Planetary Radio: Space Exploration, Astronomy and Science - Building a Better Galaxy With Javiera Guedes

Episode Date: September 26, 2011

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How to Build a Better Galaxy, this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Javier Aguedes is the brand new Ph.D. who is lead author of a paper that documents the creation of a galaxy called Eris. The twist is that she and her colleagues created Eris themselves. It took nine months of number crunching on a NASA supercomputer, but the resulting model is the first that looks like a galaxy out here in the real world.

I'll ask Javier how they pulled it off. Bill Nye finds the good, the bad and the ugly in the latest news about NASA's budget from Washington. Emily Lakdawalla reports that Japanese scientists have nearly written an asteroid's life story based on a few microscopic bits of dust returned by the Hayabusa probe. Our Big Finish will find Bruce Betts wearing his new Star Wars T-shirt. You'll get an even more coveted Planetary Radio T-shirt if you win the new space trivia contest. We'll start out this time with Bill, who was on his way to L.A. International Airport when we got the chance to talk. You sure spent a lot of time flying around places.

Well, I'm en route to Texas to the Hispanic Engineering Science and Technology Conference. We're going to get these young people in the pipeline so that we have scientists and engineers for a better tomorrow for all humankind. No big deal. And next week, I think we're going to be able to, if all goes well, talk to you in South Africa. Yeah, next week is the International Astronautical Congress, which this year is timed exactly with the anniversary of Sputnik, October 4th. And it runs all next week, and this year it's in Cape Town, South Africa. And it's really a wonderful event where you get people from all over the world

who sit down and talk. These are people that build rockets, people that build spacecraft, and people that share this optimistic view of the future through space exploration. It's a good meeting. Anything else you'd like to talk about? Well, I just thought it was big fun in the U.S. Congress. They are still going through all these machinations about the space launch system, the next rocket, which is going to have so few launches per year,

it will be a very expensive undertaking if it doesn't get canceled but the good news is the james webb space telescope is funded again and this is the kind of thing yes it's very expensive yes it's over budget yes this has gone wrong that's gone wrong but this is the kind of mission that we humans should be doing. This is ambitious. This, as the saying goes, increases the awesome and decreases the suck. This really is a fantastic thing. I'm glad that the United States government stuck with it and is doing it. Speaking of the U.S. government, you know, the upper atmospheric research satellite came down, UR's. It had no way to bring itself down.

And I mention this because, you know, the Planetary Society, Matt, what are we excited about? Well, among other things, solar sails. That's right. The solar sail, this would be pushing a spacecraft around with photons. But you could also use the same sail, after you're done flying around, you could use it for a drag break and pull a satellite like the Upper Atmospheric Research Satellite down without the need to carry all that fuel all those years and the unreliability that can result from having valves that stick and so on. So it's a big week in space news, Matt. It's exciting to be part of it.

Thank you, Bill. And may you have an efficient and very safe journey both to Texas, and we look forward to talking to you from Cape Town next week. He's Bill Nye, the science and planetary guy, the executive director of the Planetary Society, and he joins us every week here on Planetary Radio, as does Emily Lakdawalla, the science and technology coordinator for the Planetary Society and the editor of its blog. Emily, good to have you back, as always. Let's start with these results from a Japanese probe that looked like it had absolutely nothing inside it when it came back. Yeah, of course. This is the Japanese spacecraft Hayabusa, which traveled to a near-Earth asteroid named Itokawa and had quite the star-crossed life in the solar system. But through a great deal of struggle and perseverance,

they brought the spacecraft back with a sample catcher that when they opened it up looked completely empty. It really didn't seem like they'd brought anything back after all of the work that they'd done to get there and back. And yet they found 1,500 microscopic particles by scraping it with a Teflon spatula. And then they found some slightly larger particles by turning the sample

canister over and whacking it with the handle of the screwdriver a few times, which just makes everybody laugh. But, you know, I guess engineers always know how to make something work in the end. And then whacking things is often the answer. Anyway, I assumed that this amount of material with particles that were so small that they would be struggling to get any scientific results out of it. But it turns out I was wrong. Modern labs can actually make quite a lot of science out of really quite tiny amounts of sample. The results published in Science Magazine last month actually allowed them to tell a quite detailed story about the history of Itokawa, how it formed, was probably a much larger asteroid when it first formed and got smashed to bits and recoalesced and stirred up.

