Planetary Radio • Feb 09, 2022

The weather on brown dwarfs, and worlds on the eve of destruction

Please accept marketing-cookies to listen to this podcast.

Download MP3

On This Episode

Samuel grunblatt portrait

Sam Grunblatt

Kalbfleisch Postdoctoral Fellow at the American Museum of Natural History Department of Astrophysics

Johanna vos portrait

Johanna Vos

Postdoctoral Research Fellow at the American Museum of Natural History's Department of Astrophysics Brown Dwarfs in New York City Research Group

Bruce betts portrait hq library

Bruce Betts

Chief Scientist / LightSail Program Manager for The Planetary Society

Kaplan mat headshot 0114a print

Mat Kaplan

Senior Communications Adviser and former Host of Planetary Radio for The Planetary Society

Astrophysicists Sam Grunblatt and Johanna Vos are colleagues at the American Museum of Natural History in New York. Sam’s team has discovered giant worlds that are about to be devoured by their expanding stars, while Johanna has detected weather on brown dwarfs, those plentiful worlds that are bigger than planets but smaller than stars. Later, Bruce Betts takes the Olympics beyond the edge of our solar system with this week’s space trivia contest.

Brown dwarf illustration
Brown dwarf illustration Artist’s conception of a brown dwarf, featuring the cloudy atmosphere of a planet and the residual light of an almost-star.Image: NASA/ESA/JPL

Related Links

Trivia Contest

This Week’s Question:

Name all the Olympic athletes who appear in pictures encoded on the Voyager 1 and 2 Golden Records.

This Week’s Prize:

A copy of “IMPACT: How Rocks from Space Led to Life, Culture, and Donkey Kong” by meteoriticist Greg Brennecka.

To submit your answer:

Complete the contest entry form at or write to us at [email protected] no later than Wednesday, February 16 at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

What working spacecraft are at the Earth-Sun Lagrange point 2? Include those that are in halo orbits near L2.


The winner will be revealed next week.

Question from the Jan. 26, 2022 space trivia contest:

What moon in our solar system is named after a character in Shakespeare’s King Lear?


Uranus’ moon Cordelia is named after the youngest daughter of King Lear in Shakespeare’s tragedy.

Impact book cover
Impact book cover The book cover for Impact: How Rocks from Space Led to Life, Culture, and Donkey Kong by Greg Brennecka.


Mat Kaplan: Checking the weather on brown dwarfs and worlds on the eve of destruction, this week on Planetary Radio.

Mat Kaplan: Welcome. I'm Mat Kaplan of The Planetary Society with more of the human adventure across our solar system and beyond. Our progress in peering across our corner of the universe is utterly remarkable, and that's before the James Webb Space Telescope and the new generation of ground-based telescopes have begun their work. Who'd have thought we'd be able to detect giant planets so close to their stars that they're about to be engulfed, or that we, more or less, directly see storms on brown dwarfs, those almost stars, but more than planets that litter our galaxy? Sam Grunblatt and Johanna Vos are colleagues in the American Museum of Natural History. They'll join us in minutes to share the great science they presented a few weeks ago at the annual meeting of the American Astronomical Society. Shakespeare and poetry, who expected that combination on What's Up? We'll join Bruce Betts on a literary path to the stars.

Mat Kaplan: Infrared is magic. Ask anyone who hopes to do science with the JWST. It was seven years ago that an infrared camera got us a full-face image of Saturn's moon, Titan peering right through its clouds. That's the image that begins the February 4 edition of the Down Lake. Below it, you can learn about the star that the JWST will use to begin alignment of those 18 gold-plated mirrors. You can also share in our congratulations for a couple of Planetary Society alumni. Bobby Braun is a member of our advisory council. He just became space exploration sector head at the Johns Hopkins Applied Physics Lab. Laurie Leshin was both an advisory council member and had a seat on our board of directors. In May, she'll become director of NASA's Jet Propulsion Lab. I hope to welcome her back to Planetary Radio around that time. Lastly, we breathe a small sigh of relief knowing there are more eyes on the sky watching for near-Earth objects. You can read about the expansion of the ATLAS network of whole sky telescopes at

Mat Kaplan: The American Museum of Natural History sprawls across three blocks of New York City, right next to the equally iconic Central Park. You could spend days exploring it, including a giant glass cube that encloses a white sphere. That sphere houses the famed Hayden Planetarium. The Rose Center is a stunning facility that carries on a tradition that began 87 years ago. Sam Grunblatt and Johanna Vos worked nearby. They are post-doctoral researchers in the museum's department of astrophysics. They provide living proof that the AMNH does more than share the wonder of science, its staff undertakes research that is at the edge of what we know about our world and the cosmos.

Mat Kaplan: Johanna, Sam, welcome to Planetary Radio and congratulations on publications of both of these papers, which are complimentary, but separate and on your recent presentations at the annual meeting of the AAS. Welcome to Planetary Radio.

Johanna Vos: Thanks for having us.

Sam Grunblatt: Yeah. Thanks so much.

Mat Kaplan: Sam, I think we'll start with you because you were the first that I read about in that release that came from the American Museum of Natural History. I do want to talk about the department of astrophysics there as well that you're both part of, but we'll get to that a little bit later. Sam, of course, you're lead author on this paper called TESS Giants Transiting Giants II: The hottest Jupiters orbiting evolved stars. Has it now been published in the Astrophysical Journal or it's still coming up as we speak?

