Our survey of the solar system in anticipation of the next planetary science decadal survey continues with Mars, the big outer planets, and the smaller bodies that share the neighborhood. Three more great scientists share their looks ahead. Staying responsibly stuck at home is easier when you can look up at a gorgeous night sky. Bruce Betts is here to help with another fun edition of Whats Up and a Random Space Fact or two.

Bruce and Mat will record an outgoing message for your phone, if you dare.

What mission saw the first musical instruments played in space? (Human performance on a real instrument or instruments. Live. In space.)

Who was the first person to do a deep space EVA (extravehicular activity or spacewalk)? Deep space is defined as beyond low Earth orbit.

The winner will be revealed next week.

The Chandrasekhar limit is the maximum mass of a stable white dwarf star. In solar masses, what is the approximate value of the Chandrasekhar limit?

The Chandrasekhar limit beyond which a non-rotating white dwarf star will collapse is about 1.4 solar masses.

Mat Kaplan: [00:00:00] What will the next 10 years bring the rest of our solar system? That's this week on Planetary Radio. Welcome. I'm Mat Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. Last week we took up Mercury, Venus, and Earth's moon. Now our look ahead takes us to Mars. The giant outer planets, and to the smaller bodies that pepper our entire solar system and beyond.

Three more great scientists will talk about their contributions to the equinox edition of The Planetary Report, focusing on what we've already learned and the big questions that remain in each of these realms. Then we'll check in with Bruce Betts for what I think is a particularly entertaining edition of What's Up, including a new space trivia contest.

Headlines from the down link are moments away. First though, here's an opportunity I'm excited about. Our good friends [00:01:00] at Explore Mars, creators of the annual Humans to Mars summit have asked me to moderate an online discussion with NASA Chief Scientist Jim Green, and Penny Boston of the NASA Astrobiology Institute. Many of you will hear this too late to join the live event at 1:00 PM eastern on April 1, but Explore Mars will make the complete conversation available on demand.

The next Planetary Science Decadal survey, that community authored document that will guide NASA science priorities from 2023 through 2032 will place an increased emphasis on astrobiology and planetary defense. The Planetary Society supports the inclusion of these topics. It was anticipation of this next survey that inspired the interviews you heard here last week and are about to hear this week.

In person work on most NASA projects, including the James Webb space telescope, the Orion spaceship, and the space launch [00:02:00] system has stopped due to COVID-19 restrictions. One exception is NASA's Perseverance Mars rover which must blast off during a narrow July, August window while Earth and Mars are optimally aligned. If Perseverance misses that window, the next opportunity will be in 2022, along with the already delayed Rosalind Franklin rover from the European Space Agency.

Also, still in progress despite COVID-19 quarantines, NASA's Commercial Crew program, which is preparing for its inaugural astronaut launch in May. Those preparations hit a snag after a Falcon 9 rocket lost an engine during its fourth re-flight. A few days later, some Space X parachute testing hardware crashed to the ground during a helicopter drop test. Though apparently the parachute system was not at fault. It's unclear whether either incident will impact the May launch.

All of the fun and informative features of this week's down link are [00:03:00] online at planetary.org/downlink, or you can be like me and have it delivered to your inbox each week for free. We continue our steady progress from Mercury to the outer reaches of the solar system with a stop at the red planet. Ramses Ramirez is a planetary scientist and astrobiologist from the Earth-Life Science Institute. Part of the Tokyo Institute of Technology. He's also an affiliate scientist with the Space Science Institute. He joined me the other day from Tokyo. Ramses, welcome to Planetary Radio. I'm happy to have you kick off the second set, numbers four, five, and six of these conversations. With all of you six scientists who wrote articles for the current issue of the Planetary Report, and of course you took on Mars. Thanks for doing this and thanks for the article too.

Ramses Ramirez: Thank you and I'm very glad to be here Mat.

Mat Kaplan: Well, it's obviously a subject you care a lot about. We found the water up there on Mars. We [00:04:00] know more or less now where the atmosphere went. Kudos to the Maven Orbiter. We even found organics. What's left on the red planet for us to discover?

