Planetary Radio: Space Exploration, Astronomy and Science - Jim Bell Welcomes “The Interstellar Age”

Episode Date: March 3, 2015

Planetary scientist and author Jim Bell has just written “The Interstellar Age—Inside the Forty-Year Voyager Mission.” He talks with Mat Kaplan about the magnificent grand tour of the outer solar system that is now headed toward the stars.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Jim Bell on our entry into the interstellar age, 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, a conversation with famed planetary scientist Jim Bell about his wonderful new book that tells the story of the Voyager mission. Bill Nye the Science Guy will help us remember Leonard Nimoy, while later we'll visit with Bruce Betts and get some cosmic potty humor. We begin with Emily Lakdawalla, the Planetary Society's senior editor

posted a blog entry on February 26th about the Dawn mission's imminent arrival at dwarf planet Ceres. Now there's even more news to share. Emily, as we speak, a press briefing has just finished on NASA TV coming out of JPL about the Ceres mission. You also just wrote about this mission. Didn't sound like there was a whole lot of new news, but what did you hear? Well, I heard that the team is understandably extremely excited about the new images and particularly excited

about features on the surface of Ceres that they did not expect to see and are looking forward to investigating after they go into orbit next week. You must be first, at least, talking about those mysterious white spots. Yeah, you know, we did expect to see something bright on the surface because Hubble saw a bright spot on the surface of Ceres. But I have to say that they probably did not expect what they saw, which is a spot that remains so bright and yet so small that they can't resolve it in their current images. They're going to have to get closer in order to get enough pixels across to try to figure out what the heck these things are. All right.

Now, I have a very brief comment about these from Deputy Project Scientist Carol Raymond, who was at the briefing. The team is really, really excited about this feature because it is unique in the solar system. We will be revealing its true nature as we get closer and closer to the surface. So the mystery will be solved, but it is one that's really got us on the edge of our seats. Another thing that was a major topic of the press briefing you also wrote about in your great blog entry, and that's this crater with a, what, a remarkably flat floor? Yeah, it is so flat. You know, when a crater forms, it's a hole. It digs a deep hole into the surface of a world.

Now, if you have an icy world like Ceres, Ceres we know has to be composed at least partially of ice because its density is considerably less than that of rock, you expect that over time the craters will flatten. But this is a very large crater that is very, very flat, and it doesn't contain very many craters inside it. So that tells you it's also geologically relatively recent. This is a place where a lot of geology has happened. It's too early to tell that geologic story, but I can tell you it's a place on Ceres that the

science team is going to be investigating very closely once they get a little bit closer to the surface. And here is Carol Raymond once again on this topic. This may indicate a region of distinct geologic processes. And as Don goes through his comprehensive mapping, we'll obtain the data that we need to understand what this complex structure is telling us about the subsurface. But it's going to be a little while before we can see it much closer, because Don actually overshoots Ceres a little bit as it goes into orbit, and is now on the night side of Ceres. And you know, Don can do a lot of things, but I can't see in the dark. So we're not seeing the surface of Ceres right now. And we won't again for a little bit.

It's going to be a while before we get newer pictures that show higher resolution toward the end of April. But it's going to be really exciting once it starts to happen. This next chapter in the story of Ceres is going to be an exciting one. Thank you very much, Emily. Thank you, Matt. Emily Lochtewall is our senior editor at the Planetary Society, our planetary evangelist, also a contributing editor to Sky and Telescope magazine. Up next, Bill Nye with a tribute.

First, though, a bit more of Carol Raymond. It's clear that discoveries lie ahead. A series will be revealed in stunning detail, just like Vesta. Bill, we mark the passing of a guy who wasn't a scientist. He was just an actor, but he sure inspired a lot of us. Just an actor? Leonard Nimoy died, everybody, and he played Spock. And even if you have never seen Star Trek, you hate Star Trek, you hate science fiction, you hate everything.

