Planetary Radio: Space Exploration, Astronomy and Science - It’s a Hard Rain on Titan

Episode Date: January 17, 2018

A computer model based on our best data about Saturn’s cloud-shrouded moon says that torrential liquid methane pounds the surface far more frequently than previously expected. Sean Faulk and Jonathan Mitchell of UCLA explain.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Vacationing on Titan? Bring your umbrella, 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. You may need a lot more than an umbrella if you're on Titan during a real downpour. We'll talk with two UCLA scientists whose model of the climate on Saturn's big moon predicts truly titanic storms happen much more frequently than previously thought. Bruce Betts has more about the upcoming total lunar eclipse that many of you will be able to see. We open by welcoming back my colleague Jason Davis. Jason is the Planetary Society's digital editor. He just wrote about plans to visit yet another of our solar system's ocean worlds. Jason, great piece that you put in the Planetary Society blog.

On January 11th, you were laboring apparently under a misconception that I also had, but you have disabused me of, I think that's the right term, which is that Enceladus might have been the better place to send something like the Europa Clipper, not necessarily? Yeah. So I think that this misconception came from the fact that Cassini was sending us all these awesome pictures of the plumes coming from Enceladus. And there's evidence that they're linked directly to the subsurface ocean there. So if you want to sample what's in the ocean, why not just fly through those plumes and grab a nice sample and look it over? And Cassini did that to some regard.

Europa Clipper going to Europa kind of wants to do the same thing. They want to get some of that material that's coming from the ocean and take a look at it. To me, it made a lot of sense that you would want one of those big plumes like Enceladus has. But the problem is we've looked for plumes on Europa and the evidence that they're there, at least like the way they are on Enceladus, is kind of hairy. It's kind of on the edge of detectability. Hubble looked a couple times for these plumes, was really pushing the telescope's limits to the edge, and it thought it saw something. Maybe it did, maybe it didn't. So, you know, the question of whether or not there are plumes like Enceladus is kind of hanging out there. And yes, like you, I thought, why are we sending it to Europa? Why

don't we send it out to Enceladus and grab some samples there? But it turns out that Clipper, because of the extraordinary instruments it's going to be carrying, including these two mass spectrometers, shouldn't really be a problem. The mass spectrometer, there's this mass spectrometer called MassSpecs. And what it can actually do is weigh the amount of chemical compounds in any sample. And that's what you want to do when you want to see what's exactly in your ocean sample. Hubble, when it detected what it thought were plumes, it thought it was seeing about 1,000 kilograms of material per minute coming off of Europa. Mass specs can actually detect just one kilogram of material per second.

So scientists are pretty sure there are plumes there. They just don't know how big they are. That's really the only outstanding question. And it turns out even if they're really, really faint, mass specs will be able to get a sample of them. And in the event that there are no plumes at all and we don't have any direct outgassing from the subsurface ocean, there's still another way that mass specs can actually see what's in the ocean.

And that's that we've got all these cracks and fissures all over Europa. It's really compelling evidence that some of that water from the subsurface ocean makes its way up to the surface, seeps out of the cracks onto the surface, and Jupiter's radiation then blasts it. And that's what turns into these rust-colored streaks through this oxidation process. And so during that turns into these rust colored streaks through this, this oxidation process. And so during that process, a bunch of material actually gets blasted off of Europa, these same kind of particles from the ocean, or at least they, they used to be particles from the ocean and they've changed into some other stuff. Same deal. Mass specs can sniff those out, kind of do some reverse engineering, figure out where they came from, what's in them and still

figure out what's in the ocean. So really cool. Two different ways they can do it. And they're very confident that, yeah, this is no problem. They're going to be able to get it to work and answer this question. Remind us, if Clipper is able to do its job in the mid-2020s, is it going to be able to tell us that there is life in that vast ocean underneath the ice? So as much as we want to say, yes, it will find life, it looks like even the best case scenario, it would come up just short of scientists being able to say definitively, yes, that's life. Now, the mission's main goal itself is to assess the habitability of Europa. So we want a positive you know, a positive result

