you're referring to the question that I had to answer on the Swarthmore College application form.

Yes. Yeah, so the year there would have been, let's see, I graduated high school in 62. So picture fall of 1961. Swarthmore likes to think of itself as a pretty darn good liberal arts college, you know. The question was phrased, and what do you intend to do with your Swarthmore education? The implication being, you better come up with something good. Well, I was already interested in cosmology, and I really was hoping that I could study the origin of the universe. What I said in the question was, I don't know the right way to do this.

One way might be to study the properties of the universe on large scales, like galaxies and stars and things like that. But another way might be to understand the basic physics of the universe. The smallest thing I knew about then was atoms, and so I said chemistry. What I really meant was particle physics. I didn't even know that particle physics existed. Well, anyway, I got to Swarthmore. It had a lovely little observatory. I started to observe there, and I loved what I was doing.

a lovely little observatory. I started to observe there and I loved what I was doing. And at the same time, I took introductory chemistry and I really did not like it. It was too much like cooking. Standing at the bench and measuring stuff and pouring from one container to another. I just did not like it. So I went in the direction of the telescope and universe in the large. And only later did I understand that actually there were people trying to do cosmology with particle physics. And everything that I just told you about inflation and 10 to the 28th degrees Kelvin and all of that, all of that came from that direction. So I like to pat myself on the back by saying that as a high school senior, I really foresaw the marriage of astronomy, astrophysics, and particle physics that is the stuff of cosmology today. When you got into this field, there weren't a lot of women doing cosmology, to say nothing of astronomy itself.

One of them, though, was Vera Rubin, who became, was she a mentor? Oh, very much so. She was a fantastic role model. I should say how I met her. Many people think that she was my thesis advisor because I was doing my thesis at the Department of Terrestrial Magnetism, which is a Carnegie Laboratory in Washington, D.C., and that's where she and her colleague Kent Ford were located. But I was actually a Harvard student on traveling guidance, and my thesis advisor was a professor named John Danziger, who since has moved to Europe. Be that as it may, my office was right outside

Vera's office. I saw her at work every day. She was the first woman I had met who had a family, and I certainly wanted to have a family. I'd recently gotten married. Vera incredibly managed to have four kids, and every one of them had PhDs. And she would tell stories about how she'd take her kids to the park and read the Astrophysical Journal on the park bench. She had a somewhat unconventional career. I don't know that we need to go into the details of that, but she made it work. And she was the first woman I saw who made that combination work. It was very inspiring. Are you heartened to see the appearance of many more women across astronomy and across science?

Oh, of course. How could I not be? In fact, I'm very, very proud of my institution, UC Santa Cruz, which may have the largest fraction of female professors on the faculty and the largest fraction of female graduate students in the graduate program of the major departments in the country. And, of course, you chaired the astronomy department there before becoming a Merita professor. Let's go back to your work and the Faber-Jackson relationship. Is it still at the basis of our understanding of how galaxies form? I think you've sort of answered this.

Yes. I wanted to be very honest and say that we found other scaling relations for graduate students, for galaxies. I'm in the process of producing yet more right now, and interpreting them has indeed led us down very interesting alleys. I'll just tell you about the most recent one. The basic Faber-Jackson relation was most easily interpreted in terms of this expanding universe with dark matter, the quantum fluctuations acting as seeds for galaxies. Believe it or not, that all explains the Faber-Jackson relation. But there are other interesting relations that we are now discovering that revolve around when galaxy star formation turns off. And it turns out that there's a boundary between star-forming galaxies and quenched galaxies that is quite well described. It evolves smoothly and nicely from early times to now.

And I'm trying to understand the existence of that boundary. And I'm coming to the conclusion that doing so depends on having feedback that destroys star formation from these supermassive black holes. back that destroys star formation from these supermassive black holes. I'm trying to make that picture quantitative and predict exactly what the boundary looks like as a function of mass and time and having some success. I'd say this is a toy model that needs further work, but it's promising. Are you saying that galaxies may be sort of self-extinguishing? And you need to explain what a quenched galaxy is.

