Planetary Radio: Space Exploration, Astronomy and Science - Discovered: Titan's Magic Island

Episode Date: July 8, 2014

Cornell grad student Jason Hofgartner reports on the discovery of what appears (and disappears!) to be an island on one of Titan’s frigid lakes.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Now you see it, now you don't. Titan's magic island, this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. We head back to that big moon of Saturn, where a team of scientists has found something mysterious. Lead author of the paper about this discovery is Cornell grad student Jason Hofgartner. He'll be here with us in about six minutes.

Bill Nye salutes the successful launch of the orbiting Carbon Observatory 2 and teases us with word of another orbit-bound spacecraft. Today's What's Up segment with Bruce Betts is strictly for the birds. You'll hear what I mean. First up today is Casey Dreyer, the Planetary Society's busy Director of Advocacy, with news of an event some of you might want to attend. Casey, thanks for stepping in here, subbing for Emily Lakawalla while she continues her well-earned vacation. Let's talk about advocacy, but really specifically about an event you have coming up in just a few days after we record this. Yeah, Matt, we are bringing Europa to Capitol Hill.

We got a room in the Rayburn office building where all the congressional staff work. the congressional staff work. We are having some really exciting guests, and we're going to be talking about Europa as this really prime destination for astrobiology and maybe, you know, the search for life. So it's a pretty exciting event coming up. So who will be coming to this thing, and who will be speaking as well? Well, you might be surprised, but we know this guy called Bill Nye, the science guy, CEO of the Planetary Society, will be there to talk about Europa. We're also really fortunate to have Ellen Stofan, the chief scientist of NASA, will be joining us to talk about why Europa is such a compelling destination for astrobiology. Then we also have Robert Pappalardo, the Europa Clipper project scientist, all the way out

from JPL. And then, of course, we're very fortunate to have John Culberson, one of the great champions of Europa in Congress. He's a Texas 7th District, very big supporter. And hopefully we'll have a few other guests as well. But the event is geared towards people in Congress, geared towards people in NASA, but it's open to the public. So if you're living in Washington, D.C., I encourage you to come join us. It's free. And how can people learn more about this event? They can go to planetary.org slash events, and they will see the listing there. I should say that it's Tuesday, July 15th at 3 p.m. is when this is happening.

3 p.m. Eastern. Okay. I wish I could join you and go Europa. Yes, absolutely. Let's get to Europa, guys. Thank you, Casey. Happy to be here, Matt. Europa. Yes, absolutely. Let's get to Europa, guys. Thank you, Casey. Happy to be here, Matt. Casey Dreyer, the Director of Advocacy for the Planetary Society. Now a chat with his boss, Bill Nye, the CEO. Bill, I believe it's your desire to stay in Earth orbit this time around. This week, we at the Planetary Society like to reach up and out, but this week I'd like to talk, if you don't mind, I'd like to talk about the OCO-2, the Orbiting Carbon Observatory, number two.

If you're scoring along with us, OCO-1 blew up a few years ago, and there was a lot of concerns, a very expensive mission, and we got rebuilt, and it's probably a little better, and it will study the carbon in the Earth's atmosphere, the carbon dioxide, especially in the Earth's atmosphere, and this is of great interest to those of us interested in climate change, which should be everybody in the world. So it will join the A-Train, which is this system

of satellites in orbit above the Earth. And, you know, we're excited, Matt. This week we're going to have a big announcement about our own Earth orbiting satellite here at the Planetary Society, and that's LightSail. You know, as we say in space travel, you can trade money for time.

And we strongly believe that LightSail will be a very low-cost way to get between the planets, albeit someday in the future. I am really pleased that you will be joining me on stage along with... Well, you. It's you. Well, it's it's you. Well, it's not just us. It's some of the great people who are behind this project, like the project manager, Doug Stetson. And it is sold out.

All the seats are taken there at the Crawford Family Forum. I was going to ask you, I know we're on podcast on public radio. When you say sold out, it's free, right? It is free, yeah. The airwaves are free, and so this thing is free. And the seats were free, too. They just filled up in no time at all, not surprising. People will be able to watch the live webcast, and we'll have the link for that on the show page, planetary.org slash radio. And I think it's going to be fun. We have one heck of an announcement to make about how LightSail is going to make it up there into the final frontier. You know, it goes back to the really when I was in class with Carl Sagan back in the day, he spoke romantically about flying a solar sail.

