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

Episode Date: May 2, 2011

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Once again, thanks to all of you for listening and especially to those of you who become part of this program by donating at planetary.org slash radio. Here's the show. Linda Spilker with another update from Saturn, this week on Planetary Radio. on Planetary Radio. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. The Cassini Project Scientist returns with big news from the Saturnian system. That status report and all our regular features are coming up, beginning with the Society's Science and Technology Coordinator, Emily Lakdawalla.

Emily, congratulations on your promotion to NASA Administrator last night. That's right. We haven't got a press release out about it yet, but you'll be seeing that soon. It could happen. It could happen. That was Emily's line in the sketch that we did last night, our little roast and toast of Lou Friedman, which we may talk a little bit more about later today with Bruce Betts, although he wasn't there. So we'll mostly talk with him about not watching a shuttle launch.

Serves him right going without me. Anyway, you have what's up in the month of May. That's right. And this month is a fairly quiet month with business as usual, although, of course, I always have to emphasize that business as usual involves a dozen spacecraft returning data from across the solar system at numerous planets. So that's pretty exciting business. But the main piece of news, I think, this month will be the fact that Dawn is approaching Vesta. It's set to take its first optical navigation image of Vesta on Tuesday, May 3rd. It's going to be very exciting, although it won't yet be as good as Hubble can get at Vesta. That'll take

another month before Dawn gets close enough to better Hubble. And we're going to have to get your friend and blog colleague, blog contributor, Mark Raymond, back on the show soon to give us more of a preview of this. I also want to note, because we're going to be talking to Linda Spilker in less than five minutes here, and one of the things she will mention is about this storm, storms on Saturn, I should say. You've got some coverage of that. That's right. You know, we've been looking at this amazing storm crossing much of Saturn's northern hemisphere, which is visible even from Earth-based telescopes. But what people might forget is that there's actually a lot of storm

activity on Saturn. You just can't see it in visible wavelengths. But Cassini has an instrument called VIMS that sees in infrared wavelengths, and there Saturn looks like Jupiter. It's got bands. It's got swirling storms. It has all kinds of exciting stuff, and there's an animation of that on the blog. Very pretty, too, and so that's right there on the blog waiting for you, and there is something about why the moon is so creepy. That's right. This is a term from planetary geology, from cosmochemistry, actually, that invites puns.

It's not C-R-E-E-P. It's K-R-E-E-P. And it stands for potassium, which is K, rare earth elements, R-E-E, and phosphorus, which is P, which is an assemblage of elements that occurs, you know, only in certain places on the moon. And that was actually kind of a surprise. Apollo missions returned samples that contained lots of this creep material. And so geologists thought it was all over the moon. And that was actually kind of a surprise. Apollo missions returned samples that contain lots of this creep material. And so geologists thought it was all over the moon. But then when Lunar Prospector sent back a map, we found that it was only concentrated in one area around the Imbrium Basin. And now people are worried that maybe the Apollo samples aren't

really representative of the moon as a whole. And that's another good reason to go back to the moon. The whole article is right there on the blog. You can find it at planetary.org slash blog and read much more of Emily's regular coverage. And we will visit with you again next week. Thanks, Emily. Looking forward to it, Matt. Emily Lactuale is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine. Be right back with the project scientist for the Cassini mission after we hear from Bill.

Hey, hey, Bill Nye the Planetary Guy here. This week, a very exciting time. Well, the space shuttle got postponed. The heaters that keep the fuel flowing into the auxiliary power unit had some trouble in their circuit box, so we've got to wait. auxiliary power unit had some trouble in their circuit box. So we've got to wait. And I say we because the Planetary Society has an experiment flying on this mission, the Living Interplanetary Flight Experiment. We've got some well-characterized microbes and the happy little water bears. And we're going to see how they do in spaceflight as a precursor to going a round trip from here to Phobos, the moon of Mars.

Also, NASA awarded big contracts to four commercial space companies. These are companies that are in business to sell rocket trips to low Earth orbit. And this is a new era. NASA didn't used to do this. And NASA spends the most money in space of anybody in the world. And so they've hired out the short distance trips to low Earth orbit, which I admit takes a tremendous amount of energy. But nevertheless, it is a start in allowing the money that goes to the world's largest space agency to be used for something else. And then personally, for me, Bill Nye, not only am I executive director of the Planetary Society, but the retiring director had a big bash this

weekend. We had a roast and toast for Dr. Louis Friedman, Lou Friedman, who's run the Planetary Society for 30 years. He showed up in a tuxedo with Yankee pinstripes. We had a lot of baseball jokes. Neil deGrasse Tyson was there. I was there. Many luminaries from the space industry gave Lou a little bit of a hard time. And it was a lot of fun. It was really a moving event. Several people spoke very articulately. We gave Lou a plaque that features the orbits of planets rendered in gold and silver-filled wire. And Mars itself was represented by a Shurgatite meteorite, a piece of Mars that landed here many years ago. It was a very exciting event, very moving. It's the end of an era.

