Planetary Radio: Space Exploration, Astronomy and Science - Cassini Mission Update From Project Scientist Linda Spilker

Episode Date: November 18, 2014

Cassini is safe! Project scientist Linda Spilker returns with a regular update on Saturn, its moons and rings not long after learning that the mission is funded through its 2017 plunge into the planet.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Back to Saturn with Linda Spilker, 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. Cassini Project scientist Linda Spilker is back with more from the queen of planets, her moons and rings. Emily Lakdawalla was in the control room as the Philae lander died, or did it? Bill Nye shares his admiration for this brave mission and the nations behind it. We'll also learn where some of you would go if you had warp drive, as Bruce Betts and I award prizes from the movie Interstellar.

A busy show, as usual, and we'll begin it with the Planetary Society's senior editor. Emily, thank you. Absolutely spectacular reporting on a spectacular mission. Should we be celebrating or mourning? Well, a little bit of, actually a lot of celebration is what's really deserved for Philae. Philae operated for just a few days on the surface of the comet, not the long extended mission that people had hoped for.

But the plucky little robot returned, pretty good sized fraction of the data that the scientists were hoping to get. And it was just such a dramatic performance over the weekend. You were there right till the end. I was. And I was one of only three social media people who were there right up at the weekend. You were there right till the end. I was. And I was one of only three social media people who were there right up at the end. I was actually sitting in this fishbowl type room behind the main control center at the European Space Operations Center, watching the flight director and mission manager and the other spacecraft operations engineers as they watched what was, it was essentially a death watch on Philae. We were watching its batteries drain

toward the very end. They did a last ditch effort to try to raise the lander and get one of the solar panels rotated into a better position. But everything indicates that the lander wound up in a hole. And so as a result, they don't get very much solar energy during the day. So it's not really clear that the lander will ever wake up again. But if enough sun does reach that one solar panel, maybe it will, especially it's more likely later on in the year when the comet is getting closer to the sun and so the solar illumination will be stronger. All right. In the meantime, I strongly recommend, as strongly as I've ever recommended that you read anything, take a look at Emily's blog at planetary.org

because it is so dramatic and so affecting as the lights literally get turned out in the control room. What kind of science can we expect from the days that Philae had on the surface of this comet? I think the two things that I've heard that people are most looking forward to are the surface properties experiments, that is, understanding how the structure of the surface is put together so we can understand how comets work physically. structure of the surface is put together so we can understand how comets work physically. And the other one is the radio, the concert antenna, which ranged through the comet to the orbiter so that we can study the internal structure and layering of the comet. I haven't seen anything on those results yet, and I expect it's going to take a long time before we see them because it's probably challenging to calibrate it. But I'll be very excited to see those when they come out.

And of course, Rosetta is still out there orbiting the comet, delivering lots more great science. And we'll hopefully keep doing it for a long time. That's right, for at least another year. Emily, terrific work. Thank you again so much. And hope you're catching up with your family and getting some rest. Doing my best, Matt. She's Emily Lakdawalla, the senior editor and our planetary evangelist at the Planetary Society,

also a contributing editor to Sky and Telescope magazine, freshly back from Darmstadt, Germany, and the death watch over what was still an extremely successful mission, the landing of Philae on a comet. Up next, Bill Nye. Bill, of course, I just finished talking with Emily about the loss of Philae, but in a sense, also its triumph. And I would love to get your thoughts about this mission.