And now we're going to do it. It's very exciting time. It has really, I think, captured the imagination, the romance of it, this idea of sailing on sunlight. There have been some great science fiction stories. I just reread one for the first time in like 25 years by Arthur C. Clarke. It's an old idea that light, even though it has no mass, has momentum. It's quite a strange thing. Tune in.

Tune in on Wednesday, everyone. And if you're not able to join us live at 7 p.m. Pacific, you will be able to catch it after the fact. It'll be archived on the KPCC website. That'll make it easy. Thanks, Bill. I will see you again in two days as we speak. Thank you, Matt. He's the CEO of the Planetary Society. Now we go to talk to a young planetary scientist, a young explorer, who is the lead author of a paper

about the discovery of, well, we don't know what it is, floating on one of the lakes of Titan. Titan is shrouded in mystery. Well, actually it has always been that way, but the mystery used to be what was hiding under its thick, mostly opaque atmosphere. As you've heard on this program, the Cassini spacecraft has peered through that murk to reveal wonders below, along with even greater mysteries.

The most recent puzzle is a feature that suddenly appeared in one of the big moon's terribly cold lakes of liquid methane and ethane. It looked, for all the world, like an island. And then, the next time Cassini could look for it, it was gone. Word of this came to us in late June with an article in the journal Nature Geoscience. The lead author of that paper is here with us this week. We get to talk with lead authors all the time, of course, but I can't remember any that have been graduate students, not till now. Jason joined me from Cornell University in Ithaca, New York, the alma mater of Bill Nye and the longtime academic home of Carl Sagan. Jason, thanks for joining us on Planetary Radio and congratulations on

the publication of this paper, not just the publication, but serving as the lead author of this paper. Thank you, Matt. Yeah, it's my pleasure to come in the show. This is a fascinating discovery. Regular listeners to this show know that we talk about Cassini all the time. In fact, the project scientist Linda Spilker has been our most frequent guest on the program. Cassini just continues to reveal wonders, doesn't it? Yes, it does. Yeah, Cassini is actually celebrating its 10 years as of July 1st in the Saturn system. So it's done 10 years of amazing science throughout the system. And arguably, it's doing some of its best science of all at the moment now that we really know how the spacecraft operates. And in particular, as far as Titan science goes, now that we've transitioned from doing our initial reconnaissance exploration of the surface of Titan to actually doing targeted science of specific regions.

So, yeah, Cassini is really doing amazing things. There is a great little video on the Cornell website. We'll link to it from the Planetary Radio page, planetary.org slash radio. And it has, I think he's one of your mentors, Alex Hayes there at Cornell, talking about how this spacecraft has now been up there long enough that some of you young scientists, like you, I assume, were pretty much kids when it all got started. It's amazing to think that this instrument is still available and doing the work it's doing. So let's get on to talking about this discovery. Now, of course, what I'm hoping you'll tell me is that this thing that you guys are calling for fun, the Magic Island, any chance that this is a pod of cryogenic whales. Well, you know, it's not impossible, but there's no evidence to indicate that particular hypothesis. Oh, man.

Always the scientists there. All right. Let's talk about the real data and what it indicates. How did this discovery come about? Sure. It came about last year in July of 2013. Cassini was doing a pass over the North Polar Area, and it looked at one of the large seas in the North Polar region called Ligia Mare. After the pass, we were looking through the data here at Cornell, and we noticed that there was a bright region off of the southern shore that hadn't been there in any of the past regions.

So naturally, we wondered what was going on, what was the cause of that region. And there are a lot of different things that could have caused it. So we discussed that among the full Cassini radar science team, which involves scientists from around the globe. Ultimately, it wasn't clear after that meeting what really was the source of this feature. So then we began to analyze it and go through the hypotheses. And it didn't just appear, right? It appeared and then disappeared. Do I have that right? That's right, yeah. So at the time, we didn't know that.

But then in subsequent observations, that's right. We've had three observations since then in 2013, two with the visual and infrared mapping spectrometer and one with the radar system, which is where the feature appeared with the radar system. The feature was not in any of those observations. And so exactly, it disappeared again. We talked a lot about how radar has allowed us to cut through that haze with its very

dense and obscuring atmosphere. But we've talked less about other instruments. And you're saying that that infrared instrument was also able to let you peer down at the surface? That's right. So as you mentioned, the radar goes through the haze, but optical and most infrared light gets scattered by Titan's haze particles. There are a few band-specific wavelengths in the infrared, however, that are mostly transparent. The visual and infrared mapping spectrometer on Cassini uses those bands to image the surface.

All right, so if it's not a pod of my cryo whales, what is the current speculation about what's causing this thing to appear and disappear? Sure, yeah. So we went through scientific analysis essentially to show that it has to be something that actually did appear and disappear. It's not an image artifact.

