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“From the Big Bang to 30 Trillion Networked Computers (That's You!!!)”

with John Mather ’68, H'94, NASA's senior project scientist for the James Webb Space Telescope

Recorded on Tuesday, Sept. 28, 2021

 

Transcript

Sean Thackurdeen '12 Well, it's a pleasure to be with you on this starry night, as you can tell from John's background, for a lecture with one of our own, Dr. John C Mather, Class of 1968. He's speaking to us as part of SwatTalks, which are an endeavor of the Swarthmore Alumni Council, of which I'm a part. You can expect exciting speakers to dive into topics you always wished you studied while you were here. And a quick shout out to Joe Becker for helping to organize this particular talk. As we get going here, John will give a chat for a bit, and then we'll have a Q and A afterwards. So please filter in your questions during the talk, and we'll be glad to surface them at the end. Now for a bit about John, John is here to teach us what many Swatties have wondered to do in the recent decade, which is how do we properly stare directly into the sun? That one puzzled many for a while, but John, our friendly Nobel prize winner, can lead us the way. As you know, he's one of Swarthmore's five prize winners. He's 20% responsible for making Swarthmore a top school for producing these winners. But that's less about what makes John remarkable. In fact, I remember when John was on campus in 2008, I attended a lecture, partially for free food, in Parish Commons, and partially to meet John. And my first time shaking any Nobel prize winner's hand. And I remember keenly his genuine interest in engaging. It's something that I get in his lecture then, and now, which is a rare glimpse of what extraordinary knowledge and humility looks like. And if that doesn't do it for you, John is here to lift everybody's self esteem. In that 2008 lecture, he mentioned, when you wake up in the morning and look in the mirror, you're looking at the stars. All of the atoms in your body were created post Big Bang. So without further ado, here we go, Dr. John C Mather, Class of 1968.