Ramses Ramirez: Oh, there is, there's really a lot to discover on the red planet. We're just barely scratched the tip of the iceberg. Like you've said, Maven has brought in a lot of good information about accessing the atmosphere escape rates today. On Mars, as we understand them, based on solar activity, and then they've been able to come up with estimates as to how much atmosphere Mars could have lost over time.

My main focus, my main specialty is really understanding the, the early climate of Mars because then you know, that has potential parallels to how life could have started on Earth. We see interesting geologic features on Mars. Lots of fluvial valleys and networks and uh, kind of like you can think of them as Grand Canyon-like features that required a lot of water, so there's a lot of evidence that Mars used to be a [00:05:00] more Earth-like planet in the past, with a thicker atmosphere.

What Maven was able to tell us was, or infer is how much atmosphere Mars could have lost from then and now, which was a pretty big number. At least half a bar or so, which would suggest that Mars had a thicker atmosphere that potentially could have supported uh, liquid water on the surface at one point, and who knows? Maybe could have fostered conditions that were suitable for the emergence of life there too.

Mat Kaplan: So, one bar, that's the pressure of our own atmosphere here on Earth, right? At sea level. So if Mars once had that much air, it's lost half of it?

Ramses Ramirez: Yeah, that's actually, that's the, the interesting thing is that those estimates are really only a lower bound estimate.

Mat Kaplan: Wow.

Ramses Ramirez: Because they're able to, what Maven was able to do was infer some escape mechanisms. We call them non-thermal escape mechanisms. But they were very [00:06:00] strong thermal escape mechanisms, other escape mechanisms that would have been present in the past that you know, is not easy to tease out of the Maven analysis that could have to lead to even higher escape rates. So then the inference is that perhaps the atmosphere was at least one bar or more in the past. So, yeah. It's very exciting.

Mat Kaplan: Well, Mars, since you are interested in its early history when it apparently did have a lot more air. Obviously it would have been more habital back then, at least to life as we know it. Put that in quotes, and its habitability that you obviously care a great deal about. I mean, your website, habitalplanets.wordpress.com. We'll put up that link on this week's show page as well. You had a term there that I'm not familiar with and maybe you could take a moment to explain it; "dynamic habitability."

Ramses Ramirez: Yeah, this is a new term based on some [00:07:00] astrobiology reports that scientists put together the past year or two uh, to the scientific community. They've used that word and I kind of like it because it describes very well what I'm interested in as far as the scientific research goes. What that really just means is that habitability is extremely complicated, in a nutshell. And the long answer to that is that it requires an interdisciplinary approach to be able to assess the habitability of planets. You cannot just look at say the solar factors or geologic factors or the atmospheric factors.

Planetary habitability or dynamic habitability is really a systems level analysis that requires the influx of many different disciplines interacting with each other to try to answer these very tough questions. You can't just rely on biology or chemistry, or any one discipline by itself. With the influx in data that we're getting from all these missions, the Mars missions and now the Mars [00:08:00] 2020, hopefully that will give us a lot more. Should give us a lot more information and these exoplanet missions, all these different pieces from all these different fields, plus biology and chemistry will be able to ... I think we're, we're on the verge of a renaissance or renaissance of knowledge.

Mat Kaplan: Sounds like planetary science which is by definition multi-disciplinary.

Ramses Ramirez: That's right.

Mat Kaplan: All right. Let's pick up the three questions that you chose for Mars. The big question's remaining. Just as your colleagues who also wrote for this issue of the Planetary Report did. The first of these takes us back to the atmosphere. What was the atmosphere composition? Not just how thick it was or how dense it was of a warmer, early Mars. You talked about this consideration that perhaps it may have been carbon dioxide like a lot of it is now, but also hydrogen? Co2 and hydrogen?