We're not tricking ourselves into thinking that this is something that appeared that's actually been there all along. And so given simply the constraints on the timing and the brightness of the feature, we were able to come down to four hypotheses. And those are that this feature is due to waves, that it's due to bubbles within the sea, that it's due to some sort of solids floating on top of the sea or some sort of solid suspended in the sea. And really all of those four hypotheses are quite plausible at this point. And so we need more data essentially to better constrain which one is actually going on here. How much chance do we have of collecting the data that might narrow down those choices? Well, Cassini has three more years in the Saturn system,

and it's going to do a few more passes of Titan's northern hemisphere. The next one coming up is on August 21st of this year, actually, and it's going to, the radar system during that observation is going to image this area of the sea as well as most of the southern shoreline of Legia Mare. And so that observation in particular should really help us to know exactly what's going on here. How much of this appears to be related to the seasonal change that we're getting to see because Cassini has spent so much time in this system? Well, that's our suspicion that this is in fact due to that Titan right now and Saturn are transitioning between their vernal equinox or their start of spring to their summer solstice or

start of summer. And they're roughly at a point that we would call, say, mid-May here in the Northern Hemisphere on Earth, that sort of season. And it's the time when there is much more solar energy, solar flux coming down on the northern hemisphere. And so that energy could be used to power dynamic phenomena. And as this is the first real sort of change we've seen in the northern hemisphere of Titan, we suspect, in fact, that this really is an expression of the changing season, in which case it's quite possible that we'll see more activity occurring throughout the northern region as summer continues to pick up. All right. Well, I have my fingers crossed on that one. To pick up on the latter two of those

possibilities, those hypotheses that are currently under consideration, if indeed these are solids that become buoyant, that float up to the surface of that liquid methane, liquid ethane lake on Titan. Are you doing research now to figure out whether that's plausible, whether this stuff, I mean, do we know whether it would float or sink? So what we know is that if you have pure methane or pure ethane and you simply freeze them, they will not float. But if you have the methane and ethane mixture with nitrogen, there are particular compositions that could correspond to floating ices. And that was work that was done a few years ago. And so we know that it's possible that simply freezing of the liquids could result in floating solids.

And not just that, but there could also be some other solids that are brought in, say, by rivers nearby or something else that's not necessarily methane or ethane that could also float. So there are molecules, there are things that could float in these seas, although it is worth mentioning that they are quite limited because the seas are already low density. There are not many things that are even lower density than that. That's Cornell grad student and planetary scientist Jason Hofgartner. He'll tell us more about Titan's magic island in a minute. This is Planetary Radio. Hi, this is Casey Dreyer, Director of Advocacy at the Planetary Society. We're busy building something new, something unprecedented, a real grassroots constituency

for space. We want to empower and engage the public like never before. If you're interested, you can go to planetary.org slash SOS to learn how you can become a space advocate. That's planetary.org slash SOS. Save our science. Thank you. Your name carried to an asteroid.

How cool is that? You, your family, your friends, your cat, we're inviting everyone to travel along on NASA's OSIRIS-REx mission to asteroid Bennu. All the details are at planetary.org slash b-e-n-n-u. You can submit your name and then print your beautiful certificate. That's planetary.org slash Bennu. Planetary Society members, your name is already on the list. The Planetary Society, we're your place in space.

Welcome back to Planetary Radio. I'm Matt Kaplan. My guest is Jason Hofgartner, lead author of a new paper about the discovery of, well, something that looks like an island on Saturn's moon Titan. And the disappearance of that something, and its reappearance, as if Titan wasn't enticing enough with its lakes, rivers, rainstorms, and other features that, in spite of temperatures that only scientists and superconductors could love, make it appear so familiar. Jason spoke with me from Cornell University, where he is a grad student studying planetary exploration. I'm just reflecting as we talk about this on the dynamic nature of this moon.

Are you one of those who is pretty excited to find this place, which, you know, albeit it's pretty cold, but in other ways is so similar to our own planet? Oh, yeah, it's definitely, I think Titan is incredibly fascinating that way. I think it's arguably the most Earth-like body in the solar system. And in particular, because of this hydrologic cycle that it has occurring where you actually have liquids at the surface, Titan is the only other place that has liquids stable at its surface that we know of. And we now know that those liquids are exchanging between the atmosphere through evaporation and rain. And this is really the only other place where we've seen that happen.