Quenched galaxy is easy to understand. It's a dead galaxy that is no longer forming stars, and we are surrounded by them. They're called elliptical and S0 galaxies. They're red because old stars are red and young forming stars are blue. So one gauge of whether the galaxy is quenched or star forming is just to measure its integrated color. If it's blue, it's making stars. If it's red, it's not. What are the other remaining great questions about the universe that remain to be answered, that you'd like to see answered? Well, I'll start with the big question, like to see answered? Well, I'll start with the big question, which is in my backyard. And many people think that they're very doubtful that we'll ever answer this question. But nevertheless, it's a great question. So let's talk about it. And that is whether there are other universes.

Ah, great. The multiverse. The multiverse. Yeah. I tend to be a strong believer in the multiverse. The multiverse, yeah. I tend to be a strong believer in the multiverse. And the reason for this is that I think it most easily explains the properties of our own universe, which seems paradoxical, doesn't it? How could we explain our own universe by imagining that there are other universes? Well, the key here is to imagine that there is some sort of giant cosmic machine that is churning out universes in great quantity all the time. Again, our physicist friends have given us some ideas as to what that machine might look like. It's actually kind of related to inflation. Just imagine that we're making universes, and here's the key idea. The universes have to be all significantly different.

So we're surrounded by these other universes. By definition, a universe is all that you can see. And so if there are other universes, you can't see them, maybe because the fabric of space-time, if there is even such a thing, prevents information from going from one to the other. Like, for example, information can't get out of black holes very easily, for example, okay? Maybe you can't get information from one universe to another, so voila, they're there, but you don't see them. And they're all different. And when you say different, you mean that they may even have completely different physical laws and values for what we see as constants. And maybe even different things. We have light in our universe. Maybe they don't have light. We have gravity. Maybe they don't. We have four space and time extended dimensions. Maybe they have four extended other dimensions or six or something like that.

People are thinking about these things. I'm not really the expert you want to hold forth on the possible properties of other universes in the multiverse. But let's suffice it to say right now that they are wildly different from what we have today in our universe. Now, why is this a good idea? Rather than tackling the universe directly, let me give you an analogy. Let's go back to the time of the Greeks, who were pretty darn smart people. And they wondered about all kinds of things that were astronomical, including the nature of the Earth. The Earth seems to have a constant radius, for example, okay? So supposing you were a Greek physicist and you wondered, where does the radius of the earth come from? Well, if you

were Aristotle, you would say the earth is the center of the universe. And so the radius of the earth must be some very, very profound, deeply rooted number that has to do with the nature of the universe. And you'd be struggling very hard as a Greek physicist to come up with a theory for that. And you would fail because that's the wrong question, isn't it? Yes. The right question is that the Earth is not unique, that there are lots of planets out there. And the radius of the Earth is approximately what it is, out there. And the radius of the Earth is approximately what it is because that's what it takes to put us on a planet. We can't exist on Jupiter. We can't exist on Mercury, etc., etc. There's a window of radii and a window of a lot of other things, composition, water content. It's

not just Earth's radius. Let's enlarge this concept a little bit. A window in all of these properties, and we're comfortable on such a planet, and we can't exist on planets that don't lie within that window. This is called anthropic reasoning, and I think it actually works rather well to explain the properties of our universe. You know, if you take the electric charge and you change it ever so slightly, just a few percent, the take the electric charge and you change it ever so slightly, just a few percent, the properties of atoms change and you change chemistry. You don't have water anymore. You have something else. No stars, no planets, no people. We've talked about this on the show. So your listeners know that the universe looks like it's finely tuned. So one interpretation,

which is logical, is that there's a superior being who made our universe exactly as it is because perhaps the goal was to make a universe for people like us. That's one interpretation, perfectly logical. The other interpretation, though, it's not unique interpretation. The other interpretation is that there's a multiverse. And in order to make sense of that picture, you really have to believe it's there. It's not just a theoretical concept. It is there. And our universe is just one in an unbelievably large sea of universes. What you're describing is only the latest chapter in this still being written book that maybe we could point to Copernicus as writing the first chapter, where humans, we tiny beings on this tiny blue dot, pale blue dot, if you will, still contemplate the largest things that are possible to contemplate, like the multiverse.