Sam Grunblatt: Yeah. The paper has been accepted for publication. I don't believe it's been published just yet, but it should be published within the next couple of weeks or so, weeks to months.

Mat Kaplan: I know how that can go. I've heard from other people who get frustrated waiting for them to get around to it. But if we're lucky, maybe by the time people hear this, it'll be available. Thank you for sharing the abstract of the paper.

Sam Grunblatt: There's an archive version of the paper, so there's a draft that I wrote that's now publicly available. Folks want to look at that. The published paper should hopefully be out soon. I've given everything that I need to AAS, so hopefully, they will publish the paper soon.

Mat Kaplan: And Johanna, you are already over that hurdle because you were published. Your paper that you're lead author for was published, I think on January 13th.

Johanna Vos: Yeah. Mine was accepted just in December and was published in January, so it's a really nice start to the year to have one paper in the bag.

Mat Kaplan: That certainly sounds like it. And Sam, I hope you'll be following soon behind. We will put up links to both of these papers on this week's episode page at so that people can dig in deeper if they choose. Just a bit more about the paper, Sam. You had more co-authors than I could count. I noted among them though, Michelle Kunimoto and Sara Seager of the TESS team at MIT, Sara, who's been our guest many times and we hope that we're going to be talking with Michelle fairly soon. I just wonder if you'd like to comment on this big announcement from the TESS team that they've now passed the 5,000 mark for so-called TOIs, test objects of interest, those other worlds out there that many of which are still to be confirmed, but man, that's a heck of a number.

Sam Grunblatt: Yeah. It's a huge accomplishment for the TESS team and for the field of exoplanet science in general that only 25 years ago, we didn't know if any of these planets existed around any other stars other than our sun. Now, we're just finding them all over the place. We know that on average, most stars have at least one planet at this point, which is a super exciting discovery. Now with all these new discoveries from the TESS team, we're finding planets in more and more exotic environments. So not only are we finding planets around particularly small stars, but now we're also finding these planets that are at the very beginning of their lives, very close to the end of their lives, things like that. So it's been really cool to see how much exoplanetary ground we've been able to cover over the last couple of years.

Mat Kaplan: Our audience is probably tired of hearing me say this, but I am old, so I can remember. When I was a kid eating up astronomy books, they all said, one, we'll probably never see a star as more than a point of light and two, we're even less likely to ever be able to detect whether there's a planet going around any of those stars. My, how far we have come. Johanna, I think you'll be able to give us more evidence of this as well. It sure backs up the wonder that is implicit in what you just talked about, Sam, that and here we now have thousands of not just candidates, but confirmed worlds going around other stars. It's an exciting time.

Sam Grunblatt: Yeah, absolutely. I'm super excited to be able to be studying these exoplanets right now because there's so many things that even when I first started my graduate studies, for example, we didn't know. We didn't know how many Earth-like planets, for example, there were around some stars. That was something that was discovered in the last, not to date myself, but in the last decade. So it's really exciting to be in this place now where we have so many exoplanets that we know of that we can start to really investigate the statistics of these systems and also branch out beyond just stars that are like the sun to study planets around stars that are very different from our sun.

Sam Grunblatt: So around the smallest stars in the galaxy, around some of the closest stars that only people like Johanna are finding. It's really exciting to see how many different places now we can take these exoplanet studies and how many different exciting things we can learn about how planets form, what's in their atmospheres, and how similar are they to our solar system, but also how different they can be as well.

Mat Kaplan: Johanna, I'm going to jump over to you for a second because I've got to think that you are just as thankful to be living in this time when we now have the instruments that enable you to do your work.

Johanna Vos: Yeah, absolutely. When I think back to say, before we knew of any planets, I think the expectation was I can't wait until we start finding other solar systems. We thought we were going to find ourselves out there, but with these thousands and thousands of exoplanets we've been finding, we haven't really find the solar system again. We haven't gotten there yet. I think it's the technology. I think we probably will eventually, but within those thousands, they're just so weird and wonderful. I don't think anyone could have predicted the diversity of worlds that we're going to find. It is an exciting place to be right now.

Mat Kaplan: Sam, let's hear a little bit about these worlds that you've been studying and that you and your colleagues wrote about in this paper. I'll date myself again with this pop culture reference, but that it appears that they are on the eve of destruction.

Sam Grunblatt: Yeah. The planets that I've been focusing on for my research are generally planets that transit giant stars. As the sun evolves throughout its lifetime, eventually, it's going to turn into a red giant star. It'll be much larger. It'll also be cooler and it'll expand out toward Earth's orbit. That's what I'm trying to understand, is how do these planetary systems evolve? The systems that I've been studying as part of my test research program are these planets that are right on the edge of these red giant or evolved stars. The planets I've been looking at instead of orbiting their star in 365 days, they orbit in closer to three days. The sunrise is going to be pretty spectacular on a planet like that.

Sam Grunblatt: It also means that there's a lot of interaction between the star and the planet. Most of those interactions result in the planet getting pulled ever closer in toward the star. One of the systems that we found, TOI-2337 b, is particularly close to its host star and it's also particularly massive. So we believe that this planet is actually going to be inside its host star in less than a million years. It's really on the edge of destruction as you put it. I don't think it's going to be around much longer in cosmic time.

Mat Kaplan: Yeah. A million years, that's a snap of the fingers in cosmic time, right?