John Mather '68 Well, thank you, Sean. That's a lovely introduction. And I should say, if anybody really wants to know how to look directly at the sun, close your eyes. It's better for you. What I want to show you today is what we've been learning about our history in the expanding universe, and a little bit about our current project that I'm working on, the James Webb Space Telescope, which we are showing here in this very first picture. It is a joint project of NASA with the European and Canadian space agencies. And what we're showing here is a giant golden hexagon, which is a huge mirror that will be unfolded in space, soon after our launch on December 18th. And it will become a telescope out there to measure infrared light from the most distant stars and galaxies. And I'll show you more about it later. This is a project on behalf of all people. We will, of course let out all of the information we receive promptly. There are about 10,000 professional astronomers in the world whose job it is to use this telescope and figure out what it means. And it has taken many thousands of engineers and technicians to put it together. And I'm not one of those people who touches the hardware. I do a lot of meetings, I talk to my fellow scientists and my fellow engineers, and other people actually make something like this happen. To pull off a international project of this scale is something that I am astonished about. And there are people who know how to do that. At any rate, I'll show you more about it as we go along, but first to tell you a little bit about history, how did I get going? Well, in 1946, a few things were interesting. This is Lyman Spitzer, a famous astronomer at the time. And he had been working with the Red Corporation during the World War. And he wrote a little memo at the end, and he said, we should build telescopes in space, to do astronomy. So eventually, we got to do that, and eventually, we named the telescope after him. Also, way back then, here is Sir Fred Hoyle, looking a little skeptical. He was a very famous opponent of what we now call the Big Bang Theory. But he made it a very lively subject by giving it that name. So it was a very deceptive name, but we haven't been able to escape it. Then in 1946, I turned up. That's me, a little while after 1946. So just to set a little historical context, I was born a year and a day after Hiroshima. So it's been on my mind ever since that I've been a child of the atomic age, and that is a little bit of a dangerous place to be. So on the other hand, I grew up here. This is a remarkable place, also. This is a research farm belonging to Rutgers University. And my father was a statistician and scientist working on dairy cows. So, it's a beautiful spot. You can see the sky, even now, it's not that bright up there. It's a mile from the Appalachian Trail. And when I was about six, my dad told me over at bedtime that, by the way, my body is made up of cells, and in the cells are chromosomes, and in the chromosomes are the genetics that may control your destiny. He was really interested in that, because dairy cows have genetics, and that was his specialty. So I grew up knowing about that, and wondering how it would work, and thinking, well, your inheritance isn't exactly random, not exactly fair. Nobody gets the same set. So fate is embodied in this. Everybody starts with a different spot. But I thought it was a completely fascinating thing. So the next year, it was discovered, in 1953, that DNA is coiled up in the double helix, and people started to be able to read the code. Say, well, what does that mean? We still don't really know, but we've learned a lot. The year after that, I was fascinated with astronomy, and with dinosaurs and all the other things you can see in the Museum of Natural History in New York City, which was a good long drive from our farm. But I did get to go there a few times, and I am still in awe of what a museum like that can do for the public, and for me in particular, just getting me interested in the world. So that was where I got started. This is where I went to high school, in far northern New Jersey. This is a very green and rural place. And it is so rural that I took the bus about an hour each way to get to high school. So I had a lot of time on my hands to read and think and do things by myself. So it's sort of the opposite of having all the resources of the world at your hands, except, the bookmobile came around every two weeks, and they brought me all the science books I could read. So it turned out to be a good place to start. So now, stepping back though, to the question that was on my mind, even as a child, how does this all work? When they tell you in Sunday school that they've got the answer, even an eight year old child thinks, that doesn't actually sound very right. So how do we do this? So Lucretius, a poet more than 2000 years ago already had a pretty good idea. He knew of the atomic theory. He knew because evidence at the time was, a glass of water can evaporate and disappear. So how can it do that? Well, it turns into invisibly small particles. They didn't have much other evidence to go on, but they had this idea that out of those tiny atoms, things are built up. But it's all temporary. They stick together and grow, and then they fall apart. We give them names. He was aware of the linguistic nature of life, and consciousness, and then they all go away. So this was a version of more than 2000 years ago, it was quite stunning how well he tells the story. The modern version, I've tried to tell you here. We have learned about quantum mechanics. About, almost 100 years ago, we found out that all those particles you read about in school, with the electrons, the neutrons, the protons, all behave like waves, and all the waves like byte waves behave like particles. And it's very mysterious, but we do know how to calculate. So that turns out to be a very fundamental basis, because it tells you how stuff sticks together. We've learned that the universe is expanding, and this was also almost a century ago that we found this out. And we knew from later on that it started out very smooth and very hot. And it has been very unstable. This is a recurring theme of my story, that things are just unstable. Things do not stay put. And that's interesting, because if they were stable, we wouldn't be here. So the universe is very large, we can't prove that it's infinite in extent, but it's certainly very large. And it's very old, about 14 billion years. So that's something that seems to us, very unlikely, such as our own personal existence, has had time to come to reality. So isn't that amazing to us? We don't understand how to calculate that. But we have begun to learn how it works. I mentioned earlier, we've got the DNA that enables our cells to carry on inheritance. There's other kinds of stored information that give us language, for instance. Evolution was a big deal when I was a kid. I used to dream that I was a school teacher, and I was teaching evolution in the schools, and I was being challenged and sent to jail, because I wanted to teach evolution in school. So we've been having this fight also for a long time. At any rate, it's been on my mind. We have more recently learned about what biologists call homeostasis, which is a set of what engineers call feedback loops, control systems, which sense whether something is the way it's supposed to be, and do something to keep it that way. So for instance, say living cells say, well, I need food, I need to take things in, I need to put the waste products out, I might need to go somewhere to get something to eat. All of those things are built into living things, so that we can have a continuing identity. That's pretty amazing. So to give a little bit more about the physics of it. I already mentioned that quantum mechanics tells you how the particles behave. More important perhaps is that they also tell us how the particles stick together. The particles do not just stick together in random ways, like billiard balls colliding on a table. They stick together because they're sticky. They have what the scientists would call binding energy, that tells you how tightly they stick. And if they have a shape, which most of them do, then of course, they stick together in particular shapes, bigger shapes. And this is the basis of the complexity of all chemistry and living things. So those are sticky blocks, made out of the atoms, that are themselves made out of electrons, protons, and neutrons, and now of course, you know, even those are made out of littler things. A bigger force, which was the first one to be investigated by science, was gravity. Everyone knows that Isaac Newton figured this out. Then Albert Einstein figured it out better. But from the perspective of our story, gravity is the thing that makes a gas cloud from the early universe turn into galaxies and stars and planets. And it's done because it's able to stop the expansion, and pull the gaseous material back together. So in school we learned about thermodynamics. There are three laws that tell us how things are supposed to work when everything's at the same temperature. When everything's not at the same temperature, it doesn't give us very much guidance about what nature is going to do. But we have noticed that nature seems to often find a way to make what we call a heat engine. A heat engine takes heat from one place and