Ramses Ramirez: Yeah, this is an interesting idea that's [00:09:00] actually not too old. Several years ago, 2013, '14, around that time frame we had proposed this as a possible mechanism because really the story has been for you know, a long time that the climate models really predict that Co2 by itself and water vapor would not be enough to warm the planet, no matter what model. No matter how much CO2 you put in the atmosphere, the Co2 has a strong greenhouse effect, but once you get to high pressures it also likes to condense out of the atmosphere and reflect a lot of radiation out into space. So, there's kind of a sweet spot beyond which you can't maximize the warming from that and that warming was always well below the freezing point of water. So then that caused many investigators to look at other possibilities, so Co2 in addition to other greenhouse gases, maybe you know, SO2, methane, other [00:10:00] possibilities, and a lot of these have issues.

SO2 for instance is good for warming cold planets, but not good for sustaining warmth on warm planets because it pulverizes and becomes very refractive and once it gets warm, you start to rain, it actually rains out of the atmosphere. Methane also has issues with stability. The atmosphere and other things. Hydrogen, we proposed that to be the other gas next to Co2 that would have been put on early Mars, primarily based on meteoritic evidence suggesting that Mars used to probably out gas a lot of this stuff. A lot of volcanism on Mars probably, uh, on early Mars, could have been hydrogen rich based on the meteoritic evidence suggesting that the mantle, the deeper interior of the Earth could have been oxygen poor, more hydrogen rich, so from there we infer that the early [00:11:00] atmosphere on Mars could have likely also been hydrogen rich.

And it just turns out because of the radiant transfer details that the combination of Co2 and hydrogen really gives you a good bang for the buck. Co2 absorbs well at certain wavelengths. Absorption works at different wavelengths across the spectrum, but hydrogen then also absorbs well, or the combination of Co2, hydrogen absorbs well in regions where Co2 and water alone do not absorb well, so it kind of picks up these windows. Hydrogen itself is not really a good greenhouse gas, but if you put it in collisions with another big background gas like Co2, it'll, you'll be able to excite these transitions and have that combined molecular pair, Co2 and hydrogen to absorb very strongly, so that's what's going on there.

Mat Kaplan: An intriguing model, but how will we go about determining if this was [00:12:00] actually the nature of the martian atmosphere a billion or so years ago or more?

Ramses Ramirez: Yeah, this is a very good question and it's something that we will have to actually, I think, with the Mars 2020, maybe we'll get some answers. One thing you want to answer before you even answer the atmosphere composition is whether early Mars was warm or cold, so there's still that lingering debate.

Mat Kaplan: Yeah. That's your second question that you posed, uh, which has come up on the show before. Was it warm and wet or cold and icy and just got warm every now and then? But not for very long.

Ramses Ramirez: Exactly, and essentially what Mars 2020 can do and future Mars missions is start assessing. The rover's going to start assessing these terrains and look for evidence of icy features. So far, rover missions we have at [Gale 00:12:54] and the orbital missions have not found any convincing evidence of an icy early Mars, which gives [00:13:00] more weight to the idea that Mars was probably not that icy. It was a pretty warm planet in the past. We need to continue those analysis and to verify that, but that seems to be again, more promising, this idea that Mars was once a warmer and wetter planet. But given that, if we're able to show that, in conjunction with that, yes. We want to determine exactly how did it get warm? What atmospheric conditions led to its warmth?

And that's a harder question, but you know, in one sense, a Co2, hydrogen atmosphere probably one idea is perhaps that you wouldn't expect that much oxygen, if at all in such an atmosphere, so there are markers. There are these things called banded iron formations that formed on the early Earth that just required some oxygen. Not a whole lot, but some oxygen in the atmosphere, or at least near the ocean and then you know, you can get reactions either abiotic [00:14:00] or biotic. That's debated. And form these, these iron bands.

So, you know, one thought is perhaps maybe you wouldn't expect to see those sorts of formations on early Mars if it was very oxygen poor. Some people would say, "Well, you know, on a warm early Mars, you know, with say an ocean in the northern hemisphere, which is what some of us like to say, that would be a good environment. If there's just a little bit of oxygen in the atmosphere, maybe that would be enough to get you these banded iron formations. Because these banded iron formations that we see on the Earth formed these ocean basins in the past. So maybe you would get them. So it's not clear, actually, which way that would go. But if we are able to determine Mars was a warmer planet and we confirmed it was an ocean there, but there's no oxygen, then that would give weight to the highly reducing or oxygen poor atmosphere that was hydrogen [00:15:00] rich. So, it's uncertain, but that's highly debated. It's a very complex problem.