It took 10 years, and they rendezvoused with the rock in the middle of deep space nowhere. It's amazing. No, it's fantastic. It is. It's fantastic. You know, now, I'm not objective. I'm an engineer. And just to pull that off is really something. And, of course, humankind, as we always like to remind us,

may have to rendezvous with a rock as a matter of life and death sometime. So this is part of the journey. And the other striking thing for me, as your advocate over here at the Planetary Society, is they did it for $1.5 billion, $1.3 billion U.S. dollars equivalent, 1 billion euro. That's amazing. That is amazing. And the reason, I guess, is they chose the right instruments on a small enough package and they got it all the way out there and they got these amazing photographs, which will be analyzed for decades to come. Everybody's sorry that the harpoons didn't poon the harpoons didn't strike properly and everybody's sorry that it happened to end up in a shadowy crater but it's an amazing thing it's just a

fantastic thing and the other thing i remind everybody it was the european space agency which is not one country it's 16 countries working together they did and they pulled it off that's a lesson for everyone. Bill, I don't think we need to go beyond that. I do want to thank you for a new bumper sticker slogan. I'm not objective. I'm an engineer. Let's print up a carton.

We'll put it on the table at the next staff meeting. Thank you, Bill, very much. And I appreciate this. Let's change the world. He's Bill Nye, the CEO of the Planetary Society. And his book, Undeniable, is, as of this week,

on the New York Times nonfiction bestseller list. We're going to move on now to a somewhat delayed conversation. There's been a lot going on. But we're going to get a report on the Cassini mission from our regular reporter,

the project scientist for that effort, Linda Spilker. It is always a pleasure to talk with Linda Spilker. You regulars know that she has appeared on this show more than any other guest, and it's no wonder. Every time she visits, she brings amazing news from Saturn, its fantastic moons, and those beautiful rings. Perhaps the biggest news this time is that the Cassini mission won't be cut short by short-sighted budget cuts. It received the highest recommendation for continued funding right through its expected 2017 plunge into Saturn itself. Maybe by that time, Linda and her colleagues will have figured out that mysterious island on Big Cloudy Titan. Right. It's a very interesting feature. It was

seen first in the radar data back in July of 2013. And then this little island, it's off a little finger of land that's in the midst of La Giamare. That finger appeared to disappear, whatever it is, disappeared. And then they looked again recently in August of this year, and it was back. And it was back, but it looked different this time. So we're not sure exactly what it is. It might be perhaps bubbles on the lake, a floating solid, solid suspended just below the surface, or even something we haven't even thought of yet. So it's just very, very interesting. Lygia Maria is a huge sea.

It's about 100 square miles. It's the second largest sea on Titan. I suppose there hasn't been any further consideration of my suggestion last time that this may be a pod of cryo whales. That would be interesting. We will add that to the list it might also be waves and maybe it's the whales creating the waves who knows wouldn't that be fun oh man what's happening there at the surface of titan is not all of the news because you're still looking into this possibility of an ocean underneath this top ocean that's made of methane and ethane. Right. We think there might be a liquid water ocean actually underneath the surface of Titan.

And so that would give two moons, both Enceladus and Titan in the Saturn system, that would possibly have liquid oceans and would join the growing list of moons in the outer solar system that might potentially be habitable. There is also a series of images, which we'll put up a link to on the show page. People can reach at planetary.org slash radio, which is pretty mind-blowing. It's a cloudy day over the seas of Titan. That's right. As we're getting closer to summer at the North Pole, we're starting to see clouds form. We expected to see them a little bit sooner, given the clouds we saw basically half a Titan season ago in the south, but they're just now

starting to form, and they appear to be forming over the lakes. And so that's a very interesting, you know, weather. Seasons are changing on Titan. It takes Saturn 30 years to go around the sun a single time. So a season on Titan is actually about seven and a half years long. So we're just now coming into summer on Titan. And also, if you look at some of those images, there's this really bright point, sort of a specular reflection point. If we look in the near infrared, the sunlight actually goes all the way to the surface of Titan and is reflecting off the liquid in the lakes and seas on Titan and creating a bright spot that we can see in some of those visual and infrared mapping spectrometer images. Pretty cool. It sure is, and I highly recommend that people take a look at those

images. You can actually see the clouds floating by, moving along over that sea or lake on Titan. Let's go to a different moon now. What's the news from Enceladus? Well, Enceladus, we've been studying the geysers erupting from the south polar tiger stripes and actually have had about seven years of data now to try and count and see how many individual geysers are going off on Enceladus. And a paper was recently published that there's 101 separate geysers going off that we've been able to monitor. Their brightness changes with Enceladus' position in its orbit. Their brightest out at the apoaps or furthest distance in Enceladus' orbit from Saturn.

