Planetary Radio: Space Exploration, Astronomy and Science - Dark Energy Attracts? Astrophysicists Jason Rhodes and Alina Kiessling

Episode Date: August 9, 2017

JPL astrophysicists Alina Kiessling and Jason Rhodes were brought together by their fascination over the mystery of dark energy. They talk with Planetary Radio about their research and the many missions they are contributing to, including WFIRST, a unique new space telescope.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Dark energy attracts? It does, this week on Planetary Radio. Welcome. I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. Mysterious dark energy makes everything in the universe fly apart from everything else at ever-increasing speed. And yet, it brought together our two guests, astrophysicist Jason Rhodes and Alina Kiesling. The married couple will also talk about future space telescopes, finding life on exoplanets, and airships. Airships? Yeah, really. Are you ready for the great American eclipse? We've asked you before. Bill Nye has some do's and don'ts, and Bruce Betts has a sublime random space fact lined up. Casey Dreyer is the Planetary Society's Director of Space Policy.

Casey, I wanted to bring you back to talk about developments in the budget. Congress making decisions about what NASA will have to work on for Federal Year 2018. It is one of the topics we cover in the brand new Space Policy Edition, number 15, that is now available for everybody, our Space Policy Edition for August of 2017. How does the budget look, at least with what the Senate has just decided? Well, the Senate proposed kind of a midpoint between the House's really good number of 19.87 billion for NASA and the White House's OK number of 19.1.

So they came out at 19.5. It has increases for the usual suspects, including the Space Launch System and Orion. It cuts science but preserves all of the proposed cuts to Earth science. And the difference is that all of those cuts are absorbed by Planetary Science Division, NASA. And so we've got a ways to go on this budget, but overall, kind of mixed news, but generally better than most other federal agencies are looking at right now. Any thoughts as to what might emerge from whatever compromise will have to be worked out with the House of Representatives? Well, generally what we have seen in the past is that the House's proposal for planetary science tends to win out in the end. This is not an unusual situation where the House has always gone first and the Senate has always countered with their own priorities

to the House's priorities. So it's part of the normal negotiation process. I'm not particularly worried right now. What does have me concerned is that we only have about 12 working days in Congress to pass a budget before the government would otherwise shut down at the end of September. So we have a timeline that is coming closer every day, And there is a lot of work to do between now and then. So we talk about this in quite a bit more detail in the Space Policy Edition. You want to give folks an idea of the other stuff that happens in this month's show? Oh, man, it's such a great show. We talk about the issues and the increasing tensions between Russia and the United States and how that could impact the International Space Station. And we have our very first interview with a sitting congressman, Rick Larson of Washington's

second district, to talk about space and the role of science and how that impacts congressional decisions. It's a really fantastic episode, as usual, because, you know, as my completely objective perspective here, the show gets better every time. So I really recommend people check it out. My feelings exactly. From my subjective position, this was a great show. It was really fascinating to hear your conversation

with the congressman. Everybody can tune in to it. Find it at planetary.org slash radio or as a part of the regular RSS feed that ships Planetary Radio out to all of our podcast listeners. Thanks so much again, Casey. I look forward to talking to you in September. Can't wait. That's Casey Dreyer. He is the Director of Space Policy for the Planetary Society. And he and Jason Callahan and I get together once a month, first Friday of each month,

to produce the Space Policy Edition of Planetary Radio. On now to the CEO of the Planetary Society, Bill Nye, who we catch on the phone in New York, where he is signing hundreds, maybe thousands of copies of his new book. Bill, I don't suppose you've seen the cover of last Sunday's Parade magazine? Actually, I did see it. I did. Yeah. Because I'm on it. Yeah.

With a couple of nice kids. And you've all got eclipse glasses. Since this is the last Planetary Radio episode that most of the audience will hear before the eclipse on August 21st, I was hoping we could talk a little bit about some of what the Planetary Society is offering to people so they can help them enjoy this. Well, if you want a pair of glasses that enable you to look at the sun, there are some links on our site. I have a long relationship with Educational Innovations, the company that sells the Bill Nye bobblehead. And there you can get the fabulous hard plastic frame glasses, which are just so stylish, so stylish. Anyway, you can look at the sun with these

glasses on. You can look at the sun anytime. The reason everybody's so concerned about people looking at the sun during the eclipse is because it's fascinating. Our tendency as humans is just to stare at it. And when you're staring at the sun for 10 minutes, you hurt your eyes. And there's an old myth that has some, let's call it a hypothesis that's reasonable. You know, the stereotype with the pirate and he's got a patch on his eye. It's generally believed that people trying to navigate at sea using what was called a quarter staff, which is like a sextant, only not as sophisticated, would be required to stare right at the sun for a few minutes every day. And it ruined your eyesight in one eye. But all that aside, the eclipse is going to be spectacular. It's going across the world's third most populous country to wit, the United States.