the largest things that are possible to contemplate, like the multiverse. Why, in your view, is doing this? Why is cosmology relevant to those of us who live on this pale blue dot? That's a great question. Thank you. So I have two answers to that. One is an aesthetic answer. Maybe you think I'm dodging the issue, but I don't think I am. In fact, people love this question. They love this topic. If you're unhappy with that answer,

I can give you examples of other things that we love that are kind of useless, as far as feeding us is concerned, etc. Like going to the symphony and listening to a symphony. Like going to the symphony and listening to a symphony. That's pure enjoyment, pure relaxation. And I think that's in our genome. And it's very hard to avoid the forces that are embodied in your own genome. I mean, your genome is making you do what you want to do, right? So I would say, evidently, for whatever reason, just as we love music, as we love art art as we love a lot of other things that are not immediately practical we seem to love cosmology i would go even beyond that at

this intersection of art and science to say that what we get out of great art a great beethoven symphony is something we so crave and so need and and that that extends to our need to understand and wonder at the universe or the multiverse. This is true. We can wonder at Beethoven's unbelievable ability and creativity in much the same way that we stand in awe of what the universe has created for us. However, that was part one of my answer. Part two is much more practical. I am giving talks these days, making the somewhat outrageous claim that actually, of all areas of scientific knowledge that are being produced today, the single most important, practically important sphere of knowledge is astronomy. How can I say this? Because I've

just admitted that it doesn't make better cars or grow corn or anything like that. It has become important because our species is on the cusp of disaster or great things. And this is not a coincidence. The moment at which we have come of age in the Milky Way galaxy, to use Tim Ferriss's beautiful book title, to do so required acquiring technical skills and facilities. Those technical skills and facilities, we astronomers live on a technical pyramid that is produced by all the manufacturing, engineering, et cetera, et etc., design work in the world. Our telescopes couldn't exist without that as a foundation. And only recently has that foundation evolved to the point to give us those telescopes. Unfortunately, along with that foundation comes pressures, environmental pressures on the planet that go along with having lots of people because you need a big foundation mining lots of

Precious elements and creating toxic weights in the process, you know the steel in our telescopes Produces environmental waste we are we astronomers are pollutants just like everybody else To make a long story short we have come of age. We see the universe for the first time We're the first generation to see our past, to understand the physics of the past, and to predict our future, cosmically speaking. And that future looks bright. The more we learn about the Earth, the more we can see that Earth itself has a wonderful future. We've got a billion years to play with here.

Really. It's not certain yet whether or not the earth is unique. My own instinct is by the time you look at all these inhabitable windows, water, et cetera, et cetera, we'll find that the earth is rare, if not completely unique. The point is, what are we going to do with this opportunity? Does this raise a moral question for our species that people have never faced before? We've always been short-term thinkers, but now we have the possibility of owing things to future generations, millions of years down line, and to all the other inhabitants of our planet who have to be healthy, we now know,

in order that we ourselves will be healthy. So I think, to summarize, that astronomy is putting moral questions on the table that we have never faced before. It's not answering them because science doesn't answer moral questions, people do. But we need this information to even think about these things. I have just one more question for you. I know there are a lot of young people listening to this program. Some of them write in and say that they are becoming astrophysicists, astronomers, and going into other fields of science and engineering. Other than the inspiration you may have just offered them out of this conversation so far,