in that case would be able to say, yes, the ocean very much is habitable. It looks like it could support life. Now, there are a couple signs that they would get from mass specs and combined with the rest of the instruments on the spacecraft that yes, it does look like there might be something there. However, they probably wouldn't be able to say with certainty. So the two things they'd want to see would be organics and alone organics aren't an indicator of life. They're everywhere in the solar system, but they're kind of the building blocks of life. And then the second thing they would want to see would be some molecules that indicate something interesting is happening with these organics below the surface. And that'd be like methane, ammonia, hydrogen sulfide. And that would tell us that there's some process going on below the surface. So those two things, if they got a

positive result, they'd be able to say, well, this really looks habitable. And it looks like something could be there. But as one of the scientists told me, then they're going to argue that result to death for the next 10 years. And, you know, probably won't be able to say with 100% certainty until we send a lander mission there. Jason, it's a great piece. Available at planetary.org. It was posted January 11th. No plumes, no problem.

How Europa Clipper will analyze an icy moon's ocean. Thanks very much. Thanks, Brent. We're off to another ocean world now, an ocean of a very different sort on Titan. of a very different sort on Titan. In one week, Hurricane Harvey dumped more than 40 inches, well over a meter of rain on Houston, Texas. No one had ever seen anything like it.

But what if that kind of storm arrived almost annually? A computer model based on the best data from the Cassini orbiter and the Huygens lander says that is exactly what happens on Titan. Now granted, one titanic trip around the sun lasts nearly 30 of our puny years, but that kind of precipitation helps explain the amazingly Earth-like topography of Saturn's big cloud-shrouded moon. What would a thunderous rainstorm sound like there? How would drops of liquid methane feel as they struck your well-insulated spacesuit and helmet? These are among the questions I had for two authors of a paper published in Nature Geoscience last October. UCLA grad student Sean Falk was lead author of that work.

It was a few days ago on a soggy Southern California day that I engaged Sean and his mentor, Jonathan Mitchell, in an online conversation. Jonathan is an associate professor of planetary science and principal investigator in UCLA's Titan Climate Modeling Research Group. Get ready to be immersed in science. Sean and Jonathan, thank you so much for joining me on Planetary Radio for this conversation about these wicked storms that you have modeled on Titan.

You know, as we speak, Southern California is getting its first substantial rain in months. It's coming down pretty good. I've heard we might get a couple of centimeters or maybe three quarters of an inch of rain. How would that compare with one of these Titan downpours that your model has shown may very well be taking place on that cold moon? Well, this is really nothing. It doesn't even really compare with one of the great outburst storms that Titan experiences. We've compared it to Hurricane Harvey sitting over the greater Houston area for a few days and dumping feet of rain.

You know, centimeters of rain can be quite a bit, especially over a burn scar following the wildfires. But we're lucky not to have anything like Hurricane Harvey over us right now. Yeah, thank goodness. And I don't want to make light of it because, of course, those denuded hillsides are in big trouble right now in Southern California. Let's go back to Titan and let's start with the Cassini spacecraft, which it looks like it enabled the remarkable modeling that you guys have done. Is that fair to say? Yeah, absolutely. I think the model that we've used has been well established thanks to observations from Cassini,

especially of the clouds using the ISS and VIMS instruments on the Cassini spacecraft, and also the Huygens probe landing and getting a temperature and pressure profiles. It really helped get the model to be where it's at today. And then now with this study, we've been able to use, to leverage observations of alluvial fans using the radar instrument on Cassini to really compare to the extreme precipitation events that we've seen in the model so we can get a better understanding of the connections between the surface and the climate. I'm going to come back to those alluvial fans a little bit later in our conversation, but I was going to ask you next if the Huygens probe assisted you with the modeling at all,

and you just said, yeah, it sure did. Absolutely. None of this modeling really would have been possible without the constraints provided by Huygens and Cassini. have been possible without the constraints provided by Huygens and Cassini. Especially, Huygens was really good at getting, of course, in situ measurements very close to the surface. What's key for understanding the weather in the lower part of the atmosphere is how the temperature changes with altitude. And so getting that in situ measurement, even though it was only one, was really key to sort of grounding the modeling that we do. Can you remind us that VIMS instrument that you mentioned?

