Wendy Freedman
Big Brains podcst

The Expanding Universe with Wendy Freedman (Ep. 5)

Prof. Wendy Freedman discusses her research on measuring the age of the universe, her leadership of the Giant Magellan Telescope and the search for life outside our solar system.

Wendy Freedman
Big Brains podcst

Show Notes

Prof. Wendy Freedman spent much of her career measuring the age of the universe. Now she’s working on a project that may very well give scientists a chance to glimpse into its birth.

Freedman was the founding leader from 2003 until 2015 of an international consortium of researchers and universities (including UChicago) to build the world’s largest telescope high in the mountains of Chile. The Giant Magellan Telescope will be as tall as the Statue of Liberty when complete, and ten times more powerful than the Hubble Space Telescope—with the ability to look back at the dawn of the cosmos.

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Transcript:

Paul Rand: From the University of Chicago, this is Big Brains with Paul M Rand, conversations with pioneering thinkers that will change the way you see the world.

Paul Rand: Cosmologists Wendy Freedman has spent her career measuring the age of the universe. She’s also led an international effort to build the world’s largest telescope. The Giant Magellan Telescope is going to be as tall as the statue of Liberty and 10 times more powerful than the Hubble Space Telescope itself. When it’s finished, we’ll be able to glimpse back to the birth of the galaxy, it might even be able to find signs of life outside of our solar system. Wendy talked with me about her revolutionary work and why she thinks one of the greatest discoveries in the universe might be just around the corner.

Paul Rand: Well, let me ask you, you have become really quite recognized on a worldwide level for an area observational cosmology. What in the world is observational cosmology?

Wendy Freedman: Well, cosmology to begin with is the study of the universe, the grandest of all sciences, in some sense. We ask questions about the origin of the universe, the evolution of the universe, the structure of the universe, what is the universe, what makes it tick, how does it evolve with time and we can ask questions about the nature of the universe, both by applying physical laws that we know apply on earth, gravity. We’re all familiar with the force of gravity and we know about Newton’s Laws of Gravity. We may know about Einstein’s theory of gravity, it’s theory of general relativity, and those make predictions for what we should see and we now have tremendous telescopes that we can point at the sky, and we can look out at the universe and ask, what do we see, does it match the predictions and so an observational cosmologist uses large telescopes.

Wendy Freedman: I traveled to Chile, the Andes Mountains, Hawaii, various places around the world where their remote sites, dark sites, and also make use of telescopes in space like the Hubble Space Telescope. So we can ask questions, direct questions. What is the universe doing? How far away are galaxies, how fast is the universe expanding and do those match the predictions.

Paul Rand: And the thing that when people think of you and what you’re focused on, it’s typically around something called the Hubble Constant and I wonder if you can explain that a little bit?

Wendy Freedman: So the Hubble Constant is a quantity that measures the current rate at which the universe is expanding. So it’s named after Edwin Hubble-

Paul Rand: And there’s a little bit of history with him on this campus, is that right?

Wendy Freedman: There is indeed, he began his career at the University of Chicago-

Paul Rand: What do you know?

Wendy Freedman: So the Hubble Constant is a measure... NASA... What Hubble discovered is that the universe is expanding. He made measurements of the distances to galaxies and using measurements of velocities, the rate at which the galaxies are moving away from us, so it was a discovery that he made, that the velocity of a galaxy is related to how far away the galaxy is.

Paul Rand: Okay.

Wendy Freedman: So before Hubble, we didn’t know whether there were other galaxies in addition to our own Milky Way galaxy or whether the regions that he was studying were part of our own Milky Way or new stars were forming and he unambiguously established that there are other galaxies and that those galaxies are undergoing an overall expansion. Most galaxies we look at by far almost all the galaxies we see are moving away from us.

Paul Rand: And when you think about a galaxy, in some ways being infinite, then how does it expand that? Obviously, they’re not infinite.

Wendy Freedman: So, the idea, at the time that Hubble began his study of the universe, the idea was that we lived in a universe that was static, wasn’t moving and if you ask astronomers during that time, is there any evidence for the universe being in motion, there was no evidence, but what Hubble found was that in fact, galaxies all appear to be moving away from us and that together with the general theory of relativity that Albert Einstein had developed in 1915 and 1917 led to a picture, okay, if the universe is now expanding and we look out and we see galaxies moving away from us, then you could extrapolate backwards in effect like running a movie in reverse and you realize that, okay, galaxies are a certain distance now, but in the past, they would have been closer to us and there would have been a time, in fact, if you go far enough back in the past where the universe would have been very dense and very hot, and that’s what led to this picture of what we now call The Big Bang-

Paul Rand: Big Bang. Okay.