Sam Grunblatt: Exactly, yeah. In terms of exciting places to be or exciting planets to live on in astrophysical terms, these would be ones to consider.

Mat Kaplan: Tell me more about these worlds. They're not tiny. We're not talking about Earth-size planets, right?

Sam Grunblatt: No, no. These are much more similar to Jupiter. These planets range in between masses that are around half to twice of that of Jupiter and sizes that range from slightly smaller to maybe 150%. So 50% larger than Jupiter. They're really interesting because they're all gas giant planets and they're all on these short period orbits around these evolved stars, but they have vastly different densities. For example, the least dense planet in our sample has the density of around cork, whereas the most dense planet is more like a solid block of aluminum. They range from sinking to floating and that probably is telling us something really interesting about how these planets actually got to where they are today.

Sam Grunblatt: They probably formed in very different places, yet somehow, they've all ended up right on the edge of destruction around their stars. We're hoping that by studying more and more of these systems, we'll be able to understand more about how planetary systems evolve over time. Even though these planets are nothing like Earth, their solar systems might have planets that are like Earth. By understanding how these planets got to where they are, we can understand how these planets or basically how planetary system architectures change over time.

Mat Kaplan: Is it fair to say that even though they are quite unlike Earth, we are seeing perhaps the far distant future of our own world?

Sam Grunblatt: Yeah. I think that's a fair guess for us to make at this point. We can't be sure what these systems look like when their suns were the age of our sun or as evolved as our sun is today, but it's very possible that as solar systems evolve, essentially, the planets are going to inspiral toward their host stars as the star evolves. So a planet that might be where Jupiter, Saturn is today, by the time our sun becomes a red giant, it might be where we're finding these planets. Yeah, I think that's a safe assumption to make that this could be the future of our solar system that we're seeing.

Mat Kaplan: The popular description that I've always read is that as these stars age and expand, they basically just expand outward to where their planets are, that they engulf them. It sounds like from what you're saying, at least for these worlds, it's just as much the planets themselves spiraling down into the star. Is it both of these or is one of those more dominant?

Sam Grunblatt: Yes. Both of the effects are definitely happening in these systems. So the stars are getting larger, but the planets are also on shrinking orbits. That's basically due to the exchange of angular momentum in these systems. So as the stars get larger, basically, that causes the planets to then shrink in their orbits. You can't have one happen without having the other. Of course, the rate at which that happen depends on things like the mass of the star, the mass of the planet, and where the planet is relative to the star, its orbit, the shape of its orbit. But in general, you're always going to have both of these processes going on at the same time. It's this exchange of angular momentum that I like to think about.

Mat Kaplan: Angular momentum, this is where we would usually say Isaac Newton would be so proud. There's a term in the paper that I had never seen before that I hope you can explain. What is planet inflation? I know the stars are inflating or expanding. How do you apply that to these planets?

Sam Grunblatt: Yeah. It looks like in these particularly evolved giant planets, that as they get closer and closer to their star, they're going to be heating up because the star is going to be irradiating them more intensely. That increased radiation is basically heating up the planet. That heat has to go somewhere, and so it goes deep into the interior of the planet and that causes the entire planet to then expand or inflate. This is something that has been long inferred. Over 25 years, people had theories for how this actually happens, but now we're starting to find the systems where we can start to test those different theories and see what's the mechanism at which these planets are actually becoming inflated.

Sam Grunblatt: This is something that's a new area of discovery that we need these inflated planets around evolved stars to study. Now that we're finding more and more of them, we can start to say, "Okay, how does that heat get from the star into the planet?" and then how does that affect the planet's atmosphere? All of this ties into planetary system evolution overall. Again, we can observe it in these Jupiter-size planets, but it's going to be causing the same effects on rocky planets like Earth as well.

Mat Kaplan: Johanna, you have been nodding enthusiastically through all of this discussion of the work that your colleague, Sam, does and yet you've been studying very different, I don't know whether to call them worlds or not, very different sorts of objects, but they can inform us. They are informing us about exoplanets. By the way, I love the title of your paper, Let the Great World Spin: Revealing the Stormy, Turbulent Nature of Young Giant Exoplanet Analogs with the Spitzer Space Telescope. Brown dwarfs, are they planets or stars or something in between?

Johanna Vos: Yeah. Brown dwarfs are these amazing mysterious objects somewhere between planets and stars. We think most of them probably form like stars, but honestly, we think some of them are probably planets that were thrown out of their orbit early on. They bridge the gap between planets and stars. They are so interesting. We've really discovered so many interesting things about them. One of my favorite things about brown dwarfs is that the very first brown dwarf was announced at the same conference as the first exoplanet was announced. So on this one day, these two amazing fields of astronomy were born and they've flourished together over the years and really, there's so much crossover. They inform each other a lot.

Mat Kaplan: Tell me about the specific objects that you study, because I guess even among brown dwarfs, there's a lot of variation in size. You study the somewhat smaller ones, but they're still pretty big.

Johanna Vos: Yeah, totally. You can take brown dwarfs and split them into two populations, young and old. The old brown dwarfs, they've been around for a giga-year. Their masses will be somewhere between 30 Jupiter masses and 80 Jupiter masses. However, the young objects, and these are the objects that I've been studying very intensely, they can range in mass from maybe two Jupiter masses or one Jupiter mass all the way up to maybe 20, 30 Jupiter masses. A lot of these objects are truly just these isolated, free-floating exoplanets. They're very similar to directly imaged exoplanets of which we know of about 30, but they just don't have a star.