Mat Kaplan: Hmm. A lot more to learn. Of course oxygen, it wouldn't be definitive evidence that there was or is life on Mars, but it wouldn't hurt to find some or evidence of past oxygen. Um, and that leads us to your third question and it is of course the big one. Did or does life exist on the red planet? Are we closing in? Are we getting closer? Now particularly with looking forward to the 2020 rover, now known as Perseverance and Rosalind Franklin which sadly we've learned is going to be a couple of extra years getting there while the European Space Agency and the Russians iron out the kinks.

Ramses Ramirez: Yeah, unfortunately, yeah. It's getting postponed. I think maybe it's due to the or partly at least this current epidemic, but um-

Mat Kaplan: Not helping.

Ramses Ramirez: Yeah, that's definitely not helping. As far as this question about did life exist or life, does it currently exist [00:16:00] on Mars, that's a ... That's the big million dollar question right there. You know, I said earlier if Mars was warmer and wetter and had a thicker atmosphere, as a lot of atmospheric and geologic indicators seem to imply, then that certainly would have fostered the conditions, uh, uh, especially if there was with liquid water evidence also that we're seeing, that would have fostered, uh, the conditions necessary for the emergence of life. And perhaps we'd be able to find evidence in the way of fossils uh in the rock record, but that's uh, that would probably require a man mission to send folks there. Planetary geologists and planet paleontologists that can dig up the surface and see if there's any evidence of fossils. Uh, which would be very cool if we found them. Because that would-

Mat Kaplan: Wouldn't it?

Ramses Ramirez: That would suggest a second ... I mean that would have extreme implications because if we able to, especially determine that life had emerged [00:17:00] independently, the suggestion would be on an exo-planetary scale that perhaps life is relatively common if two planets in our solar system, the first two that we begin to deep, dig deep, we find fossils that least microbial life or some sort of primitive life is pretty common in the universe. So, that's really cool.

Mat Kaplan: It's a much better sample than a sample of one, isn't it?

Ramses Ramirez: Exactly. It definitely would at least prove that life is possible outside of our planet, which has very strong scientific and philosophical implications. We don't think that there's life on the surface of the present Mars because it's pretty sterile, but there could very well be. Not just fossils, but actual living creatures underneath the surface that are shielded away from the radiation. So we, you know, little microbes or something that we'll have to prove, but I think we'll be able to show that pretty soon, in the next several years or so I hope we'll be able to [00:18:00] make headway on that question.

Mat Kaplan: You and me both and probably everybody who listens to this show. Of course, there are those, we won't have time to go into this particularly, but you do mention in the article, there are those who believe that we already found micro fossils that came from Mars on ALH84001, that mysterious uh meteorite. But, we'll save that for another time. Are you one of those who like pretty much every other scientist that I've spoken to, believes that the holy grail, at least for robotic exploration is still sample return?

Ramses Ramirez: I certainly think, you know my opinion of the holy grail is sending people there.

Mat Kaplan: Yeah, that, that's why I included the word "robotic," because I know how you feel about boots on Mars. We're going to get to that in a second, but okay, but short of people.

Ramses Ramirez: Yes. Well, short of people uh, sample return could definitely be, I would have to agree that that's probably the best thing that we can do aside from [00:19:00] remotely analyzing you know samples spectroscopically or what not, but yeah, sample return would be the next best thing we can do aside from actually sending people there. I would agree with that.

Mat Kaplan: Let's get to humans. You wrote a great 2018 blog post for Scientific American that I read at the time, didn't realize I'd be talking to you a year and a half, couple years later. You called it, Forget the Moon. So you apparently think, or I should ask if you still think that we humans ought to be exploring Mars alongside our robots. I mean it seems pretty clear that you think that ought to be our target.