And this is a developed world country, the United States is, with an interstate highway system. So anybody who's really motivated can almost certainly get underneath this thing. It's going to be cool. You're going to be someplace, right? I am. I'm going to be at Southern Illinois University, which is going all out. It is the eclipse crossroads because it is the spot that will also be in totality in the 2024 total solar eclipse. But they have three days of celebration planned. We've got Planetary Radio Live, a big stadium show. It's going to be a blast. And you

will be at Homestead National Monument. Yeah. So, you know, this expression land office business, the Homestead National Monument helps us remember the importance of the Homestead Act, which enabled mostly European settlers to make their way across North America in a legal fashion. And the Planetary Society has a longstanding relationship with this national park. And it's going to be big fun. It's right in the path of the eclipse, and I will be there. And we will also have all sorts of fabulous Planetary Society things going on with the eclipse. And our Junior Ranger booklet will be available, and we recommend that everybody get underneath this thing. everybody get underneath this thing.

I'm reluctant to call it once in a lifetime, but it's really hard to have a total eclipse go right across. You know, normally eclipses are in the middle of the ocean or they're over polar regions. They're just hard to get to, but this one is easy to get to. And for all of the folks who will not be able to get to totality but will at least have a partial eclipse, we've got good stuff for you, too, at planetary.org slash

eclipse, including Bill's terrific series of videos that were produced specifically for this cosmic event. It's going to be literally cosmic, Matt. Thank you, Bill. I appreciate it, and make sure you wear those

glasses. I will, absolutely. Carry on, sir. We'll see you under the eclipse. Let's get dark. We won't see you. It'll be dark. That's Bill Nye, the CEO of the Planetary Society, preparing for the great American eclipse on August 21st. Me too. Another nice long conversation for you this week as we welcome Jason Rhodes and Alina Kiesling. They were first united by their shared fascination over the greatest mystery in astrophysics, dark energy. That common bond was given legal status when they married three years ago. Jason is a principal scientist at the Jet Propulsion Lab and is also JPL's project scientist for the lab's involvement with WFIRST,

the telescope that will follow the James Webb Space Telescope into orbit. Alina is a JPL research scientist working on WFIRST and several other missions, including some that Jason contributes to and that we talked about in a recent conversation at Planetary Society headquarters. Jason Rhodes, Alina Kiesling, thank you very much for joining us on Planetary Radio. Thanks so much. It's a real pleasure to be here. We're very excited to be here. Let me tell you about your special status.

As far as I can remember, you are only the second married couple to appear together on this program, the first being Linda and Tom Spilker. So congrats, or I guess I'll lean in your case, good on you. Thank you so much. I'm going to come back to that because there's a fun story about how you were brought together by something dark, dark and mysterious. But let's talk about some of the work that you have underway. You have similar interests, but you work on – there's some overlap, right, at JPL, but separate projects as well, correct? Yes. And I'm thinking, like in your case, Jason, of WFIRST, where you are the project scientist at JPL for WFIRST, the telescope after the one that will follow Hubble. I mean, so we've got Hubble up there now, JWST, which we just heard the launch may be delayed yet again into 2019.

Not the fault of the spacecraft this time, but a launch conflict. And then WFIRST. Tell us about it. It's come up on the show before, but remind us. It's come up on the show before, but remind us. WFIRST is NASA's next flagship, which is what we call missions that are quite expensive and ambitious in their science. And it's going to be launched in the mid-2020s. We're thinking around 2025. And it will have a number of science goals. One of the science goals will be to study the dark energy that's actually causing the universe to expand faster and faster.

Another science goal will be to find exoplanets, that's planets outside of our solar system, through a huge survey of the center of our galaxy, and we'll find thousands and thousands of these exoplanets. Finally, we're going to do coronagraphy, and that is where there's an occulter, much like the eclipse that's coming up, that would block the light from a star and allow us to actually study the planet that's orbiting that star in very great detail and take a spectrum of that planet and see what the planet's atmosphere is made of. And we have talked about these so-called star shades once or twice previously on the show. It is quite a piece of technology. And we need to

talk a little bit about some of the challenges that any mission would face trying to make use of one of these. But basically, it's an artificial eclipse. Right. Actually, WFIRST is not necessarily going to be using a star shade. It's going to be using what we call an internal occulter, which means the occulting of the star, the blocking of the. It's going to be using what we call an internal occulter, which means the occulting of the star, the blocking of the starlight is going to happen inside the telescope with this instrument called a coronagraph. What we are doing with WFIRST is we're trying to make sure it's compatible and ready for a starshade should NASA decide to launch a starshade in the 2020s. So we're not planning that yet, but we're trying to plan ahead to make sure that we could accommodate a starshade if one is approved.

And this starshade would be what we call an external occulter, where this big disk that actually looks like a flower flies about 30,000 kilometers away from WFIRST, flower flies about 30,000 kilometers away from WFIRST, and it's about 30 meters wide, and it would block the light from a star, but it would be just the right configuration to allow the planet's light to come into the WFIRST telescope. And again, that will allow us to study that planet in very great detail. You wrote about this not long ago for us. It was a June 23rd blog post about starshades that people can find at planetary.org. And we'll put up a link to that blog on this week's show page that you can find at planetary.org slash radio. Why are these starshades, why do they have that odd scalloped flower shape? The flower shape is to allow for a process called diffraction. If the star shade was

just a disk, light at the edge of the star shade would actually get bent by this diffraction process back into the WFIRST telescope. But instead, we have this scalloped shape that looks like a flower. And what this does is it diffracts the light or bends the light at the edges of the star shade away from the telescope. This is the starlight. We don't want any of that starlight getting into the telescope. And the reason is we need to block out the light from the star at a ratio of about a billion or 10 billion to one. That is, for every photon that comes from the planet, we have to block out 10 billion that comes from the star in order to be able to study that planet in detail. That's pretty impressive performance.