Wendy Freedman: And in-

Paul Rand: Because by understanding that-

Wendy Freedman: By understanding that. So it’s an interplay between theory, the theory of general relativity and observations on these very large scales that we can get a picture of what is the universe like and for the first time we realize it’s changing, it’s evolving. There was a time in the universe, we had this tremendous explosion and the universe has been expanding, but-

Paul Rand: But The Big Bang theory was began to be understood by the understanding of the Hubble Constant.

Wendy Freedman: Yes and so it’s the measurement of the Hubble Constant, which is a relationship between how fast a galaxy is moving and how far away it is and that was what Edwin Hubble did. Now, the time he made his measurements, he didn’t have the technical capability to do it very accurately. He did the best that he could and it really, until the time of the Hubble Space Telescope, the launch of a telescope above the Earth’s atmosphere, and that’s when I came into the field, very lucky to have come in at a time where we could make these measurements extremely accurately and so Hubble... The Hubble Constant gives you a measure of both the age of the universe and its size.

Wendy Freedman: So if we can measure that accurately, then we can actually date when the Big Bang happened and when I began my studies, there was a debate in our field about what the age of the universe was. We did not know it better than a factor of two. So the universe was either 10 billion years old or 20 billion years old and that’s a big discrepancy. That’s a very wide range and so there was another case, in fact, the two directors at the observatory that I worked at, who tried to discourage me from working on the problem, because there were indications from some people that the age was very old. We knew that and so why measure it and that’s one of the beauties of science is that we don’t know what the answer is.

Wendy Freedman: We don’t have a textbook where we can turn to the back where the answer is to the problem is and say, ‘‘Okay, now we know.’’ We really do have to measure it and that’s, what’s so exciting about the field. We have the opportunity to do that.

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Paul Rand: And so one of the next big iterations, discoveries is likely going to becoming out of the next projects that you’re working on called the Giant Magellan Telescope.

Wendy Freedman: That’s right. So the Giant Magellan Telescope is a new telescope that we are in fact, in the process, it’s under construction in the Andes Mountains in Chile-

Paul Rand: And it’s out in the desert, is that right, in Chile? It’s high in the mountains but in the desert?

Wendy Freedman: Yeah, it will be located in the Andes Mountains, the Atacama Desert in Northern Chile and we go to remote sites because it’s first of all, dark, away from city lights, but also it’s in the desert, which means it doesn’t rain very much and if you want to look at the night sky, you want your telescope dome to be open and so that’s why we go to these high mountain deserts, and it will be the largest telescope of its kind in the world when it’s completed.

Paul Rand: And just in terms of the size of the actual telescope, I’ve heard as large as the statue of Liberty, is that an exaggeration?

Wendy Freedman: That’s no exaggeration. The telescope, if you want to compare in scale is comparable to the height of the statue of Liberty. This is a mammoth facility and it will be 80 feet in diameter and it will be made up of seven independent mirrors, each one of which is about 27 feet in diameter. These mirrors are interesting in their own right. I could go on about the mirrors and how we make them. They’re actually made in a rotating oven. That’s like a cauldron. We melt the glass as the oven is spinning. So each one of these mirrors is 27 feet in diameter and as the oven heats up in temperature, the glass is melting, we make the original parabolic shape that we want the mirror to have.

Wendy Freedman: So it’s like if you spin a bucket that has water in it, you get the forest centrifical force pushes up the glass of the side and you get the original shape you want and then we use a computer controlled lap to polish the mirrors and these mirrors now have been polished to 1000000th of an inch and by which I mean, bumps on the surface are smaller, the range of the size of bumps than a millionth of an inch. So you can imagine this gargantuan structure that has to be balanced to incredible precision so that we can make these measurements, which will have 10 times the clarity that we can achieve in space with the Hubble today, times 10 times.

Paul Rand: Somewhere you talked about this, right now, you look at it, it looks like a smudge, and then going forward, it’s not going to, what’s it going to look like?