The guy changed the world. His interpretation of this character really changed the way many people perceive, I think, ourselves. In his context, that is to say, in Spock's world, was a scientific and optimistic view of the future, that through science and technology, things one day would be better. In fact, all the traditional problems that you and I have of food, shelter, clothing, these are all solved in Star Trek's future. Instead of being apocalyptic, as so many science fiction stories are, Star Trek was optimistic. And that optimism, that optimistic view of the future came from their understanding of the cosmos.

view of the future came from their understanding of the cosmos. They flew around the cosmos effortlessly. Boom. And then everywhere they went, the stories were about, well, were about people, were about how humans or how sentient beings get along. It's something that I think affected all of us. So here's a plug for the blog post that I put up over the weekend. It's my tribute as a science fan to Leonard Nimoy. I think people who believed that, you know, emotionless logic was uppermost in Spock's mind. No, they didn't get it. Spock wanted to know. He was a scientist. He wanted knowledge. He was curious. Yeah, exactly. He was half human. And then his, you may recall, his father, rather Spock, asked his father about his mother. She's illogical, isn't she? His father said, she's always been so. Indeed. Why did you marry? And he said, at the time, it seemed the logical thing to do. Oh, it changed the world. I couldn't agree more. Thank you, Bill. We will all miss him.

We will all miss him. And it just shows you as part of a collaboration, Gene Roddenberry had this great vision of the future and the actors brought this remarkable storytelling to it. It's really something.

Thanks, Matt. Live long and prosper, Bill. Good advice, sir. Thank you. He's Bill Nye, the CEO of the Planetary Society, a trekker, a trekkie like yours truly. And he joins us most weeks here on the radio show. Coming up next, we're going to talk to his buddy, actually, Jim Bell. I've often called scientist and author Jim Bell the Ansel Adams of Mars.

It's a compliment he earned through his magnificent work creating and sharing images of the red planet, especially those taken by Mars rovers Spirit and Opportunity. The results included his best-selling books, Postcards from Mars and Mars 3D. Jim has taken on a new literary challenge with his latest work, The Interstellar Age Inside the 40-Year Voyager Mission, has just been published. It's a sweeping yet personal biography of the historic grand tour of our solar system by twin spacecraft that are now venturing outward toward the stars. Dr. Bell is a professor in the School of Earth and Space Exploration at Arizona State University. He's gearing up to continue his exploration of Mars with the main cameras on the coming 2020 rover. Jim also serves as president of the Planetary Society,

and it was at Planetary Society headquarters a few days ago that we sat down to talk about the book. Jim Bell, welcome back to Planetary Radio. Great to be here, Matt. I love Planetary Radio. I'm going to guess that a lot of people, myself included, think of you as almost exclusively a Martian. But what I learned from this terrific book is that you cut your teeth in the outer solar system on the Voyager mission. It's true. That's where I got my start. It's kind of my motivation for writing the book. Voyager has had just a huge influence on my life, on my career, as it has for so many other people. I do think of myself as having sort of some outer solar

system roots. This is partly a personal story. Because you were involved with the mission, it's far more than that, as I'm sure we'll get into as we go on. But I want to start with that personal side. Take us back to the fall of 1985, and you're a student at Caltech. Your mentor, Ed Danielson, drops by at the end of the day with an invitation for you. Yeah, so Ed was a member of the Voyager imaging team. Super amazing guy, jolly fellow, always with a smile on his face, always with a helpful piece of advice or tip or something.

And I was working for him as an undergraduate doing some crazy kind of work called image processing. Nobody knew what that was at the time. And there was a single computer that was used in this group. It was grunt work. It was perfect for a student. He had me working on displaying images of Saturn from the 1980 flyby of Voyager. And these were 800 by 800 pixel images.

And the display would take 30 seconds to sort of like scroll the picture down. It was like watching paint drip down a wall, you know, 30 seconds just to display a picture on this workstation. And that was cutting edge. And then I had to click and find the edge of the planet and fit a limb profile, and that was great work. But it was grunt work, and he needed somebody to do grunt work, And the computer was available in the wee hours of the morning, perfect for a student. And I'd overlap with Ed in the mornings usually when he would come in. And he knew I was doing this work, and he knew that I just loved looking at the pictures of Saturn and other pictures that were kind of lying around in his office and coming off the printer.

And I knew that he and others were getting excited about the Uranus encounter coming up. We occasionally could see pictures on that workstation or elsewhere at Caltech of this bluish blob getting slightly bigger every day. And it was still just a dot, a point of light. And that falls when he said, hey, you know, by the way, I'm allowed to, you know, get a couple of extra people into the encounter. And, you know, would the way, I'm allowed to get a couple of extra people into the encounter. And, you know, would you like to would you like to come? And I was just like speechless. Yeah, sure.