It's an infrared instrument on the Cassini orbiter, right? Yes, yeah. It's the Visual Infrared Mapping Spectrometer. Talk about this model. What kinds of factors had to go into creating it, and how complex is it? Is this something that has to run on some pretty powerful hardware? Well, I want to start out by saying our colleague, Juan Lora, was really responsible for the initial development of the model. He put it together basically as a graduate student at the University of Arizona, and we've been using it as our workhorse since then. I would call it something like intermediate complexity. So there's a whole philosophy in understanding

climate that comes from the earth community that uses a whole hierarchy of models, all the way from very simple models that don't even have any physical dimensionality except for time, all the way up to comprehensive models that have vegetation cycles coupled in with the climate system, for instance. In our modeling, we focus on the sort of philosophy that simpler is better in the sense that the observations are really what ground us and keep us from going too far into sort of just speculation, I guess you'd say. And so we've settled in on this intermediate complexity model that has really gotten us a long way in understanding both constraining the model against the observations, primarily from Cassini,

but also from ground-based observations, but also enables us to really dig into the model simulations and find how they're working, how the weather works, what are the controlling factors, and so forth. And we do run it on state-of-the-art hardware, although these intermediate models don't require hundreds of CPUs to run on. We can run them on a handful, maybe 16, between 16 and 64 processors. And the advantage there is that the intermediate complexity models run fast compared to the more comprehensive ones. And so we can test sensitivity to different parameters and boundary conditions. And that's the exploration that allows us to get a better understanding of how the physics works, the physics of these systems, the physics of the climate as a whole, and how it interacts with the surface. Is this model still a work in progress?

I mean, we've heard on this program that a lot of that data from Cassini is still being worked on and revealed. Yes, absolutely. And that's part of what I'm completing my thesis work on is adding specifically parameterizations of surface hydrology into the model. And so this is adding surface runoff. So when the precipitation happens, that rain has to go somewhere and it runs off into areas of lower elevation. And so using topography data that we've gotten from Cassini, we can determine if it rains in a given spot where that methane will flow after precipitation events. And then furthermore, you also have infiltration perhaps happening. We're not really sure of how quickly this is happening or if it's happening to a very

extensive degree, but this is something that we it's happening to a very extensive degree. But this is something that we're going to allow in the model and see if we can constrain a little bit more. And then also, once that methane infiltration goes into the subsurface, then it could flow horizontally in the subsurface as well, based off of topography and how much methane is in the subsurface. And so we basically put in a sort of analog to a water table that we have in the groundwater systems on Earth into this model for Titan. We're looking at that and we're developing that right now. And it's so far leading to some pretty interesting results

and seems to be important in the climate and weather of Titan. This really is remarkable. And the more you describe, I mean, like the existence of, if not a water table, perhaps a methane table on Titan, the more it sounds like it resembles the systems that we're familiar with here on Earth. I mean, do you find that pretty striking? In some ways, it's very striking, but I've come to expect it at this point because there's been so many remarkable discoveries, especially from the Cassini-Huygens mission, that make Titan look so familiar to us relative to what we see on Earth. It's really been a fun exploration. And at the same time, each of those instances that tell us that Titan is similar to Earth, Titan always has its own take on the physics. So for instance, we have tropical systems or tropical climate along the equator

on Earth, and that has to do with something called the Hadley cell or the overturning circulation in the tropics. On Titan, because of the very, very strong influence of seasons, the equator ends up getting the dry subtropical deserts that we have on Earth end up squeezing together and coalesce on the equator. And those wet regions get moved to higher latitudes, but only in a seasonal sense, like the monsoons on Earth. It's a great example of how climate in this case is very similar to Earth. It operates on the same principles, but Titan has its own take on the way it's distributed in latitude. And just adding on to that, you know, that's a great point of how the Hadley cell is different and is partly perhaps responsible for why we see a lot of the surface liquid at the poles on Titan.