puts it out at another, and then can do something on the way. So, a steam engine or gasoline engine is a heat engine, which takes the energy of a hot thing and turns it into rotary motion, so we can have something useful to do with it. Nature seems to find these things also, and I'll show you a picture of that one, one of them, later. So that's the physics behind all of this. And the tricky part is this non-equilibrium thermodynamics, the instability that leads to complexity. So here's some examples of instability liberating energy. I can get a lot of money if I go rob a bank. Or, it's also illegal to go rob the public by lobbying Congress for favors. If you're really good at this software business, you can get a dollar from every one of the people living out here on earth, and you'll be a very rich person. Or if you have an idea that can grow into an organization, you can build a company, or you can build a country. That's another kind of instability. This is the instability of an idea that can grow because we human beings propagate the idea and do something. I already talked about releasing gravitational energy. I'll show you a picture of a hurricane. It's another kind of instability. And finally, as mentioned before, we are the complex living systems, we are collecting energy, and we are also unstable. So in school, in college, I was able to do this problem. This is a very simple problem that Euler did in 1757. If you're an architecture student, you need to know how to do this. So you want to build a column, like the Greeks built their columns, to hold up the temples. This tells you how tall you can make the column before it'll buckle instead of just standing there. So the answer is, it has to be about less than 20 times tall, wide as it is. Said that wrong. Less than 20 times as tall as it is wide. So he was able to calculate that from math, which is pretty cool. Not everything can be calculated. Some things are just too complicated. So for instance, molecules are a little too complicated. So when we say, how do the molecules of life grow? The situation on the right hand side is the answer that we used to have for most of my life. Even scientists said, I do not know how this happens, it must be really impossible for living material to grow spontaneously. And now I think we have a different approach, which I hope to illustrate a little bit. But I don't think it's quite true that a miracle is required. So my thought would be, life is probably a thermodynamic imperative. It was thought when I was young, and I think scientists shared this thought with the religious people, that we are very special, we are so special that it could not happen without divine intervention. I'd say, now we don't know how to do that. But you know, we do have one bit of evidence that sort of tends in the direction to say, well, maybe it was really, really, really special. So that is, when you examine the genetics of all living things, very similar. The biochemistry, the cycles of how the individual cells do things, very similar. We share an awful lot of chemistry with plants. So how has that happened? Well, one way would be, we're all descended from the very first living thing. And it still leaves open the question of whether that very first thing happened quickly or very slowly. But that's an interesting question. It is not actually the only answer. What if our ancestors ate the neighbors? Or just we produced better? Or what if it was done many times? So this is a wide open scientific question, as far as I'm concerned, and we do not know how to approach it. We are hunting for evidence. Here on earth, we can hunt for evidence to say, well, what's a good place to try these kinds of chemical experiments? And the one that appeals to me is where warm water comes bubbling up from the rocks at the bottom of the sea, and you see the most astonishing chimneys growing up full of little tubes and channels where chemical reactions could be occurring. So that's one place that some people favor, but it could be something else. We have basically one data point about this, that pretty much as soon as there were oceans here on earth, according to the fossils, and the layers of rock, it didn't take very long before there were fossils of some kind of life. So it's hard to answer this very well because most of the rocks you would need to find to answer this question have been reused, and recycled themselves, and turned into new rocks. So only a little bit of evidence about that, but that's fascinating. It did not take very long for life to turn up, after there were oceans. What happened then? It took a couple of billion years before life got really complex, to have multicellular forms, according to the fossil record. And then it took until only half a billion years ago for the things with eyes and legs to turn up, and to be able to swim around. So, animals. Not very long ago. And then only a half a million years ago, creatures with fossils and bones that looked like ours turned up. And we don't quite know how much like us they were, but they certainly have similar skeletons. So that's pretty interesting about us. It means that life occurred quickly, and human life, well it took the entire history of the earth for us to turn up. So that's slow. What else could we find out about? We could go looking elsewhere in the solar system to see if there are living things elsewhere, or were living things. And we could look at other solar systems. And this is no longer technically impossible. So the particular thing we would be especially interested in is oxygen on a planet around another star. So it's not impossible. And of course, we are working on it. So just to give you an example of a spontaneous heat engine, I told you that this happens naturally. In this case, I've got you a picture of Hurricane Harvey. So what does a hurricane do? It takes heat from the equator and helps transport it to the Poles. So it was gonna go there anyway, but it got there faster, because this structure could be built by natural flows of air around the oceans, and the, anyway. I have it here, partly because we care deeply about it. This hurricane hovered for a quite a long time, like a couple of weeks, over the vacuum tank that we were using to test the James Webb Space Telescope in. So we dealt with that one in person. At any rate, this is the idea that complex systems can occur if they can extract energy from a flowing energy. So fundamental principle, that nature seems to follow that we don't fully understand. So I promised to address the question of, who am I? And obviously, I don't know this answer. I can tell you some different perspectives that can be taken. As we have already said, a living cell is a digital computer. It reads its own digital code on the DNA. And somehow it knows what to do with that information. It also communicates with the neighbors, electrically, mechanically, and chemically. And it's remarkably structured so that it can keep itself going, and repair itself, or even replace itself when it's old. So that's that's us. So that's the biological version of it. Emphasizing the digital code at the core that tells it how to work. Then you say, well, maybe we should talk about the network neighborhood nature of this object. That is to say our bodies. And here I'm pointing out that actually, these could be viewed as a super computer, a network. Same thing, but now we're just focusing on the communication. You can put your tongue firmly in your cheeks, and say, well, this is nature's way to cause trouble. Here we are. Our job is to increase entropy, and increase the release of carbon dioxide, and cause an extinction. So that's another thing that we're currently up to at the moment. Not that we can assign a conscious intent to that. Could also say, well, okay, all this information about what's going on with all those cells, that's information. Couldn't I record that, and isn't that somehow my essence? And the upshot is, well, maybe so, but I don't know anything practical you could possibly do about that. When the science fiction writers talk about beam me up, well, that's probably not gonna happen. You can say, well, okay, that's enough of that science. What about the way that we talk with each other? We're interesting in our own selves, with our feelings, and our connections, and our intentions, and I'm a creative person, I'm related to people. And finally, we get to the completely mysterious question of, I seem to be aware of myself, it's consciousness, and nobody quite knows how that works, even though an awful lot of people write books about it. So I'm just not convinced that we know. I hope somebody does, but anyway, so this is my small version of saying, this is who we are, but it's clearly not nearly enough. So I wanna talk a little bit about how astronomers come to claim these things. So of course, we look back in time by looking at things that are far away. Might travel very fast, but the speed is not infinite, it's just really fast. So if I could look at the center of our own galaxy, I would see it as it was about 25,000 years ago, 'cause we know the speed of light, and we know how far away it is. If I wanna measure distances, I draw triangles, surveying, like the ancients did, or I use the relative brightness of standard candles, if I can argue that those standard candles are the same, and measure the ratio of brightnesses, I can get the