Sure. That'd be great. You know, and because I, you know, I try to explain to people, my kids, my students, you know, what what the world was like without Internet. Right. Without the ability to experience these things in near real time, like we do now, you know, we get Mars Rover pictures out there in real time. Cassini does the same thing. We all watch comet landings in real time. And, and we're just so used to experiencing that now, but back in the day, right back in the mid eighties, there was no internet. And so the only way to experience

this was to be there, to be in the room, if you wanted to experience it. And I had no specific job. I wasn't on the imaging team. I wasn't in the field yet. I was a lowly undergraduate. And yet the opportunity to be in that room was like gold. And so I jumped at it. And you found stuff to do. I found stuff to do. I was a gopher, really. There was a couple of us. I learned later that Heidi Hamel, vice president of the Planetary Society, was also in that room. And I vaguely remember meeting her. She was also a student. And so there were a few of us who were just kind of hanging out in the shadows waiting for somebody who needed a photocopy made or somebody to pick up a sandwich or get a cup of coffee

or do some grunt work, kind of like congressional pages, just hanging out in the back, trying to stay out of the way because the room was getting crowded. And occasionally, they'd kick everybody out of the room for some team-only meeting. And occasionally, it would get too loud. And so everybody would get kicked out of the room. And so we were just trying to be kind of mousy and quiet and just soak it in through some kind of cosmic osmosis to figure out – to see what was going on. And it was just spectacular. Next year, 30th anniversary of that Uranus flyby, the first one that you got to witness in person.

That's a pretty big anniversary. It is. But there's so many with this mission. It is. It is. But there's so many with this mission. It is. It is. And, you know, that was kind of a bittersweet thing because it was just spectacular to see that planet come into view and all of its moons and with the strange geology and the rings. And that was an amazing experience. But then just a couple of days later is when Challenger exploded.

And that changed everything, right? And all of a sudden all the media interest was diverted and the coverage was all about Challenger. And so it was a success for NASA, but at a time when there was also a lot of problems. And sadly, we haven't been back to that portion of the solar system since. I'll come back to that a little bit later and your longtime friend and colleague, Heidi Hamel. There are so many wonderful real-life characters, people really that I think of as heroes in this story. We've already mentioned Ed Danielson. We can't go through all of them. There's just no time. But I want to ask you about three of them who come up over and over as you tell the story of this

decades-long continuing mission, beginning with Charlie Colhase. Charlie Colhase, who's also a great friend of the Planetary Society, is just an amazing character, absolutely, an amazing person, and just an incredibly skilled engineer. I have just the greatest respect for Charlie and the team of about a dozen people that he led trying to figure out how to thread this incredible needle of sending both spacecraft to exactly the right place at exactly the right time, he and they had an impossible job, right? They had to, without supercomputers, without even laptops, pen and paper sometimes,

they had to figure out how to manipulate the trajectory of the spacecraft, both of them, so that they not only passed really close to each planet because we want high-resolution pictures, but passed as closely as possible to all the moons that were out there, which were in their own racetrack orbits around the planets, and hit perfectly the spot needed to slingshot them onto the next planet. He told me these stories, some of which I recount in the book about, you know, 10,000 possible trajectories and these folks kind of laboring over, you know, well, we've got

these constraints and we don't want to pass by the planet on the night side because the darn scientists want to take pictures of the clouds and the sunlight. Throw those possible orbits away. And they went through, you know, it took them years to go through and find the two solutions that they eventually flew those spacecraft on. And I'm convinced, and so is he, that they did the best possible job they could. And it was a lot of hard work, and it really paid off. Two needles in a haystack. Exactly.

Fascinating. Here's the next one. Candy Hanson. Candy Hanson, who started out on Voyager as someone called a, well, kind of a sequencer and a representative liaison between the scientists and the engineers. Of course, she's gone on to be a leading scientist on Cassini and other missions, Mars missions since then. Her role was to speak both languages, the science language, the jargon. We want these kinds of photometric observations with these exposure times, you know, and we're trying to get after these particular geologic processes or whatever.

And she understood that language, but she had to translate that into the language that the engineers were speaking, which is the commands, the detailed commands for the imaging system and other instruments, ones and zeros that the Deep Space Network speaks in. And she did that really well. And she was the person that also the science team would kind of throw under the bus at the last minute and say, hey, go tell the engineers we need to change the sequence. And there's only two hours to go. And she'd be like sheepishly, oh, we need to make a tweak. And instead of getting them all upset, she would bake them cookies or make some other wonderful remarks or bribes.

Cookies were the big one. And she endeared herself to that group as well. And she's a great example of how it's the communication and close interaction between scientists and engineers that make these things happen. Okay. Finally, the incom, Ed Stone has been the project scientist for Voyager since I think 1974 or 5, somewhere around there, before launch. The project has had 10 project managers, but one project scientist, Ed Stone. And I think of Ed as the king of Voyager.

