Planetary Radio: Space Exploration, Astronomy and Science - Journey to the Center of Jupiter: Creating Fantastic Pressure With the World’s Largest Lasers

Episode Date: August 19, 2014

Physicist Gilbert "Rip" Collins of the Lawrence Livermore National Lab will tell us about recent use of the world’s most powerful lasers to recreate conditions at the cores of giant planets.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Hello, dear podcast listeners. It's been a long time since I've left you a special message. Just a quick one this time. I could ask you to support Planetary Radio and the Planetary Society, but I won't this time, at least not with your wallets. to us when you enter the contest or just send us a little note. Another place you can do that is in the podcast aggregator, whether it's iTunes or Stitcher or somewhere else where you listen to Planetary Radio. You can rate us, you can review us, and those things really count. They mean a lot to us. We have a higher proportion of five-star ratings in iTunes than any other podcast I've been able to find. Hope to keep that up. If you like what you hear, please consider doing this, either a rating or a review or both. We'd sure appreciate it.

I've got a great show for you this time. It's really fun, a fascinating interview, and you're about to hear it. So here's the show. Thanks for listening. Here's the show. Thanks for listening. Giant lasers and the bizarre cores of planets, 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. You might think I was talking

about two different topics in that opening teaser line, lasers, cores of planets. You'd be wrong. Today we go to the Lawrence Livermore Lab's National Ignition Facility, home of the world's most powerful lasers, where they are reproducing the fantastic pressures at the center of giant planets like Jupiter. Emily Lakdawalla previews a Martian encounter with a comet, while Bill Nye is collecting stardust, real interstellar stardust. Out there at the other end of the show, Bruce Betts is waiting in his office to tell us what's up. First up is the Planetary Society's senior editor.

Emily, first question, is our Earthling flotilla in orbit around Mars in any danger? The answer to that question is we think probably not. But just to be super extra safe, they're going to take the orbiters that are at Mars and hide them behind Mars during the closest approach of all the dust at the comet. Which resulted in this terrific graphic that we have up. It's part of this August 13th blog entry of Mars protecting the poor little orbiters. It's sort of funny because Mars has a bad reputation for what it generally does to spacecraft. But in this case, Mars is going to be helping our spacecraft stay safe. So no danger, hopefully, but you're still pretty excited about this. Oh, yes, because what we have now is a long period comet that's never been into the inner solar system before flying past a veritable flotilla of scientific spacecraft

that are poised and ready to do at least a week's worth of observations on this thing. What are they actually going to see? Will they see the nucleus of this comet? There's only one spacecraft that's going to be able to get us any detail on the nucleus of the comet, and that's Mars Reconnaissance Orbiter and its super high-resolution camera, HiRISE. But all of the

other orbiters, and even the rovers, are going to be able to take pictures that show us the coma and also study what happens when a gigantic comet coma impacts the atmosphere of a planet with an atmosphere. There's actually one mission that's going to be arriving there just before the comet gets there, whose sole purpose in life is to study the upper atmosphere of a planet. And the MAVEN team is so excited about being able to see what happens when a comet coma hits a planet. And that, by the way, is a mission, MAVEN, that we will be talking about on an upcoming Planetary Radio Live in late September. So stay tuned for that as well. In the blog entry, you've got a day-by-day

rundown of what will be happening. That's right. And there's a whole lot of different kinds of observations designed to study the coma, what its structure is, how it varies over time, learn the spin rate of the comet, learn how bright or dark the surface of the comet is, because all the comets we've seen so far to date have been extremely dark, but we don't know if they're born that way or they get that way on repeated passages by the sun. And this comet has never passed the sun before, so it could turn out to be bright. Finally, there's going to be a really awesome opportunity with the Odyssey spacecraft to image Mars and the comet in the same long strip, and I can't wait to see that. I hope it works. It's all coming up. Stay tuned. Serendipity and