So now at the Planetary Society, we're going to move forward and, dare I say it, change the world. I get to fly. Bill Nye the Planetary Guy. It was a pleasure to once again visit the Jet Propulsion Lab a few days ago. I sat down there with Cassini Project scientist Linda Spilker to talk about some of the latest revelations from her team and spacecraft about Saturn, its moons, and its rings. Linda, welcome back once again. Thanks, Matt. I'm happy to be here. Do you know, I think I figured out that you have appeared now on the program more than any other guest. Wow. Well, thank you. But you're the only one who can talk about your spacecraft at Saturn. So let's do that. And there's so much to talk about, I do want to jump right in. And this time we'll start with the planet and something that I guess is only beginning to

get a lot of public notice, and that is this big storm that you've discovered. There's a huge storm on Saturn. It's the first time we're seeing a storm at mid-northern latitudes. The seasons have changed. And we're spring on Saturn, and we have this great storm. We have Cassini images, and the amateurs have been wonderful in filling in the gaps in our data when Cassini isn't observing Saturn. This storm appears to have completely wrapped its way around the planet, and we're continuing to watch it evolve, and we're continuing to study it.

This is a theme that you came up with the last time we talked, late last year, of how the amateurs are really playing an important part. Oh, absolutely. There's some incredible pictures coming back from the amateurs from all around the world, and they're eagerly sharing them with the Cassini teams as well. amateurs from all around the world, and they're eagerly sharing them with the Cassini teams as well. Speaking of interesting things going on on the planet, there is one that you have found this positively eerie connection to a moon that has been puzzling people and amazing us for a long time, and that's Enceladus. And it looks like it's, well, it's electric. That's exactly right. It's an electrical connection between the moon Enceladus and Saturn's pole. And it creates a footprint. Enceladus has these plumes coming out of the South Pole.

They get ionized, create a plasma, in particular electrons. They can spiral along the field lines that connect Enceladus to Saturn. And when they hit the atmosphere, they create a glow, an auroral glow, very similar to the Earth's aurora. And so we're seeing for the first time the auroral footprint of Enceladus on the pole of Saturn. Does this have anything to do with those geysers on Enceladus? Oh, absolutely.

Those geysers are providing the material that can become ionized and provide the electrons and protons and the things that can then be caught by the magnetic field to crash into the atmosphere and create the aurora. Jupiter's moon Io also has a footprint, volcanic activity on Io and a similar auroral footprint on Jupiter. And you've actually been able to image the aurora. And what about the connection between the planet and Enceladus? Is that something Cassini has been able to capture? Well, the first thing that gave us a clue is in flying through that field line that connected Enceladus to Saturn, we found an enhancement in the electrons and protons, an indicator that there

might be an auroral footprint. We then looked with the ultraviolet instrument, and sure enough, in the ultraviolet, you could make images of not only the auroral oval, which we knew about on Saturn, but also this tiny Enceladus footprint as well. It is literally an electrical circuit. That's right. That's right. A connection from this tiny distant moon into the atmosphere of Saturn. And any time, you know, it's a dynamo. I mean, you've got this thing flying through a magnetic field.

You're going to get some electrons and protons racing around. Incredible. While we're talking about moons, I'd like to turn to Titan. I don't know if I should let you use the line or me. It never rains, but it pours. Because you have seen weather on Titan. Right. Dramatic weather. Basically, April showers on Titan. For the first time, we've seen evidence of a huge methane rainstorm on Titan covering a

large area, darkening a portion of the surface in the arid equatorial region where we had previously seen dunes. And what's so fascinating is we had seen channels in the equatorial region, but we didn't know if the channels were from a time earlier in Titan's history when the climate was much wetter, or if it was something that happened episodically on Titan. And now it looks like it's most likely a seasonal effect. It's now spring on Titan, and that brought April showers, and the Cassini cameras captured that change. Now we got to remind people, this is not water rain like we see reshaping the Earth. Right, it's a methane rain that the temperatures on Titan are so cold

that water ice is frozen out and forms the bedrock, if you will, of Titan. And we've seen methane as a liquid before in the polar regions in the lakes, but this is the first time we've seen evidence of a massive rainstorm in that more arid equatorial region. The best line that I saw in the press release was that over a period of, what, a couple of weeks, you actually saw changes in the terrain, in the surface? Right. We saw darkening of portions of the surface, and then as time went by, I actually saw, as the evaporation started to take place, additional changes.