He's a benevolent dictator who rules wisely from his perch up on high in the exosphere, watching the solar wind interact with the magnetic fields. And his science is what I call the squiggly line science, the cosmic rays and space weather kind of stuff.

Stuff that shows up on graphs, not in photographs. On graphs and charts, exactly, not in photographs. And yet he's just as excited as anybody else about the amazing pictures and other kinds of measurements that aren't his personal science in the mission. And his job was even harder than herding cats. And the cats in this case were the science teams, the dozens and dozens of scientists for the 12 experiments or so on the spacecraft, who were all vying for this precious resource called time.

Remember, Voyagers were flybys. They're not orbiters where you can loop around and have multiple chances to look at things, or rovers where you can stop and turn around and go back and redo things. These were flybys, first-time flybys in some cases, one time only. Maybe you'd have the second spacecraft coming behind you for Jupiter and Saturn, but that wasn't the case for Uranus and Neptune. You got one shot. You're traveling at 10 miles a second and you get one shot. Everybody wants to make their measurements at the best possible time. And so there's all this competition. And Ed's job was to adjudicate that, to choose.

He confesses in the book, he's done it before, that it's a really hard thing to say, well, you get to do your science now and then you have to wait and then they get to do their science. But somebody had to do that. And he managed to pull it off without upsetting people

in a really fair and equitable way. And the result is spectacular scientific data sets from all the instruments from the spacecraft. And he's also just level-headed. He's very, very scientifically careful and conservative. When Ed says this is the result, like Voyager 1 has left the solar system, people believe it. And that's an important critical characteristic of a project scientist, a scientific leader in a project like this. And that was an announcement he was very careful about. You talk about the process of deciding, has this spacecraft actually left the neighborhood?

Yeah. So, you know, the sun and all stars around us have these bubbles around them, these heliospheres they're called, the magnetic fields and cosmic ray, solar wind and all that, that sort of keep the cosmic rays from outside the bubble from coming in for the most part. The instruments that Voyager 1 has were not the full set of instruments because one of the magnetic field instruments had failed back at Saturn. And so in order to really tell that they'd left this bubble of our sun, you needed not only the cosmic ray instruments like Ed's, but you needed the magnetic field measurements as well, and they didn't have them.

And so when they popped out of the bubble and saw the cosmic rays change dramatically from the solar kind of particles to the interstellar kind of particles, a bunch of people jumped up and down and said, Yay, we've left. But Ed was like, well, we really don't have the magnetic field data to tell us for sure. So he was very conservative and very cautious. Then a big solar flare happened that provided some additional information that made the case. Voyager 2 has all the working instruments. So Voyager 2 will pop out of the

bubble sometime this year or next year. And it should be pretty unambiguous. All the instruments that are needed should say, hey, we're out. And then we'll have two spacecraft traveling in interstellar space. Everything that we've talked about so far in relation to this mission and everything you talk about in the book makes me think of these two spacecraft on somewhat similar trajectories. Not anymore, but they were at one point. This is like, I don't know, how many? Eight, nine, ten different missions all being done by these spacecraft?

It's mind-boggling. It is mind-boggling, It is mind-boggling. And it's really a manifestation of the fact that they are so well equipped in terms of their instrument suite to make measurements throughout the electromagnetic spectrum and imaging and squiggly lines and thermal measurements, et cetera. etc., and also that they have encountered so many different kinds of objects, planets, moons, interstellar dust, rings, interplanetary dust, all these different areas of science, which are all brought together in one ship of exploration. Planetary scientist Jim Bell. He'll be back in a minute to tell us more about his new book, The Interstellar Age. This is Planetary Radio. Greetings, Planetary Radio listeners. Bill Nye the Science Guy here.

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Can I go back to my radio now? Welcome back to Planetary Radio. I'm Matt Kaplan. Planetary scientist and author Jim Bell's latest book is The Interstellar Age, Inside the 40-Year Voyager Mission. The book covers every component of this incredibly complex undertaking, all of its science, its magnificent discoveries, and the amazing team behind it.

You're listening to our complete conversation about the book at Planetary Society headquarters a few days ago. The Arizona State University professor was on one of his frequent visits to the nearby Jet Propulsion Lab. You were largely a camera guy, not exclusively. Say something more about the challenges that were faced by the imaging team in this one shot they had at each one of these bodies, especially Uranus. Yeah, yeah. I mean, huge challenges. And remember, this is 70s technology.