Wendy Freedman: It will bring immediately into focus what is happening in the distant objects of the universe where we’re trying to understand how are the first galaxies in the universe forming, for example and when we take images now with the Hubble Space Telescope, and we point at the same region of the sky for weeks or months, add up the signal, integrate it. So we can see very faint objects. They look like smudges. That’s what I was referring to and then with this telescope, we’ll actually see detail, or what are these galaxies like, how did they form, when did they form and we can ask questions like, are there other planets that have masses comparable to earth and right now our technology allows us to say a lot about planets that are like Neptune or Uranus or the heavy planets, like Jupiter and Saturn, but we don’t have a telescope yet that has enough sensitivity or resolution clarity to actually make measurements of planets with the masses of the earth.

Wendy Freedman: So in our field, the new developments have come with new technology without exception from the time that Galileo first turned a telescope to the sky in 1609, every time we’ve built a new capability, we’ve made new discoveries, which is why we’re so excited.

Paul Rand: And so what role does the University of Chicago play?

Wendy Freedman: The University of Chicago is one of the early founding partners of the Giant Magellan Telescope, which is one of the things that really excites me being here now at the University of Chicago and plays a role in both the development of the scientific case for the telescope. There are people on the faculty who are very interested in development of instrumentation on the back end of the telescope and it’s played a huge role in the leadership of the telescope.

Paul Rand: The Giant Magellan Telescope, you think will be functional in 2022?

Wendy Freedman: It’s 2024.

Paul Rand: 2024.

Wendy Freedman: That’s when we will have first light for the telescope, assuming everything stays on the current schedule. So we’ve now cast the mirror for the... The fifth mirror for the telescope, and it requires seven and ultimately, but we will go ahead with the first four mirrors-

Paul Rand: So it’s operational.

Wendy Freedman: Not yet. You have to have a mount, a steel mount when you place these mirrors, and you can point your telescope to any region of the sky. You have to have an instrument at the back, so you can collect the light that’s coming to us from the distant universe and so that... None of these things, can you buy off the shelf, right. They’re all being done piece by piece by a very talented group of engineers around the world. So it’s under construction.

Paul Rand: Okay. So you’re going down, you told me two or three times a year. You check in on things. I’m sure it’s quite remarkable.

Wendy Freedman: Oh, it is remarkable to watch this telescope being built from the ground up and we started the project in 2003. So for 12 years, I led the project, put together the partnership to build the telescope. So I really have watched it from the beginning and now actually seeing the pieces of hardware come together and there’s now a little city on the top of the mountain, there’ll be 250 people working there under peak construction, when that when the telescope is actually in the mount, the enclosure. It’s like, it is a 22 story building, but it has to rotate because you want your telescope to be able to look out at any region of the sky. So this is a complex piece of machinery.

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Paul Rand: Okay. So in your wildest dreams, you’re thinking my goodness, what we could possibly achieve with this next development could be X, Y, or Z. What do you think of, what do you dream of as you start thinking about that?

Wendy Freedman: I think if we actually were able to detect earth mass planets established that they truly had the mass of the earth, and then we could take a spectrum, divide the light into a rainbow and look for features that would represent water, carbon dioxide, methane, ozone, the kinds of signatures that would be telltale signs of life, if we really were able to show that there’s life on a planet outside of our own solar system, that will be one of the discoveries that I think not only will be exciting for astronomers, but will change our perspective, humankind’s perspective on our place in the universe.

Wendy Freedman: So I think that would be a monumental discovery-

Paul Rand: So you think that’s going to happen?

Wendy Freedman: That’s something in principle that the GMT could do, and we don’t know what kind of life, but we’re now... We’re at the... So I think that’s, what’s so exciting right now is we’re living in a time where you can actually ask these questions. They’re not science fiction right now. We really can’t ask. People have speculated about these things for millennia. Is there life elsewhere in the universe? Are there other planets? Now we know there are other planets, are there other galaxies? We know there are other galaxies, we know the universe is expanding and it’s just a tremendous time to be just alive, I think.

Paul Rand: Does the prospect of that excite you, scare you something in between?

Wendy Freedman: It excites me.

Paul Rand: It excites you.

Wendy Freedman: There’s no question. Yeah. I think it’s one of the most exciting things that we, as a human species, have done. It’s a journey and I think it’s exciting and it’s as beautiful as art or music or literature, all of the things that we do as a human species and the fact that we can ask these questions and make measurements and test our ideas, if they’re wrong, they’re wrong and we can do that. It’s extraordinarily exciting, I think.

