Planetary Radio: Space Exploration, Astronomy and Science - A Passionate Conversation with Carolyn Porco

Episode Date: November 13, 2019

The outspoken planetary scientist who led the Cassini imaging team finally sits down with Mat Kaplan for a revealing, fun conversation. We also talk with astronomer Jay Pasachoff while he watches tiny Mercury crawl across the face of the Sun. Chief scientist Bruce Betts was in the Planetary Society parking lot enjoying the November 11th transit of Mercury. He joins us from there for What’s Up. Learn more about this week’s guest and topics at: https://www.planetary.org/multimedia/planetary-radio/show/2019/1113-2019-carolyn-porco.htmlSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Our first ever conversation with Carolyn Porco and the transit of Mercury this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society with more of a human adventure across our solar system and beyond. She is one of the best known planetary scientists on our planet, a leader of the imaging community for decades, and she doesn't shy away from controversy. And it's about time she was our guest. Join me for a revealing, funny, and often profound interview. Did you catch the transit? Bruce Betts did. I talked with my WhatsApp partner as he watched tiny Mercury crawl across the face of the sun on the 11th of November. High above Southern California, the man who may be the greatest living eclipse and transit chaser

was at the Big Bear Solar Observatory that we visited in August of 2017. Jay Pasikoff is Field Memorial Professor of Astronomy at Williams College, but he travels the world studying phenomena like this transit. I reached him on his mobile phone moments after he exited his car next to Big Bear Lake. Hi, we're just arriving at the observatory. Well, some people have been here already. Just a second. Would you carry on? Are you under the dome yet? No, just approaching the dome now, and we've been meeting and organizing, and some people have been here already this morning. That's great. How are the skies? Oh, perfect, absolutely perfect. You're not looking at the sun, I know, not yet, because you're too smart to do that without protection, but are you walking out on that spit of land out toward the dome?

Yeah, we are on the causeway, and cameras are up there. Hello, Glenn. You've acquired the sun. So there's a 4-inch solar telescope here, and Glenn Schneider from Arizona, University of Arizona, is here, and it's underway. Sounds like a transit party.

Yes. A dozen people at dinner last night. It was very nice. While you wait your turn, I assume you're going to be at an eyepiece before too long, and you can tell us what you see. No, no. We only have a video image at the moment. What do you see? Well, I see a tiny dot. That's good. That's terrific. Just the right size. No sunspots today because we're at real solar minimum. We're seeing about half of it here from California.

But when we move into the big telescope, it will be many, many pixels across. It will be very dramatic. So that's why we're doing this from California. I do have one of my students, Christian Lockwood, is at the Embry-Riddle Aeronautical University in Daytona Beach, Florida, with some other cameras and telescopes to try to see the whole transit there, and in liaison with people in Chile who can see the whole transit. And we're trying to compare with some people in Germany, but I gather it was cloudy there this morning. Oh, as it is here, unfortunately, where I am, I'm hoping the clouds will still burn off

while I will have a chance to see that little black dot go across the face of the sun. Good luck. I did arrange for the Seelestad in Robinson Hall, the Lunday Center at Caltech, to be available. That's great. While I have you, please remind us why scientists like yourself still get so excited about transits, other than the fact that it's just thrilling to see something like this happen when it happens so rarely. Well, it was the confirmation in 1631 when Pierre Gazzendi in France saw a transit that Johannes Kepler had predicted using his new laws of orbit that really proved that Kepler was right and Copernicus was right.