Mat Kaplan: But that's key to this, right, because it's made them so much easier to observe. We hear frequently on this show about the challenge of trying to pick a planet out like the ones that Sam is looking at when it's circling next to this gigantic source of light.

Johanna Vos: Exactly. When you have a planet right beside a star, it's completely overwhelmed by this glare of the host star. But when you have these just isolated exoplanets in the Milky Way, you can point, well, maybe not a regular telescope, but a regular space telescope and learn so much about the object. We were able to point the Spitzer Space Telescope at a sample of these giant planet analogs to learn about their atmospheres in exceptional detail and in a lot more detail than we could do for exoplanets around a host star.

Mat Kaplan: And there is the most remarkable bit of information about this work that you're doing. It's really key to the work, of course, that you are actually observing weather on these worlds.

Johanna Vos: Yeah, exactly. We are trying to understand what the clouds are doing and how they're changing over time. We basically point the Spitzer Space Telescope at these worlds. We watch them for about a day each, so about 20 hours each. If these objects, if these worlds have clouds in their atmospheres, we can actually detect that by how bright the planet is at any period of time. Maybe the easiest way to visualize this is to think of Jupiter. I'm sure you guys know that Jupiter has this big storm called a Great Red Spot.

Mat Kaplan: Oh, yes.

Johanna Vos: If you were to stare at Jupiter with a telescope, its brightness will actually change quite substantially as that Great Red Spot rotates in and out of view because it appears dark compared to everything else. We're really trying to find these Great Red Spot analogs on these distant worlds.

Mat Kaplan: I would expect that maybe these have to be fairly large effects to cause the difference from one side of the planet to the other that you can actually observe.

Johanna Vos: Yeah, exactly. This is partly because of just the beauty and the precision that Spitzer gives us. We actually can detect these fluctuations on very small scales. But when we looked at this new sample of young brown dwarfs, we spent 600 hours just staring at the sample of objects, we found that they're more likely to show these cloud-driven fluctuations than their older brown dwarf counterparts. You can think of them as their older brown dwarf parents or whatever. When they do show these fluctuations, they're bigger. So they're more dramatic than those old brown dwarfs that we had studied previously are.

Johanna Vos: This is really exciting because the whole point of this survey was to set expectations for directly imaged exoplanets. With the recently launched James Webb Space Telescope, with upcoming 30-meter telescopes, the technique we just used will just straight away be used on directly imaged exoplanets. From this work, we now know that they're very likely to have these cloud-driven fluctuations and those fluctuations are likely to be pretty big. We can expect. We know what amplitudes to expect. So it's pretty exciting. We're standing on the precipice of really understanding weather on worlds orbiting stars other than our own.

Sam Grunblatt: What Johanna is doing is so exciting because it really sets the precedent for what's happening for not only directly imaged exoplanets, but basically the entire population of exoplanets that we found that we can actually study with James Webb. Something that I'm really excited to do with one of the planets I've been working on is to exactly use James Webb to study its atmosphere, to look for these sorts of things that Johanna's been studying. Her work is really setting the precedent for the future of the exoplanet field in a lot of ways. I think it's really cool to have that all right here at the museum.

Mat Kaplan: I'm so glad to hear both of you talking about what you're looking forward to when the James Webb Space Telescope really starts to deliver the great science that we all expect and hope for. It just happens that as we speak, in a couple of hours, I'll be talking for the second time to John Mather, the senior project scientist for the James Webb Space Telescope. I'm sure he would be so pleased to hear the two of you looking forward to being able to use that great observatory.

Mat Kaplan: More of astrophysicists Sam Grunblatt and Johanna Vos in seconds. Like what you hear? Share the cosmic goodness by giving us a review or rating in Apple Podcasts. It's the nicest thing you can do for us that won't you cost you anything.

Sarah Al-Ahmed: There's so much going on in the world of space science and exploration, and we are here to share it with you. Hi. I'm Sarah, digital community manager for The Planetary Society. Are you looking for a place to get more space? Catch the latest space exploration news, pretty planetary pictures, and Planetary Society publications on our social media channels. You can find The Planetary Society on Instagram, Twitter, YouTube, and Facebook. Make sure you like and subscribe so you never miss the next exciting update from the world of planetary science.

Mat Kaplan: Johanna, I'm just wondering how you're able to do this with Spitzer. Here's a telescope that's pretty venerable now, used up all of its cryogenic cooling capability quite a while ago. I knew it was still doing some of this work, but I'm really amazed that this somewhat elderly space telescope is able to do this work for you.

Johanna Vos: Yeah, it is amazing. When you think about missions, when people come up with missions, they have no idea what the telescope is going to be used for decades later. This technique didn't exist when Spitzer was launched. We didn't know we could detect these changes in brightness. It seemed wild to think we could do this for a world outside the solar system. But this program was one of the last large programs that was carried out before Spitzer was retired. It was the last cycle. It was our last chance to do this because Spitzer, it's just the ideal instrument for this technique. You can stare at these things for hours. You can stare at them for days if you want. It's the perfect wavelength, that lovely mid-infrared range that is just completely inaccessible from the ground. When Spitzer was retired, I was very, very upset and I think JWST will be amazing, but 600 hours to do a survey of brown dwarfs, it will be a very big ask for a telescope like that.