Ramses Ramirez: Yeah, certainly when I wrote that article there was certainly a large of tension in the community. There still is about whether we should go to Moon or Mars first. I definitely prefer Mars. I think, you know, we do have technology to go there and carefully, I think we can have a successful scientific mission there, sending people there. But I can understand the value [00:20:00] of the Moon as well. Wherever you know, we decide to go,

Ramses Ramirez: ... of the moon as well. Wherever we decide to go or do, if we're going to do a Moon mission first or a man, a mission to Mars first, you know, I'm on board with either one, but I just, my preference is, uh, from a scientific return mission and I think Mars has even more potential. That was really the point behind that article.

Mat Kaplan: I'll say what I've said in the past. I sure hope I'm around to see, uh, those first men and women, uh, set foot on the, on the Red planet, uh. Ramses been great talking with you. I gotta ask you one more question though. How'd you end up in Japan?

Ramses Ramirez: Oh, this is, uh, an interesting question. The Earth's life sciences too where I'm working at right now is just a, uh, I've been keeping my eyes on them for a long time, ever since I was PhD student. And you know, I think they do a lot of great work here. We have, uh, it's really, it's an astrobiology Institute and as you know, as I've discussed throughout this, the show, it's very important to, to have an interdisciplinary approach for these [00:21:00] types of origin of life and life problems, astrobiological problems. And the Institute specializes in that. Came here, gave some interviews, they really liked me and I, uh, I'm now a scientist here. I just really feel in line with the philosophy of the Institute.

Mat Kaplan: That's great. Sounds like a pretty adventurous as well. I mean, if you had the chance, would you, uh, leave Japan and be part of that first mission to Mars, be the astrobiologist, uh, with a, with a pickax and looking for those fossils?

Ramses Ramirez: Yeah, sure. If, if, you know-

Mat Kaplan: [laughs].

Ramses Ramirez: [laughs]. I were, you know, if, if, if I were called to, to do something like that, yeah, that would be great for humanity. I would, I would say. Yeah. Um, [laughs] I would definitely, uh, uh, be among those, uh, trying to look at these rocks and features and seeing what we can find. There's a lot of hypotheses. I definitely want to test some Mars, so if nothing else, if I can't go, at least, you know, I'd be able to guide or give my advice as to what scientific [00:22:00] direction should be taken on the Red planet.

Mat Kaplan: Ramses you've got my vote if, if anybody asks.

Ramses Ramirez: Thank you.

Mat Kaplan: Um, thank you. It's been great fun talking to you and, um-

Ramses Ramirez: Thank you Mat.

Mat Kaplan: Let's, let's go to Mars.

Ramses Ramirez: Yes, definitely. I agree with that [laughs]. Amen.

Mat Kaplan: That's planetary scientists and astrobiologist Ramses Ramirez. We'll shift to our more distant neighbors, the giant outer planets in a minute. Please help me welcome a new sponsor to Planetary Radio with it comes a heady opportunity for all you creative plan RAD listeners. This time it's genuine rocket science. I know because I've got a bottle of it.

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Kunio Sayanagi is an associate professor in the Hampton University department of Atmospheric and Planetary Sciences. Kunio thanks for joining us on Planetary Radio. As we've worked our way out through the solar system, we have finally [00:24:00] reached those big outer planets and you start your article right off by saying that learning about these worlds, the four of them Jupiter, Saturn, Uranus, and Neptune really means learning about every discipline within planetary science. Can you talk about that?

Kunio Sayanagi: Yes. The other planets have 95% of the planetary mass in the solar system and it covers every discipline of planetary science. My favorite, of course is atmospheric science because I specialize, specialize in the atmospheres, but of course the outer planets have many moons as well. Each of those moons offer an opportunity for serious geology, exotic geology that that can be compared to all other bodies in the solar system. And of course, Jupiter has the strongest magnetic field of all planetary bodies, so that offers a lot of science as well. And on, on, on top of that, each of the four giant [00:25:00] planets has extensive systems of rings. Each of the rings is a prototype for the protoplanetary disc where all the planets formed.

Of course protoplanetary disks happened long time ago and we can't see those locally now. But rings offer an opportunity where clumps of ring particles meet and grow and possibly form new satellites in those rings. And the outer planets captured the first materials that the protoplanetary disk had, so by studying the composition of the outer planets, we can study the original material that we had in our solar system.