Yes. And it's technically quite difficult, and I should say technically challenging, but we've got the right people up at JPL and other places in the U.S. working on this. So as you know, my colleague, our board member Bob Bucardo, has his Planetary Post series. And within his new edition, just posted a day or two before we recorded this, he visits in the high bay at JPL where they're learning how to unfold these gigantic shades. It's like an origami project. Alina, you've seen it. Yeah, it's exactly like an origami project. They've actually employed a staff member in the Starshade Lab who did his PhD on origami and mathematics, and he's been able to help them designing ways to use origami techniques in order to fold out the star shade in a really efficient way.

Talk about the crossroads of art and science. Yeah, exactly. It seems to be there in this case. I want to come back to that internal occulture in a moment, but there are other challenges to making a star shade work. For one thing, this big, flat piece of stuff that has to unfold also has to be how far from the telescope that's actually going to do the imaging? Alina? For WFIRST, they're thinking about having a 30 meter diameter star shade that will be around 30,000 kilometers away from the telescope. But for

another mission that I'm working on, which is a study for the Habitable Exoplanet Imaging Mission. And this is a future mission that might launch in the 2030s. It's a much bigger telescope. It's got about a four meter diameter aperture. And the star shade we're considering for that is 72 meters in diameter and would be at around 100 to 120,000 kilometers away from the telescope. Good God. Okay. So the first thing that occurred to me when I heard about these was, all right, we've examined this one star system, didn't see anything alive there. Now we're going to slew to another one? Well, easy for the telescope, but that starshade is going to have to cover a lot of space.

That's exactly right. So one of the considerations when planning these missions is the path that the Starshade will take because you need to conserve as much fuel as possible. So it's a travelling salesman problem. You have your primary targets that you think are going to be the most interesting and then you try to work out the most efficient way for the Starshade to travel between them. But there will be weeks of slew time between when you do an observation with the Starshade and when you do the next observation, which leaves the telescope open to do a lot of other really interesting science beyond the exoplanet science, even for Habecks with general astrophysics as well.

Yeah, if you've got a four-meter telescope out there, in the case of Habecks, this more distant project that you're working on, I suppose you could get a lot more done with WFIRST as well. I would imagine that the alignment also is really critical between the distant star shade and the telescope. Exactly. That's one of the key challenges that is still being investigated. It's how to track the star shade when it's in front of your primary star that you're trying to observe. And then you need to keep it incredibly stable. So in the plane of the sky, you're thinking about movement of plus or minus one meter at really enormous distances.

But then you've got a little bit more leeway in terms of the line of sight. So we can be doing maybe a hundred kilometers or more with the separation in the line of sight, but on the plane of the sky. You're talking about the Y-axis, you've got a little bit more leeway, but the X-axis. Well, so the Z-axis really. Z, oh, of course, of course. Forward, back. Yes. Got it. And so it's X and Y that you have to do incredibly precisely. And this is one of the key challenges facing Starshade. We need really precise guidance cameras on the star shade to keep it in position and to react slowly enough to not move the star shade with a quick impulse. And it's a challenging problem that is definitely an active area of research. Is there reason to believe that these technical challenges can be met in the

timeframe that we're talking about here, possibly for WFIRST. Almost certainly you would need this right for Havix in the 2030s if we're lucky enough to get that mission approved. My answer to that is every day I go to work at a place that a few years ago landed a car on Mars using a crane. And so if you ask, is there a way to solve this technical challenge? I would say yes. My colleagues at JPL and our colleagues in industry and colleagues at Goddard Space Flight Center are working on this. And I think they're overcoming these technical challenges. They actually relish these challenges. There's a dedicated Starshade development program that's currently underway with the specific goal of increasing

the technological readiness of the Starshade in time for a WFIRST potential launch. So there is a specific program dedicated. All right, best of success with that effort. More immediately, though, back to that internal occulture that you were talking about, Jason, which, I mean, you were talking about the starshade might achieve that 10 billion to one contrast ratio. The internal one is no slouch, especially as I learned from your blog post, compared to what we can do today. Yes. Today we have coronagraphs that can do this contrast ratio of about a million to one. And the one that we're building now, are planning to build for W first, we'll be able to do about a billion to one. And that's going to open up some really, really interesting science. We'll be able to, for the first time, do direct

imaging of planets in reflected light. That is, the planets aren't giving their own light, they're reflecting the starlight, and that's what we're going to see. We'll be able to see planets down to about the size of Neptune and study those planets. We won't, with this billion-to-one coronagraph, be able to study planets the size of Earth in what we call the habitable zone, which is the distance from the star where liquid water could occur and we think might harbor life. where liquid water could occur and we think might harbor life. But we're going to take the technology a thousand times better and just one factor of ten less than what we'll need to actually study an Earth, which is something that we hope to do in the future, for instance, with HABEX. Not bad, three orders of magnitude, and then just one more to get to HABEX,

which is what we will need to get those images of Earth-sized planets. And maybe more important, the spectra. Talk about why. So we're very interested in getting the spectra of these exoplanets because that's where we're going to learn about whether there are signs of life on these distant exoplanets. of life on these distant exoplanets. So HABEX's goal is really to measure the spectra of these rocky earth-like planets in the habitable zone around sun-like stars and it will use both a starshade and a coronagraph to do this and it will measure the spectra and be looking for things like oxygen and ozone and methane and these are all indicative of life.