orbit around Mars as a comet passes close by. Thanks so much, Emily. Thank you, Matt. She is the senior editor for the Planetary Society, our planetary evangelist, and contributing editor to Sky and Telescope magazine. Up next is the CEO of the Planetary Society, Bill Nye. Bill, it is a pleasure to talk to you this time across your desk at Planetary Society headquarters. Yes, here in Pasadena, California. And the exciting news is only 100 million years old. Bits of dust from a very aptly named spacecraft. Yes, from stardust. So the idea, everybody, we find meteorites here on the ground on Earth, and we've sailed through the plumes of comets, which are in orbits around our sun. But this dust, recovered from the Stardust spacecraft, is believed,

well, it has come from between the stars. And normally, the radiation out there, the pressure of sunlight and so on, makes this dust not last. It accretes, goes and becomes something else, vaporizes, is not there anymore. But this is only 100 million years old, and so it could give us, it will give us, another insight into those two questions. Where did we come from? Are we alone in the universe?

It's cool. It's a fantastic thing. Just that we have a spacecraft that can go out there, wander around, and come back with this stuff and put it in a laboratory. And wait, wait, there's more. The dust was found embedded in this capturing gizmo by regular people who work diligently as hobbies. Because it's tiny. Tiny.

And you've got to look at it with a microscope and see if you think what you see there is really interstellar dust. And they've identified seven particles, Matt. But here's the thing. It's like watching CSI, Crime Scene Investigation. If you find this dust, it came from another star, okay? If I may, like, deal. It's like the real thing.

And so this is where you can gain tremendous insights from tiny bits of evidence. Great talking to you, Bill. Thank you, Matt. the real thing. And so this is where you can gain tremendous insights from tiny bits of evidence. Great talking to you, Bill. Thank you, Matt. He is the CEO of the Planetary Society, Bill Nye the Science Guy. Stay tuned. We're going to go from bits of dust to the cores of giant planets. One of the very few ways humans have found to create thermonuclear fusion that doesn't blow away cities is with big lasers. The biggest of those lasers is at the Lawrence Livermore National Lab in California. Physicist Rip Collins will soon tell you how the National Ignition Facility manages to do this, but what RipIP will mostly

tell us about is the use of those fantastically powerful beams of light to reveal the terribly strange things that happen when matter is subjected to millions of times the pressure we feel at sea level here on Earth. This work has never before been accomplished in a way that accurately simulates the pressures found at the center of giant planets like Jupiter and millions of others in our galaxy. The results were described in a recent issue of the journal Nature. Rip Collins is one of the co-authors of that paper. I got him on the phone a few days ago. Rip Collins, thank you so much for joining us on Planetary Radio. My pleasure. I got to tell you that when I saw this press release, I just knew I had to talk to somebody up there.

It's science geek heaven. Giant lasers, refining quantum mechanics, and what is really happening at the core of giant planets. I mean, what more could you ask for? You guys must have been somewhat jazzed to be pulling this off. Absolutely. We get pretty excited when we come to work each day. I think the ability to not only look out at the night sky and look at the planets that we have in our solar system, but think about planets that are being discovered outside our solar system, and then try and take them apart with experiments in the laboratory, that's quite exciting.

Very exciting and very cool. All right, give us an introduction to this amazing device, first of all, called NIF, the National Ignition Facility. It is a massive laser facility. It has 192 beams with two megajoules of blue light that is used to illuminate a target, and typically the target is something that allows us to explore how to generate and control fusion energy in the laboratory. And this is a pretty simple story. You take hydrogen, a hydrogen shell, think about a tennis ball where the rubber is solid hydrogen. And because hydrogen is so light, it starts out at about a fifth the density of water. We're in California, so it sort of feels like tofu. And then at the center of that tennis ball is hydrogen gas. And the idea of this experiment is to compress

that tennis ball-like looking object, compress the hydrogen from a fifth the density of water to about one and a half kilograms per cc. So that's a hundred times the density of lead. So that's the essence of what we call inertial confinement fusion. So the dense hydrogen gets very, very dense. The inside of that tennis ball gets very, very hot. And that starts a fusion process that cascades to a burning thermonuclear wave that essentially produces a massive amount of nuclear energy. Very much as we see happening every moment on the sun. Absolutely. Here is a case where you've repurposed this incredible machine, replacing that hydrogen with diamond? Yeah, there you go. Well, one of the things that this facility offers is not only the massive amount of energy, but it also has an exquisite fidelity in how you turn the laser on in energy

and thus intensity as a function of time. laser on in energy and thus intensity as a function of time. And what that allows us to do is not only study very, very hot thermonuclear plasmas, but it allows us to squish solids and keep them solid to just outrageous densities. And we started with diamond because diamond has a few interesting material properties that allows us to squish the diamond and keep it from getting hot to very, very high pressures. Why was it important to avoid making this thing really hot as you put these incredible pressures on it? So I'm going to start talking about units. And for me to talk about units, I guess if it's okay, I'm going to take a step back and talk about what pressure is. Sure, please do.