Mat Kaplan: What, with hundreds and hundreds of scientists itching to get time on the JWST.

Johanna Vos: Yeah. Exactly.

Mat Kaplan: Sam, I imagine, I assume that the worlds that you're looking at, they're among those 5,000 that TESS has discovered so far and TESS is still very much alive. I think we established, you're also looking forward to what the JWST will be able to do for your work, but what about ground-based telescopes, the whole new class of giant, 30-meter and up telescopes?

Sam Grunblatt: Yeah. First off, in order to confirm any of these planets as real planets as opposed to just planetary candidates require those ground-based telescopes. The observations that we got to confirm the three planets in my paper came from, I think, five different continents or something like this. They're all over the world. It's really this global collaboration that has made these sorts of planet confirmations possible. That's also part of why there are so many authors on my paper. Yeah, I think that there's a lot of potential for ground-based telescopes to teach us more about exoplanets as well. Something that has been pioneered over the last few years is using ground-based observations to find planet transits as well as space-based observations, such as TESS and Kepler, which have been doing these transit observations for almost a decade now.

Sam Grunblatt: By combining this ground-based and space-based data, we can actually start to look at these transits in more than just one wavelength. By doing that, we can start to then learn a little bit more about the planetary atmosphere and start to get at some of the stuff that Johanna and her team have been doing with the brown dwarfs with Spitzer data for so long. By looking at all of these different wavelengths and by using these much larger telescopes or light buckets, as I like to call them, to do that, we can get much more precise parameters, for example, on the planet radius. The planet radius is a function of wavelength, which is telling us something about potential hazes or different molecules, different gases, or even clouds that could be in these planets' atmospheres. All of the different telescopes that are coming online in the next five years are really going to revolutionize what we can learn for these types of systems.

Sam Grunblatt: Something that I think is cool to think about is again, that Johanna has been able to get the actual light from the exoplanets or the brown dwarfs themselves. Just to highlight how different that is from what I'm doing, everything that I do with either TESS or these ground-based telescopes, all of my observations are of the star, not of the planet itself. There's lots of things that we can learn about the planet by just looking at those, the inverse signals as how that affects the star. But in order to actually get it observing the planet itself, like you said, that's impossible to do in these really high contrast systems where you're so close to the star, but in order to understand the atmospheres the way to get at that for those particular systems is through direct imaging, is through these systems where you don't have that crazy contrast.

Sam Grunblatt: So it's been really cool to be at the museum because we have this transition from one end of the spectrum to the other, like Johanna said, where some of us are looking at the coldest systems and the other... I'm looking at the hottest systems. It's really neat to see how the connections can be made between the two different sides of exoplanet science. Like Johanna said, we're trying to move toward the middle so that we can understand those more temperate worlds and how they affect planetary systems or entire solar systems like our own to understand how these planets form and evolve over time.

Mat Kaplan: Sam, yeah, I think it was before we actually started recording that Johanna talked about this convergence that you're talking about with the advancements that are taking place. But Johanna, do you see this as well?

Johanna Vos: Yeah, absolutely. I think with the upcoming telescopes, James Webb Space Telescope, 30-meter telescopes, the work that Sam and I are doing are getting closer and closer together. Our end goal of pretty much everybody doing some form of exoplanet science is to look at Earth-like planets, look at their atmospheres, look at, is their life on these planets, and we're all getting closer and closer to that goal. It's nice that we're coming from all these different directions and bringing different knowledge to that question. But yeah, we're definitely creeping closer and closer together and these new telescopes are helping us do that.

Mat Kaplan: I have to ask, have both of you made your request for time on the James Webb Space Telescope?

Johanna Vos: Yes, we have. The cycle one proposal deadline was a crazy time. I look back and I'm like, "How did we get through that?" But yeah, we have put in lots of proposals. I'm involved in a few. I'm involved in some early release science that is focusing on directly imaged exoplanets. I'm also involved in proposals focusing more on the brown dwarfs and particularly on the coldest brown dwarfs. The James Webb Space Telescope opens up the mid-infrared for the first time since 2009, which is when Spitzer had to cut off that part of its job. This mid-infrared is where we find the coldest worlds out there. So the coldest object we know of is a temperature of about 250 Kelvin, which is like the North Pole on a cold day. So these are the types of worlds. We can find them now, but we're going to characterize them with the James Webb Space Telescope and look for things like clouds in their atmosphere.

Mat Kaplan: Sam, you got your question.

Sam Grunblatt: My experience was very different from Johanna's. Actually what happened with me was around a week before the deadline, I had a conversation with one of my colleagues and he offhandedly mentioned like, "Hey, one of these planets would be very cool for a James Webb proposal." So in a week before the deadline, we threw everything together with a lot of help from more experienced or maybe more ready folks like Johanna on putting this proposal together. So our proposal was specifically to observe, again, transits of one planet in our survey that's actually the least dense, so the planet that's like cork.

Sam Grunblatt: The idea is if we observe transits in very many spectral wavelengths, we can actually get at what's in the atmosphere of these planets. We can start to look for spectral features that would indicate that there's water or carbon dioxide in these planets or in the atmosphere of this planet. We put in the proposal. Unfortunately, it was not accepted. Essentially, they told us, "This looks cool, but we'd like the planet to be published first." So now we've gone ahead and done that and we're hoping to try again for cycle two.