Mat Kaplan: So much more to explore out there. We'll talk a little bit in a couple of minutes about what we've learned recently and what still remains to be learned and how we might go about doing that, the missions that are being talked about. Um, but [00:26:00] first I want to talk about the decadal survey process with you, which comes up very frequently on our show because you obviously agree with pretty much every other planetary scientist that it is a very important process.

Kunio Sayanagi: Yes, of course.

Mat Kaplan: You mentioned that even before the decadal survey process, you can look back more than 50 years and there were reports that, uh, that talked about these kinds of goals for, for first study of the outer planets. Apparently we have quite a, quite a history of curiosity about these worlds.

Kunio Sayanagi: When I started talking about the decadal survey or the writing about the decadal survey, I wanted to be precise, so I started reading some older document and I started to finding references to big survey that the National Academy did in 1965. As far as I can trace, that was the original point where scientists got together to formulate these big questions.

I was almost shocked that the three [00:27:00] questions really haven't changed since then. They are worded differently, but they, the three are about the origin of life and how life evolved. So that's one question. Another one is other source system formed and evo- evolved. And the third question is usually worded in many different ways of it, but it's, it is about present day processes. Studying how the processes are working today and still making the solar system evolve.

Mat Kaplan: I'm struck by the last part of that last question that you posed in the magazine. How do we get such diverse worlds, uh, because it'd be wrong to think of these, these four planets as, as being terribly similar. I mean, they obviously share some similarities, but you see, um, uh, plenty of reason, uh, to uh, identify them individually.

Kunio Sayanagi: Yeah, um, so we don't have to constrain ourselves to just to giant planets. I am a planetary atmospheric [00:28:00] scientist, so I am basically interested in weather and climate. Those are inherently present day processes but when we say weather, we can study it two different ways. Of course, earth offers a lot of opportunities. We live in this atmosphere so we can study a lot of things in situ. But to make progress we tend to study extreme events where we are challenging our knowledge, right?

So we can either wait for extreme things to happen on earth or we can seek out extreme things that are always happening from earth parameters and the relative to earth parameters, of course. And the giant planets offer big atmospheres. So they offer a lot of opportunities. And another thing I like saying is that planetary sciences, just like psychology, my wife is a psychologist by the way-

Mat Kaplan: [laughs].

Kunio Sayanagi: So I like saying that. In psychology you do not understand one person, one person to death to [00:29:00] understand human mind and behavior, right?

Mat Kaplan: Yeah.

Kunio Sayanagi: So in studying planetary weather, we don't just study one planet to say that we understand whether. We study all the planets we can study and try to understand underlying laws of physics that governs the weather.

Mat Kaplan: There are always surprises, aren't there? I mean, every time a mission has gone either to orbit a planet or to pass by one, we, we've talked many times on this program about the surprises that wait for us and, and frequently the theories that have to be rethought.

Kunio Sayanagi: Yeah. Um, my favorite example is the hexagon on Saturn.

Mat Kaplan: Yeah.

Kunio Sayanagi: Of course, and I, I just came off of the Cassini mission. I was an affiliate of the imaging science team, have you talked about the hexagon on this show before?

Mat Kaplan: Oh, many times, uh, both, uh, with Linda Spilker, the project scientist for Cassini, Linda is still, uh, the person, the individual who's been on the program more than anybody. And, [00:30:00] uh, not that long ago with the Carolyn Porco.

Kunio Sayanagi: Oh, great. My core specialties, atmospheric dynamics of the Zion planets so the hexagon on Saturn is one of my favorite features in planetary atmospheres. Um, the hexagon was found in Voyager data with the spacecraft flew by Saturn in 1980 and 81. The hexagon in the data, of course, it was not noticed until 1988 because it was in the polar reason and both of the probes, both of the Voyager probes flew by Saturn in the equatorial trajectories. So the hexagon was in the heart defined spot and those images. But in the 1988, there was a paper that got published and then that was very puzz- puzzling.

