Planetary Radio: Space Exploration, Astronomy and Science - Talking with JPL's Blaine Baggett and Ed Stone About "The Stuff of Dreams"

Episode Date: February 25, 2014

JPL’s Blaine Baggett and former JPL director Ed Stone talk “The Stuff of Dreams,” a documentary about an era in planetary exploration that was both exhilarating and exasperating. Emily Lakdawalla explains why Curiosity has joined the fraternity of backward driving rovers on Mars, and Bill Nye considers the not-too-distant future when airliners and spaceliners will share the sky.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The best space movie you can't see, 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. Today we'll welcome back former JPL director Ed Stone, who has been the Voyager mission's project scientist for more than 40 years. Joining Ed will be Blaine Baggett, director of a new documentary about what was probably the most difficult time in the history of the lab. We catch Bill Nye just before he gets on an airliner

that may soon be sharing the sky with space liners. just before he gets on an airliner that may soon be sharing the sky with space liners. You should also prepare yourself for a somewhat zanier-than-usual edition of What's Up with Bruce Betts. Much less zany, though quite illuminating, is our opening conversation with the Planetary Society's senior editor and chief blogger, Emily Lakdawalla. Emily, is there some kind of rover club on Mars and driving backwards as part of the hazing? It's pretty funny. We now have the third rover on the surface of Mars that is trying to solve some driving problems by driving backwards. But it's for different reasons for every rover. But yeah, Curiosity has joined the club and is now capable of actually quite long distances

driving backwards. And they've been really racking up the meters recently. And why have they made this choice? Well, apparently, and for reasons that I can't quite explain, the problems that tend to cause holes to appear in Curiosity wheels don't seem to be as bad when they're driving backwards. Honestly, I really don't know why that is, but it seems to be the case. I actually read a planning document at some point that said that the rocker bogey suspension system, which is the same kind of wheel and arm mechanism that's on all JPL-built rovers, it actually operates slightly better going bogey first than rocker first, which is the backwards driving direction. And they turn it around in the rover designs because that way if a rover gets itself into trouble, it's automatically pointed in the better driving way to get itself out of trouble. Oh, those clever devils at JPL. That's very interesting. Look, before we run out of time, say something about these route maps that you're very proud of. Oh, yeah. Well, I recently

indexed all the different images that there are from orbit of the Curiosity landing site. And part of those images from orbit are images that are anaglyphs or 3D views. And so I've started producing route maps showing where Curiosity has driven in 3D. So if you happen to have red and blue 3D glasses, please go check out my blog and see for yourself the way that the terrain changes over time. Now Curiosity is driving into valleys instead of up on ridges, again, as a part of the strategy to avoid doing further damage to the wheels. And I've got my Spirit and Opportunity 3D glasses right here, and I'll tell you, it's a very nice effect. And you've got another 3D image, except that this one comes from the moon,

where I'm guessing the Chinese Space Agency would love it if U-2 would drive backwards. Yeah, unfortunately, it looks like they're having real trouble getting the U-2 rover rolling again. They haven't been specific about what the problem is, but at least the rover is awake and talking to Earth controllers, which is definitely the lion's share of the battle when you run into problems on a spacecraft. So that's the latest from the moon. The rover is not roving, but is still at least capable of doing science. All right, Emily, we'll be checking in again next week, of course. Thanks very much. Thank you, Matt. She's the Planetary Society senior editor and our planetary evangelist and a contributing editor to Sky and Telescope magazine and ever so much more. That's Emily Lakdawalla. Up next is Bill Nye, the CEO of the Planetary Society. Bill, you globetrotter, you, we catch you in Minneapolis. Before we let you run off to catch a plane, what are you doing there? We did the Sophia.org, which is a new part of the flipped classroom. So you watch some of your lecture at home, and then you go to class, and the teacher has those extra 10 minutes with you one-on-one because you watch some of the lesson or even a science demonstration at home on your tablet, your computer screen, your handheld device, whatever the kids are using. And before that, you know, before that, I was at Oklahoma State, Stillwater, Oklahoma, nothing but fun down there, let me tell you.