And it's actually now kind of evaporating over time. It'll probably only be around for another couple hundred million years. Boy, a lot of knowledge to get out of almost nothing returned, but still enough to call Hayabusa a successful mission. Just one other thing to mention, and we'll call this the image of the week. You describe it as something that's becoming routine. Yeah, it's kind of amazing to think of it as being routine. But now we have a spacecraft in orbit around another planet that can take photos of other spacecraft that we've sent to the surface of another planet quite regularly. And the latest photo from Mars Reconnaissance Orbiter of the Opportunity rover sitting on

the surface of the rim of Endeavour Crater after its long drive. And, you know, as usual, I think the thing that always gets me is not seeing the rover, but actually seeing the tracks trailing behind the rover. That just boggles my mind. And that is a September 24 entry on the Planetary Society blog at planetary.org. If you want to read about

Itokawa and what we've learned about it from Next to Nothing, that was on September 20. Emily, thanks as always. Thanks so much, Matt. Emily Lakdawalla is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine. Stay with us.

I'll be right back, and I think we'll build a galaxy. Avi Arruguedes is a young scientist we'll keep our eye on. She just earned her Ph.D. in astronomy and astrophysics from the University of California at Santa Cruz. Her legacy already includes lead authorship of a paper accepted by the Astrophysical Journal. already includes lead authorship of a paper accepted by the Astrophysical Journal. It documents the birth of Eris, a simulated galaxy that looks and behaves more like a real galaxy than any other model. It wasn't easy to create the model in computer code,

as you'll hear in my conversation with Javier at her current institution in Switzerland. But massive mathematical simulations are clearly her passion. The poor quality of our Skype connection didn't keep me from thoroughly enjoying the discussion. Javier, thank you so much for joining us on Planetary Radio. Thank you for the invitation. And, of course, I first looked for you at UC Santa Cruz, but that's not where you are at all. How is it that you ended up there at the Institute for Theoretical Physics in Zurich? I'm actually at the ETH in Zurich. It's 10 miles from the Institute. The whole work I did for my PhD

was done at UC Santa Cruz. The day after my graduation from my PhD, I actually came to Zurich to take a postdoc position here. The postdoc offer from the Swiss people was, I couldn't resist. I don't blame you. Congratulations on leading this work, which has apparently created the first simulation of a galaxy or the formation of a galaxy that really seems to look like nature. And I'm looking right now at a beautiful rendering of your galaxy. So I guess you're in the business of building galaxies. Yes. So I'm in the business of simulating things in general. So the first simulation that I did was on the formation actually of planets of the size of the Earth around Alpha Centauri,

which was a hot topic at the time. And we actually found that in all our simulations, planets could form there. There's actually a team of people working in Chile to look for those planets. I hope we find them that close by. I'm really hopeful, yeah, that the observations are going to take quite a while. But if we do find a terrestrial planet around Alpha Centauri, that would be a big deal. And so, yeah, in the business of simulations in general, I've simulated planetary systems, I've simulated black holes going around galaxies, and this latest simulation was on the formation of the massive spiral galaxy that moved away. Why did you name your galaxy Eris?

Because in the scientific community, there was a big dissonance about what would actually be done through simulations like this. And there was a large group of people that were trying to simulate galaxies like this, and they just wouldn't come out right. When we managed to run a simulation that actually reproduced what we see in reality, we thought we would call the simulation Ares because Ares is the Greek goddess of discord.

Very good. We knew we would cause some trouble. Well, you are causing trouble because your galaxy is much more like what we see in nature. In fact, it, I guess, has real similarities to our own galaxy, the Milky Way. Is that fair? Yeah, so it's slightly on the low end in terms of mass for what the value of the Milky Way is thought to be. But in terms of the ratio between the disk and the bulge, for example, the Milky Way has a very extended disk and a small bulge.