So this is the first time we've seen such a dramatic change over such a large area on Titan. So is this comparable to any place on Earth? I mean, is it really the same mechanism, albeit taking place in really chilly weather? Well, it might be similar to a downpour in the southwest in the United States, or perhaps in the tropical regions around the Earth. When you have seasonal change, you also develop these tropical storms. And perhaps on Titan, this happens during the spring and fall, close to the equinox periods. More from Cassini Project scientist Linda Spilker in a minute.

This is Planetary Radio. I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager. Linda Spilker in a minute. This is Planetary Radio. Intelligence is in the universe, and it built the first solar sail. It also shares the wonder through this radio show, its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages, and I hope you'll consider joining us. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt.

Our nearly 100,000 members receive the internationally acclaimed Planetary Report magazine. That's Planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. As part of one of her regular updates, Cassini project scientist Linda Spilker was telling us how Saturn's moon Titan is eerily familiar. Sure, the rain is liquid methane, but it's still rain, and that rain runs down to the seas, leaving its mark along the way.

I wish I'd worn my surf Titan t-shirt, but we won't even get into the seas. Maybe we'll save that for our next discussion. I know there is a lot of healthy debate, I think you've called it, among scientists who are trying to figure out what is shaping this moon, this fascinating moon, and some who are still looking for geological forces and others who are saying, you know, maybe it's just all that rain and weather. Well, one of the biggest puzzles about Titan is the source of the methane that's driving the weather. There needs to be some source, or over the lifetime of the age of Titan,

the age of the solar system, that methane would have disappeared by now. So there's some speculation that perhaps cryovolcanism exists. It brings out a water-methane-ammonia mix, and we get methane gas into the atmosphere of Titan. Now, we haven't seen any evidence for change like we've seen with the rainstorms. And so the jury is still out on whether or not there has been or could be active cryovolcanism on Titan. But there's some tantalizing hints, a region around Sotra where there's a tall peak and a caldera

that perhaps might be reminiscent of a volcanic peak with a caldera next to it. But we're still looking into and trying to figure out exactly what's going on on Titan. So as I said, the jury's still out. You ever feel any kinship with the folks who are looking at the methane on Mars and wondering where that's coming from? Right, yeah. We haven't talked about the rings yet. I think there's evidence in the story that I think you're prepared to talk about of just how much deeper our understanding of this entire Saturnian system has become thanks to Cassini.

Go ahead and tell us the story. Well, the advantage of having Cassini in orbit for such a long time, it's getting close to seven years, is that we can look for subtle changes, and in particular have seen those changes in the rings. Initially, we saw a ripple or a warp in the D-ring, the innermost ring near Saturn. And then as the sun set on the rings, we got near Equinox, anything that stuck up above or below the rings would cast a shadow. And we found that this ripple not only encompassed the D ring, but the C ring as well. So we had 12,000 miles of a ripple. You can think of this ripple like a groove in a phonograph record.

And if you unwrap it and move backward in time, you can figure out when the event occurred that might have started the ripple. figure out when the event occurred that might have started the ripple. The interesting piece of the puzzle also is that after seeing the warp in Saturn's rings, then some individuals, Mark Showalter and Matt Hedman, went to look at the Jovian ring too. And they saw ripples there as well. And unwinding the ripples in the Jovian ring led us to the time period of Shoemaker-Levy 9. So it appears that the dust from the breakup of that comet, probably hitting the ring particles in one area over a period of maybe a couple of days,

actually tipped the ring just a little bit. Then Jupiter's gravity turned that into a ripple, and we think that's what caused it at Jupiter. So for Saturn, when we trace it backwards, we find that the event would have occurred when Saturn was on the other side of the sun from us. So we couldn't have seen the impact. The first thing we did is say, okay, do we have any data on Saturn? But it was behind the sun at that time. So we now have evidence that these impacts happened both at Saturn and Jupiter with some regularity. So now I suppose you've got some scientists and you as well just praying that some object decides to come through that ring and cause some more