ratio of distances, I can now survey the whole universe. Back in 1929, people were starting to do this. Also, you can measure the apparent velocity of stars coming toward you or going away from you. If you spread out the light of a star into a rainbow, you will see that it has marks across the rainbow that are due to chemicals in the atmospheres of those stars. The sun is like that too. So if you see that all of the wavelengths has been changed, relative to what they are here, in a systematic way, you can say it's because the object is coming toward us or going away from us, and you can use this to measure the velocity very precisely. So back in 1929, we got this very first measurement from Edwin Hubble. This is the first graph that shows the expansion of the universe, 1929. So each of those little dots is a galaxy, which as you know, is more or less 100 billion stars held together by gravity. And the obvious trend here was a big discovery. The farther away, the faster. So if you divide the distance by the speed, you get the apparent age of the universe, which he got wrong, as we always get things wrong the first time. But anyway, the fact was pretty obvious. The universe is seeming to expand, everything's running away from us. And now we know this is called the Hubble Lemaitre Law, because Georges Lemaitre was a theoretical cosmologist, and he said, this should be true. And now we call it the Hubble Lemaitre Law. By the way, he was also a Belgian priest, Catholic priest. So he got to deal with the religious implications of these measurements. So in 1968, I left college to go to Berkeley, California, for graduate school. In 1970, I started work on a thesis project to measure the cosmic microwave background radiation, which is the leftover heat of the early universe. My thesis project failed. Did not function properly. I got to write a thesis about a failed experiment. And I ended up getting a job at NASA in New York city. After I'd been there about six months, NASA said, we want proposals for new satellite missions. I said, boss, my thesis project failed, we should do it in outer space. He said, we'll call up our friends and we'll write a proposal. So astonishingly to me, it worked. So 15 years later, after the first napkin sketch, this went into space, and it measured the Big Bang. So I'm not gonna tell you very many details. Just to say, what's the upshot of the expanding universe story? It's very hot and very compressed when it was young, no center and no edge, expanding into itself. There's no first moment, this is not a firecracker. When people call it the Big Bang, you can hardly help thinking that it's a firecracker, a finite explosion at a place and a time. And actually what we mean is the entire universe is expanding a way into itself. And anyway, so this is the picture that Sir Fred Hoyle hated. And he never gave up. I think he was wrong. So I got to show my graph many times. I got to go see the King of Sweden. I came home with a nice check of funds, which we have used to support ballet dancers, 'cause my wife is a ballet teacher, and also scientists and engineers who want to contribute to NASA, especially, or to work on Capitol Hill in science policy. So how do we know all these things are true? Well, of course we don't. But we have the evidence. So the Hubble Space Telescope was launched just a few months after that satellite, the COBE satellite, and it is still working beautifully, although it has glitches occasionally, because it's been visited five times by astronauts to make it better. So there it is in beautiful outer space. It's a not all that big telescope. Its diameter is 2.4 meters, about eight feet. Which isn't that big anymore. But it certainly was a huge effort to put it up then. So they took a picture with it. This is a picture of a small piece of sky, where there's two stars to speak of that you can find here, and all the rest of these little images are galaxies. Astronomers look at this picture, and they said, we were hoping we would see the very first galaxies growing. We hoped we would be able to see so far out in space, and so very far back in time that there wouldn't be any galaxies there. And the answer is, we're sorry, this is not a good enough telescope to do that. Please build us another telescope that's more powerful, more sensitive, and can pick up the infrared light from the most distant galaxies that are running away so fast that the light starts out at visible wavelengths and is now infrared. So, okay, that's a big challenge. We also have observations and theories. This movie that I'm showing you is a computer simulation of the way that we imagine the universe growing galaxies. The supercomputer people have taken an imaginary box of early universe, populated it with random variations of density. And then they said, okay, computer, make it go, see what it's going to do. So what it does is it grows galaxies very quickly. In the first billion years, an awful lot of galaxies have already grown. And the picture is rotating, so you can see the three-dimensional structure. And once in a while, you'll see that these galaxies are strung together in threads and sheets. Like right now, we're looking at it edge on. So that was a big surprise. How can random structure turn into such obvious structures? So it's not just that the eye can always see something in a pattern. Also you see in the movie right now, there are explosions happening. Explosions happen in astronomy for two big reasons. One is that stars get old and they blow up. When they've run out of fuel. The other is that black holes can form, and if material will fall into a black hole, then a huge amount of gravitational energy can be released, and a great explosion can occur that way. So this is happening, explosions of this sort, for billions and billions of years. And it runs along like that, and then it begins to quiet down. And age nine billion or so, the solar system is being born on the outskirts of one of those very ordinary little galaxies that's swimming across in the picture. So things are quieter now, which is good. If there were a black hole in the neighborhood, the solar system would have been sterile. Everything would have been fried. At any rate, a beautiful movie. It shows you something astronomers can never actually see in real life, because we can never wait billions of years to see something happen. So closer up to say, we have another picture taken by Hubble. This is one of those great spiral galaxies. And I have on the lower right, a little sketch that was made in 1845 by an astronomer with a big telescope, and a kind of pretty good hand with art. So he'd got the main picture there. We see two galaxies that are about to crash into each other. Here's something that's also part of a important story of where did we come from? This is an example of a star that blew up. On July 4th of AD 1054. Which we know because you could see it at the time, astronomers wrote it down, and we can still read what they wrote. So this is important, because it tells us, this is how most of the chemical elements of the earth that you see were liberated into space. The Big Bang gave us hydrogen and helium. And here we see the other chemical elements come flying back out from the exploding star in the middle. So this happened in the neighborhood of where the sun grew up some billions of years ago, and that's why we have earth. So when you look around the house and you look in the mirror, you are indeed, as Sean said, looking at the remains of exploded stars, and you don't think about it, but it's miraculous. How else would you like to find out? Well, we have also built a telescope in South America to look for not only the distant universe, but also stars forming planets. This electronic telescope has made an image of the star in the upper left corner there. It shows dust grains orbiting around a central new star. Dust grains that are glowing because they're a little bit warm. And the astonishing thing is that this looks a little bit like the rings of Saturn. So we imagine that there are planets growing in the dark rings in between the bright ones, and that this is a future solar system that will have something like nine planets. If you were to come back in 100,000 years, most of the dust would be gone, and you would still see the planets. So, we will learn, we will find out more, and it is not just all gonna be imagination forever and ever. We actually get evidence. So now I wanna talk a little bit about the Webb Telescope, the James Webb Space Telescope, James Webb was the second administrator of NASA. And he went to Jack Kennedy with a plan for the Apollo Program, in 1961. In 1969, astronauts actually walked on the surface of the room. It was in a big hurry, it was extremely dangerous, and it worked. And I'm still astonished that it could be done, because it took much longer than that for us to build this telescope. At any rate, as I mentioned earlier, it's a joint project of NASA with European and Canadian space agencies. And it has now got a launch date of December 18th. It is going up on a European rocket from French Guiana. And if I don't run out of time, I'll show you how that works. So here's basically the steps that it takes NASA to build a great telescope and put it up into space. Skipping an awful lot of parts, but first we put it together, here in Greenbelt, Maryland. In a very clean room. It's kept