And if we're able to measure those kinds of elements with HabEx, it's one of the most exciting discoveries, I think, that humanity will have made because it's the first signs of life outside of our solar system. I sure hope I am around when those results start coming back. So here you are now, both having expanded your field of expertise to exoplanet research, but it's not where either of you started. There's a reason that dark energy keeps coming up on this show. Well, because I'm personally so fascinated.

It is such a baffling, exciting mystery. Each of you came into this business, I think, largely because you were interested in this, or at least you were interested in dark energy before you moved into exoplanets. Why is it so fascinating to the two of you? Dark energy was, I would say, discovered or named about 20 years ago. And for a long time, we thought we knew that the universe was expanding, but we thought that expansion was slowing down. And about 20 years ago, two separate groups of astronomers at nearly the same time actually realized that the expansion of the universe was speeding up. And dark energy is the name given to

whatever is causing that. So I like to say that dark energy is what we call our ignorance of what's causing this accelerating, expanding universe. We really don't know what it is. We don't know if it's that we don't understand gravity at the largest scales. We don't know if there's some new force in the universe. We don't know if there is some new component to the universe. in the universe. We don't know if there is some new component to the universe. And so what we're really trying to do with missions like WFIRST, Euclid, and the ground-based Large Synoptic Survey Telescope is gather the data that will help us constrain our ignorance of this dark energy phenomenon. And I got into dark energy because when I was in graduate school in the 1990s, that's when these astronomers were making this discovery of the accelerating expansion of the universe.

And I was one of the early pioneers of using this technique called weak gravitational lensing to study dark matter, which is a whole different phenomenon. Which we understand slightly better, I'm told. Slightly better. But it turns out that this weak gravitational lensing technique I was using is also very powerful for studying dark energy. And so that's how I got into dark energy. And ultimately, that's how I ended up meeting Alina. You were also interested in this weak gravitational lensing and something that has also come up on the show now and then using basically general relativity and the fact that heavy things, massive things bend light. You could use this to look at things that we might not otherwise be able to see. Exactly.

So weak gravitational lensing is where light from distant galaxies in the universe is traveling past very massive objects like galaxies and other clusters of galaxies and it gets bent around them and so we're able to see very very small shape changes in the weak lensing regime by looking at thousands of galaxies and seeing how they are aligned around these big lensing objects. I was interested in gravitational lensing and making computer simulations of this gravitational lensing, and I visited Caltech in 2006 and looked up some people that were working there,

and Jason was one of the people working at Caltech at the time. And we became friends and we stayed in touch while I was in graduate school in Edinburgh. And then I was able to get a job at JPL starting in 2012. And about a year after I started, Jason and I decided that we might like each other a bit. And the rest is history. Yes. As far as I know, you may be the first couple brought together by dark energy, which is normally not something that attracts. That's right. That's right.

Remind me. And you said that this show might air on August 9th. Yes. So I'll just let you know that's actually our third wedding anniversary. Oh, happy anniversary, folks. Thank you so folks. A little in advance as we're speaking, but as people hear this, they can join me in wishing you a very happy anniversary. Thank you very much. Back to the dark energy itself. You know the term cosmological constant, that thing that,

you know, Einstein came up with and then threw out because he thought, ah, this can't be the way things work. Are we any closer to understanding what dark energy may be after trying to figure it out for the past nearly 20 years? I would say we're not a lot closer to figuring out what it might be. Which I think is delightful, by the way. It keeps us employed, so that's good. We have been making ever more powerful measurements, and by powerful I mean greater statistical precision on our measurements. So what we're doing really is we're shrinking the error bars on these dark energy measurements. And what we are finding is that all of our results are basically consistent with a cosmological constant, which is the most simple explanation for dark energy. But we don't have a physical reason why there would be this cosmological constant pushing the universe apart. So we don't have an underlying understanding of the physical reason, but we are finding that it looks more and more like a cosmological constant.

But since we don't have any reason to believe it is, we think that it's still important for us to get smaller error bars, better precision on our measurements, because there are a lot of different theories that would look like a cosmological constant with the data that we have now. But if we get better data, we might be able to distinguish between these different theories. Jason Rhodes and Alina Kiesling of JPL. They'll return with much more in a minute.

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Welcome back to Planetary Radio. I'm Matt Kaplan, this week spending a few minutes with Jason Rhodes and Alina Kiesling of the Jet Propulsion Lab. Dark energy brought them together. Understanding it remains their goal, or at least one of the goals for this very busy couple. We were talking before the break about current thinking regarding dark energy. Is there the possibility that this is wrapped up somehow in the concept, also unproven, of the multiverse, that there is some influence from other universes. We find that we hear about the multiverse.

Lena is smiling and shaking her head. We do hear about the multiverse, but it's not what I'd call one of the mainstream theories that's really giving us anything predictive with the data that we have today, especially the dark energy data today. So a multiverse theory is not allowing us to make predictions and then go measure those in the dark energy regime. So it's not science, at least not yet. Not in what we do. I gather that there are some other astrophysicists and cosmologists who are starting,

I think, making the first attempts at defining some predictive things from the multiverse, but I don't think we're quite there yet. Alina, I hesitate to ask because I don't know whether you'll be able to explain this in terms that I and maybe some of our other less sophisticated listeners can understand. But you said something about simulations, and I saw prominently in your JPL resume this reference to n-body simulation. Is that the kind of simulation you were talking about? Yeah, so I used to work in generating these n-body simulations, and what they are is simply a dark matter only simulation.