I'm glad to hear it. And with all this flying around, I think it's interesting that our topic today is how before too long, planes like the one that you're about to get on are going to be integrated into the same air traffic control system as commercial spacecraft. At least that's what the FAA is working on right now. Already planning. Right now, these commercial spacecraft are operating out of the desert of California. They're operating out of New Mexico, Texas. And so if you're flying from Dallas-Fort Worth to Los Angeles, which is what people do, if you're going to leave Los Angeles and go to

Central America, you're going to cross paths with rockets full of people. I mean, how cool is that? And so we got, I guess, we got to have the big plan and they're already doing it. Who knows, two or three or five years in advance. This is exciting. It really is. We took this out of a story in Space News that the FAA is, they have this next-gen air traffic control system and they're building the GPS systems

it'll be working with. Apparently, they're just not tough enough yet for the rigors of spaceflight, but they're working on it. They're working on it. So- The big thing I can tell you that when I worked in avionics, Matt, the big thing is cooling and vibration. Those are your issues.

And rockets have a tendency to vibrate like a crazy thing. So you've got to watch for that. And I imagine there's one thing that could lead to another where these devices would not be in the pressurized in the cabin. When you try to cool things in a vacuum, you've got to be watchful. It's exciting. Come on. It's avionics. It's spaceonics.

Go catch your airplane. Thank you, Bill. Thank you, Matt. I brought a big net. It should be no problem. I've got to fly, Bill. I'm the planetary guy. It's called The Stuff of Dreams,

and it dramatically documents one of the most triumphant eras in the exploration of our solar system. Ironically, this new film is also the story of one of the most challenging and even discouraging times for planetary exploration. It stars colorful characters who just happen to be the scientists, engineers, and administrators who led the Jet Propulsion Lab and its greatest mission of the late 70s and early 80s. Blaine Baggett directed the documentary. He's also executive manager of JPL's Office of Communications and Education. I met Blaine in his office where we were joined by one of our most frequent Planetary Radio guests. Ed Stone ran JPL for 10 years, but by the time Ed became director,

he had already been Voyager Mission project scientist for nearly 20 years. He's now had that job for 42 years. Ed remembers the exhausting and exhilarating days when Voyagers 1 and 2 began the treks that would take them across the solar system and beyond. These first smart robotic explorers would soon reveal unimagined vistas of worlds we barely knew. Gentlemen, it is always a thrill to come to the lab and talk to people who I regard as heroes. This is a great, great opportunity because I get to talk to not only the two of you, but we get to talk about some of the heroes of the past here at the lab during what was a particularly difficult time. In fact, I somehow led myself to believe

that this new film, which is terrific, had to do mostly with the Voyager mission, but really it's much, much more than that. And with apologies to Charles Dickens, Blaine Baggett, you directed it. Would you agree that it's sort of the best of times, the worst of times? Indeed was, and in fact,

I thought about using that as the title, but at the end, I thought, well, it's been heard a few times, so maybe I would try something else. It's been done. It's Stuff of Dreams, which is based upon one of the characters in the film. I want to congratulate you again. I think it's a remarkable documentary. For many reasons, it's so honest. It's so straightforward about the challenges that were faced at that time. Well, that's my training. I come out of public broadcasting, doing documentaries. And so it doesn't matter where I'm working. The notion is you go about doing a film and you try to present the facts as best you can

and get to hopefully something significant about what did it mean looking back. Selfishly, I also was thrilled because there were so many people that I've been lucky enough to have on this show or come in and out of our doors at the Planetary Society who are featured in the film. Just talking about ones I know, Charlie Colhaze, the inimitable Lou Friedman, who has a big part. Linda Kelly, I know her as Linda Kelly from when she was a colleague. The first person, Ed, to see those mighty volcanoes on Io. That's right. And she has a terrific bit in this.

And then, of course, really central to the whole period is this, I would say, a towering figure of Bruce Murray, who really the story revolves around, doesn't it, Blaine? It is. The story of Voyager has been told before, so when I approached this, I said, how can we do it differently? How can we add something to the texture of the history? And Bruce Murray is a very interesting fellow in and of himself. His Achilles heel, I think, was that he was so passionate about what he wanted to do, but he was a little bit of a bull in a china shop.

You've got this person who comes into the lab, has a fantastic vision, many of which came to be years after he left. Yeah, yeah. Those purple pigeons. That's right. That's right. But at the time he was here, he really, really had a hard time with what was going on. Because to the public, fantastic things were happening.