So in terms of the ratio between those quantities and in terms of the distribution of the stars in the galaxy, I think we're doing a pretty good job. So what is it about this model, this simulation, that allowed you to do so much better than many, many people who have tried doing this in the past? Basically, we took a really high risk, particularly because I was, you know, trying to get a PhD out of things like this. And the risk was on just running a simulation with an extremely high resolution. And that required that we use a lot of particles in the simulation.

So the mass in the simulation is tracked through particles. And that meant that the simulation took a long time to run. So this is a simulation that took nine months to complete. And this was on quite a large supercomputer. Yeah, this is on the NASA supercomputer at NASA Ames. And so this is not a simulation that you can do over two weeks or three weeks or a month. This is something that took an immense amount of time. And a few people were willing to not only to spend the time to do it, but I mean, imagine if after nine months, your

simulation turns out to be something completely ridiculous and that doesn't fit reality at all. You know, it's a very high risk project. That's why not many people were trying to do things like this. I also read in the press release that the model takes into account perhaps a more realistic simulation, not just of the galaxy itself, but of the stars that form it? Yeah, so we're not simulating reality here, but we're trying slowly, little by little, to approximate to what reality actually does. And what reality does is that stars form in

very dense clumps of gas, and this gas is very cold and dense. In the simulation we cannot reach the densities of those molecular clouds that we see in reality because they are too dense and too cold and we cannot resolve them basically. We don't have the resolution to do it. But previous simulations were forming stars in places where actually stars cannot form at all in reality. So in this simulation, what we did is by increasing the resolution, we reach higher densities in certain places in the galaxy, and those places are approximately more like the places where real stars form in nature. So that was the key. You really, even with this model, even with as difficult as it was to create,

you're not quite at the level of reality that we see all around us in the universe. No, not at all. Everything that we do in the simulation is an approximation. We can do approximations that are as good as we can do in order to finish the simulation in a realistic amount of time. can do in order to finish the simulation in a realistic amount of time. But nature, of course, does something with much more resolution, to put it that way. We don't have the resolution of nature.

That's Dr. Javier Aguedes, lead author of a paper about the creation of ERAS, the most realistic galaxy simulation to ever emerge from a supercomputer. We'll pick up the conversation when Planetary Radio continues. I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager. Then I joined the Planetary Society to become part of the real adventure of space exploration. The Society fights for missions that unveil the secrets of the solar system. It searches for other intelligences in the universe, and it built the first solar sail. It also shares the wonder through this radio show,

its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages, and I hope you'll consider joining us. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio Welcome back to Planetary Radio. I'm Matt Kaplan.

Eris is the somewhat simplified galaxy simulation that nevertheless looks and acts like the real thing. Javier Aguedes is the young Ph.D. who was lead author of a report about Eris and its creation. It will soon be published by the Astrophysical Journal. about Eris and its creation, it will soon be published by the Astrophysical Journal. Before the break, Javier explained how the inclusion of those giant clouds that become the birthplaces of stars was essential to the success of the model. But these stellar nurseries were not the only vital factor. What about dark matter, which has been implicated lately in the formation of structures like galaxies.

Yeah, so dark matter is one of the most important components in the formation of our galaxy. So the dark matter is in there from the beginning. So in the beginning of the simulation, there is only dark matter and there is only gas. And the distribution of the dark matter and the gas is from what we observed from the very early universe. We don't observe directly the dark matter, but we see the imprints in the light, particularly of the cosmic microwave background. We can estimate roughly what the distribution of dark matter looks like,

even though we actually don't know what it is. But we assume that it interacts with everything else gravitationally. And we put it in at the beginning of the simulation, and it's there throughout until the end of the simulation. And it's an extremely important part because basically it envelops the whole thing. So it's containing the galaxy together. Without the dark matter, it would have been impossible

to form a galaxy like this. You've already talked about what it took to actually run this model, the kind of computer horsepower it took. What did it take to create the model, to create the programming, the algorithms behind it? And do you think of yourself as sort of half cosmologist and half programmer mathematician? Actually, the code that was used in the formation of this galaxy was developed by a large group of people. Those people are spread all around the world right now.