clean because you cannot easily wash the dirt off a telescope. We put it on a shaker to see if it would survive launch. And it did. We put it in a big shipping container and we put it in a big airplane, the C5C aircraft, making a little bit of use of military hardware. Flew it down to Houston, Texas, where that hurricane went by. And we put it in the giant vacuum tank there, which is the same vacuum tank the Apollo astronauts used to walk down their little ladder onto the surface of the moon. After we were done with that, and it worked, we put it back in the airplane, took it to California. And there, we put it together with the warm part of the observatory. Made sure that it would focus and unfold and all that stuff. Then we put it back in the shipping container. And then we are sending it eventually down to French Guiana, through the Panama Canal, to the launch site. And this shows you the diagram of the rocket with a telescope at the top. And December 18th, this is what we're supposed to do. Someone pushes the button and it goes straight back out into outer space. It is going to be a million miles from us, around an area called the Sun-Earth Lagrange Point. And, well, it's an interesting place. Long stories. This is our scary movie. This is of how it will unfold in space. It takes about two weeks to do all of this. We unfold the solar panels 'cause we need solar power. We unfold an antenna to talk back to the earth. We unfold the umbrella, the structure that holds the umbrella. And from my perspective, as a scientist who will use this observatory, I think this is a miracle. From the perspective of the engineers who built it, this was a giant challenge. And from the perspective of the test people who say, prove to me that it's going to work after you get there, it's a big headache, because you have to be 100% sure, you have to make sure everything you can possibly do to test it has been done. At any rate, that's all been done, and it's all buttoned up to go to the launch site. And you say, well, how can you order something that complicated? And here's another confession to make. You could not order this telescope if we had never had a Cold War, were not fighting against the Soviet Union, and did not have to invent spy satellites, and anti-satellite this and that. So we depend on the capabilities of the defense industry to be able to realize something this complicated. So, how are you gonna make sure it works? Well you have to have two of everything. And you have to test it, and test it, and test it. So that's the big, beautiful golden bird, or golden flower. So how good is it? Well, we're gonna be able to see extremely well. If you were a bumblebee hovering at a distance of the moon, away from the telescope, we would be able to take your picture. And we will also be able to see everything else in the solar system from Mars on outwards, even if they're very bright. I'll show you what we're gonna look at, we're gonna look at that picture that the Hubble took, only better. See the first galaxies. We're gonna be looking into clouds like this, where stars are being born today, along with their planets. And we hope to see better. You see the visible picture on the left is quite obscured by the dark dust clouds. The dust becomes partially transparent, even with the infrared that the Hubble can do. And so this is how to look inside a dust cloud to see the birth of stars. We will be looking at the places in the solar system which might be alive, or might have been alive. So on the left is Europa. It's a little satellite of Jupiter, found by Galileo himself. We now know from having a satellite probe out there that it's covered with ice, and under the ice is a liquid ocean. And every now and then water comes spitting out between those cracks. And so if you could fly a probe through that water cloud that's coming out, you could ask, are there organic molecules in that water? That would be a hint that maybe something's alive in that ocean underneath. We're also going to this satellite of Saturn, we've got the geological map of that one on the right. This is a place where we've already landed a payload. And we know that the surface has got lakes and rivers, and craters. And those lakes and rivers are filled with liquid hydrocarbons. That's what rains in that atmosphere. And it has got enough atmosphere to be able to fly a helicopter. So we're also sending a helicopter out there. This would be a place to look to see, not only is there a sign of life, but does life have to be like what we have here, or could it be dramatically different? So we'll be looking at places like that. We will be looking at places like this. Every now and then, a planet may happen to go in front of its home star. And we know hundreds and hundreds of these where we know when it's going to do it. So if we're very good at this, we hope to be able to measure the effect of the atmosphere of those planets going around other stars. So we are planning to hunt for the signs of life. Not that we expect to see them, but we'll be hunting for them. Water, and carbon dioxide, and methane, and other molecules could be seen, in principle, by this method. So it'll take us a while, this is a hard project. So we're not going to be able to tell you right away after launch that this is true, but we'll try. So, how cool is this? Well, we'd like to know, is the earth special? Personally, my opinion is, yes. It's very unusual, among all the planets we've found, here in the solar system, and everywhere else. And so we don't know how special it is. That's one of the reasons we want to go look, see what's out there. But we seem to be special. Among other things, we have a big moon, we have a big magnetic field, and we have continents and oceans, and we have the continents zooming around as they float and bump into each other and plate tectonics moving. So it's a fascinating story of geology here on earth. And we don't know whether that's a necessary feature to enable life. So how far could we go? I do not know. We can send robots everywhere, and we already do. We have sent them to all of the planets, and lots of comets and asteroids. We've brought back some pieces of comets and asteroids and the moon, and we are planning to bring back some pieces of Mars. So it's hard, but it's interesting, and it tells us things we could never learn just from studying the earth. Obviously, computers are getting smarter. There will be a time when they can beat us at everything, including golf, I think. But that's gonna be tricky. And the big question will be, here in our world, who runs them? And it's probably not you and me. That makes us a little bit vulnerable. So if you wanna go to Mars, it's too bad for us, it's gonna be a very dangerous trip. And when you get there, at least the plans that we currently have, it's not gonna be a comfortable house, it's gonna be a very small house. And you'll be there with some of your friends, we hope you're still friends when you get there. If you wanna go to the nearest star, it's tough. It's gonna take, with any technology that we've been able to imagine, it's something like 100,000 years to get to the nearest star. So not that you wouldn't try, but if you are an intelligent robot and we're sending you out there, you could say, oh, I don't want to go. If you're that smart, why would you not have an opinion of your own? So that's gonna be an interesting challenge. I don't think what we've heard in science fiction stories is really gonna come to be. I'm sorry. So, now I wanna say a little bit about the perspective, where does astronomy fit into the science and history? So this is a fascinating book by Neil deGrasse Tyson and historian, Avis Lang. They basically say astronomers have been working with military stuff, all these many generations, ever since Galileo. And we'd like to be more aware that we are completely peaceful, but we basically couldn't do most of what we do if the military didn't need telescopes too. So it's even been argued that the reason we have all this wonderful technology at our fingertips these days is because we have been fighting each other all these many centuries. So I don't know if I like that idea, but it seems there is evidence for it. So I like to think that at least we're getting something useful and beneficial for all of people out of this process. So it's not as expensive as people imagined. When you say I'm gonna spend $10 billion on the Webb Telescope, which is about the American budget for it, it seems like an immense amount of effort, and cost. But nevertheless, when you compare it with what else is going on in the world, it's still small. The budget for telescopes is about two tenths of the percent of the worldwide space budget. So where's all the rest? It's all this stuff you use daily, and you don't think about it. Communication satellites, GPS, all the security systems that are up there. So, pretty interesting to think about the effect and our position in the world, as astronomers. We benefit from war even why we hate it. So a tricky question. Galileo sold telescopes for lots of purposes. So, what is gonna happen to us all? I do not know. My crystal ball is broken. But I like what James Lovell said after he went up and circled around the moon in Apollo 8. He said, this is it. If you think about it, you go to heaven when you're born. So, thank you for coming. I'll be happy to have some questions.