Dr. Stone was making one discovery after another and presenting it to the public. But Bruce Murray, the director of the lab, was struggling to actually keep the doors of the lab open. Could you even imagine anybody else if having an easier time? I mean, somebody I think says in the film, or it's in the narration, maybe he did as well as anybody could have been expected to do in face of maybe the greatest challenges that this great institution ever faced. It was a time where if you're NASA, you look and you say, you've done the first reconnaissance of the solar system. We're trying to rebuild the human program. We want to build the first major

space telescope and explore beyond our own solar system into the galaxies and galaxies beyond. And so you've got to make hard choices because NASA doesn't have a printing machine to do, you know, more for money. It still doesn't, doesn't. No, it still doesn't. In fact, we're facing many of these same problems today. That's one of the things I like about the film is that you can almost find yourself in the same situation. It's a dilemma that you, at the same time, you've built up this infrastructure here at the laboratory in terms of expertise. It's what matters, human capital.

You don't want to lose that either. So if you're a person in Washington trying to make decisions, what do you do when you have all these great ambitions, great expertise, and how do you keep all those balls juggled at the same time and not lose any of them? keep all those balls juggled at the same time and not lose any of them. Ed Stone, I suspect that if it had not been for your mission and a few other bright spots, a lot of great people here might have just said, I don't need this, to hell with it, and left this facility. And it would have been, I think, a national tragedy, if not an international one.

I mean, do you ever think about that? The significance beyond science of Voyager? Well, there's no doubt that Voyager has a much broader reach than just science, and it has a tremendous reach in science alone. But the fact that the public has become so engaged with the whole sense of exploration, learning things, which is really what science is all about, and that's what Voyager did. Day after day, year after year. It's been teaching us things that we often had no idea were there to be discovered. I was struck once again. Once you got past the initial troubles, which are very well documented in this film, how little we knew about where Voyager was going and how much we learned from these two spacecraft. It's mind-boggling.

It really is. And in fact, all the scientists realized we were on a mission of discovery, but none of us had any idea of what was out there waiting for us. And so time after time, our terror-centric view of the solar system was just blown apart by what Voyager was returning from its journey. And that continues even today. One of my favorite things about the film, another of my favorite things, is how much footage you were able to pull out of the archives here, film and stills, that documented

some of the highest high points and some of the lowest low points. Was this stuff difficult to dig up? Excruciating. stuff difficult to dig up? Excruciating. In part because some of this archive was sitting back in an area that no one knew about, had not looked at it for a long time. Film over time deteriorates. So we were able to save some of this. Ironically, another irony for me was that we used everything we could find to put into the film. But earlier in the history of JPL, there's much more footage. I think what was happening at the time of Orger was that they were doing press conference after press conference after press conference, but there wasn't much footage about what was going on behind the scenes. That is something that we just scraped together to do the best job we could.

Unfortunately, we also have so many of the people who were involved, so we have the first-person recollections of those folks. We scraped together that footage. We went through a painstaking recovery of that footage in terms of going through color corrections and all kinds of restoration. Something else that is great fun is to look at what was no doubt, Ed, state-of-the-art animation. We're really able to see what this spacecraft is up to,

which now looks pretty primitive, with one exception that I'll come back to. You were looking at that stuff. Well, initially it was wireframe animation, very simple outlines of the spacecraft and the planets and so on. It was only when Jim Blinn became engaged that he really developed the field of computer graphics, where now these were real images constructed by a computer of the spacecraft flying by a real image of a moon. And I think it really increased public engagement tremendously because they have more of a sense of being there with the spacecraft. Yeah, and talk about spinoff

benefits. It sounds like Hollywood owes Jim Blinn and other people here a very, very big debt. Well, it certainly opened their eyes to the possibilities of today, what's in almost every film, computer graphics. Blaine Baggett and Ed Stone will be back to tell us more about the stuff of dreams. This is Planetary Radio. Hey, hey, Bill Nye here, CEO of the Planetary Society, speaking to you from PlanetFest 2012, the celebration of the Mars Science Laboratory rover Curiosity landing on the surface of Mars. This is taking us our next steps in following the water in the search for life to understand those two deep questions. Where did we come from and are we alone? This is the most

exciting thing that people do and together we can advocate for planetary science and dare I say it, we can advocate for planetary science and dare I say it, change the worlds. 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. The Stuff of Dreams is the latest in a series of documentaries by JPL's Blaine Baggett that trace the amazing history of the Jet Propulsion Lab. It premiered a few days ago to a packed house at Caltech, where Ed Stone is vice president for astronomical facilities. The bad news is that you can't yet see this wonderfully produced film that documents one of the most critical times in the history of robotic space exploration. It wasn't just the political climate. Both of the Voyager spacecraft suffered serious problems when they began their trip to the stars. I'm going to come back to what I talked about, those early days of the Voyager mission that are so well documented in this film. Were there times when you wondered if you were going to get spacecraft very far beyond Earth's orbit, much less out to the outreaches of the solar system?