You know, most of the lakes and seas are in the polar regions, especially in the northern hemisphere. But part of why we do this sort of incremental modeling is to see what are the, you know, what are the different effects or different features of Titan that may be responsible for these ideas. So it's possible that because you have lower topography in the polar regions, and then if you have precipitation, that runoff might be helpful in transporting the methane towards the poles as well. So that might be another factor. It's important to sort of keep in mind that Titan is itself a large system that's very complex and very much like Earth.

And so we want to look at these different parts of that system. And we do that by modeling. Sean's work is a great example of this approach of simpler is better. The boundary condition is at play here. So the surface boundary condition in our climate model had been up into very recently within the last few years, the equivalent of a swamp, a global swamp on Titan. So the idea being that without any direct evidence otherwise, maybe Titan's surface is just wet everywhere. But we found that we weren't able to match the various observations of clouds and near-surface conditions observed by Cassini and ground-based telescopes with that boundary condition. Our collaborator Juan Laura and I decided to restrict the liquids at the surface to the polar regions north and south of 60 degrees. And what we discovered is that if you do that artificially in the model,

the model will tend to build surface liquids back up at at the equator what we had to do is add in infiltration in the surface so that precipitation that occurs at low latitudes gets wicked away towards the subsurface table that was completely artificial and that's the boundary condition we've been using for the last few years. That result directly motivated Sean's thesis project to add in realistic surface hydrology so we don't have to do this artificial thing of making the liquids at the surface disappear at the equator and keeping them only in the polar regions. That's UCLA planetary scientist Jonathan Mitchell. He and grad student Sean Falk will return in a minute with more about the weather on Saturn's moon Titan,

including their speculation about what it would be like to stand in a titanic downpour. This is Planetary Radio. Hi, this is Casey Dreyer, the Director of Space Policy here at the Planetary Society. And I wanted to let you know that right now Congress is debating the future of NASA's budget. The House has proposed to increase NASA's budget and also increase planetary science in 2018. The Senate, however, has proposed to cut both. You can make your voice heard right now. We've made it easy to learn more if you go to planetary.org slash petition 2017. Thank you. Thank you. Advocate for space and educate the world. The gift of space starts at planetary.org forward slash give space.

That's planetary.org forward slash give space. Because, come on, it's space. Welcome back to Planetary Radio. I'm Matt Kaplan. My guests are Sean Falk and Jonathan Mitchell of UCLA. Sean is the grad student who served as lead author of a paper with dramatic conclusions about the climate on Saturn's big moon Titan, the frigid world that nevertheless resembles our own Earth in so many ways. Jonathan is associate professor of planetary science at the university,

a senior author of the paper, and Sean's mentor. What surprises you most about this model when you run it? I read that the results regarding the frequency of these really big storms was kind of a surprise in itself. That to me was a big surprise, yes. I know that in previous conversations, for instance, Alex Hayes has pointed out that there's a huge amount of liquid available in the atmosphere in the form of vapor, methane vapor in Titan's atmosphere. So the quote is that if it all rained out, you would have a global ocean several meters thick, five to seven meters thick or something like that, that would cover the entire moon. meters thick or something like that, that would cover the entire moon. The problem with releasing that or getting that vapor out of the atmosphere is that the atmosphere itself is so cold and dense, it's very difficult for that type of material to get rid of any heat that is produced in the

atmosphere. And as we know, when liquids condense, they release latent heat. And even though the latent heat of methane is lower than that of water, it's still a lot of energy that's released, heat that's released into the atmosphere. And the atmosphere is just not very good at getting rid of that heat. you might expect these storms to happen every millennium or so, because if a huge amount of latent heat is released, it will take a long time for that heat to be radiated back to space and allow the atmosphere to have the capacity to absorb another of those big latent heat release pulses. So to see them happen sort of every 50 Titan years may seem like a long time, but that actually isn't a very long time compared to what I expected. Does the model predict that there are, in addition to these really huge downpours, that there are lighter showers on a more frequent