So dark matter interacts only through gravity. And we approximate the density field of dark matter in the universe using these point particles that are approximating the density field. And so those are the N, the number of bodies. those are the N being the number of bodies. And so we have a simulation box that we fill with these point particles to approximate the dark matter, and then we switch on gravity and allow it to evolve over time. And gravity is actually a very simple thing to model. So N-body simulations are very straightforward to model when compared with

simulations that include normal matter or baryons, as we call it in astrophysics. Once you've got baryons in your simulation, the normal matter, it actually interacts through other means. And so there's radiation and light and heat and all of these other very difficult processes that we're not entirely sure how to model yet. So one of the ways that we try to understand the universe very simply to start with is just using the dark matter, which is challenging and annoying normal matter into the dark matter simulations using modeling techniques. Or we can run some more sophisticated and challenging hydrodynamic simulations that take a huge amount of time on the supercomputers. I was going to guess that this is a very complex model and probably you need some pretty heavy duty iron to run these models. Iron as in the element? Iron as in processing, sorry.

Oh, yeah. Old term, probably from railroading. Yes. So supercomputers are really essential in both in-body and hydrodynamic simulations. aerodynamic simulations. And it's one of the biggest challenges that we're facing for these upcoming surveys like Euclid, WFIRST and LSST, because we need so many simulations in order to prepare for these missions and in the analysis of the data eventually. We're having trouble working out how to collect all of the resources that we need for these three surveys, in addition to coming up with intelligent techniques to reduce the number of simulations that we need in the eventual

analysis of the data. And that's one of the things that I'm working on pretty prominently at the moment, trying to find areas of collaboration between these surveys and projects where we can share simulations and potentially work together to reduce these overall requirements. This is a fascinating point that had not occurred to me, that essentially the software, the algorithm challenges may be as great as the hardware challenges of building these spacecraft in starshades. Absolutely. And I don't remember when you used to do these simulations, you called them in-body simulations. Do you remember what in was? How many particles were in the simulations you did?

Typical simulations these days are coming out at a trillion particles. So these are very big simulations and there's not that many of them running. They're called flagship simulations. But a common large simulation today is one trillion particles. Like a flagship mission. We do know, though, apparently, that whatever dark energy is, it's pretty thin stuff, right? I mean, there isn't a whole, there isn't a lot of it. It's just that it fills the universe. That's right. Like gravity, it's actually a very weak force on its own, and it's only with huge objects or huge scales, cosmological scales, that gravity and dark energy start to become dominant.

The only reason our bodies are held on the Earth is because the Earth is this huge, huge thing, and, of course, our bodies themselves are held together by much stronger forces, the electromagnetic force. So it's only by studying huge swaths of the universe that we've been able to even make measurements of dark energy. However, there's a project that we're just thinking about now at JPL that might allow us to make what we call direct measurements of dark energy interactions

using actually single atoms in a special contraption flying within our solar system. So we would build an apparatus with an atom held very tightly, and we would see if we can shield it from gravity and then somehow detect the effects of dark energy. it from gravity and then somehow detect the effects of dark energy. But we still are very unsure about which dark energy models are the most correct or fit our data. And so there's lots of dark energy models where we could see some signal with this experiment, but there's lots where we wouldn't see anything. So we're still exploring that sort of theoretically. One atom held in vacuum? What, what, electromagnetically? Yeah, it's basically like that. This is a contraption that people are working on for other reasons at JPL and we thought, okay, this might work for a dark energy experiment. And here I've been impressed

with the LISA mission holding a much larger mass in the center of a field, I guess, or not in a field, in a spacecraft, the LISA Pathfinder mission, which has just been pretty successful, apparently, for gravity wave detection. or what we need to do this dark energy mission within the solar system. And so it's by seeing where that technology is going, where that technology is taking us, that some clever people have thought of new ways of using it to study different aspects of the universe. That's one of the great things about working at JPL. You see some technology and then there's somebody else that says,

oh, we could use this in this new way and things snowball. This is why it's such a thrilling place even just to visit. Time for a devil's advocate question, or maybe I'll call it an anti-science question. Why should we care? Why should we understand dark energy? Alina? It's a really good question, and one of the things that I will often say when people talk about why do we do this kind of research, I take it back to Einstein's general relativity. When Einstein was coming up with his theories of general relativity, nobody knew that that was going to lead to GPS satellite navigation

and to any number of fantastic things that we rely on and take for granted today. With our dark energy research, we don't currently know what it's going to lead to, but that doesn't mean that it won't be something that we rely on as essential to our daily life sometime in future. And so there's real value in pursuing these blue skies research things for potential commercial benefits down the road. But also just from a romantic point of view, understanding the universe that we live in and how it evolves and what's going on is better for humanity. Knowledge is power. If I think of some of the most profound questions that we can ask ourselves as humans, what is the universe made of?