And they get a little bit dimmer as they go closer in. But 101 geysers, that's a lot of activity going on on Enceladus. Yeah, it's got Yellowstone beat. Are these fairly stable, or do new ones appear and old ones stop being active? I think we've seen a couple of them turn on and off, but pretty much, especially the larger ones, appear to be continuously active. The biggest geysers are associated with the hottest regions in these tiger stripes. There's like little, you can imagine, like little pinholes basically almost in the tiger stripes. And this emission is coming out.

The geysers are coming out. They're very, very narrow, the region from which this emission is coming. How about yet another moon where you may have found another hidden ocean underneath the surface of that body? And I can never remember, is it pronounced Mimas or Mimas? I tend to pronounce it Mimas. I think either one is correct. Either pronunciation is correct. Yeah, that's another moon. It's about the size of Enceladus. It's closer to Saturn than Enceladus is. And if we look at just its surface, it's just heavily cratered and appears very ancient. And Mimas is in an orbit that's slightly elliptically shaped.

And so it actually wobbles back and forth a little bit. It keeps one side pointed towards Saturn. But very much like our moon, it vibrates or tends to move from side to side as it goes about its orbit. And using the images, the imaging team did a very careful study. And it turns out that the amount that it vibrates is about a factor of two more than it should be if Mimas were just a solid, you know, solid body all the way through. And so they have a couple of very interesting ideas for what might be causing this additional wobble or libration. And one of those is perhaps there's a liquid water ocean underneath Mimas's crust. So that's one possibility. The second one is that maybe Mimas has a core that instead of being round is actually more football shaped. And perhaps

this very unusually shaped core is the source of causing this libration, this wobble back and forth. And we're going to, of course, continue to take more data, more images with Cassini, and to study this problem even further. But very interesting, this tiny ancient world that might have an ocean underneath. More with the Cassini mission's Linda Spilker is a minute away. This is Planetary Radio. Hi, Emily Lakdawalla here. Thank you for listening to Planetary Radio. The Planetary Society has lots more ways for you to hear the latest news

and see the greatest pictures from around our solar system. I lead a growing family of expert bloggers at Planetary.org. We cover nearly every angle on space exploration. And you can find us all over online, tweeting and posting to our popular Facebook and Google Plus pages. We're also producing great new videos for our YouTube channel. There's no doubt about it, we really are your place in space.

Random Space Fact! Nothing new about that for you, Planetary Radio fans, right? Wrong! Random Space Fact is now a video series too. And it's brilliant, isn't it, Matt? I hate to say it, folks, but it really is. And hilarious. See? Matt would never lie to you, would he?

I really wouldn't. A new Random Space Fact video is released each Friday at youtube.com slash planetarysociety. You can subscribe to join our growing community and you'll never miss a fact. Can I go back to my radio now? Welcome back to Planetary Radio. I'm Matt Kaplan with more of our most frequent guest, Cassini Project scientist Linda Spilker. Linda joined the Cassini mission in 1988,

nine years before its launch. She has served as head scientist for the last five. We were talking before the break about Titan and Celadus and more of Saturn's more famous daughters. There are, of course, many other moons out there in the Saturnian system that we could talk about. But there is one we maybe haven't paid enough attention to in our past conversations, perhaps in part because it kind of creeps me out. And that would be Hyperion. The reason it creeps me out, it's all those holes.