They're in Washington, in Seattle, here in Zurich, also in the UK. So it's a very huge team of people that created the code. So basically, what we did was to use this code and prepare the conditions that we think were appropriate for simulating a galaxy like this. So going back in time, you know, basically millions of years after the Big Bang, and to put it all in together with the code, and that allowed us to run the simulation to today. But yes, it's a kind of combination of you have to be a little bit of a computer scientist and you also have to be a bit of a cosmologist in order to do things like this.

Yeah, no question. Do you know when the paper is going to appear in the Astrophysical Journal? I just got an email a second ago saying that it will appear in, I think, the next edition. Wow. Congratulations on that. Thank you. Listen, you are basically fresh out of UC Santa Cruz with a spanking new Ph.D. certificate on your wall. How is it that you came to be the lead author of this paper, work that is gathering a lot of attention? You have a team of people and everybody does the very important parts of the project.

But at some point, some person just takes the lead and begins to do most of the work. And actually, the paper itself was written by many of us, not just myself. So it was a very big collaborative effort. So because I was doing most of the analysis and running the simulation and things like this, we decided that I should be the first author. But it was really more, I mean, it doesn't really mean anything. The whole group worked together in the same amounts, you know. So it was a teamwork.

What is ahead for you? Is your future in Zurich, or is there a chance you'll be returning to California? I have a postdoc position in Santa Barbara for next year, and I have an offer from Zurich for six years. So I am supposed to be returning to Santa Barbara next year. And we'll be happy to have you back in California, but it sounds like you have some choices. And when you say Santa Barbara, you're talking about UC Santa Barbara? Yeah, UC Santa Barbara, the Calvary Institute for Theoretical Astrophysics.

So regardless of where you end up, more simulations in your future? Oh, absolutely. No doubt. Tell us, what would you most like to simulate? I mean, would it be refining this galactic formation model, or do you have other things in mind? Both. One of the most important things is to know what if we use even high resolution? What happens if we spend even more time in simulations like this? What happens

if we add more physics? And also what happens if we try to form even larger spiral galaxies or even elliptical galaxies that are nothing like spiral galaxies? Elliptical galaxies are big and massive and mostly red in color. So can we simulate those? And also another question that is very important is what is the role of black holes in the formation and evolution of these galaxies? Because most galaxies, as we know, do have a central massive black hole. You know, I should have asked, does Eris have a black hole in its core? Eris does not have a black hole. Earth does not have a black hole. The point is that people argue that sometimes you need black holes at the center in order to produce galaxies like ours.

But the result of this simulation shows that you don't need to have a very active black hole at the center. Maybe the function of black holes is to threaten galaxies that have even bigger masses. But at the mass range of the Milky Way is probably not necessary. But we are working on this, and we will run a version of Ares with black holes in the future. I wish you many more years of very successful simulation, and that you get closer and closer to what we see in the universe around us. It sounds like you'll be asking for a lot more hours of supercomputer time across your career. Yeah, no doubt.

Thanks so much once again for joining us on Planetary Radio. No, thank you, Matt. We've been talking with Javier Arguelles. She is currently at ETH Zurich, but she is fresh out of UC Santa Cruz where she earned her Ph.D. And that's where she began this work of simulating the galaxy that she and her colleagues call Eris. It is a galaxy that exists only on supercomputers and in beautiful images like the one in front of me, but it comes closer to approximating the galaxies we see around us all over the universe than any other simulation. And I'll be right back for a less-than-simulated conversation with Bruce Betts for this week's edition of What's Up. We're in the office of the Director of Projects for the Planetary Society.

That's Dr. Bruce Betts. So it's time for What's Up. Thank you for welcoming me to your home. Welcome to my spacious office. It's actually a little cramped in here. Did you see my really cool t-shirt? I did. Thank you so much for wearing that today. And I know that you did have friends on Alderaan. If you don't know the context, folks, you've got to listen to last week's show from Pat's, the Pacific Astronomy and Telescope Show. Up in the night sky,

Jupiter dominating the evening sky, super bright. Get a telescope. Not Alderaan. That explains the asteroid belt. Now you're going to make me all sad again. I'm sorry. Go ahead. No, seriously. Jupiter really bright. Pull out a telescope or even some steadily held binoculars. Check out the Galilean satellites, the four largest moons of Jupiter, which you can watch move from night to night, almost like they're real, and going around Jupiter as a planet. Yeah, and check out Mars.