basis here and there on Titan? Yeah, absolutely. We see those, particularly in the polar regions, actually. We see that the most total accumulation of methane occurs in the poles, which is consistent with seeing the most lakes and seas in those regions. And so you do sort of have this sort of persistent, you know, small scale precipitation events happening in particular in those regions. But the most intense events happen actually at the lower latitudes, which is actually what surprised me more, is that you have in the mid-latitudes in particular, where you have these really, the sort of Hurricane Harvey level events occurring,

quite astounding to me to see that you didn't get the, even though you have the most methane in the poles, you didn't get the most intense events there. But yes, you do have that sort of persistent low magnitude events happening pretty much all over. Maybe this would be a good time to talk a little bit about those so-called alluvial fans that I really love to see as I drive through the Southwest. Can you describe them for anybody who hasn't had that pleasure and why the ones on Titan have been so important to this work? Yeah, so these are large features produced by sedimentary transport. You basically have, after a large precipitation event, you have these sediments that are transported down a gradient, down a slope.

They sort of fan out into these cone shapes, and That's what we observe as alluvial fans. They happen on Earth, and they're most observable in arid regions, but they happen in all regions on Earth, arid and humid. But on Titan, we've been able to detect them recently using the radar instrument on Cassini. And we actually find that they're most prevalent in the mid-latitudes. find that they're most prevalent in the mid-latitudes. We can see that from our precipitation distribution. We see that the most extreme precipitation events are actually occurring in the mid-latitudes, right where we see these alluvial fans.

So, you know, these alluvial fans cannot be created without heavy precipitation. There are other factors that go into their formation, namely what the material is of the surface. But regardless of that, you still need this sort of intense precipitation event to trigger that sediment transport and initiate alluvial fan formation. And so it's astounding that we see the alluvial fans in the same regions that we have in our model have noticed where we have the most extreme precipitation events. And so that's showing that you have this just as on Earth, where you have that connection between extreme precipitation and alluvial fan, between the climate and the surface. You also have the same, from our study, you have the same relationship occurring on Titan as well. I've seen pictures of this, and it never ceases to amaze me how much it looks like what you see in the southwest of the United States. But speaking of that surface

material, it's very different, isn't it? Are we talking about that hard frozen water ice that makes up these fans? I should say that we don't know for sure, but we think so, yes. We think it's, we know that the crust or the lithosphere of Titan is made up of water ice. We know that from the gravity measurements and the mass and the size and the meat density and so forth. The spectral properties of the materials in the observations that are available from Cassini and ground-based telescopes don't really tell us much in terms of what the material actually is. So it's probably a mixture of stuff. It's definitely the water ice, but there's also something mixed in that rains out of the atmosphere. In Southern California, we get

smog development in the summer months especially, and this process happens naturally in the atmosphere of Titan. And these produce longer and longer particulate chains that then finally rain out as this smoggy soot. And that probably has been going on for a long time and most likely built up a regolith of sorts, maybe a very cold, tarry regolith of some sort. We don't really know. I should mention also that the Huygens probe, when it landed on Titan, took pictures of the surface. And what we see are rounded stones

of several centimeters across that are almost certainly water ice pebbles that probably are sitting in a dry lake bed or maybe even in transiently filled regions that collect runoff as these storms infrequently fall on the hills that surround it. So we do know that there are ice pebbles and so forth that are moved around, but we don't know exactly what the surface is. The more I hear, the more I think we've got to go back to this little world. How do you feel about the recent New Frontiers mission down select? It doesn't mean it's going to happen because there is competition still. But that down select included Elizabeth Zippy Turtle's Titan drone, which would have the ability to flit here and there on Titan.