Hyperion. The reason it creeps me out, it's all those holes. I mean, it looks like there is a flock of space wasps that I'm afraid are going to come back to roost at some point. But you've made some very interesting discoveries about this other moon. Right. Yes, Hyperion, it's a very irregularly shaped moon, and it looks like it has a very porous surface. What we discovered recently is that there's a static electricity that appears to play a role on Hyperion. And so this would be the first confirmed electric charge on a moon besides our own moon. And so it was very interesting. Cassini was flying by and essentially got a jolt. You can imagine a discharge of static electricity. If you move your feet along the floor and touch a doorknob, sometimes you get a spark.

Well, Cassini got one of those jolts, about 200 volts or so, telling us that there was a static electricity built up on Hyperion, perhaps coming from, we think, maybe the ultraviolet light that's part of sunlight, as well as the ions and electrons and things hitting the surface have caused Hyperion to build up a charge. So very interesting. And we think that other worlds, maybe comets or other small bodies, might have the same kind of electrostatic effect. And maybe some of the surface features that we see on these bodies maybe have to do with the movement of the tiny dust grains caused by the static charge that's on them.

Was this just sort of serendipitous? I mean, was Cassini designed to discover this kind of static discharge? It was really just serendipitous. We actually had a flyby. It was back in 2005. And in looking at the data from the Cassini plasma spectrometer and some of the other fields and particles instruments, it's where we first noticed this signal. And it just took a while to puzzle out what might be going on with this tiny moon.

All right, let's jump over to the rings. There are many things I'm sure that we could say about them. But there was one particular story I found about the F ring. Can you explain to us why it's not a very healthy place to be an infant moon? Oh, in the F-ring. The F-ring is very interesting. It's very dynamic and changing, and it gets these clumps as part of it. And we think what happens is that there are tiny objects, tiny moons that crisscross through the F-ring.

that crisscross through the F ring. And actually, as they're crisscrossing through, they're going through collisions and sort of breaking apart and creating these very interesting structures. And so the F ring is very dynamic and changing as you look from year to year. And we think it might have something to do with the moon Prometheus. Prometheus is an inner shepherd of the F ring, and it has an orbit that's slightly elliptical, so it moves further away and closer to the F ring and every 17 years it lines up with the F ring in such a way

that maybe that's a very active turbulent period to create a bunch of these new objects that then as time goes on as the 17 years go on they crisscross through the F ring kind of like race cars you know going past each other swiftly, and some of them break apart, and their numbers go down until 17 years later, you get an event with Prometheus close to the F ring, and you start all over again. Just a fascinating and very interesting, very dynamic ring, changing on very short timescales, sometimes even as short as days. I hate to bring up the topic of coming to the end of Cassini's investigations, but there is much more to come, of course. Tell us about what you and the rest

of the team have decided to call the grand finale. Yeah, the very end of the mission, we have a series of 22 orbits where you actually dive in between the innermost ring and the top of Saturn's atmosphere. And we were calling that initially the proximal orbits, proximal for being close to, close to the planet. And so we decided to have a contest to have the public help us decide what might be a good name. And we got something like 2,000 different suggestions. And the winning suggestion was the grand finale orbits. So those very last orbits is part of the Cassini grand finale is what we're calling it. It's going to be almost an entirely new mission. Again,

I mean, you've already, in a sense, just because of what Cassini has been able to do out there for so long, some people would describe it as several missions already, but this is going to be really new and exciting, isn't it? Oh, absolutely. We can do some incredible new science. We'll be able to really understand much better the gravity field of the planet itself. You know, how big might the core be inside of Saturn, the magnetic field. We'll get the mass of the rings for the very first time. And there's huge uncertainties, about 100% uncertainty in the mass of the rings. Plus, just be flying through a place that no spacecraft has ever flown through before.