what advice would you give young women and men who intend to follow in your footsteps? Well, many things are changing in this world at rapid pace, but I would say the art and strategy of becoming an astronomer has not changed very much. In order to be a good astronomer, you need to learn physics, first of all. So study hard in physics and understand it at an intuitive level as much as possible so that you can solve problems in your head. You can make movies of physics problems in your head without even having to write down an equation. What did Einstein call them? Thought experiments? Thought experiments. Good. Absolutely. That's first and foremost. You need to apply yourself

hard throughout school and throughout graduate school. But I would say, though, the magic of being an astronomer is having access to the big picture. So don't lose sight of larger issues. We've been talking about cosmology here. We've been talking about cosmology here. We've been talking about the future of our species. I really think that the role of astronomers is to inspire the human race in these larger arenas. So focus, yes, day to day on your craft, but never lose sight of where you and the world are going. Marvelous advice. Thank you very much, Sandy. Before I let you go, your work continues, right?

I read about a new, is it a spectrograph, spectrometer, a Deimos that you're a part of? Well, Deimos was built for the Keck telescopes. It was one of the major spectrographs out at Keck. It was commissioned in 2001, but the 30-meter telescope needs a spectrograph like Deimos. A while ago, I said we should be taking spectra of as many objects as possible. Deimos typically takes 150 spectra at a time. We're trying to build an instrument like that for the 30-meter. It's called WFOS, and it's let out of Santa Cruz here. So my colleagues and I are thinking about that. Thank you for all of this that you've told us about, your past contributions,

and best of luck as you continue this work that is helping us understand where we live in this best of all possible universes, at least for we humans. Of course, we don't know that, but it's working out pretty well so far. Thanks very much. I've totally enjoyed this. As have I. We've been talking with Sandra Faber, astronomer and university professor emerita at UC Santa Cruz, and so much more across the recent history of astronomy and cosmology.

And we will move on now to talking to the astronomer we talk to every week, Bruce Betts, with this week's edition of What's Up. We are joined by the Director of Science and Technology himself. Bruce Betts is here. Welcome back. Thank you. I want to start. I should have warned you I was going to do this, but I don't think you'll mind.

The new series of Random Space Fact videos is getting a lot of attention, even from NASA. Yeah, we're very excited working with NASA. NASA's Planetary Defense Coordination Office, they helped review it, and they've got them on their website. We've also got the United Nations Office of Outer Space Affairs letting people know about them. And just this morning I heard from the head of ESA's, European Space Agency, Planetary Defense Office, and they will be utilizing it.

I don't know how, but they'll be using them. So if people want to watch the videos, there are six, roughly two minutes each random space fact form about NeoThread, AsteroidThread, Planetary Defense. You can find them at planetary.org slash defense. They've got everything, even talking dinosaurs. Indeed they do. All right, what's up? Indeed they do.

All right, what's up? Well, besides fabulous videos from the Planetary Society, we've got Jupiter still hanging out, looking super bright in that evening sky. Look up in the south, brightest star-like object up there. It's Jupiter. Saturn a little trickier to find, but up all night pretty much. It's up in the east in the early evening. And Venus looking super bright over in the east in the pre-dawn. We move on to this week in space history. I've got one to make you feel

old, Matt. 20 years ago, Mars Pathfinder landed on Mars. That is such a great anniversary. And I'm figuring out who to talk to about that because that should be marked. And I want you to know I didn't need that to feel old uh you're welcome all right we move on to random space fact hey whippersnapper neptune's moon triton is thought to be a captured object that originated in the Kuiper Belt as a trans-Neptunian object. Got a little too close to Neptune and was successfully captured into orbit there. It orbits retrograde, the opposite motion of the planet's rotation. And it's the largest moon in the solar system to do so. And that's kind of the biggest evidence that it's a captured object.

Very cool moon, too. Cool surface. It just seems like anytime anybody says retrograde, it ought to have echo behind it as well. I know, and I was disappointed with myself just now that I didn't at least say retrograde. Okay, good. We covered it. Anyone who's watched my class knows that I can't help myself usually. covered it. Anyone who's watched my class knows that I can't help myself usually. We move on to the trivia contest, and I asked you, what are the names of Venus's two large highlands areas, sometimes referred to as continents? How'd we do, Matt? Wow, a very good response, I think, because we're giving away that brand new and really nice Planetary Radio t-shirt. I still don't have one of my own.