And we know that it's mostly dark energy and then some dark matter and then the normal stuff. So understanding that dark energy and dark matter is part of one of the answers to one of the most profound questions we can ask. And, of course, another really profound question is, are we alone? And with this exoplanet research, we're trying to take the first steps to answering that too. So I feel really blessed that I get to work every day on what I find two of the most profound questions that I could ask or that anyone could ask. And of course, as Alina said, I think, who knows what the commercial applications are in the future.

I'm so glad that you used the word romance because I think that's very appropriate, the romance of this investigation. But it does bring me back to the romance between my two guests. And I'm just thinking if, you know, you probably at home have the same discussions all of us have about bills that have to be paid and groceries that need to be bought. And then does dark energy come up? Well, today we made this progress on the Euclid mission, which I want you to talk about in a moment, Alina. Am I right? Yeah, we certainly talk a lot about work. I think we're both each other's strongest advisor and advocate. Critics as well, I bet.

Probably that's true as well, yes. We definitely talk over the things that we're working on when appropriate. Jason is in a position sometimes where he has to not tell me things. I might be on the other side of a firewall, and it's kind of interesting. On WFest a year or so ago, Jason was working on something, and it ended up that I knew less than most people because he kept so much from me. That can be very bad for marriage, you know, Jason. She actually said, oh, I'm impressed you did that. I'm proud of you. That was your job.

You did a good job. And as she said, we're sort of each other's biggest advisor and critic and sounding board for ideas. And Alina described the romance of science, and we talk about that. But there's also, when you're talking about billion-dollar missions, not surprisingly, there's also some politics involved and some jockeying for position. And, of course, a lot of what we do, we have to apply for funding and grants and awards to enable these things. And so we're a sounding board for that for each other. You know, you should apply for this or this would help your proposal. We do quite a bit of talking about work things, both the romance and the politics.

quite a bit of talking about work things, both the romance and the politics. I would think that international missions, and most of them are nowadays, can be even more challenging on the political, the human, the administrative side. I mentioned that mission Euclid, which is a European Space Agency mission, but with great involvement by the US, much of it through JPL. And I know you're working on that, Alina. I don't know if this is one that both of you are working on or not. Actually, yes, both of us are working on it. So Jason is the U.S. lead for one of the science teams. He's also the U.S. representative on the Euclid Consortium board. So Jason's in Europe 10-ish times a year for the Euclid mission. I go to Europe maybe three or four

times a year for the Euclid mission. And it's really interesting to work on a NASA dark energy mission and a European dark energy mission. So the NASA one is WFIRST. Euclid is the European one. And then we've also got a Department of Energy dark energy mission, which is the LSST, Large Synoptic Survey Telescope. These three missions, they all have very similar goals, but they're being run by different agencies. And it's really interesting to see the differences in how all of those missions are being prepared for. And each one has a different way of doing things. And it's been fascinating to learn. Jason, what is Euclid? Is it similar to WFIRST? So Euclid is a smaller telescope than WFIRST. WFIRST will have a two and a half meter

mirror. Euclid will have a 1.2 meter mirror. Euclid is going to dedicate its six-year lifetime completely to dark energy, surveying about 15,000 square degrees of the sky. That's about a third of the sky that Euclid will survey, both in optical and near-infrared colors and spectra. So we'll get spectra and what we call photometry, just straight pictures of the sky. If you want to compare to something, Hubble Space Telescope in its almost 30-year history has probably surveyed 20 or 30 square degrees of the sky. And we're talking about with this new Euclid Space Telescope starting in about 2021, we're going to survey 15,000 square degrees of the sky.

And that's actually how we're going to get the statistics we need to really, really nail down some of these dark energy theories with Euclid. So we're very excited to be part of Euclid. NASA is providing the infrared detectors, the infrared camera for Euclid. And in exchange, we have about 80 U.S. people working in Euclid and Exchange, we have about 80 US people working in Euclid on the science side. What's your involvement, Alina? My involvement these days is really thinking about how to get the cosmological simulations that we were talking about earlier. It's difficult for any one of the surveys to do all the simulations by themselves. And so my particular role has been in coordinating between Euclid LSST and WFIRST and trying to determine the types of coordination that might be needed

in order for all of these missions to get what they need and to share their resources. And so I'm co-leading a task force at the moment that's writing up some recommendations that will be given to the agencies, NASA, NSF and DOE, as well as the leads of the projects, LSST, WFIRST and Nucled, giving recommendations on where they should be putting investments and forming collaborations and sharing agreements in order to get all of the supercomputing resources and simulations that they need. Tremendous amount of coordination required. You've brought up this telescope, ground-based telescope, LSST.

It's come up two or three times now already. And speaking of cameras, I saw a spec for this telescope, which will be online apparently pretty soon. Now, I think of my little home camera, the one that's still a dedicated camera. I think it has 12 or 14 megapixels. How many megapixels on the camera on this telescope that's about to come online? 3,200 megapixel camera is what the website said. So that's 3.2 gigapixels. Yes. Good Lord.