It took a long time to really come up, come up with an explanation. In 19- 1991, um, there was some theory papers that proposed, um, theoretical explanation for [00:31:00] those things. For the hexagon. But it was difficult to prove it was, it was not until 2010 and after when the computer simulations and became sophisticated enough to test those ideas and I've been a part of a couple of those papers. Basically it's a meandering jet stream.

Even in the Voyager data, it was very clear that at the center or the along the outline of the hexagon, there's a jet stream that's blowing eastward along the hexagon, hexagon outline. So we always knew that it was associated with a jet stream, but why it was meandering in the six sided shape was something where you couldn't really explain until the 2010s.

Mat Kaplan: I would bet them that you are just as fascinated by those six cyclones that, uh, have been imaged by Juno, still actively orbiting Jupiter that are Jupiter South pole. In fact, there is a [00:32:00] gorgeous rather stunning image of the cyclones in, in your article, in the planetary report.

Kunio Sayanagi: Yeah. So it's definitely puzzling that those cyclones do not merge. This is a knowledge we have from earth, Austin dynamics, by the way. So when we place vortices that are spinning in the same directions, they usually merge. That's what we would have expected at Jupiter when we place cyclones close to each other, any two would merge, but to find six of them together was a big sock at the beginning.

So I actually have a graduate student who's been studying the dynamics of that. I don't think he's found a case that found a way to keep them apart, but there is a postdoc at Caltech named Chang Lee. I think he just moved to Berkeley. Um, he found a way to keep the cyclones from merging. He just [00:33:00] presented the results at the AGU meeting last December and I think, um, I'd been waiting for that paper to come out.

Mat Kaplan: That's great to hear. And I wish we had more time to talk about what we've learned already, but we probably should go on to talking about the mission so that you're looking forward to in the next few years and you identify a, a several that you're, you're pretty excited about beginning with Europa Clipper.

Kunio Sayanagi: Sure. So that is what has become of what was the recommended by the last D. Kayla survey? The last, D. Kayla surveys, top three picks for a large class mission. These are the missions to be directed, uh, directed by NASA, managed directly by NASA. The top one is Mars Sample Return. That became a Mars 2020. The next one as recommended by the decadal survey, it was called Europa Jupiter Orbiter. It was an orbiter to orbit around Jupiter, but its main target was going to be [00:34:00] Europa. That is the Clipper mission that we are talking about now.

Mat Kaplan: And then of course the enormously exciting, not that Clipper isn't, a but Dragonfly, which is really fired the imaginations of so many people that that mission that uh, will be headed to Titan, although not for a few years yet.

Kunio Sayanagi: Yeah, it is part of the new frontiers program, uh, the program has supported a series of really exciting outer planet missions. The first one was a New Horizons mission. And then the second New, New Frontiers mission was Juno. It's doing really exciting science at Jupiter studying the atmosphere and interior, the latest excitement they're about to publish or they have just published, I haven't seen the paper, one of the core goals was to determine how much water Jupiter collected when it formed. That's going to tell us when and where Jupiter formed in the solar system so that [00:35:00] when the paper comes out that's going to be really exciting. And then of course the third one is OSIRIS-REx that's going to a near earth asteroids and then the fourth one is going to be Dragonfly.

Mat Kaplan: I want to mention at least in passing the European Space Agency's current preparation for the JUICE mission that Jupiter Icy Moon Explore another orbiter. I want to go further out in the solar system too and give some sympathy once again to pour a Uranus and Neptune and all those scientists who've been waiting for us to visit those outer planets once again, what would you like to see happen at one or both of these worlds and not just you, but what is being talked about in the community?

Kunio Sayanagi: Among the planets, Uranus and Neptune are the only ones that have not been visited by an orbiter. Uranus and Neptune have been visited by Voyager 2, Oh, I was in the second grade, I was, I was attending school, primary school and Japan. [00:36:00] When I started hearing the news on the radio and on TV about the Voyager 2 fly by of Uranus, I started asking a lot of questions to my parents about a Uranus and what Voyager 2 was doing out there.

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The Next 10 Years: Continuing our Solar System Tour - The Planetary Society