And so it's really exciting to see that this occurs elsewhere and to be able to study it now under a different set of chemistry. Do you think this is going to continue to be an area of study for you as your still just getting started career continues? I hope so. Absolutely. My thesis is going to be on Titan. And I, you know, I really hope that I'll be able to pursue a long career studying Titan. It's an absolutely

fascinating world. And there are still so many mysteries that we that we need to resolve on Titan. You know, going back to that video that's on the Cornell site, the one we'll link to, there was something you said that I really liked, and it had to do with you enjoying being in the room. What did you mean by that? Yeah, well, you know, it was really quite a special opportunity for me. When we had this pass, the data came down, and then we were looking at the new data, at the new imagery. And, you know, we were probably within the first dozen or, you know, at least 20 pairs of eyes that are looking at this data. And so that was really special because the reason, one of the big reasons I had wanted to get into planetary science, in fact,

was to be a part of active exploration, to be there as discoveries are occurring and even to help contribute to those discoveries. And that was something that I thought would, you know, take a long time and a lot of hard work, which has happened, but I expected even more hard work. And because I'm here at Cornell and the amazing Cassini mission, I was able to have that happen already and be a part of this team. And it was

really special. Who are some of those mentors that have given you this opportunity, the professors who are guiding you at Cornell? Yeah, Professor Jonathan Lunin is my thesis advisor, a member of the Cassini radar team, and he's been absolutely fantastic. And Professor Alex Hayes at Cornell also. Working with them is really special. I have an office. They're both two doors down from me, and so we're in constant conversation throughout the day and talking about Titan and new ideas that we're bouncing back and forth. So it's really a fun atmosphere to be a part of. The technique that is used to find these surface features and whether there have been changes on the surface of Titan, it sounds a lot like the techniques that are used to find new asteroids

and to look for yet undiscovered Kuiper Belt objects. Am I right? Well, it's a technique that's commonly called blinking, where you're basically looking at past images and new images, and you put them on top of each other and you do a fast blink. And then when you do this, the eye is quite good at picking out differences. And so, yeah, that's what we used initially. And that's a great way of picking out regions of interest. But then subsequent to that, of course, there's a great deal of work that actually goes into proving that that's not just some bright spots due to some other reason. So beyond Cassini, as we wrap up here, what do you and other planetary scientists wish you could do at or with Titan to reveal even more of the nature of this pretty amazing world? Well, certainly it's to go back.

There is definitely a lot to be done on Titan to. Well, certainly it's to go back. There is definitely a lot to be done on Titan to learn, and so it's to go back. And there are a lot of different ideas of exactly how we should go back, whether it should be an orbiter, an airplane, a balloon, a lander of some kind. I have my favorite, which is a boat. As I mentioned, Titan is the only place that has stable liquid, and so it's really our first opportunity to go sailing on a different world.

And if we do land in these seas, then that would be an amazing way to study them. We could study their composition in detail, understand their depth, their shorelines, their currents, all this sort of nature of these seas. And that would be really excellent. So it's possible. It's just a matter of making it happen. And I'm a big fan of that boat proposal as well. I have a nice picture of it. To go with my T-shirt that has the motto Surf Titan on it.

Okay. It is a very exciting place, and it's an exciting discovery, Jason. I want to thank you again for joining us on Planetary Radio to talk about this and wish you a tremendous career that has obviously gotten off to a very good start. It was my pleasure. Thanks for having me. Jason Hofgartner is a graduate student. Yeah, you heard that right. A grad student who is the lead author of this article that has revealed the existence of a transitory figure, a transitory object appearing on a lake on Titan. They call it, for fun at least, the Magic Island. I don't know. Did anybody have the TV show lost in mind when they said Magic Island?

No, we didn't. But Magic Island has certainly been a good phrase to use. It's gotten us a lot of attention. So it's gone good. The other phrase that we sometimes kick around is the peekaboo island because of the way it's appeared and disappeared there, too. We will have lots of references to the solar system,

what's up in the night sky, to take a look at when we talk to our friend, Dr. Bruce Betts, in just a moment. it's time for a post fourth of july what's up with the planetary society's director of science and technology here he is bruce betts welcome I hope you had a nice holiday. It was quite lovely. Yeah, it's just hot and humid here. Nothing I know. I know you Midwesterners and Easterners and Southerners, you all think we're wimps, and we are, but it's hot and humid here. I like air conditioning. Me too. We'll start with the pre-dawn. We've got Venus still hanging out low in the pre-dawn east.