And now we can do other things. Glenn Schneider and I have started looking at transits of Mercury back in 1999, and we showed, for example, historically that at the edge of the sun you can see an effect known as the black drop effect that in the past led people mistakenly to think that they had discovered the atmosphere of Venus, whereas really it was this effect that we've been studying. So we always try to see that and do better. And then it's just fun to measure the distance between the Earth and the Sun, which of course is known already, but we recreate this by observing from distant locations on Earth. And then the people in spacecraft can calibrate how sharp their imaging is when

they have a good distant object of a known size against the background that they're looking at when they look at the sun. So there are a whole lot of reasons to still look at the transits of Mercury. Other than the fact that it's still so exciting, you still do get a big kick out of this, don't you? Oh yes, it certainly is very good. And in addition to the scientific team I'm working with, we brought my daughter, Deborah Pashnikoff, and grandchildren, Lily Kuttner and Jacob Kuttner, who are ages nine and seven, and we hope to excite them in the next generation to see this event and to see the big telescope. Jay, I wish I was with you in that beautiful spot at the Big Bear Solar Observatory. Thanks

for checking in with us, and I hope the skies stay clear and you get a great view from the big telescope under the dome up there. Thank you very much, and I hope a lot of your listeners are able to see the transit. I do have a webpage. It's at transitovenus.info, I-N-F-O, dot info. But once you click on transitovenus.in info, there are links to the 2016 transitive mercury, and then for today's, and we'll try to post some stuff as soon as possible. But also, if you look at the 2016, you can see the quality of what we can see with this big, bare, huge telescope.

Excellent. And we'll put that link on the episode page as well, at planetary.org slash radio. Thanks, Jay. Great to talk to you. Bye-bye. So long, man. Jay Pasikoff, studying and enjoying the transit of Mercury across the face of the sun on Monday, November 11.

Just time for a quick look at the downlink. Planetary Society Editorial Director Jason Davis' digest of planetary science and mission news, in honor of Carolyn Porco and the entire Voyager mission team, we'll start with the publication of five new research papers based on Voyager 2's passage into interstellar space a year ago. The twin spacecraft have now been out there 42 years. China has delayed the ambitious Chang'e 5 sample return mission. It's now expected to leave for the moon in late 2020. And if you haven't seen it yet, check out the gorgeous panorama of the southern sky created by TESS, the Transiting Exoplanet Survey Satellite. It's made from 208 separate snapshots. This and more are at planetary.org

slash downlink. Carolyn Porco is one of those people who can make an hour or more fly by and leave you wanting more. It's not just that she has great stories to tell. Stories about her leadership of the Cassini imaging team across the Saturn Explorer's long mission, about her earlier involvement with the Voyager spacecraft, and the fascinating origin of the pale blue dot, about her colleague and friend, Planetary Society co-founder Carl Sagan, and even about the part she played in the creation of Contact, the magnificent film based on Sagan's only novel. the magnificent film based on Sagan's only novel. No, it's also her persona, humor, and feistiness, her word,

that have made her such a popular science commentator. Settle in for a rollicking good time. This is more overdue, this conversation, than any other I can think of. There are still a few other people I'd love to get on the show, but you should have been on a long time ago. Thank you for coming to Planetary Society headquarters for a conversation. Well, thanks for having me, finally. I'm here. I'm here, finally. That's what counts. I'm a little anxious because you're a pretty good podcast host yourself. I caught you on Neil Tyson's show talking to none other than Sean Ono Lennon. Yeah, we were hanging out for a while.

He was very interested in science. And, you know, one thing led to another. And he came on StarTalk, All Stars. I was an All Stars host. And he also did a StarTalk Live in New York City with me. I heard that one, too. Yeah, that was fun. With Neil.

That was a lot of fun. Yeah. Yeah. He's one of these people who, not a scientist, I mean, like me, although I'm not a musician, much less the son of an even more famous one, but he knows his stuff. He obviously loves talking to you about the stuff that you have spent decades doing. He's very intellectual. He's hip. He's very intellectual. He's hip. He's very hip. It was great getting to know him. Thank you for all the great pictures.

Oh, those are my babies. Those are literally those they feel like. I'm sure the way I feel about what we did with Cassini and all those beautiful images is the way parents feel about their kids. It was such a joy and a privilege to do that. I felt like we were the, it was our duty to return the visual record of our travels around Saturn. And that's kind of how I looked at the job, how I presented it in anything I wrote about Cassini on my website or so on. Like it was the romantic adventure I wanted people to feel in their gut.