Currently, all of us, we live at one atmosphere of pressure. And so all of the chemistry and material stuff that we're used to playing with is at one atmosphere of pressure. And pressure has a unit of energy density. So an atmosphere is just a good unit of energy density. Now, if we go to the bottom of the ocean, take a real deep dive, you can reach pressures that are tens to hundreds of atmospheres of pressure. And that's an important pressure range or energy density range because that is comparable to the energy density of what controls metabolic processes. So typical processes of life that we know begin to change.

If you go to a thousand or thousands of atmospheres of pressure, that's the energy density or pressure required to sort of crush materials that we're used to thinking about, like aluminum or other materials. That just is the pressure that one would apply to crush the crystal lattice. At a million atmospheres, then you have the energy density, which is comparable to a chemical bond. And so it turns out the center of the earth has pressures or energy densities on the order of 4 million atmospheres. So the chemistry in the deep interior of Earth is fundamentally different than the way

we think about chemistry here on the surface of Earth. Now, when you get to tens of millions of atmospheres of pressure, which is what we were exploring on these experiments at the NIF, you now start to fundamentally change the atoms themselves. And this is where the quantum mechanics actually begins to change from the ordinary way that we think about it. So when you have materials at these, what we call atomic pressures, the atoms all of a sudden begin to play a very different role than how they typically behave, even at the very center of the Earth. Physicist Rip Collins of the Lawrence Livermore National Laboratory.

He'll tell us more in a minute. This is Planetary Radio. Hi, this is Casey Dreyer, Director of Advocacy at the Planetary Society. We're busy building something new, something unprecedented, a real grassroots constituency for space. We want to empower and engage the public like never before. If you're interested, you can go to planetary.org slash SOS to learn how you can become a space advocate.

That's planetary.org slash SOS. Save our science are at planetary.org slash B-E-N-N-U. You can submit your name and then print your beautiful certificate. That's planetary.org slash Bennu. Planetary Society members, your name is already on the list. The Planetary Society, we're your place in space. Welcome back to Planetary Radio. I'm Matt Kaplan. Physicist Rip Collins is telling us about pioneering work at the Lawrence Livermore Lab's National Ignition Facility

that has used the world's most powerful lasers to subject that lovely form of carbon called diamond to fantastic pressures. Pressures that would be found in the cores of giant planets like Jupiter and elsewhere in the universe. like Jupiter and elsewhere in the universe. Ripp and his colleagues are seeing strange, even bizarre effects that do not quite fit even the already bizarre predictions of accepted theory. You know, historically, if you opened up your chemistry book from high school or college, all of the phase diagrams, the way we thought about how materials behaved at very, very high pressures is we would squish something like carbon, and the outermost electrons on the carbon atom would essentially get confused as to whether or not they belong on the near carbon atom or the neighboring

carbon atom, and they would go into what we call a conduction band. And those electrons, which we call Fermi electrons, essentially control all of the mechanical and electronic behavior of matter. Essentially, high-pressure science was incredibly simple. So you squish something, electrons pop out, they move into a Fermi C, and those Fermi electrons control all of the physics, and the atoms, the cores, essentially stack into the closest packed structure you can imagine, and that's the way everything behaved. Now, it turns out that at these exotic pressures, exotic things are now predicted to happen. And instead of matter compressing to these very close-packed structures,

it's thought that the electrons, the core electrons, essentially get squished into interstitial sites. essentially get squished into interstitial sites. They pair and produce something like an ionic solid, which adds a degree of complexity to the structure that no one had predicted 10 years ago. Wow. Now, all of a sudden, physics fundamentally changes. When you say the core electrons, these are the electrons that that atom would not normally share as part of a chemical bond? Absolutely.