Sean Thackurdeen '12 Thanks so much, John, for that great talk. I think especially ending on this quote by Jim Lovell, it lifts up one of the comments in the chat here. One person in particular found it interesting that we didn't talk so much on the origins of the universe, and that mankind thinks in terms of beginnings and ends, but maybe there are no such ends, and the universe always was, and always will be. And I'm kinda curious to muse a little bit on that idea.

John Mather '68 Yes, I skirted around that a little bit, but actually, the different perspectives about the beginning, I tried to say, there is no first moment of the universe. Mathematically, we can't do that. If you try to imagine the expanding universe running backwards, you say, I go back and back and back, and things get hotter and hotter, and denser and denser. And finally, I run out of imagination. I just do not know how to go beyond extreme temperature and density. So you could call that the Big Bang, but it doesn't mean time began. We just don't know what it means. So as far as I can tell, the universe did not come into existence out of nothing. It has always been, it's just that the clocks only have ticked 13.8 billion years. But there was not a first moment. There was not a creation event, in the story that astronomers tell. And what happens later on? Well, the way that it looks now is the universe will continue to expand forever and ever.

Sean Thackurdeen '12 And that really gets to a few more pointed questions about, I suppose, various theories out there, and thoughts on the universe. So a couple of folks have asked your thoughts on the cyclic view of the universe by Professor Steinhardt, or thoughts on the multi-verse theory as espoused by Sean Carroll and Max Tegmark.