These are not digital CCD cameras like you have in your cell phone or in your home camera. These are old school. They're called Vidicon, just like the old style TVs, an electron gun scanning a trace of electrons across a phosphoring screen. The kind of TV I learned how to make TV on. And they are cranky devices. Yes, they are. Yes, they are. And they respond to changes in temperature or magnetic fields, and they can warp and bend and have blemishes.

And there's all kinds of challenges. And one of the things that Ed Danielson was responsible for was calibrating these things. And he taught me a lot about that and made a big influence on what I do for my career these days. So part of it was just dealing with these cranky old technology cameras, but they worked great. And then as I started getting farther out, two things happened. First Saturn, then Uranus and Neptune. Those planets are farther and farther from the sun. And as you get farther from the sun, sunlight falls off as one over R squared, and it gets darker. If it it gets darker that means to get the

same quality of image you have to take a longer exposure picture but you don't know how bright the moons and other objects are out there really so you don't know how long to expose you have to make your best guess and the other thing that was happening as the spacecraft passed these planets is they're getting sped up they're going faster and faster and so not only do you have to keep the shutter open for longer but you're kind of whizzing past these objects much faster and so there's much more potential for blurring both voyagers have their cameras on what's called a scan platform and so as they were passing by Jupiter and Saturn, the camera was kind of being tracked, almost like a telescope, being tracked in the opposite direction to minimize that smear. And the scan platform did that beautifully until Voyager 2 went behind Saturn, going really fast and doing a lot of complicated things, and the scan platform got jammed. And it never worked again the same way.

There was a little bit of data lost at Saturn. There was some consternation and sadness about that among the team, and I've written about it in the book. It's probably one of the worst things that happened in terms of failures on the mission. But it didn't affect the trajectory of the spacecraft. It was still on course for Uranus and then hopefully Neptune. But they couldn't scan the camera anymore.

They couldn't move the camera opposite the direction of motion and remove that blur. And they knew they'd have to take even longer exposure pictures. And so they figured out, very clever people, Charlie Colhase and a team of engineers, managers at JPL, how to make the entire spacecraft act like a scan platform. Basically, to do a pirouette on the axis of the entire spacecraft opposite the direction of motion while the images were being taken. They called it image motion compensation.

It was totally new. They invented it. They came up with it just out of the cleverness of their brilliant minds. And they made that work at both Uranus and Neptune. And so, you know, you get this amazing vision. If you were looking over the shoulder of the spacecraft, watching it do these kind of little ballet pirouettes in different directions as it was pointed in different ways.

And that worked absolutely beautifully. This theme is one that has come up on this show before. And it happens mission after mission after mission, where these brilliant people back here on Earth reinvent their spacecraft or teach it to do something that it was never designed to do. This is such a good example of that. It is. You've been through this, right? In fact, it's the first example. It's the very first example because the Voyagers were the first spacecraft with reprogrammable computers. We don't even think about that these days.

We take it for granted. Every time you run a new app, you're reprogramming your computer. The spacecraft that had come before, the Rangers, some of the early mariners, they didn't have this flexibility of completely changing the programming. But that was a new technology cutting-edge thing in the mid-'70s was to be able to say, okay, that program you were running before, forget about it. Here's a new one. Uploading it to we're going to make the spacecraft dance now. And that was a big deal. And not easy because the computing power of the Voyagers is very poor compared to spacecraft today, compared to electronics today. One of my colleagues told me there's more computing power in the key fob that unlocks your car than there is on the Voyagers, and that's true.

Nonetheless, they were able to use these innovations at the time, like reprogramming, to achieve these amazing things. As long as we're talking about the spacecraft, will wonders never cease? I mean, here this has been, what, 40 years and all these magnificent discoveries with 1970s technology at best. It's so really shocking to learn that at the core of all of this and key to getting that data back here to Earth

is an 8-track tape machine. Yes, an 8-track tape player. Anybody who drove a car in the 70s may have had an 8-track tape player. I did. It's the same technology, essentially. And the cool thing is it still works great. How many of us have 8-track tape players that still work? Yeah, it's like Opportunity still crawling out on Mars.

Exactly. And even that had problems, induced problems that they had to deal with. If you remember, those of you who remember using 8-track tapes, you'd get to the end of the tape and you'd hear this big kind of ka-chunk, right? And then it would switch tapes and switch tracks and reverse itself or rewind. And when that happens, the same thing happens on Voyager. It goes ka-chunk and starts to rewind. And that action actually induces motion in the spacecraft because it's just free-floating in three dimensions in space. And that was a surprise when they started seeing it shortly after launch.