So you might have it before me if you're the winner. And I suspect it's going to be Luis Nunez. Luis of Davenport, Florida, who said that those two highlands are Ishtar, found near the North Pole, and Aphrodite is found near the South Pole. Those indeed are the highlands. One of them is a little closer to the equator,

but they are quite separated. So yes, Ishtar, Aphrodite, that's right. Go with it. Congratulations, Luis. You'll get that T-shirt and a 200-point itelescope.net account. Say it with me now. The Worldwide Network of Nonprofit Telescopes,

or not, I see I said it wrong. Say it with me now. of Nonprofit Telescopes, or not, I see I said it wrong. Say it with me now, the nonprofit world... No one can say it with you. The Nonprofit Worldwide Network of Telescopes that anybody who is a member of that network can sign up to use and point anywhere around the universe. That's the same prize package we're going to have the next time around, but we'll get to that in a minute. First, I wanted to tell you, Neil Ashleman, Neil Ashleman of Davenport, Iowa, he said the correct reference to these highlands is that they are venereal.

He says, yes, venereal. It just doesn't sound right. It doesn't sound sanitary. I think that's why most people, venereal. It just doesn't sound right. It doesn't sound sanitary. I think that's why most people use Venusian. As I will continue to. Norman Kassoon, he says, As you might expect from a planet with such an alien atmosphere, the snow which caps the Venusian mountains is seemingly no less exotic.

With the high temperatures on the planet's surface, water ice is impossible, of course, even if there was water around. It's made from lead sulfide and bismuth sulfide, more commonly known as the minerals galena and bismuthmanite, which I think that's pretty amazing. They form a nice soup, by the way. It's tasty. Can I have a little more bismuth in my soup, please? Nathan Hunter, Portland, Oregon. He said, you should have Jeffrey Landis on the show to talk about building cloud cities on Venus. I had to look this up. I'd heard of the proposals for cloud cities outside of Star Wars, that is. And it's true. He did propose this and that you could use just breathable air to

support these balloons because the atmosphere becomes so dense. Does that sound plausible? Yes, because also it's a carbon dioxide atmosphere. So it's not only the high density, but also the higher molecular weight of carbon dioxide compared to oxygen and nitrogen. higher molecular weight of carbon dioxide compared to oxygen and nitrogen. I'm ready to go. I would love to visit Cloud City and meet Lando. Finally, Daniel Chang in Davis, California. Venus, the planet with so much love, it burns.

I think we're back to venereal. Oh, sorry. He does add, love the show, keep up the great work. We'll do our best, Daniel. And we'll do that beginning with the contest for next time. So for next time, tell me, in honor of the Pathfinder 20th anniversary of its landing, who submitted the name Sojourner Truth for the Mars Pathfinder rover named in a Planetary Society-led contest? Go to planetary.org slash radio contest.

You have until Wednesday, July 12th, wow, halfway, more than halfway through the year, at 8 a.m. Pacific time to get us the answer and maybe win yourself that brand new Chop Shop designed Planetary radio t-shirt. It's in the Chop Shop Planetary Society store with a whole bunch of other cool stuff, including the great Venn diagram Planetary Society shirt. I want them all. I want the whole set. And a 200-point iTelescope account.

And with that... Would you wear them all at the same time? If it's cold enough, we're done. All right, everybody, go out there, look up in the night sky, and think about how cool a square hat would be. Thank you, and good night. I will add that to my

collection. We'll put it in the Chop Shop store. Yes! Planetary Society square hats. He's Bruce Betts. He's no square. He joins us every week here for What's Up. It's hip to be square. Planetary Radio is produced by the Planetary Society of Pasadena, California, and is made possible by its utterly cosmic members. Daniel Gunn is our associate producer.

Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan. Clear skies.