Mat Kaplan: Well, best of luck to both of you. It's also good to hear that being on the same team there at the American Museum of Natural History, that there's some synergy paying off there. Neil deGrasse Tyson once told me that he only agreed to run the Hayden Planetarium and the Rose Center because the museum assured him he'd be able to continue his astrophysical research. I guess the two of you are also proof of that. I don't know why I was surprised to learn that there was research of the kind you're doing underway at a museum. After all, the AMNH has had paleontologists doing research for forever. So I shouldn't have been surprised, but I just wonder about what it's like to be a part of this organization, this institution, a grand institution that is also so much about making science accessible to the rest of us, not just the people who conduct it like the two of you. Johanna?

Johanna Vos: Yeah. Working at the museum is honestly a dream come true. The department is really young. It's only been around for maybe 20 years. There's not that many people, but we pull in amazing astrophysicists from all over New York. It's like a hangout area for astrophysicists in New York, which is really nice. Loads of people are passing through. Then the opportunities to share our science with the public are just amazing, because it's so important that James Webb Space Telescope was built with US taxpayers' money. So I really think it's important for us to explain to people why it's so important. Having the planetarium right there is so amazing. We also have our own software for the planetarium where we can show actual data around you in the planetarium.

Johanna Vos: We can load into a data from Gaia. You can fly through the universe to go along with the press release of my paper. We made this incredible video of zooming out from the Earth and seeing all of the brown dwarfs in space around you. You can literally fly through it and see everything.

Sam Grunblatt: It's really cool.

Johanna Vos: It really makes you feel close to the universe and close to our nearest brown dwarf neighbors. So yeah, it's an incredible place to work and it's so nice to see members of the public from kids, high school kids, all the way to adults. They are so excited in the research we're doing.

Mat Kaplan: And Johanna, I read that you are making presentations that's a part of what you like to do, working with young people and others.

Johanna Vos: Yeah, absolutely. We have a lot of programs at the museum for young students. One of the programs I'm involved in is called the SRMP program, which stands for the Student Research Mentoring Program. I have three high school students work with me throughout this school year and they contributed to this work that we've just been talking about. They looked at all of the light curves. They find out if there was clouds on each of the worlds and they're truly involved in research, which is a really rare thing for high school students. So it's really amazing that we have the opportunity to do that.

Mat Kaplan: Sam, I hope you could also talk about what it's like to be part of this research team, this research department at one of the most famous museums on this planet.

Sam Grunblatt: Johanna really hit the nail on the head when she said it's a dream come true to work at the museum. Growing up as a kid in the New York state school system, I remember being a maybe elementary school or middle schooler going to visit the museum and seeing the planetarium shows and being blown away. Now being able to be on the opposite side of that is really incredible. Like Johanna said, the museum really is a great meeting place for all sorts of astronomers and astrophysicists in New York City as well as in the larger New York area. It's really great to have all of these great people coming through, but then also have that connection to the public, which really, I think, is really important for us as scientists to remember that everything that we do is largely funded by the public and is for the public's benefit.

Sam Grunblatt: To have that direct connection at the museum, to see all of those young kids coming in and to think, "Oh, yeah, I remember being those kids," I want to show them all the coolest stuff that I can find out that they can find in the museum. The planetarium's over there, the dinosaurs are over there kind of thing. It's really an amazing experience. One of the other things that's so great about it is that the science going on there is really great too. We have a really strong team of scientists working on a wide range of different topics. We've been lucky in that even though we only have four professor equivalence in the department, we have a wide range of galaxy exoplanet, even cosmology studies going on. Even across the teams, we're able to bridge those connections and work together on these sorts of James Webb proposals or looking at how planetary systems evolve. That's something that we're very interested in at the museum.

Sam Grunblatt: It's been great for me in so many levels, scientifically and just spiritually or something like that, that I've been able to give back to my community, but also be part of this amazing scientific institution that's doing great work, that's building up these connections and that's getting the general public excited about science and the research that we're doing all over.

Mat Kaplan: I love that sense of completing the circle that it was, in part, the museum that inspired you to go in the direction that has brought you back to that facility. I can't wait for my next visit. I'm a big kid. I've talked about my visits to the Griffith Observatory in Los Angeles helped to put me on the path to talking to people like you and making me feel so fortunate to do so. I got one more question for you, Sam. I was surprised to see, back to science now, that you also use stars to learn about the structure and history of the Milky Way galaxy. Do I have that right?

Sam Grunblatt: Yeah, that's right. Depending on the day, I wear different hats. Sometimes I'm wearing more of a planet scientist hat, sometimes more of a stellar scientist hat. But the secret is they're really the same hat.

Mat Kaplan: I want one of those hats. How does that-

Sam Grunblatt: They're holographic. They look different from different angles. I think that's what it is.

Mat Kaplan: Great. Even better. Johanna, what's next for you? Obviously, you hope you get that letter that says that you're going to be using the JWST to continue this research, but what in addition to that?

Johanna Vos: Yeah. Next for me is definitely leaving my isolated objects behind even though I love them so much, but we've learned so much from them that we're just ready to take on these directly imaged exoplanets with all of the knowledge we've built. They're so hard to observe, but when you observe them, it's so useful because you're getting photons directly from the planet. We know what their clouds are like. We know what their atmospheres are like. We know what's in their atmospheres. We know how fast they're rotating. We know so much about them and I think we're just fully ready to get the observations we need of planets orbiting their host stars. As we get bigger and bigger telescopes, that literally means we're getting closer and closer to the star and to smaller and smaller planets. So closer and smaller is in my future.