You're trying to take a picture when that happens. Trying to take a picture and everything. All of a sudden, the stars jerk around. It's like, what the heck is going on? Oh, it's the tape player. So they had to learn to compensate for that, to predict that that and deal with the idiosyncrasies of that technology. Just one more spacecraft fact. And it's really, it's as much a testament to the deep space network as anything else. You mentioned in the book, those 23 watt transmitters. I mean, we've got a dim

light bulb here, right? That's when it starts out on the spacecraft. If I counted the zeros correctly, when that signal reaches the big dishes of the DSN, it's one quintillionth of a watt. Yeah, I don't even know what it's called. It's like 10 to the minus 16 or something like that, right? Some tiny, tiny number. And it's the whisper of a flea, really. How do they do it? They do it because the frequency is very well known. It's very specific, very narrow frequency. And they're using radio telescopes that are, you know, 230 feet across, 70-meter telescopes that can pick up fleas' whispers out at Neptune and beyond. You know, these three stations in California, Spain, and Australia. The true sort of unsung heroes of the space program, people 24 hours, seven days a week,

holidays, doesn't matter. They're constantly listening and tuning in to these 30 or 40 spacecraft that humans have sent out in this mini armada to explore the solar system. It's a really, really cool thing. I told you I'd come back to your friend Heidi Hamel. She has been one of the strongest voices for years for getting a mission back out to – Jupiter and Saturn at least are getting some attention. Cassini, still doing wonderful work. Juno, almost at Jupiter. Uranus and Neptune, they're literally out there in the cold. I mean, do you agree with her?

Do we need to revisit? Yes, we do. Absolutely. And I know it's going to happen. It's just a matter of when. And one of the important legacies scientifically of Voyager is the discovery with the data from the spacecraft that Uranus and Neptune are not like Jupiter and Saturn, that they are fundamentally different kinds of giant planets. Jupiter and Saturn are gas giant planets. They're like the sun, mostly hydrogen and helium. Jupiter and Saturn are gas giant planets.

They're like the sun, mostly hydrogen and helium. Uranus and Neptune are different beasts entirely, and their interiors are made of much more volatile material, high-pressure water, ice, and other ices, for example. And we now refer to those kinds of planets as ice giants, not gas giants. And we'd never been up close with an ice giant except for the flybys of Voyager 2 many decades ago. And what we've seen since then with Hubble Space Telescope and other measurements is that both of those planets have changed dramatically since 86 and 89.

They have strong seasonal changes. They change in response to how the sun changes during its cycle. And we've just got these little snapshots, these brief glimpses since 86 and 89. I just proposed a discovery mission to try to solve that and launch a new space telescope to really monitor the weather and the variations on Uranus, Neptune, and the other planets as well to tackle this problem. Because we will send a Galileo, a Cassini kind of orbiter to Uranus and Neptune eventually. a Cassini kind of orbiter to Uranus and Neptune eventually. It actually bubbled up. A Uranus one bubbled up as a high priority in the last planetary decadal survey of the scientific community.

And so it's going to happen, and we need to know more about them than we know from Voyager. But that's our start, and that's what gave us our clue that these are fundamentally different. And what missions like Kepler are discovering is that many, maybe most planets around nearby stars are kind of Neptune class. Maybe ice giants are the most common class of planet in the nearby galaxy or beyond. And we have two of them in our own solar system, and we know so little about them. So lots of imperative to study these kinds of planets in much more detail.

So these two spacecraft, one of them probably almost certainly now outside the solar system, the other one not far behind, tens of thousands of years from now, tens of thousands of years after their radioactive batteries have passed away, they're going to be traveling on through the galaxy. You make a recommendation, a request, one last action that you hope these spacecraft will take before those batteries die and they're out of touch forever. I actually had a couple of recommendations. One is I wanted to try to, there's still some fuel in the tanks, little thrusters that are used to maneuver the spacecraft and do that dancing I was talking about. the little thrusters that are used to maneuver the spacecraft and do that dancing I was talking about,

they're not actually headed for any star or planetary system. But maybe if we point them in the right way, like just before we lose communication, and fire the thrusters, completely empty the tanks, maybe we can angle them a little bit and maybe head them towards a nearby star system. That would be kind of cool. Who knows if there's anybody there to pick them up, but maybe try to intentionally go explore in a passive way a nearby star system. That's one thing. And the other thing I wanted to see, getting back to the 8-track tape player, is that, again, before we lose touch with them,

they're carrying these golden records, which is a message from Earth circa 1976, 1977. But they've done so much since then. We've got all these greatest hits, pictures and other measurements of what our solar system is like. Let's upload a set of postcards from our solar system onto the tapes for the Voyager. Much is this going to happen with the New Horizons mission? Much is what's going to happen there, except this will be an analog tape version, not a digital version of what John Lomberg is pulling together for New Horizons. So an analog tape version, put the postcards back on.