Absolutely. Typically, we think of the valence electrons as being the big players in science. And Fermi electrons, I mean, that's named for the great Enrico Fermi, who I guess thought a lot about this kind of stuff. Absolutely. Yeah, he sort of developed much of the framework and how we currently still piece planets together, theoretically. You're basically showing what has been suspected, I think, that what's happening at the center of giant planets, and we know that there are lots and lots of these around the galaxy

because we've found hundreds of them, is a pretty strange place. Yeah, I guess that's the most amazing thing is we live in a universe that is filled with this exotic material all around us, and we never knew it existed. What does this tell us, if anything, about how planets form. In essence, this really provides the first exploration into the deep interiors of these massive exoplanets, as well as Jupiter, Saturn, Neptune, and our own solar system. In some sense, it really just paves the way for being able to make and recreate those states in the laboratory so that now we can explore them with very high-fidelity tools, typical tools that one might use in a material science lab on a benchtop. But we have to do the experiments very, very fast, right?

So faster than a billionth of a second. That's the trick. So is there a lot more to be done with this work? Oh, yeah. Oh, yeah. I mean, in some sense, what we did was we squished carbon to these incredible pressures, and what we found was that, in fact, carbon is incredibly stiff at those very high pressures, much stiffer than we would have expected.

And what lays before us now is an exploration of the atomic structure, the electronic properties, and really what the chemistry is in detail at those conditions. And only then can we really start to put everything together so that we can have a pretty good detailed model of the structural components of planets. You know, scientists have woven together a series of constraints that we believe are pivotal at allowing life like ours to form on Earth. And so the question that is quite natural is, do those constraints or are those constraints matched on these other planets? And that only can be answered

by really a detailed understanding of the materials at these extreme conditions. That's a direction that would be really beautiful to, you know, push. This work, from the sound of it, goes far beyond this work on the cores of giant planets. It really has something to tell us about the structure of the entire universe. That's the way we think about it. We're just about out of time. I just want to see if you want to comment about what this

also seems to say about the serendipitous nature of basic research and building big, expensive machines to do that basic research, that it may take you in directions that probably weren't expected when NIF was first built. Well, that's a lot of pressure on science and the funding of big science because it's typically sold on a monolithic goal. And this particular facility was built and run for a major component of developing and controlling fusion energy. I really believe that over the next decade, the science that will be really most profoundly impacting humans, we haven't thought of. And I think that it may not have anything to do with the type of work we're doing or the fusion work, but it'll be something that some young kid comes along and thinks up. The unknown unknowns. Oh, that hurt. Yeah, I'm sorry.

Sorry to, I won't even attribute that quote, but it does seem appropriate. Thank you so much. This is absolutely, as I said, utterly fascinating, and I'm so glad that you could join us on Planetary Radio. My pleasure. We've been talking with Rip Collins. He is a physicist at the Lawrence Livermore National Laboratory, not too far away from me, up in Northern California.

He is a co-author of this paper, which was published in the July 17 issue of Nature. The title is Ramp Compression of Diamond to 5 Terapascals. Title is Ramp Compression of Diamond to 5 Terapascals. We will have the link to that abstract on the show page that you can get to from planetary.org slash radio. Up next, a look at the night sky, theme today, I am sitting in the Director of Science and Technology's office. That's Dr. Bruce Batts. It's great to see you in person, just as I did Emily and Bill. Get out of my office.

I will, in good time. In good time, my lad. All right. Remember when you said something about your favorite superhero or the best superhero? Yeah, kind of. Well, we did get a response, actually. You didn't ask for them. Nicholas Schmidt in Lompoc, California.

He said Star-Lord, the old one from the 70s with the awesome space opera, because he became an astronaut just to hunt down the aliens that killed his mom. That's a nice plot. Very intense. It's not quite Shakespeare, but okay. Maybe it was written by Shakespeare. Star-Lord. I like it.