Mat Kaplan: So as you leave those brown dwarfs behind, I guess we should notice we have not yet in this conversation, it's becoming more apparent that there are an awful lot of them in our galaxy.

Johanna Vos: Yeah. They are truly all around us. The search goes on. We haven't even mapped all of them. The weird thing about brown dwarfs is that down at the coldest end, they're giving off so few photons that they're very hard to find. We're involved in the citizen science program at the museum too called Backyard World where we're searching for these coldest objects using WISE data from the WISE telescope. That weird thing about these objects is when you do discover a new, very cold world, it's always right beside you. It's like it's been there the whole time, but you could just never see it. It's disorientating. You think, oh, yeah, we've mapped out from the Earth outwards, but not really. It's all of the neighbors we're still finding. We didn't realize they were there.

Sam Grunblatt: Maybe to connect that to some of the stuff that I've been doing.

Johanna Vos: Yeah.

Sam Grunblatt: Working with planets around giant stars, I'm really interested in trying to map how does the planet population change in different parts of the galaxy. We're getting to the point now where we can actually do that. We can get the ages of these stars and now we can try to start to understand their planet population as well. But the crazy thing is that Johanna is showing us that we might not even understand the planet population in our own backyard. The frontiers are all around us and here at the museum, we're trying to push them in all directions.

Mat Kaplan: Exciting times to be doing the kind of work that you're doing.

Johanna Vos: Yeah.

Sam Grunblatt: Absolutely.

Johanna Vos: We both feel very lucky.

Mat Kaplan: And I feel fortunate, lucky to have been able to talk with both of you today about this great work. Please keep it up. Give my regards to Dr. Tyson, your colleague there at the American Museum of Natural History. As I said, I cannot wait for my next visit, especially if we're past these bad pandemic times. Thanks for joining us today on Planetary Radio.

Johanna Vos: Thanks for having us. It was really fun.

Sam Grunblatt: Yeah. Thanks so much. This has been a great experience. Really appreciate it.

Mat Kaplan: Time for What's Up on Planetary Radio. Here is the chief scientist of The Planetary Society. Bruce Betts is sitting virtually opposite me ready to tell us about the new sky and deliver a random space fact and all kinds of other fun stuff. Hi.

Bruce Betts: Hi, Mat.

Mat Kaplan: Let's go right into it. What's up there?

Bruce Betts: Hey, in the evening sky, say goodbye to Jupiter, but you can still catch it a little bit longer. Bye.

Mat Kaplan: Bye.

Bruce Betts: In the evening, low in the west, but it'll be coming to pre-dawn skies everywhere in a few weeks. But for now, we've got the pre-dawn skies, three planets, super bright Venus over in the east. To its lower right and edging below it will be Mars over the next week or two, looking much dimer. Into their lower left, for a little while, a brief appearance of Mercury looking like a bright star, but not nearly as bright as Venus. In the evening sky, don't forget to check out Orion over in the east in the early evening. That bright star is Sirius, the brightest star in the night sky. On it this week in space history, it was 2001 that NEAR Shoemaker spacecraft became the first orbiter to land on an asteroid. Then in 2015, we had the unexpected arrival of the Chelyabinsk impactor that exploded in the sky over Chelyabinsk, Russia injuring about 1,000 people, roughly a 20-meter diameter asteroid hitting the atmosphere and breaking up and sending shock waves down. So hey, it's dangerous out there.

Mat Kaplan: Lots of asteroid news. Stay tuned for a near-Earth object related prize in today's contest. Speaking of Shoemaker, Gene Shoemaker, you're going to have some big announcements soon, right, about the Shoemaker NEO grants.

Bruce Betts: I am and you're going to talk to people and it's going to be cool.

Mat Kaplan: It's always fun to talk to these people who are just trying to save the world, as the boss says.

Bruce Betts: Like I said, 2015 was Chelyabinsk. It was 2013. It was on February 15th UT, so I apologize.

Mat Kaplan: Apology accepted.

Bruce Betts: Thank you. Onto random space fact. There have been, since the Voyager 1 and Voyager 2 spacecraft launched, been flying through space, been working the entire time, still working, there have been 23 Olympic games held including the one currently going on. That's another measurement of how long the spacecraft have worked.

Mat Kaplan: I love how putting it in terms like that, finding that kind of analogy just drives it home so well.

Bruce Betts: They're really, really impressive. I'm an Olympic fanatic when the Olympics are on, so we got a lot of Olympics. But first, we'll go to the previous trivia question. For all you English majors out there and cultural people, I asked you what moon is named after a character from Shakespeare's King Lear. How'd we do in that?

Mat Kaplan: We had a terrific response. I'm not surprised. You're a literate bunch out there. Now some of you submitted another moon of Uranus, Oberon, but Oberon of course isn't in King Lear. You must be mid-summer nights dreaming.

Bruce Betts: I think you're confused. Oberon is in The Iron Druid Chronicles.

Mat Kaplan: Yeah. And so is Cordelia or actually Cordelia was pointed out to us by a couple people like [Keith Landa and Mel Powell 00:45:10], is a principal character in Buffy the Vampire Slayer and the Angel spinoff, which is obviously, what they had in mind. Are we on the right track here with Cordelia?