John Mather '68 Yeah, so both of those are fascinating ideas. And as far as I'm aware, there's very little that we've thought of that we could measure, to tell whether any of them is right. The cyclical theory says, well, maybe the universe has expanded before, and then collapsed, and come back in on itself, and bounced. And so, well, why not? How would you know? So right now, there's very little you can measure that would tell you if it did that. Scientists are arguing very heatedly about this, but that's my opinion. The multi-verse is a little different, and it suggests that maybe there are many universes connected, since we have at least some mathematical descriptions that say, this is how a certain quantum mechanical process could produce a whole universe. And so, how am I to say? The way that it looks, you would never know if the others were there. Conversely, you would have no reason to say they are not. So, that would be fun. Someday, we may have an idea that something you could measure. Okay.

Sean Thackurdeen '12 And questions are surfacing as well about the web telescope. You know, some of the risk to its success, and also, perhaps a nod to the complex systems that you mentioned earlier. But to what extent is the telescope, I suppose, repairable, or self-repairable after launch?

John Mather '68 Okay, well, it is repairable in the same way that the Hubble is repairable now, which is that we have two of everything where you possibly can. You know, when you have hundreds of thousands of little electronic parts, it's pretty likely that one of them will fail sometimes. So the best way to deal with that is you have two. It's unlikely that they'll all fail at the same time. So that's the method that we used when we fixed the Hubble last time. We do not have, currently, a capability to visit the web telescope to service it. We think we might, sometime. And so we have designed it so that we know how to latch onto it if we ever get a chance. But our main job is to make sure we don't need to. Yeah, it's risky. This is a very high stakes game. And so we think we've done what we should do. We have not said, that'll be okay, when we shouldn't. I tell people, you know, John Mather's opinion has no effect on hardware. Don't ask me if it's gonna work. You can ask me, did we do the things that it would take to find out if it will work? And I think I can answer yes, on that one.