Verily. All right. You can tell I have the microphone going back and forth this time unlike our usual format i'm going to keep it over by you as you tell us what's up maybe next time i'll do it in shakespearean iambic pentameter but this time i think we're going going boring so pairs pairs of planets is what we got going on this uh this week or two if you look in the pre-dawn east, very low. Venus and Jupiter just coming off being less than half a degree apart, and they will separate pretty rapidly. So catch them over the next few days. Two brightest planets. Venus is the brighter one. Venus is heading down out of view

over the next few days and weeks, and Jupiter is heading up into the sky higher and higher. In the evening sky, with the closest point being August 27th, Mars and Saturn growing closer together through August 27th, then growing farther apart. Mars looking reddish, Saturn looking yellowish, and they're hanging out. It's pretty cool. Look in the south in the evening sky for Mars and Saturn.

We move on to this week in space history. So in 1975, in this this week Viking 1 was launched. In 1976 in this week Luna 24 returned samples from the surface of the moon and in 1977 in this week Voyager 2 was launched. Big week. Big week. A lot of other stuff not even getting to. A lot of space stuff happened this week. Speaking of space, we move on to... Space Fact! We have a minute or maybe 30 seconds until everybody runs over to your door to find out if you're okay. I had to go especially loud since we're in the office today.

So Triton, the big moon of Neptune, if that was interesting, was discovered only 17 days after the discovery of Neptune. Discovered by a different astronomer, by a British astronomer, William Lassell. Thank you. We'll go on to the contest. All right. In the trivia contest, we asked you, who was the first Mars

rover named after? How'd we do, man? Wow, this is really interesting, because I knew the rover's name. I had forgotten who it was named after. Our winner this week, should he be correct, is Ray Bonner of London, the real one across the pond. He said the Sojourner Rover was named after Sojourner Truth, the American abolitionist and civil rights writer. It is currently residing at the Carl Sagan Memorial Station on Mars. It is indeed Sojourner Truth out of one of the many naming contests the Planetary Society has actually helped run with NASA and projects. That was the other thing that I didn't know, that we had had a part in that, that we got

these 3,500 essays from kids all over the world. Indeed. By the way, Ray says that he listens to planetary radio when he's writing in the tube, which people do in London. That sounds painful. It probably is, but not as painful as what Ryan Broger goes through in Hartford, West Hartford, Connecticut. Get this fun fact. Plan Rad podcast made my last dentist visit much less painful.

Wow. I knew we were used for sleep problems. I didn't know we were used as an anesthetic as well. We're happy to help. We're often either a local or a general anesthetic. I think a general, usually. Yeah. I don't know.

You're going to like this one. It's from Stephen Coulter, a regular listener. He says, just happens I have both the initial and mission completed Hot Wheels set of the Pathfinder Sojourner mission. Cool. I have those too. Do you really? Yeah.

Are they here at the office? Can I see? Can I see? Somewhere, but they got buried in a box right here. We have curiosity right up here that, you know, the new stuff, but see, there it is. But Pathfinders in the broken spacecraft box. You leave them in the package like you are curiosity? Well, yeah, because I don't want them to get damaged because, you know, Martian environment. Yeah, right. Why didn't they think of shrink wrapping the actual Curiosity? I think they did, actually.

All right. What do you got for next time? What were the names of the five pocket mice flown on Apollo 17? Apollo 17, little known fact, flew five pocket mice to the moon and back. What were their names, at least according to the astronauts? Go to planetary.org slash radio contest. And you have until the 26th, the 26th of August,

at 8 a.m. Pacific time to get us that answer. Can we get extra points if they tell us whether they were in Neil or Buzz's pocket? Apollo 17. Oh, Gene Cernan's pocket. Okay. Just for the record, they weren't in anyone's pocket. The astronauts didn't even interact with them during the mission. They shunned them.

I don't think it was their choice. But anyway, people can tell us all about it when they enter the contest. Say goodnight, Bruce. Alright, everybody go out there, look out at the night sky, and think about ways to keep Matt out of my office. Thank you, and goodnight. No, really, thank you. Ain't gonna happen. He's Bruce Betts, the Director of Science and Technology at the Planetary Society. We just visited with him for another edition of What's Up.

You know that Stardust story that Bill and I talked about? You can learn more in an August 15 blog entry from Bruce. It's all at planetary.org, of course. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by the stardusted members of the Society. Clear skies.