of these waves. Right. That would be wonderful if another cometary dust tail or something happened to intersect Saturn's rings and we could watch in real time as this ripple formed in the rings. That would be wonderful. My point was that compared to seven years ago, I wouldn't even hazard a guess as to how many times you have multiplied our knowledge of this planet and all the stuff going on around it, all thanks to the spacecraft. Right. Just the longevity of having a spacecraft in orbit. The spacecraft is healthy. The instruments are working. And so we're continuing to learn new things about Saturn and continuing to revise and write books now about Titan and about the Saturn system itself. So as you do this, folks like you who this has been your life for decades, and you have a large science team, but we just

heard that you are inviting more scientists to join the party. Right. We're inviting a group. We're calling them participating scientists. They can apply through the Cassini Data Analysis Program, and they can then join the Cassini teams to use data from Cassini, data even immediately from Cassini, for a project that they'd like to follow. And what's really interesting is if you think about it, we selected the Cassini teams back in 1990, and that's over 20 years ago. And so there's a whole young generation of scientists

that weren't around to propose to be part of the teams. And we're opening it up to everyone, but, of course, that group in particular might be very interested in joining the Cassini endeavor. I wouldn't be surprised. We're almost out of time. Got to ask you about the spacecraft health. Every week I read that report online. It says the spacecraft is in an excellent state of health.

How can that be? It's amazing. But if you look at Voyager, the Voyager spacecraft has been going strong for almost 35 years now. So I think if Voyager can do it, so can Cassini. Let's hope so. It's a privilege to come here and share this wonderful new science, new results from Cassini. Well, we will do it again, I hope, in another three or four months. Linda, it is always a tremendous pleasure,

and I'm sure you'll have new wonders to describe when we get together again. Great. Thanks, Matt. Linda Spilker is the project scientist for Cassini, that spacecraft that has been unveiling secrets, making discoveries out at Saturn now for all those years that we just talked about, and with any luck is going to keep doing it, maybe with a whole new crew of young scientists for many, many more years to come. Let's see if we can uncover some secrets with our friend Bruce Betts as we go into

our What's Up segment in just a few moments. Bruce Betts is here, at least virtually, via Skype. He's the Director of Projects for the Planetary Society. Just returned from Florida. No launch, huh? Bummer. Yeah, I think it was you. I blame you for being so upset that I was going to the launch and you weren't. You've delayed the America's Space Shuttle program. It was worth tens of millions of dollars or whatever it cost to delay something like this for a while.

Just to make sure I didn't see it. Yeah, turn those heaters off. You're a bad man. But powerful. What did happen while you were back there? I mean, they got the critters loaded and everything. Yeah, so after a little delay, the sample tubes with our shuttle life organisms were successfully loaded into what's called the Crest-1 experiment block. This was done by ITA, one company, and then the whole thing was arranged by another company called NanoRacks. So that actually ended up working well.

It was about midnight one night when I was over in the Space Life Sciences building there at Kennedy Space Center witnessing and trying to make sure things went well and trying to encourage them not to let me touch the flight hardware. And you have a nice picture of that building in a blog entry that you did, the Planetary Society blog that we'd always talk with Emily about. And it has all kinds of great images. My favorite, as you might imagine. You can guess, can't you?

Yes, I can. Yeah. What is it? Bodily fluid what? The body fluid cleanup kit. You can guess, can't you? Yes, I can. Yeah. What is it? Bodily fluid what? The body fluid cleanup kit. As people have been listening for a while, I'm trained as a planetary scientist, a physical scientist. And any time I go to places like ATCC where we loaded organisms or the Space Life Sciences Lab, there are things that just, they just give me the willies. I really did not want to be somewhere that had in the hallway, things on the walls that said body fluid cleanup kit.

I don't even want to know why they have that there, but I'm pretty sure I don't want to be in the same building. I didn't see any of those when I was under the dome at Palomar. No, no, they don't have those astronomical observatories. They don't when you're looking at spacecraft images on computers, writing software. You just don't have body fluid cleanup issues. I mean, you may, but it's not a regular hazard of the job. Well, at least you know once again now that you've gone into the right field. So please use that field to tell us about the night sky. All right. The most exciting part of the night sky is the end of the night. The pre-dawn got four planets coming up. They're still pretty low, so look not too long before dawn over in the east. Venus should be pretty easy to see, super bright jupiter over the next week or two is going to be getting higher up and so get quite easy to see because it's also really bright but not quite as bright as venus and then a little more challenging will be mercury which is the

less bright white thing and then mars looking reddish and and dimmer and all of those are going to be shifting positions all throughout May and a little into June, making for a wild and crazy planet ride. And Saturn is our one planet friend, besides the Earth, in the evening. And you can check that out already up in the east in the early evening and then high overhead by the middle of the night looking kind of yellowish. early evening and then high overhead by the middle of the night looking kind of yellowish this week in space history we had the first flight appropriately this week of the space shuttle endeavor the one that i saw on the pad sitting there quietly welcome to the club uh so it first flew in 1992 we'll get back to that in just a moment with the random space fact.