Actually, my feeling was that we had built really a tremendously capable spacecraft, and our challenge was to learn how to fly it. And what I soon realized was it takes smart people to fly a smart spacecraft, and it really did take us a while to learn. And the only challenge was learning before something serious happened. But the spacecraft was programmed to take care of itself. So in fact, was always doing what it should do to sort of protect itself. We had to learn how to use the spacecraft so it didn't get into the mode of having fault protection triggered, where it can continue on our planned journey rather than on what was happening to it. Is it fair to say that the spacecraft in some ways were smarter than the apprentices who were learning how to run them? Well, the spacecraft was as smart as we made it,

of course. And the thing, the challenge was that it was experiencing environmental things that we had not anticipated. And in doing so, it was following very well the script which we had put in it. But in fact, we realized that we had not really anticipated properly all of the effects that the spacecraft would have to deal with. Is this another way, in terms of the level of autonomy that was built into these spacecraft, that really set the course for maybe almost every mission that is followed? Oh, yes. Now all the missions now are all flown by computer and several computers were on the spacecraft, all programmed, of course, now much more sophisticated because the computers now, of course, are much more capable than the one which is on the Voyager

spacecraft. I want to ask you about some of the other people is on the Voyager spacecraft. I want to ask you about some of the other people who are interviewed in this film. You are, of course. Wonderful, wonderful men and women, some of whom we've lost. You knew most of them. What was the feeling of working as a part of this team all those years ago? Well, it was very exciting. I mean, you know, there was a period we spent basically from 1972 to 1979 getting ready to launch and launching. And it was only in 1979, seven years after we

started, that we were then flooded day after day with Discovery. So it was a very long period of getting ready. And then it really just a flood. It was just wonderful. Do you remember those moments, and some of them are in the film, of people just watching monitors and suddenly seeing something brilliant and jumping up and down for joy? That's right. Every day was like that. That's what made it so unusual. Most scientific progress is much more measured than what we had because this came in huge bursts.

I think that's something which I hope younger people can walk away from this film understanding is how little we really knew at the time. They take it for granted, right? Young folks that you can Google anything and come up these amazing images and go to all these places. But the scientists did not know. Were there moons out there like the moon of the earth? Were they just these kind of barren places? And instead, these fantastic worlds that would be the vacation unimaginable if you could go to some of these places and be close to them. Do you remember what you were thinking, Ed, when you guys first saw those close-up shots of Io? Well, we didn't know what to think. We had never seen anything that looked like Io before. It had no impact craters on its surface at all. It wasn't until the plumes were discovered, the eight active plumes on Io, that it became very clear that this was the most volcanically active body in the solar

system, 10 times the volcanic activity of Earth. That's how different our perceptions were than they had been before Voyager. We thought Earth was the only place that had active volcanoes. You'd have a weather report here, there you'd have a volcano report. That's right, yeah. Make map makers crazy. Yes, it would. Blaine, if I remember correctly, Bruce says in the film, Voyager may have

been the greatest mission of discovery since Captain Cook. Do you agree? I do. I do. Because it is a journey into the unknown. We did not risk any lives. That has to be taken into

account. But in terms of the knowledge that was gained, it is the equivalent, absolutely, of Cook. There are a couple of other Marie-isms in this. I already threw one of them out there, purple pigeons. And the flip side of that coin, gray mice. Would you explain those? I don't know the origin of purpleon, how they dreamt it up. But the idea was,