Paul Rand: There’s a great amount of awe that goes into what you’re doing. As you’re thinking or seeing or learning something that’s just completely awestruck you?

Wendy Freedman: There are so many things that have developed, just since the time that I entered the field, and I think none of us really could have imagined. One is the possibility of making measurements that for example, things that Einstein had predicted would happen, but he actually discarded because they were so small as a possibility that they would ever be measured and one good example, I think of what’s happened in our field is the ability to make measurements of tiny, tiny, tiny differences in the background radiation, which is a remnant from the Big Bang.

Wendy Freedman: So if there was a Big Bang, another one of these testable ideas, we should see the remnants of that today, this tremendous explosion, what happened to all the radiation from the Big Bang? That was a prediction that was made. It was a discovery that was made, in fact, serendipitously led to a Nobel Prize, results that came out in 1965, that you could measure the background radiation, this remnant from the Big Bang.

Wendy Freedman: Now we can make those measurements so precisely that to one part in 100,000. So the background radiation is the same in every direction we look, but there are tiny, tiny differences with thousands of a percent and we can actually measure those now and they tell us something about the nature of the universe and that’s only one example of the kinds of things. So Hubble Space Telescope was launched. We measured the expansion of the universe and I think the rapid pace of discovery and what we learned in all of this, the universe isn’t like what we thought at the beginning.

Wendy Freedman: We, it turns out, are not like most of the matter in the universe. So everything we know, what this table is made out of, the clothes we’re wearing, the air that we breathe, all the molecules that are in the periodic table that we learn about in high school, that’s only a tiny fraction of the overall mass plus energy in the universe.

Wendy Freedman: It’s 5%, that’s it. We are unlike what most of the universe is made out of. This is neither results that we’ve only learned about in the last couple of decades. Moreover, not just the mass is different, but it turns out we are not only expanding, the universe is not only expanding, as Hubble told us and Einstein’s theory is consistent with, but it’s speeding up in its expansion. So these two components, one is called dark matter. It’s matter, very different from the stuff you and I are made out of and then there’s this, what appears to be a force, a repulsive force that’s causing the universe to speed up and together, those two things, the dark matter and dark energy make up 95% of what the universe is made out of and we just had no idea that that was the case.

Paul Rand: 95%.

Wendy Freedman: 95%. We are the tip of the iceberg and we don’t understand what those things are yet. There people working, hundreds of scientists all over the world now, trying to understand what is this stuff, but the evidence that’s been piling up based on telescopes, primarily and experiments that are being done in under ground laboratories around the world, trying to understand what is the stuff that is filling the universe? So we could not have predicted this and-

Paul Rand: And now we might start getting a little closer to some additional answers here.

Wendy Freedman: We just may and we’re very likely to do that.

Paul Rand: Well, let me turn a little bit, I have a offbeat question for you. Do you believe that the people that are in your field are more or less spiritual than those outside of the field?

Wendy Freedman: So I think that’s a very individual thing and how you would define spirituality, you could do that in different ways. I think if you’re thinking about the universe and the origin of the universe, the evolution of the universe, that’s a very spiritual kind of thing and it might not be everybody’s definition of what spiritual is, but I think we all, again, as a human species have-

Paul Rand: Innate craving.

Wendy Freedman: Innate craving to understand where it all came from and I think it’s extremely exciting endeavor to be part of that process to probe and ask question, how did this happen, why are we here and a lot of those questions now we’re beginning to answer, which is not to say we have all the answers. I think we never will but yeah, in some sense that’s a spiritual quest.

Paul Rand: Very much. Well, like you said earlier, what a great time to be alive and in your field.

Wendy Freedman: Yeah. I couldn’t say it better. It is a great time to be alive and to be in my field.

Paul Rand: It’s all very fascinating. Wonderful. Well, thanks for coming in and talking with us today.

Wendy Freedman: Oh, well thank you for having me. Pleasure.

Paul Rand: Big Brains is a production of the UChicago Podcast Network. To learn more, visit us at news.uchicago.edu and subscribe on iTunes, Stitcher, Google Play and wherever else you get your podcasts and if you liked Big Brains, you might enjoy another UChicago podcast, Knowledge Applied, taking you inside the research, reshaping everyday life. Thanks for listening.

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