And it'll be a chance to directly measure the composition of the ring particles, directly measure the composition of the very topmost piece of Saturn's atmosphere. And just really a very exciting time with a lot of new science and surprises. I'm sure there will be surprises, things we haven't anticipated or even thought about until we get there and start performing those orbits. And Linda, I'm especially pleased to be able to say that this mission will not end before it's time just for lack of money. At least that's how things are looking now. I'm so glad that you're going to be able to take this right out to that end of mission when Cassini loses itself in the great planet Saturn. Oh, I'm glad too. The senior review went very well. And what's really ending our mission is that we're running out of fuel, that we want to make sure that we don't leave Cassini when it's out of fuel in a place that

might accidentally run into either Enceladus or Titan. So for planetary protection, our very last orbit on Cassini will actually get a nudge from Titan, a distant nudge from Titan that will send us deep into Saturn's atmosphere. That will burn up the spacecraft, basically just vaporize it, and that will be the end of the mission. But it's really not lack of money, but rather running out of fuel. And there's not much you can do about that. There are no gas stations out there. Right, right.

Linda, it has, as always, just been spectacular talking to you about this spectacular system that Cassini continues to explore and will keep doing so for a few more years. And I look forward to the next conversation. I do too, Matt. She is the project scientist for Cassini, a mission that she has been part of since long before it set out for that giant ringed planet, Saturn and its fascinating moons and rings. And we do check in with her pretty regularly here on Planetary Radio. Let's check in with somebody that we talk to every week, and that'll be Bruce Betts for What's Up.

Time for What's Up on Planetary Radio. Bruce Betts is at the other end of the line, ready to deliver on the universe this time, and we'll find out where people would go in that universe if they had warp drive. It's our big interstellar-based contest this week. Welcome back. Hit us with the stars. Slap, slap. I'm going to stick with planets.

Mars up in the evening sky in the southwest looking reddish on November 25th makes a lovely pairing with the crescent moon, again low in the southwest in the early evening. Jupiter up in the middle of the night in the east and high overhead in the south in the pre evening. Jupiter up in the middle of the night in the east and high overhead in the south in the pre-dawn, looking very bright. On to this week in space history, the first ISS module, Zarya, was launched this week in 1998. And going farther back, 1969, Apollo 12 made the second human landing on the moon.

ISS first module, 1998, 16 years ago. Oh my goodness. Yeah, they've been gone for a while. On to Random Space Fact! Sort of an older Scooby there. I just have to say, with the wonderful Rosetta landing, all the excitement, the Philae landing, lander of Rosetta, I started doing some weird calculations to come up with a truly random space fact, at least having to do with Philae, and I think I did.

The mass of the Rosetta Philae lander compared to the comet it landed on is about the mass of an ant compared to a fully loaded 747-400. I love it. I get so happy when the numbers work out so nicely. I'm going to award you a Planetary Radio t-shirt. Yes! Oh, it's like a dream come true. All right, we'll move on so we can award other people Planetary. No, award them things.

If you had warp drive, where in the universe would you go, and why would you go there, looking for funniest or most awe-inspiring or whatever we were in the mood for? Tell us, Matt. Tell us about the entries that you and I have both carefully reviewed. We had many, many, many. Thank you to all of you who entered this special contest. We cannot read all of them.

I do have a few, a few runners up. How's that? We had four from the same address. Three of them appear to be two brothers and a sister. Levi, who's 11, Benjamin, who's 13, and their little sister, I'm guessing, Emily, who is eight years old. They all had great entries for us. And from the same address, we got from Charlie, I'm 10 years old. They all had great entries for us. And from the same address, we got from Charlie, I'm 10 years old, I would travel to the galaxy that Star Wars is in. You know, it is a galaxy

far, far away. We got so many others that were really terrific. Robert Lee, I'd go to Mongo and fly with the Hawkmen against Ming the Merciless. I kind of like this one with the enigmatic name. This is the name that the person gave us. Event Horizon. I would pick a direction. Any direction. We can always count on Torsten Zimmer to entertain us.