Bruce said, we've got to be more imaginative. He really felt that the way that the planetary exploration program would succeed is by bringing the public along instead of just the science. It had to be science and the public. And so he wanted exciting ideas. He said, let's call them something special, something unusual. You don't see a purple pigeon flying. So somehow they came up with the idea for something very interesting. And the opposite of that is a gray mice. A gray mice is something which is dull and small

and doesn't get anyone really excited. Bruce Murray didn't want any gray mice is something which is dull and small and doesn't get anyone really excited. Bruce Murray didn't want any gray mice. He wanted ideas that were purple pigeons that would ignite the imagination of the public. He wanted to have rovers on Mars. He wanted to map Venus with radar. He wanted to go to Comet Halley with solar sails, this incredible idea of solar sails. He thought big. He had really interesting ideas. And as I said earlier, many of them came true, just not on his watch. Yeah. There are so many other great segments and stories that are told

in this film. For right now, Blaine, as we speak, it can't be seen. When and how will, do you hope at least, that people will eventually be able to see this film? What we're trying to do is an entire history of the laboratory from the very beginning through whatever the current time will be. And so I really want to compile them as a whole before we really do a major national release. These will be. And so I really want to compile them as a whole before we really do a major national release. These will be evergreen. These will be on shelves for years and years to come. And

I do these in my spare time. This is not my day job. And I do them about one a year. And so we're up to the 80s now. Maybe in about three years, four years, I'll have the rest of them done. And then we'll talk about a mass distribution then. All right. A lot of stories left to go. I see a good miniseries in the future. Ed, the audience would never forgive me if we didn't get an update on what's going on with the spacecraft. Now, I think since we last talked to you, officially outside the solar system, at least one of them? Well, it's outside the solar bubble, not outside the solar

system. The sun creates this huge bubble around itself for the wind of the sun. And Voyager 1 left that bubble in 2012 and is now in the space between the stars, interstellar space, which is filled with stuff that has come from the explosion of other stars, not stuff from our sun. And still a lot of influence from our solar system, right? I mean, the Oort cloud is still... We're still inside the solar system in terms of the Oort cloud, which is a cloud of comets. In fact, we don't get to the inner edge of the Oort cloud for 300 years more, and we don't get through it for 30,000 years more. So that part of the solar system is much bigger than the bubble the sun creates around itself. How much more life do we have in these spacecraft? We have about 10 years more lifetime. It's electrical power. It's

a natural radioactive decay of plutonium-238. And by the year 2020, we'll have to turn off our first science instrument. And by 2025, we'll have to turn off the last one because we won't have enough power. What are you looking forward to? What additional science might we get from Voyager 1 and 2? Well, outside, we are in a region which material has come from other stars. The magnetic field is from the Milky Way galaxy itself, and we're going to observe how that matters. There's a wind, an interstellar wind,

compressing the heliosphere and piling up outside of our bubble. And we will now be journeying into this region where the wind has piled up, the interstellar wind has piled up material that's come from other exploding stars. Going on four decades later, still a terrific mission, and you're still the project scientist. That's right. I still get to walk into my, and you're still the project scientist. That's right. I still get to walk into my office and learn something new almost every day. And, Blaine, you get to work with guys like this. It's a great privilege to tell this history and to meet the kinds of people that I get to meet. It's a great job.

Gentlemen, it is a great privilege to have spoken to you for a few minutes on the show. Thank you so much. Best of luck with what I think is a terrific film. And Blaine, I hope you'll be able to get it out there where people can see it as soon as possible. Thank you very much. Blaine Baggett, director of the Stuff of Dreams and JPL's executive manager of the Office of Communications and Education. Joining us in Blaine's office was former JPL director Ed Stone of Caltech, who has been the Voyager Mission Project Scientist for 42 years. Back with Bruce Betts in a moment. Time for What's Up on Planetary Radio.

Bruce Betts is on the Skype line, which is a shame because I've got something for you from my trip to JPL, where I picked up the interview this week with Ed Stone and Blaine Baggett. So you're just going to have to wait, I guess, until we see each other face to face. Sorry about that. You just keep teasing me. I know. And it's such a great gift. Hey, speaking of great gifts, I had a listener.

It was Mark Wilson. Sent me this picture. Have you seen the photos of supermodel Kate Upton in the Zero-G plane, the Vomit Comet? I did. You admit it? It's okay. You can. Well, it's your fault.