Well, for me, there truly are sirens on Titan because when I got started working on Titan in grad school, Cassini had just captured into Saturn's orbit and Huygens was getting ready to be released and land on Titan. And it was just too great of an opportunity as an atmospherist and planetary scientist to pass up. And I thought that, you know, naively at the time, I thought it would just be sort of a, you know, a way to learn about planetary climate. And I've been working on it now for the better part of 13 years. And, you know, as Cassini just wound up this, its final mission this past year, I sort of had the sense and the planetary community has the sense that the focus, the spotlight moves to another object and people sort of have to be agile in what they work on. And so I was prepared to do that. But just to have another opportunity possibly coming up to go back to Titan sort of blew my mind. I was very excited about it. There's much more to be done on Titan, even with the Cassini data.

But to have it in the public eye and to potentially have a mission returning, such an exciting mission, to me is just yet another example of Titan calling me back. I would be very excited about this mission because it would really stoke public interest, I think, just in the sheer imagination of the idea alone. And, of course, we get some of the questions that we've been talking about today. We get a lot better answers to some of these questions as far as getting closer to the surface and seeing what the distribution is like of maybe some more alluvial fans and seeing the surface material, getting an idea of that, and really being able to zone in on some of the smaller questions that we have and that relate to a very large degree to the global climate and weather of Titan. So I think I'd be very, very excited about this mission. I think it's great. Sean, it sounds like you're kind of where Jonathan was about 13 years ago in your career, since you're currently a grad student working with him at UCLA. And yet you are the lead author

of this paper. How does it feel? I really do need to say and stress that this is a very collaborative effort, you know, not just with me and Jonathan, but another faculty member here at UCLA, Sulgi Moon, who's a geomorphologist and really helped us out with, you know, understanding the connections between precipitation and how they are expressed on the surface. That's, you know, and looking at some of the statistics that we do of, you know, what makes a rare precipitation event and how do we get these probabilities? That was really all Sulgi. She really helped us out with that. And then, of course, Juan, Juan Loro, as we've talked about, really developed this model and helped me out a lot with understanding how the model works and with understanding the connections also between

the surface liquid distribution and weather. And so this has really been an extremely collaborative effort. And I feel like we're all sort of co-authors on it. But of course, it's been great to have the opportunity to go through the publication process and see what it's like and what reviewers are like and what's necessary to really make a strong and interesting paper. But again, I really need to stress the mentorship that I've gotten from Jonathan, Sylvie, and Juan all. It's been a really great experience. Jonathan, it sounds like you're able to give Sean a pretty spectacularly valuable experience there.

I should put the spotlight right back on Sean because he really is a fantastic student. He has done everything and more that I've put in front of him and really do anything he sets his mind to. So it has been a great collaborative effort. I totally agree with Sean in that regard with our collaborators, Juan, Laura and Solgi Moon. It is important, I think, for students to have these sorts of experiences to lead a study. It gives them the key experience and leadership that they will need in whatever career they choose down the line. This was just a fantastic opportunity that really grew organically from the folks we have here. That includes especially Seulgi Moon, as Sean pointed out,

the folks we have here. That includes especially Seulgi Moon, as Sean pointed out, our colleague here at UCLA, another faculty member. It's a delight to really be able to do this and get some high profile sort of coverage of it as well. But I just can't stress enough how great it's been working with Sean, having him here these years. I can't let you guys go without sharing a little bit of imagination beyond the science that you've been delivering. In case you've considered it, I certainly have. What would it be like to stand in the kind of big storm on Titan that your model says probably occurs maybe once every Titan year or so? I mean, would methane rain feel different hitting your spacesuit than water? Yeah, Sean and I were talking about this before we got on the phone. It's a great question. One of the fascinating things about the way water behaves with solids

here on Earth is that water is very, the water molecule has a high polarity to it. And so it makes it a very good solvent, things dissolve in it well, but it also makes it a good detergent, which means it sort of wets surfaces really well. And you see this on a car windshield, for instance, or a window. When it rains, you'll see these streaks forming down the sides of the window as the rain falls. A fascinating difference between water, the condensable in our system, and methane, the condensable in Titan's system, is that the polarity of the methane molecule is much lower. That will make it significantly less effective as a solvent, depending on what the material is, but especially for solid materials.