So somebody or someone finds Voyager a million, 10 million, 100 million years from now when they're still perfectly intact. Not only will they know where they came from, they'll know something about where they've been. Last question. You mentioned it, greatest hits. If I forced you, if I held you down and forced you to name what really stands out in this mission that has a continuous line of tremendous accomplishments, what would you respond with? Yeah, I mean, the textbooks have literally been rewritten by Voyager. I mean, the textbooks have literally been rewritten by Voyager.

And in 77, when they were launched, we knew that there were planets out there and they had moons. And we could see the disks of Jupiter and Saturn kind of fuzzy in telescopes and do some limited kind of science. But the moons were just dots of light. We had no idea what those places were like. We didn't know until Voyager that Jupiter has this moon called Io, which is the most volcanically active place in the solar system, much more than the Earth, that has this moon called Europa with this flat, icy shell and liquid water, salty ocean, maybe three times the volume of Earth's ocean underneath. We didn't know that Titan has this huge, smoggy, hydrocarbon-rich atmosphere that might be what the early Earth's

atmosphere was like, one of the moons of Saturn. We didn't know that all four giant planets have rings. Now we thought just Saturn, right? And now we know they all do. So there's so many individual things you can point to, and I don't pick any one of them as my favorite or anybody's favorite. But I think there's one class of discovery that Voyagers have made that stand above everything else, and that can all be encompassed in the

word diversity. The diversity of the worlds in our solar system is much richer than we ever imagined before Voyager went out there. All of these different places, all of these different styles of atmospheric, geologic, magnetospheric processes that are happening out there, all of these different places, all of these different styles of atmospheric, geologic, magnetospheric processes that are happening out there, including some habitable worlds out there, which people are trained that you want to be a habitable world. You've got to be close to your star. It has to be warm. It can't be too warm like Venus. It can't be too cold like Mars.

It's going to be just right. Goldilocks planet, all that stuff. There's a lot of truth to that. But there are also environments way, way out there where other energy sources besides the sun, like tidal energy, can heat the interior of a planet, can make liquid water available, and certainly there are organic molecules out there. So that diversity in our solar system, right here in our own backyard, much, much deeper diversity than we could have imagined is, in my mind, one of the greatest legacies of Voyager. Here, here. You were a little nervous about writing a book that wasn't full of pictures, right?

It had only a handful of those images. Yeah. Yeah. I wanted to do a big picture book. But instead, it ends up being kind of a cool story. And we did get a color insert into the book. But instead, it ends up being kind of a cool story. And we did get a color insert into the book. So it has some great assets, including many that are put together by sort of members of the amateur image processing community that the Planetary Society works with,

Emily and her, Emily Lactuala and her colleagues who work on reprocessing of old images. I was able to get many of them into the book because they're just spectacular. Modern computers applied to older data produce wonderful results. Just one more piece of the legacy of this incredible mission. Absolutely. May I say, it may not be loaded with pictures, all those beautiful images you had in the previous books, but you do write some beautiful prose images.

It's told with passion from an insider, and it was a lovely read. Just one more thing. I've got a couple of lines there from very near the end of the book. Would you read those for us? Absolutely. We are all living right now in an amazing golden age of exploration, of our planet and of our solar system. And if we look closely in our mind's eye,

we can see the Voyagers quietly ushering us to and across the threshold of the interstellar age. I think Carl would be proud. Thanks. Thank you, Jim. Great to have you back on the show. Great to be on the show, Matt. Planetary scientist Jim Bell's new book is The Interstellar Age, Inside the 40-Year Voyager Mission. It has just been published by Dutton.