That's one camera? I mean, how big is that chip? You never build a very big chip. And so what they're doing is they're taking many, many of these chips or CCDs and what we call mosaicing them together. Yeah, because silicon wafers are only so big. That's right. And the other thing, of course, is if one of those chips dies, you want to be able to swap that out and swap in a new one. This is one of the huge benefits of a ground-based

telescope, that if a chip dies, a camera dies, somebody can fly down to LSST, which is being constructed in Chile, and swap that in. With Euclid or WFIRST, if one of those chips dies, a camera dies, somebody can fly down to LSST, which is being constructed in Chile, and swap that in. With Euclid or WFIRST, if one of those chips dies, we just have a dead part of our camera because there's no flying up and swapping out a single chip. Like a bad pixel on my laptop's display. That's right. I'm going to be stuck with it. And we will certainly have bad pixels. And to take care of that, one of the things that we do, actually with any of the telescopes on the

ground or in spaces, it's called dithering. It's where you take a picture and you move the camera a little bit and take another picture and then move it again and take another picture. This will happen four times at each pointing on the sky for Euclid, between 10 and 20 for WFIRST, and hundreds of times for LSST because they'll keep coming back to the same area of the sky. And that way you always have a good pixel on each area of the sky at least once. There is only one additional project

which I am so intrigued by because I know next to nothing about it and only discovered it as I was doing my research on the two of you and it popped up for both of you. And I don't know if you know the one I'm talking about, but it's called the 2020 Airship Challenge. Okay, exoplanets, dark energy, that I understand, but airships? Right. So what we are trying to do is we are developing a challenge where NASA would put up prize money for companies or universities or whoever to go build an airship, which people don't usually use the term airship, but I think everyone knows what a blimp is. kilometers and we want something that would be able to stay up in the initial stages just for one day, 20 hours or so. And this is where the 20-20-20 comes up, flying at 20 kilometers with a 20 kilogram payload for 20 hours. We want to incentivize that because there's a lot of science that could be done with either a telescope that looks up at the stars or some instruments that look down at the Earth at these what we call stratospheric altitudes.

And the way we sort of stumbled into this is I've been working on this WFIRST project under one name or another. It changes names and it changes focus. But I started working on a dark energy space mission in 2002, And we're hoping to launch WFIRST in 2025. So by the time it launches, I'll have been working on it for over two decades. And that's a really long time. And we're hoping with something like carrying a telescope on an airship to the stratosphere, you get some of the benefits of almost being in space. But we think you could do this on timescales of a few years. It doesn't take the decades that a space mission takes to plan and

execute. When might this challenge be opened up to institutions and the public to apply? Jason and I have been working on developing this challenge for the last couple of years and we're really just waiting on NASA headquarters to have the kind of funding available in order to go ahead with the challenge and there's definitely still interest in pursuing the challenge and we actually received an email this morning asking about it so people are definitely interested in the challenge, but it's a matter of funding because building airships isn't cheap. And so we need to make sure that the prize money associated with winning the challenge is commensurate with the amount of money that it would take to participate in the challenge. Within both the earth science and the astrophysics

community, there's enormous interest in having this kind of capability available particularly because airships unlike balloons would be able to maintain a station over a single point on the earth and so for earth science being able to do the diurnal cycle observations so observing through a day night cycle would be really exciting. And geosynchronous orbit is one of the more expensive orbits to launch a satellite into. So hopefully this would open up a cheaper way of doing those persistent long-term stairs. Yes, geosynchronous also being much, much higher, far above the stratosphere. And I'm thinking of planes like SOFIA, that big 747, which is also not cheap to run, but also can't hang over the same spot for 20 hours. Exactly.

And while we talk about 20 hours as being the first step in our challenge, the challenge would also have a second step, which would be 200 hours, which is a little over a week, with the goal of hopefully having these airships airborne for months at a time if they're successful. And there's a long history of the military trying to develop these stratospheric airships. And ultimately, they had some requirements that were really too difficult. They wanted to be able to remain stationary in very, very high winds with huge payloads. to remain stationary in very, very high winds with huge payloads. And it's very difficult to develop the materials to hold the helium in the airship. And so micro tears were meaning that attempts were causing these airships to not maintain their altitude. And when the military pulled out, they discontinued the programs. And so we're really trying to make sure that we can incentivize the companies to finish the development in the name of science.

You share the most fascinating lives or life. Did it occur to either of you back before that fateful meeting when Alina, you looked him up, looked Jason up at Caltech, that you would end up going on through life together. It took me by surprise. Sometimes you say we have this very exciting life, and I think in a lot of ways we do, although I think, okay, what will we do when we go home tonight? We'll decide, all right, what are we going to watch on TV tonight? Or, you know, what are we going to have for dinner? So it's a somewhat mundane life in some respects. However, when we watch a movie or something and see co-workers

getting together, I always think, oh, you should never date someone at work. And then I say, oh, but yeah, we're the exception. Yeah, this works perfectly. So when I met her the first time, we met at Caltech because I think she came on a weekend and you can't get foreign nationals into JPL on a weekend. So I said, oh, meet me at my Caltech office. That first day I met her, no, I certainly didn't think, oh, I might marry her someday. I thought this young woman has a lot of energy. She's very outgoing. We had a good conversation. And then she did a good job of keeping in touch, saying, hey, I'll be at this meeting where weak lensing and dark energy are

going to be discussed. Are you going to be at this meeting? Oh, OK, I'll be there. Let's meet up. And then eventually, when she came to work at JPL, okay i'll be there let's let's meet up and then eventually when she came to uh work at jpl we just became best friends and then decided let's move on from there anything to add alina i think jason jason got it all right uh he was he was correct when uh when he asked me to to go on a date with him even though we'd been hanging out for a year already. It's pretty great to have your best friend and husband in the same field. We get to travel together sometimes, but then he's also away a lot, which is sometimes difficult, but that's part of the job. I wouldn't have it any other way.