It would probably also make it less of a detergent, which means that when it lands on hard, solid surfaces, it would probably bead up as if you had placed some sort of rain repellent on your car windshield or on your car, waxed the metal on your car, the paint on your car. And you see these beads run off very quickly. So Sean and I were joking that you probably, if you wanted to put windshield wipers on your visor or your helmet, you probably want them on the inside rather than the outside, because you probably have no problem getting the methane to wipe off the outside if it rained. But the inside would probably fog up

pretty quickly because of the great temperature difference with the outside and the water vapor that's you're expelling in your breath. You keep those defrosters turned on. Absolutely fascinating. I am really pleased that I asked you that question to close out this great conversation. Guys, I just want to thank you and congratulate your entire team there at UCLA on this great work. And I look forward to hearing more as you zero in on what conditions are actually like on that amazing little world called Titan. Thank you, Matt. And thanks for the great questions. It's been a delight. Yes. Thank you very much, Matt. Appreciate it.

That was Sean Falk, graduate student in geology at UCLA. He's the lead author of this paper, which we'll put up a link to, at least you can read the abstract. It's called Regional Patterns of Extreme Precipitation on Titan, Consistent with Observed Alluvial Fan Distribution. It was published by Nature Geoscience last October. And with him, his mentor, Jonathan Mitchell, UCLA Associate Professor of Planetary Science and a senior author of the paper. Jonathan is also the principal investigator of UCLA's Titan Climate Modeling Research Group. We're going to take a look at the night sky now, as we do every week with Bruce Betts. Time once again for What's Up on Planetary Radio.

We have the Director of Science and Technology for the Planetary Society joining us. That's Bruce Betts. Welcome back. Hey there, that's Bruce Betts. Welcome back. Hey there, Matt. Good to have you. Before we get into the night sky and all that other good stuff, you know, I just talked with Jonathan Mitchell and Sean Falk. People heard me ask that last question about what would it feel like to be in one of these monster downpours on Titan.

A few days later, after the interview, I got a note from Jonathan, the associate prof at UCLA, that he really has to think about this some more. He may have been too overconfident in his story about that. He says, while it is the case that water form streaks because adhesion is competitive with cohesion and that methane has a much lower polarity than water. Apparently, the adhesion is so low with methane. He said he really has to think about this and maybe do some laboratory testing or molecular dynamics simulations. He said methane rain almost certainly behaves differently on glass than water rain, but I can't say for sure how right now.

Glass, because he was thinking of the visors for the helmets that astronauts are someday going to wear on that moon, right? You, this gives me an idea that you should totally volunteer to go into the environmental chamber and have methane rain dumped on you. And you can also record it. I would love to do that. Of course, I prefer to actually be on Titan, where I've already volunteered to have the remote control for the drone if that drone gets sent to that moon.

If we could send you a billion miles away, we would. With a good internet connection, of course. All right, enough of that. What's going on up there? All right, let's start with the big unusual, which is a total lunar eclipse where the moon will enter completely into the Earth's shadow on January 31st. It will be visible from Asia, Australia, the Pacific Ocean, Western North America, although Eastern North America will get some of the partial eclipse

before the moon sets, and Eastern Europe. The greatest eclipse time in UT is 1330. For us, that's 530 a.m. For much of North America, the moon will actually set in eclipse in the pre-dawn. That's the big news. You also got planets in the pre-dawn sky, but lunar eclipse coming up is what's super groovy. Yeah, and how. How? The Earth enters. No, no, no, no, no.

No, you're doing it. We'll do that another time. All right. All right, we move on to this week in space history. It, no, no, no. We'll do that another time. Alright. Alright, we move on to this week in space history. It was 2006, 12 years ago. New Horizons launched on its way to Pluto and now on its

way to a Kuiper Belt object. Alright, we move on to... Random Space Fact! You know what? We had somebody hinting that we should get your evil twin E--Curb, on the show sometime. And it occurs to me that was almost E-Curb's voice. We should do a What's Up with E-Curb someday.