It's still kind of dim and reddish, but it's a really cool planet. It's rising after midnight by an hour or two, but in the pre-dawn, it'll be up high, high, high in the east. We move on to this week in space history. In this week in 1958, NASA was founded. Ah!

People think we plan this stuff. Do they really? No. I didn't think so. And in 2007, the Dawn spacecraft was launched, now playing at Vested, doing cool stuff. After all these years, NASA's still doing some pretty cool stuff. Yeah. We move on to... Random space fact.

Love that. URs getting a lot of publicity the upper atmospheric research satellite slamming into Earth's atmosphere burning up in a fiery thing by the time people hear this they and we will have known where it came down and who upon right

we hope not we hope not or you're going to have to re-record this segment yes right we can't be giggling about it if it comes down on the White House or something. No, we already know. It's not coming down in North America. Oh, good. I didn't realize that they'd narrowed it down that far. Good for us. Yeah. Not necessarily good for everyone else. What's that town

Muammar Gaddafi is in hold up in at the moment? No, I'm sorry. You're confused. This is an uncontrolled reentry. I see. Anyway, thought people should know a little bit about it. It had quite the illustrious history. Launched in 1991 from the space shuttle.

As many people have been hearing, size and mass of a school bus coming into the atmosphere. It had 10 science instruments. Did all sorts of observations. A lot of them lasted all the way until they were turned off in 2005. Measured ozone, chemical compounds found in the ozone layer which affect ozone chemistry and processes. Also winds, temperatures in the stratosphere, as well as energy input from the sun.

Multi-talented. Multi-talented. And able to make really bright lights in the night sky at the end of its mission. Unfortunately not able to leap tall buildings. Depends on how you look at it. Let's go on to the trivia contest. I asked you, who discovered Saturn's moon Mimas? And I assume the answers were either Darth Vader or Grand Moff Tarkin.

Yes, because we know that Mimas has often been compared to that sinister battle station. Why, here it comes now. All right, who actually discovered Saturn's moon, Mimas? Why, it was William Herschel in 1789. It was his son, John, another very significant scientist in that period, the birth of modern science, who got to name it. And the big crater that makes it look so much like our friend the Death Star is named Herschel.

How appropriate. Yeah, that's great. Do you know, I know the stuff I got to drop this in because it's such a good book. The Age of Wonder by Richard Holmes. What a terrific book. And it traces this sort of beginning of modern science. And William Herschel is a major, major character in the first or second section of the book. So highly recommended.

And you want to know who won. I do, I do. First time, Kenneth Hudek. You say who? Hudek. Kenneth Hudek from Wheaton, Illinois, is going to be picking up the Planetary Radio t-shirt this week. We did hear from lots and lots of other people. Here's the quote that Curtis Lewis and a bunch of other people sent in. This is how William Herschel noted it in his journal the night he discovered it. The great light of my 40-foot telescope was so useful that on the 17th of September, 1789, I remarked the seventh satellite then situated at its greatest western elongation. Nice.

They wrote pretty in those days. Did he say anything about the feeling of evil or hearing ominous march music in the background? I think he did add that he felt a sudden ripple in the force, as if millions of people... Well, you know how it goes, I think. Again, you have to bring it back to Alderaan. All right, new trivia contest for you all. How many days did URs spend in space before its fiery plunge? How many days did URs spend in space? Go to planetary.org slash radio to find out how to enter. And you have until Monday,

October 3rd at 2 p.m. Pacific time to get us that answer. Okay. All right, everybody, go out, look up at the night sky. Think about your favorite color, red. Thank you, and good night. Did I ever show you the great bumper sticker that I've got? It's a red bumper sticker, but it says, if this bumper sticker looks blue, you're too close. He's Bruce Betts, the Director of Projects for the Planetary Society, and he joins us every week here for What's Up. Planetary Radio is produced for the Planetary Society, and he joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California,

and made possible by the Kenneth T. and Eileen L. Norris Foundation and the members of the Planetary Society. Clear skies. Thank you.