He said, I'd go for a beer at the restaurant at the end of the universe. Not the only reference. We got to Millaways, the restaurant at the end of the universe. Got one from Colin McGrath as well. But Torsten also said, I would travel to the second star on the right straight on till morning. I would boldly go where oh, wait, my wife just told

me to sell the damn drive thing on eBay because we really need a new dishwasher. There you go. Sorry about that, Torsten. Hope you get a good price for it. Charlie Harris said he'd head for the great attractor in the Hydra-Centaurus supercluster to prove once and for all that the supposed gravitational anomaly is really just Matthew McConaughey reaching through the fabric of space-time to hold my hand.

Paramount Pictures thanks you for that one, Charlie. We have this one from Eric Hebert that I think you liked a lot, didn't you, Bruce? I did. It made no sense, but it made me laugh anyway. He said, I would find the Voyager 1 and 2 spacecraft, clean them up, shine the gold records, check the oil, charge up the batteries, and then allow them to continue on an extended mission. But both of us had a problem with that. But both of us had a problem with that. If you've got Warp Drive, to heck with Voyager. Go explore yourself.

In lieu of Warp Drive, go Voyager. Yeah, really, go Voyager. We're down to our winners. Here we go. In third place, Mark Little of Port Stewart, Northern Ireland, because he wrote us a poem and he was smart enough, he was wise enough, to put Bruce and me in it. That would never influence us, Matt. Never. Fix Kepler-186 on the chart, engage Warp Factor 9. Play Matt, Bruce, and the gang on repeat. Be there in four months' time.

Our payload's destination, Planet F, the most hospitable spot by far. Colonists in planetary radio garb will bring the society to the stars. Nice job. Nice job, Mark. And also, scientifically interesting is the Kepler-186f is the first habitable zone planet confirmed by observation. And great kissing up. So, Mark, you're going to get some interstellar swag out of this. And who knows, maybe we'll throw in a Planetary Radio t-shirt. Here's number two. This came from Sarah Lubert, Sarah Lubert of Pennsylvania. I've recently heard that there

are potentially hundreds of other planets capable of sustaining life as we know it. If I had a warp drive, I would explore these planets as long as my short human life would allow to answer the question, are we alone? Ah, profound and cool. All right, here is our big winner. It's Mark Schindler from Honolulu, Hawaii. He made us laugh with, I would travel to the supermassive black hole at the center of the Andromeda galaxy and do what any small boy would do, spit into it.

I was actually thinking of something other than spitting that a lot of boys would do, but that's okay. We'll leave it at that. He said, I would do this at M31, that's the Andromeda, just in case something bad happens. It's not my galaxy. Ah, adolescent boy humor. All right, Mark, so you get the biggest pile, the best of the swag for the movie Interstellar, which is, of course, still out there in theaters,

and highly recommended by yours truly, having seen it twice, as I mentioned last week. We'll move on. What have you got for next time? Something a little more concrete. What is the approximate mass of the Philae lander that just landed on a comet? Go to planetary.org slash radio contest. Get us your entry. Isn't it equivalent to an ant? It is equivalent to an ant. So you can work this backwards if you know the mass of a fully loaded 747-400 and the mass of an ant, or you can just look it up. Either way, it'll be good. All right, everybody, go out there, look up at the night sky and think about cobwebs and where you think they

are that you just can't quite reach. Thank you and good night. Probably none of them on Philae, not yet anyway. He's Bruce Betts, the Director of Science and Technology for the Planetary Society, who will join us again next week here on What's Up. The deadline for this week's contest is Tuesday, November 25th at 8 a.m. Pacific Time. Oh, and the prize? How about a beautiful 2015 Year in Space wall calendar? But wait, there's more. It's the highly informative Year in Space wall calendar. But wait, there's more. It's the highly informative Year in Space desk calendar featuring my annual summary of what to look forward to throughout the solar system.

Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by the members of the Society. Clear skies. Music Music Music Music