Time for What's Up once again on Planetary Radio. Here is Bruce Betts, the Director of Science and Technology for the Planetary Society. Welcome back. How are things? Hunky-dory, spiffy, keen, swell. How about you, Matt? It's kind of wet outside, but I'm in here where it's relatively warm. If there was a night sky, we don't really have much of one the last few days here, what would we see? If there were not clouds, you would see still Venus and Mars low in the west shortly after sunset, although they are getting farther and farther apart, and Mars is gradually sinking lower and lower. So Venus about 100 times brighter, the really bright thing in the west in the early evening, Mars below it

much dimmer looking reddish. But you can once again spin your head around and see Venus. No, you can see Jupiter. Well, if you spin your head around and see Venus. No, you can see Jupiter. Well, if you spin your head all the way around, truly Linda Blair. But otherwise, spin it half the way around and see Jupiter looking bright in the east up in the early evening and Saturn coming up later in the evening. We move on to this week in space history. In 2004, 11 years ago, Rosetta was launched. And right now in the midst of its primary exciting mission, hanging out at a comet. It's a shame it takes so long to get places in the solar system.

They'll have to do something about that. It really is. Why don't you work on that? I'll get on it. Speaking of getting places, in 1979, Voyager 1 flew past Jupiter, giving us all sorts of cool imagery and data. How appropriate for our conversation with Jim Bell today, and folks should stay tuned, because that's going to come up during the trivia contest.

Folks should always stay tuned. Well, you're right, you're right. Moving on to... Just think if I'd remembered to get Jim Bell to say random space fact, we wouldn't have been treated to that this week. Yeah, he probably would have said it exactly the same way. Ceres, in honor of Don getting captured by Ceres gravity going into orbit later this week, we have some Ceres random space facts and trivia. Ceres was originally announced as a comet then was known as a planet then an asteroid then a dwarf planet prior to discovery rumor has it series was a

tinker taylor soldier and spy a little known fact there which is what random space fact is all about all right on to the contest all right we asked you and uh what I'm guessing was a popular and disturbing topic, how many bathrooms or toilets are there on the International Space Station? How do we do? to provide us with space potty humor. But regardless, we did get this entry from Sheridan Gillum in Australia, who said that he believes, now, okay, here is why everyone in the world wishes they were Australian. He says there are two Dunnies on the International Space Station. Yes, Dunnies. I have no idea if that's true or not, but there are two toilets. Sheridan, good on you. He picked this up. And our prize this week, what he picked up is a 200-point iTelescope.net astronomy account worth $200 American, not Australian.

Although iTelescope.net, I think, is more or less based in his home nation. And we're going to send him a Planetary Radio t-shirt. He added this bloody rip a podcast. Is that a compliment? I think it is. Yes. I think the bloody is the strongest indication of that.

For anybody who's curious out there, there is a YouTube video that actually has astronaut Suni Williams showing you one of the potties on the ISS, and in great detail. It's a TMI experience. So we'll thank listener John Harrison for that. We do have some other stuff here that I just have to mention. First, a straight one from Ilya Schwartz, our regular in Maryland. He says, indeed, there are two toilets, but a new one is being worked on, a next-generation space toilet called the Universal Waste Management System. It's universal. Ohms.

From Kev Knowles in New Zealand. He couldn't resist this. It's an example of a place where astronauts boldly go where no one has gone before. And finally, this that I think you'll enjoy from Ron Rose. Common question on Google, apparently, is how many bathrooms are on the Death Star. This conjures images of Darth Vader taking care of business. So I really hope I win to soothe my mind from the mental image I have endured. Sorry, Ron. Better luck next time with this, and you'll have to live with that image, as will the rest of us.

I'm done. I'm done, too. No, no, no. Tell us what to do for next week. Going back to something more conventional, thankfully. Who discovered Ceres? And in what year? Go to planetary.org slash radio contest. Get us your entry.

And we're going to give you this time until the 10th. That would be Tuesday, March 10th at 8 a.m. Pacific time to get us the answer. And how's this for a prize? A copy of Jim Bell's brand new book, the one we just talked about, The Interstellar Age, Inside the 40-Year Voyager Mission. But this one is signed by Jim Bell. Cool. Get those entries in. All right, everybody.

Go out there, look up in the night sky, and think about what you don't know about dunnies. Thank you. Good night. Good on you, Bruce. He's the Director of Science and Technology for the Planetary Society. By the way, that video, that too-much-information video, we'll put a link to it on the show page this week. Of course we will. It'll be at planetary.org slash radio.

He is the Director of Science and Technology who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its ever-voyaging members. Josh Doyle created our theme music. I'm Matt Kaplan of the Planetary Society. Live long and prosper, everyone.