Bruce Betts: Yes. Yes, you are. I always assumed, as does the United States Geological Survey astrogeology branch, that it was named after Shakespeare's King Lear character, but who knows? Well, actually we do know because it was named a long time ago, but maybe it was a prescient view of Buffy the Vampire Slayer and Angel.

Mat Kaplan: Well, regardless of the source, I do have a winner for us. I forgot to look it up, but I think he's a first time winner. It's [Bruce McNair 00:45:58] in North Adelaide, Australia who said Cordelia. He also says he loves the show, keeps him up to date with lots of space news. Congratulations, Bruce, a name we like a lot. I hear you like it down there, down under as well.

Bruce Betts: Hey. Hi, Bruce.

Mat Kaplan: Bruce, we're going to send you or actually is going to send you a Planetary Radio T-shirt. It is a very cool shirt. All of us wear them a lot at the society. Some people wear them more than me, but I love to wear mine. Hopefully, you'll also enjoy wearing yours., that's where you can find the entire Planetary Society collection of shirts and other cool merch. I got more for you. This from the pun master Robert Klein, when I am going to roll to Cordelia, I will take a Regan with me for protection.

Bruce Betts: Ha, ha, King Lear's daughter's names. Ha, ha, ha, ha. Funny.

Mat Kaplan: What a bounty of poems even though our poet laureate took the week off. We have three to share with you.

Bruce Betts: Please tell me they're all an iambic pentameter.

Mat Kaplan: I didn't count. I don't know. Let's see. You have to know that Uranus was the Greek God of the sky for this one. Spurn by her father, cast into the night. Cordelia sought the sky God in her plight. Mysterious and silently, she flew so close, but never reaching her love true.

Bruce Betts: Wow. That was almost like real poetry.

Mat Kaplan: Almost.

Bruce Betts: As much as I can judge that, which is really not at all.

Mat Kaplan: Yeah, it's poetry is in the ear of the beholder. Here's [Jean Lewin 00:47:48]. A daughter of nobility rejected by her pops, later proven true of heart. Her faith, this could not stop. Brought to life within a globe, to was here, she rose to fame, now shepherding Uranus' rings. Cordelia is her name.

Bruce Betts: Oh, another good one.

Mat Kaplan: Finally, from [Daniel Kazard 00:48:07] who usually just sends us the fun little graphics that he puts together. 'Tis Cordelia who loves her majesty Uranus, according to her bond, no more nor less. Although perhaps a little more, still is the band that ties the twain is in decay until to finally unite them in her death.

Bruce Betts: Wow.

Mat Kaplan: It's dark, but I didn't realize this, that Cordelia's orbit is decaying and she's going to bust up someday.

Bruce Betts: Yeah. King Lear, man. Dude, what were you thinking? Tool.

Mat Kaplan: Really? Get your head out of that planet, King Lear. Can I say that? I did say that. All right, we're ready for another one.

Bruce Betts: Back to Voyager and the Olympics. So Voyager Golden Records, most of you are familiar with these, messages out to the universe sent with Voyager spacecraft. Here's your question. What Olympic athletes appear in pictures on the Voyager Golden Record? Name all of the Olympic athletes that appear in pictures on the Voyager Golden Record. Go to

Mat Kaplan: Wow. Who knew? Not me.

Bruce Betts: I stumbled across it when I was trying to come up with some interesting Olympic thing and it was like, "Wow, I didn't know that. Huh, that would make a good trivia question," and here it is.

Mat Kaplan: Well, thank you [Andrew Yen 00:49:36] and everybody else there who made all those choices. You have until the 16th, that's February 16th at 8:00 AM Pacific time to get us the answer to this one, this Olympic scale question, and somebody's going to get a brand new book called Impact. It was just published about a week ago as I speak, Impact: How Rocks from Space Led to Life, Culture, and Donkey Kong by planetary scientist Greg Brennecka, who's up at the Lawrence Livermore labs. I have read not all of it, but a good part of it and it's very entertaining. He throws in a lot of humor and some fun hand-drawn illustrations. You ready for a random near-Earth asteroid fact?

Bruce Betts: I am indeed.

Mat Kaplan: King Tut was buried with a knife made from an iron meteorite. That's out of the book.

Bruce Betts: Yeah. I believe there were also tektites involved, but I'm not sure. Tektites being when an impact occurs into the Earth and a splash of molten rock cools going through the atmosphere and then lands. But I could be wrong on that. I was just trying to pretend like I knew something.

Mat Kaplan: Well, the answer might be elsewhere in this book, Impact, which will be yours if you win this brand new contest. So good luck to all of you and good luck to you, Bruce. Thank you.

Bruce Betts: Thank you. Good luck to you, Mat. All right, everybody. Go out there, look at the night sky and think about ski jumping on Enceladus. Thank you and good night.

Mat Kaplan: Someday, right? I mean what a great venue for the Winter Olympics. Don't step in the plumes. Don't step in the tiger stripes. That's Bruce Betts. He joins us every week here for What's Up. Planetary Radio is produced by The Planetary Society in Pasadena, California, and is made possible by its Olympian members. Your gold awaits at Mark Hilverda and Jason Davis are our associate producers. Josh Doyle composed our theme, which is arranged and performed by Pieter Schlosser. Ad astra.