I want to work with my best friend. Congratulations on your progress with this romance made across the cosmos. I just come back to that thought that we have maybe the first scientific proof that dark energy can both attract and repel. energy can both attract and repel. I sure look forward to staying up on all of these projects that we have talked about, but also hearing about your own progress as you help the rest of us understand what's going on in our universe and maybe find out if we're alone here as well. Fantastic. Thank you.

Thanks for having us. This has been a lot of fun. It has been a pleasure. Thank you so much. We end this long and lovely episode of Planetary Radio as we always do, by visiting with Bruce Betts, the Director of Science and Technology for the Planetary Society, and this week's helping of What's Up and much more. Welcome back. What's up? There's all sorts of great and exciting stuff up in the sky, Matt. We got the Perseid meteor shower peaking August 12th and 13th. You got increased activity of meteors before and after

that by a few days. Viewing is going to be a little bit hampered by a gibbous moon, but you can still check out the bright ones. And then of course, on August 21st, we've got the Great American Eclipse, a total solar eclipse that will cross the United States from Oregon to South Carolina. And a partial eclipse will be visible from pretty much all of North America and Northern South America and the very western edge of Western Europe. As we have said, there are many resources to help you enjoy this. Appreciate this at planetary.org slash eclipse. Among those resources is that piece that you wrote, Bruce. There is indeed an overview of eclipses in general and this one in

particular. Very nice pocket guide to everything that we can expect from the Great American Eclipse. All right, we move on to this week in space history. It was 2005, 12 years ago, that the Mars Reconnaissance Orbiter was launched. Still doing great work around Mars. Getting a little creaky, but still doing its job. And on to... Why so sad? You're going to see the eclipse.

Yay! Speaking of which, the August 21, 2017 total solar eclipse will be the first total solar eclipse to cross both the U.S. Pacific Coast and Atlantic Coast since 1918. Wow, that's so cool. Okay, this gets better and better. You should probably go see it, Matt. I'm going to. All right. We move on to the trivia contest. And I asked you, how much closer is Mars to the sun at perihelion, so closest point to the sun, than at aphelion? How'd we do, Matt? I didn't see any answers that disagreed with the majority opinion here. The majority opinion, I hope, being the correct answer. Random.org chose

first-time winner Mike Reitmeyer. Mike Reitmeyer in Ridgefield, Washington. 42.5 gigameters closer or roughly 42.5 million kilometers or in the ballpark of 26.4 million miles or if you're getting really fancy, he says about 0.285 astronomical units. Close enough? Yeah, yeah. The real point is a decent distance. Mars's orbit is significantly elliptical, although still more circular than anything, but there's a big difference from one, from perihelion to aphelion. And here's another request from Mike. He says, if Bruce is still grudgingly doing random space fact impressions, how about Marvin, the aptly timed

Martian? We'll think about that for next time. Unfortunately, I do a terrible Marvin. It's the only impression that I do reasonably well. We'll have you do it. All right, should we try it? I'm afraid I'm going to have to disintegrate you. Bummer.

Anyway, Mike, we are going to send you a Planetary Radio t-shirt. The brand new design from chopshopstore.com. It's so cool. I like it. And a 200-point itelescope.net astronomy account. Of course, we heard from others like Craig Balog in Woodbridge,

New Jersey, who said that the distance, we're talking about the difference between those two points in the orbit, about 142 light seconds, which sounded about right, just from my in-the-head calculation, which is not a very good thing to depend on. I trust it, man. Adam Kajokar in Calgary, Canada, 354 billion Mars bars. Now I've rounded, I've rounded somewhat because they were much more precise than this. That includes Mel Powell, who says about 22,567,000,000 cloned Bill Nyes stacked head to foot. Yikes. And finally, from Steve Wienel, he said, Yeah, Mars' orbit is surprisingly eccentric, much like my uncle who lives alone in the woods.

Okay, now we can move on. When is the next total solar eclipse on Earth? The next total solar eclipse after the one on August 21st, 2017? Go to planetary.org slash radio contest. This time you have until the 16th. That's August 16th at 8 a.m. Pacific time to get us the answer and win yourself that Planetary Radio t-shirt, the new one, and a 200-point itelescope.net astronomy account. That's worth a couple hundred bucks American and

comes to us from iTelescope. They operate this worldwide network of telescopes on a non-profit basis. And with that, we are done. All right, everybody, go out there, look up the night sky, think about strawberries. Thanks. Good night. Okay, now would be the time for me to do my Jimmy Cagney impression, if I could do one. See the cane mutiny, folks. That's Bruce Betts. He's the Director of Science and Technology for the Planetary Society, who joins us every week here for What's Up. Need more proof that everyone in Carbondale, Illinois has gone eclipse crazy? Witness the music that has taken us out of this week's episode. Shadi Frick and Mike Baltz are the Seadale musicians who created the Eclipse. You can hear this instrumental

version and one with lyrics on SoundCloud. And you can learn more about Southern Illinois University Carbondale's big celebration at eclipse.siu.edu. I dearly hope to see you there. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its United members.

Danielle Gunn is our associate producer. I'm Matt Kaplan. Clear skies!