Sean Thackurdeen '12 Thanks, John. But, kind of going back to the abstract and the metaphorical, I think some folks are asking, some of the most, I think important, or prioritize unanswered questions in astronomy, and would be glad for your thoughts.

John Mather '68 Oh, what are the most important questions in astronomy? Well of course, there are several big mysteries right now that astronomers are talking about a lot. As you know, we've got something called dark matter, that seems to exist, and has a lot of gravity, and is very important to our own history. We wouldn't have been here without it. We have named a telescope, actually the Vera Rubin Telescope in South America is designed especially to go measure that. She was one of the people who first noticed this effect. We are very interested in the dark energy, which seems to make the universe accelerate faster and faster. We don't have a reason to expect either of these things. We have plenty of theories that have them, and we have plenty of theories that don't have them. So the observation was a big surprise, in both cases. We currently have a discrepancy between the rates of expansion measurements. If you say, I think I understand this whole thing with the cosmic background radiation, and the rate of expansion measured with the galaxies, they are to match, but they don't. So that's a big mystery. I think there are others, which I'm hoping we'll get some results for from the new telescope. What happened right away after the Big Bang was, what were the first objects that grew out of that primordial material? Is it just the stars and galaxies that we know today, or was there something else? Closer to home, what about all those planets? Everything we know about planets around other stars has been a surprise. When I was young, people thought they weren't there because we couldn't imagine how they could ever be formed. Now we know they're there, but none of them are like Earth. So what's the matter here? What does it take to have a solar system that looks like ours, with an earth that looks like ours? We have no idea.

Sean Thackurdeen '12 Well, that similarly lifts up, I think one of the questions that was posed, which is, some of the information and discoveries you're most eagerly awaiting. And I think that that kind of speaks to that. One person has even, I think in the line of a philanthropist, is asking your recommendations for folks wanting to, I suppose, support inquiry into the origins of the universe, life, and consciousness, as you all described, with a certain amount of dollars, where would you allocate those resources?

John Mather '68 Oh my goodness. I do not have a good plan. I know the people that are interested in consciousness have a place to go to, called the Templeton Foundation. The foundation has given funds to support that kind of work. Actually, where I've been more interested in philanthropic things is to support scientists to learn how to work with Congress. Few years ago, Bill Foster was running for Congress for the first time as a physicist in Illinois. And he called up and asked for my endorsement. I said, sure, I'll be happy to endorse you. Tell me why you're doing this. And he gave me his story and I thought, I want more people like you to go to Congress. So how can I make that happen? So I've been sponsoring through the Society of Physics Students, which is a undergraduate organization, two summer interns for about eight years, to go down and work with Capitol Hill, and learn how that's done. And one woman said she was gonna run for president after that. She didn't do it yet. But they all say this is a fascinating thing to get into, and I think it's really important that scientists need to understand what's going on with politics. It's harder than it looks.

Sean Thackurdeen '12 Yeah. I'm really looking forward to the film, when John Mather goes to Washington.

John Mather '68 I'm not going, by the way. This is not something I know about. I just want somebody else to know.

Sean Thackurdeen '12 I think that initial slide that you had shared about the Big Bang, and I think misconceptions about it, I think many folks are asking for additional resources to how that they can understand that, I suppose the first instant.

John Mather '68 Yes, okay. I don't know a good place to go looking. I wrote a book with a coauthor, and when I looked back at it, I thought, we did not do a good job either on that one. The public and astronomers have been quite confused over, what is the Big Bang story? So the Wikipedia is awfully good about physics. But when I go there, I can always recommend that one.

Sean Thackurdeen '12 And maybe, this is one that gets to kids as well, how you have an incredible story, I think kind of growing up on a farm, and I think at a research station as well, But one person has asked, how can parents encourage their children to get interested in science?

John Mather '68 Oh my goodness. I think the essence of being a scientist is being curious. I just want to understand, I want to know. So wherever your kid is, say, well, what's under that rock? What do you think is behind that? How do you think that works? Can you go look at it? Can you dig it up? Can you measure it? Can you think about it? How does this go? And, I'm afraid that people think science is a big book of facts, but it's actually the opposite. It's a big book of questions. How does this work? How does that work? And it's a process that we have, where we engage in learning this. So, I wanna get evidence. I do not know answers. The sort of summary talk I used to give, my wife said is, I don't know, you don't know, we don't know, we all don't know. That was science. So I think that's an opening for children, because that's what we're all doing. We're all learning together here in the school of the universe.

Sean Thackurdeen '12 Thanks, John. And it seems we're right at time here. But wanna thank you for this incredible and illuminating chat.

John Mather '68 Okay. Thank you, Sean. Thanks everyone for coming. I love talking with you, and I think it's a fascinating topic.

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