But first, also remembering that 50 years ago this week, Freedom 7 suborbital flight, and Alan Shepard becomes the first American in space. Wow. Not too long after Yuri, but long enough that it was only a little ballistic flight. So we had some catching up to do. We did indeed. So now we move on to Random Space Fact. I really do have sympathy for you. In fact, I have empathy for you. I am sorry that this worked out the way it did. Or maybe you're crying over something else. I have no idea.

I'll give you the Random Bruce Fact first, and then I'll give a real space fact. I did see a shuttle launch, so you can still hold that against me. But I have also been to at least four different launch attempts at the Cape. Two shuttles and two

robotic missions, all of which experienced delays when I tried to see them. Wow. So they now have me on a blacklist officially. Don't come back. All right, on to the actual random space fact. Endeavor. Let's give some information on Space Shuttle Endeavor.

It was the fifth and final NASA space shuttle built for space, constructed as a replacement for Challenger. And as we mentioned, it first flew in 1992 and it is named after the British HMS Endeavor, the ship which took Captain James Cook on his first voyage of discovery and that's why we spell it with that pesky British spelling with that U towards the end. I'm reading a book called Age of Wonder in which that first voyage by James Cook plays a very important part. Well, then you may know the answer to the trivia question.

Oh, my gosh. Oh, my gosh. We'll come back to that in a moment. First, our trivia question we are going to answer this time around. I asked you what was the first spacecraft asteroid flyby? How'd we do, Matt? Very well, very well. Good response this week. And our winner was Rhys Naylor, first time winner in Brandon, Manitoba, Canada. Rhys told us that it was the spacecraft Galileo on its way to Jupiter, of course, but at first it flew past asteroid 951 Gaspra back in what year? 1991. And it actually did another asteroid flyby on the way to Jupiter,

picking up a little extra exploration there, and then passed Ida and discovered its little tiny moonlet, Dactyl. First ever asteroid flyby Gaspra. Let me give you an answer from our friend Ed Lupin, Edward Lupin, down in San Diego. This gets honorable mention. He says the answer may change when the Grunt mission returns data, but Mariner 9 approached the moons of Mars, which may be captured asteroids, in 1971. And then he went on to mention Galileo.

Didn't get picked by Random.org, but Edward, our compliments for that nice answer. Interesting point. I have to distinguish. Once they're captured, they are moons. They are not asteroids. Let me mention before you go on that I forgot to mention last week. I never gave the name of the winner. Oh, my gosh. Ted Judah. Ted Judah in Petaluma, California, won the t-shirt last week. He says, rhymes with Red Buddha, which I can't imagine why I would have forgotten to use that, but I did. So congratulations for the second time, Ted. All right, we move on to our next trivia contest, including for you, Matt. Don't tell us the answer if you've read it, but I'm sure you're reading about it. What rare astronomical event did Captain James Cook's Endeavor sail to the South Pacific to observe when it sailed in 1768?

Go to planetary.org slash radio and find out. I do. I do know because of this book. As of if you'd asked me a month ago, I wouldn't have known. But my lips are sealed. Wow. Book learning. Nice job.

And way to seal those lips. You got until Monday, May 9, Monday, May 9 at 2 p.m. Pacific time to get us the answer to this latest space trivia question. And we're done. All right, everybody. Go out there, look up at the night sky, and think about breadfruit. out there, look up at the night sky and think about breadfruit. I mix

my South Pacific voyages and thoughts and reflections. Ever had any breadfruit? I did once, yes. Oh, I've only had bread and fruit, but never breadfruit. It's not bad. It's better than, well, poi. Well, sure. So are

some forms of glue. Say goodnight Bruce sorry for the insults to the tarot root fans out there you've already looked at it you've got me all frazzled talking about poi I have nightmares about poi let's not think about that anymore thank you

poi oh poi he's Bruce Betts the director of projects for the Planetary Society. He joins us every week here for What's Up. Next week, the Lunar Reconnaissance Orbiter's Richard Vondrack returns to share new revelations about Earth's closest companion. Planetary Radio is produced by the Planetary Society in Pasadena, California and made possible in part by a grant from the Kenneth T. and Eileen L. Norris Foundation. Clear skies.