And if you can get a really clear shot at the horizon for the next couple weeks, sometime in the next couple weeks in the pre-dawn east, you can see Mercury not too far below Venus. On the 24th of July, the moon will be making a lovely pairing with Venus and, again, if you can see lower down, Mercury. Is there a bird outside your window? Yes. How nice. That's my pet. The blue bird of happiness. And in the evening sky, we've got Mars and Saturn up in the south

looking reddish and yellowish and spiffy keen. Now I hear a wild animal in the other room. Almost extinct, it's called a typewriter. I know that typewriter. They keep that one around just for old time's sake, I think. And they like typing checks and forms and mostly just enjoy the sound, I think.

Speaking of sound, actually, this has nothing to do with sound other than you're hearing me on to this week in space history. It was 2003 that the rover Opportunity launched during this week, headed off to Mars, still working amazingly on the surface of Mars. 35 years ago, two interesting things, well, multiple interesting things happened. Two I'm going to tell you about. Voyager 2 made its closest flyby of the Jupiter system and Skylab re-entered the Earth's atmosphere, terrifying the world.

Yeah, there have been a few of those scares since then, but that was one of the first for a really big object, wasn't it? And now we move on to random space fact. And they're off. So International Space Station is not surprisingly, they try to shield it from micrometeorites and orbital debris. There are different shielding configurations, including from modules from different countries. But one example is the amusingly named Stuffed Whipple Shield, which consists of an outer bumper and underlying blanket of Nextel ceramic cloth,

and Kevlar fabric to further disrupt and disperse the impactor, and that's spaced a distance from the module pressure shell itself. So layering, always popular in trying to protect. They had a hit not long ago. They just noticed a small one. Everything worked like it was supposed to. And a Whipple shield. Isn't that what protected the Stardust spacecraft? It is indeed,

named after, I may get this wrong, but I think Fred Whipple, the man who conceived it. It's not made of toilet paper, is it? Not that Whipple? Well, gosh. I don't think that Whipple. Please don't squeeze the spacecraft.

Obscure reference for those of you not well-versed in 1970s American commercials. Let's move on, shall we, to the trivia contest. And I asked you, what are Montes, or mountains, named for on Mercury? How'd we do, Matt? This is the sort of summer-like period for Planetary Radio's trivia contest, so it's a good time to enter, actually, because you do have a better shot.

Everybody who did enter, well, with one exception, got it right. We got an entertaining one from our old friend Torsten Zimmer, who said that the only mount that is known on the planet, the only single mount, is Caloris, I guess, from the Latin word for hot. He said they missed the opportunity to call it the Mounties Python, unfortunately, or perhaps fortunately. Our winner, though, is Austin Hinkle. Austin Hinkle, first-time winner.

He also said that the mountains on Mercury are named using various words for hot from many different languages. Exactly. And how appropriate with you complaining about the heat here. Yes. It's the people, the Mercurians, they think the Midwesterners and Southerners are wimps. So it's all relative. Austin, he is from California. California, Kentucky. He is from California. California, Kentucky. It's a little tiny town. I had to look it up, of course.

It's on the Ohio River, maybe 20 or so miles southeast of Cincinnati. And I bet it's a lovely, though humid place. Named for words for hot. Well, he's going to get to wear a very cool Planetary Radio t-shirt, which is what we're going to give away again this week. Speaking of Skylab re-entering, on what highly publicized international stage were parts of Skylab literally displayed shortly after it re-entered the Earth's atmosphere? Go to planetary.org slash radio contest. Get us your entry. Wow, I'm stumped.

You have until the 15th. That would be Tuesday, July 15 at 8 a.m. Pacific time to get us this answer. Hey, and before we say goodbye this time, now most of the people listening to this, it probably will have gone by, folks, but you can still catch the archive. If you listen to the show really soon after it's posted, you may still be able to catch our live webcast all about LightSail, a big announcement

that we have about the Planetary Society's SolarSail project. We're doing it Wednesday, July 9, at 7pm Pacific Time, and Bruce is going to help me close out the show with a solar sailing edition of What's Up. Thank you so much. You're welcome.

My pleasure, Matt. It's going to be fun. We're going to throw out some solar sailing swag. And maybe we'll have something to give out in the trivia contest as well. Yeah, it's going to be fun. We'll put the link up on the show page that you can reach from planetary.org slash radio. Now we're done. All right, everybody, go out there, look up in the night sky,

and think about singing birds. Thank you, and good night. Yeah, and shut that window, but it's humid outside. He's Bruce Betts, the Director of Science and Technology for the Planetary Society, who joins us each and every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California,

and is made possible by the methane-surfing members of the Society, Cowabunga and Clear Skies. Thank you.