We should indeed. Oh my God. He's somewhere. He's around. Closer than you think. Speaking of twins, Gemini 8 was the mission that had the first docking of two spacecraft in orbit, but also suffered the first critical in-space system failure on the U.S. spacecraft that made things exciting as Neil Armstrong and David Scott started spinning and spinning and spinning. But it all worked out okay. First, how clever of you to make that twins segue. I have several random space facts just sitting around and I grab the one that makes the most relevant. Also, we should note that it was Neil's amazing performance, basically saving

himself, his partner in that mission that helped get him the job of being the first guy to step on the moon. Dave Scott certainly credits him with the amazing skills to stop their spacecraft from spinning. They were docked to an Agena upper stage from the rocket. That was the test thing to dock to. We'll come back to space docking a little bit later on. All right, we move on to the trivia contest. And I had asked you who proposed the names that we all use for the Galilean moons of Jupiter.

So Io, Europa, Ganymede, and Callisto. How'd we do? Well, I already told people two weeks ago that it wasn't Galileo. And there's a good story behind that. Bjorn Gedda, a longtime listener in Sweden, who has not won the contest in, get this, six years, almost to the day. He came up with Simon Marius. He was a very interesting guy, as it turns out. Astronomer, mathematician, medical doctor in Germany. Apparently, working from a suggestion from Johannes Kepler, came up with those famous names of what we still call the Galilean moons. At least that's what was indicated by most of these answers. Is he correct?

That is correct. answers, is he correct? That is correct. Marius did this stuff. And we heard from Jordan Tickton, by the way, that he may have started his observations of the Galilean moons just one day after Galileo started to make notes about that stuff. So he came up with these names, but Galileo was really unhappy about it, as we heard from a whole bunch of people, Galileo was really unhappy about it, as we heard from a whole bunch of people, because Galileo had named the moons after the Medicis, his patrons in Italy. And he refused to use those names that Marius came up with. So we got the Galilean moons, but Marius' names for them, which I thought was pretty interesting. It's a fascinating story. Andres Ospina,

listener in Bogota, Colombia, he makes a reference to the visitor from Earth that is at Jupiter right now. Not really looking at the moons, but definitely looking at the planet. He says, don't you feel a little bad for Jupiter, who for 400

years has been living with his four lovers, and now NASA has sent his wife to check on him. Juno, for anybody who didn't catch on to that. Finally, the poet laureate at Planetary Radio, Dave Fairchild. Galileo tried to name the Medician stars and add that band of brothers to his patron repertoires. and add that band of brothers to his patron repertoires. But he lost out to Marius, who used the lady loves of Jupiter to name the moons that orbited above. Thank you once again, Dave, and everybody else. We do love to hear from you.

I should mention, I suppose, that Bjorn is going to receive a Planetary Society T-shirt and a 200-point itelescope.net astronomy account for use of that worldwide nonprofit network of telescopes. And we have more people now donating their account, their free account that they're getting if they're a winner in the contest to schools and astronomy clubs. And so they're very happy to cooperate with that, the folks at iTelescope. So they're very happy to cooperate with that, the folks at iTelescope. And those are the same prizes we're going to have for this next contest that Bruce is about to begin. All right. Here's the question. What was the first in-space docking of two unmanned spacecraft? So two robotic spacecraft.

Go to planetary.org slash radio contest. Good one. You have until the 24th. That would be Wednesday, January 24 at 8 a.m. Pacific time to get us this answer. We're done. All right, everybody go out there, look up the night sky and think about concentric circles. Thank you and good night. Like a wheel within a wheel. 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. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its members

who braved the storm. Daniel Gunn is our associate producer. Josh Doy, composed our theme, which was arranged and performed by Peter Schlosser. Please give us an online rating or review. I'm Matt Kaplan. Clear skies.