You forwarded it to me. Did I forward it? Yes. Yeah. I thanked Mark. He said that, you know, Sandra Bullock in Zero-G is good. Kate Upton in Zero-G is better. I don't know about that. Kate Upton doesn't make me laugh. Sandra Bullock makes me laugh. Yet another message from Mark Wilson. He says, at the end of Gravity, spoiler alert here,

folks, Sandra Bullock crash lands in Lake Powell on the Arizona-Utah border. Now, here's what I didn't know. At the beginning of Planet of the Apes charlton heston crash lands in lake powell that's two spacecraft now at the bottom of that lake well three if you count the aliens okay i've wasted enough time what's up gosh oh i just don't know where to go with this so we'll go to the night sky and uh heavenly bodies yeah so jupiter uh still easy wonderful bright super bright object in the south in the early evening but by uh later evening getting to be a a party got mars brightening up as it comes to its closest approach in mid-april so it's uh looking brighter than nearly nearly any other star now looking reddishdish up in the east around 10 o'clock in the evening.

It's near the brightest star in Virgo, Spica, right now, but actually brighter than Spica by quite a bit. And then coming up around middle of the night, midnight-ish, we've got Saturn coming up in the east. And then in the pre-dawn, Venus just being the dominant star-like object over there low in the east. If you're picking this up right after it comes out, you can catch the moon next to it on the 25th and 26th. But generally you can just check it out over there no matter when you're picking this up. A little later on, we'll get Mercury coming back. We move on to this week in space history. Ten years ago, Rosetta launched.

Rosetta, the spacecraft that still, by plan, has not reached its primary target. But it will this calendar year party on Rosetta. So really cool. And it woke up and it's ten years ago it launched, headed to a comet. We move on to Random Space Fact. And I have to apologize because it was my intent to get Ed Stone saying Random Space Fact. Now, wouldn't that have been cool? I completely forgot.

Everyone is sad. This one I pulled off the Year in Space calendar. If you're looking for a pretty calendar, you can still pick up the yearinspace.com. You can pick up the calendar. And on there, you would find out that in Titan's atmosphere, liquid methane falls slower than on Earth, got a lot lower gravity and even a thicker atmosphere, and comes in drops up to twice the size of Earth's raindrops. When they remake the Butch Cassidy and the Sundance Kid, it's a whole new thing to raindrops keep falling on my head.

Methane raindrops keep falling really large and slowly on my head. Brr. All right. Okay, we move on to the trivia contest. What region is between ultraviolet and gamma rays in wavelength? How'd we do, Matt? Big response once again. I don't know what has caused this to take off,

so perhaps the Beyond Earth letterpress poster from Chop Shop, which has been won this week by Juliana, and she knows that I'm going to mess up her name. She said it would be okay. Juliana Z... Oh, never mind. You know who you are juliana it's the juliana who lives in rhinebeck new york where i honeymooned at the beekman arms the oldest in in america george washington slept there and so did i although not together

oh this is a particularly weird show, and I blame you. Do they have a plaque? They do. They absolutely have a plaque. No, I meant that says Matt Kaplan's. Are you sure? No, I keep writing to them saying I'll pay for it, but not so far. You know what? I haven't given the answer. It's x-rays, right? Yes. Yes, indeed.

Okay. I only have one other note to read to you. This one came from Nick Ray, R-A-E. Remember that name in Peoria, Illinois. He said, on a related note, we're having our first child in April and we are planning for her to refer to my mom as, wait for it, Gamma Ray.

I thought you'd like that. Nice. I hope they name her X. I'm sure you've never heard that joke before. Yeah, I bet. Okay. Well, thank you. And we're ready for another one. What is the approximate range of elevations on Venus? So like on Earth, it's around 20 kilometers, a little bit more, separating the top of Mount Everest

from the bottom of the Mariana Trench. What is that number on Venus? Approximately from the top of the mountains to the bottom of the plains. Go to planetary.org slash radio contest. Get us your entry. When should they get that in by, Matt? Tuesday, March 4.

Remember, we've moved the deadline and I'm moving it a little bit more, not quite as much, but moving it back, and this will just make it a little easier for Bruce and me. Let's make it 8 a.m. on Tuesday, March 4. That's 8 a.m. Pacific time, of course, and we look forward to seeing your entry. All right, everybody, go out there, look up in the night sky, and think about liquid crystals. Thank you, and good night. Is that when it snows on Titan? He's Bruce Betts, the director of projects, 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 the jolly members of the Society. Clear skies.