It was romantic. It was. It was romantic. And your duty, I like that, to get these out and to share them with the world. Well, yeah. Remember, I got started in this business on Voyager. Voyager is where everything began as far as I'm concerned. And I've said many times I've led a charmed existence. And part of that was having as my first professional assignment right out of graduate school to be a member of the most iconic, far-reaching, historically significant, I mean, on and on it goes, mission of them all.

And that was Voyager. I haven't shown you yet, but just the other side of the wall behind you here are four posters. One of them is our own light sail, but we were asked by a partner who does wonderful graphics. He wanted to determine the three most popular planetary science missions of all time. And so we helped him out. We did the polling for him. Of those three, two are Voyager and Cassini. Of course. The third being Curiosity on Mars.

Not surprising, is it? No, not surprising at all to me. Everybody loves Voyager. I give a talk, and I even, in a talk about Cassini, and I mention Voyager, people clap. I mean, they realize, it was, God, it had all the elements. You know, it not only was the journey into forever, and, of course, that was underscored by the record,

which, of course, Carl led the development of, the Voyager record that had symbols of us, really had tokens of us in it. So it really felt like, oh, all of us are on this spacecraft making our way across the solar system and into interstellar space. It had that wonderful look back of our own planet to say goodbye, and then it spun on its heels and headed off into eternity. But it also was the grand adventure that really showed us in detail what our solar system was like. Because if you think about it, most of our solar system resides beyond the orbits of the asteroids. That's where most of the mass is. Or if you want to even talk about the volume that the planetary orbits carve out, in a sense, it's all beyond the orbits of the asteroids.

It's in the outer solar system. So we didn't know what our solar system looked like until Voyager passed Jupiter, Saturn, Uranus, and Neptune. And it's so hard to describe what it was like to be on that mission. Every single thing was new. And you knew, we knew, I knew, at the time, I knew that this was absolutely historic. I'd have these moments when I was in imaging team meetings, and I became an official member in October of 1983 when I went to work for Brad Smith at the University of Arizona, right out of graduate school.

So I participated in all the planning from then on for Uranus and Neptune, and I just remember times when the conversation might have turned to something that I wasn't intimately involved in. So maybe I dozed off or I was daydreaming. But I'd have these moments where I felt like I was hovering above watching this group of people talk about what was going to happen clear across the solar system. And it was something out of science fiction. Yeah. But it wasn't. It was real. And it was happening. And it was such a rush. It was a rush as it was happening. We knew as it was happening, we were doing something historic.

You can only explore the solar system for the first time once, right? That only happens once. And so just the mission itself, what it was going to accomplish, what it was going to say about us. Plus, of course, it had Carl as a member of the team, and he just was so capable and eloquent of reaching people and letting them know the significance of this mission in a way that scientists just were not doing at that time. I also attribute part of the love for Voyager to Brad Smith, who was the imaging team leader. And he also was eloquent in the press conferences and classy. And it didn't hurt that he had movie star good looks. I mean, you know, he was commanding and witty. So it had all those wonderful features.

And for all those reasons, people really resonated with it. So it does not surprise me that it ranks up there as the most popular mission. I think, to me, it is the Apollo 11 of the planetary program. It has that kind of iconic stature. And it doesn't matter that there will be missions that will be more profoundly scientific than, scientifically productive than Voyager. Cassini is one of them. We went deeper. We went in greater detail.

We went more comprehensive at Saturn than Voyager could. It doesn't matter. It was the first, and it was a beautiful first. And like I said, it provided people such a touchstone into their cosmic significance that it's just very beloved. And then, of course, Cassini was spectacular to the nth degree. And we carried better instruments. We were better prepared. Because of Voyager. Oh, yeah, because of Voyager. I mean, even things like figuring out what exposure times in our

cameras had to be was a challenge. But it was nothing like Voyager. I mean, Voyager, we were finding new things and figuring out what the exposures had to be was a big deal. You know, you didn't want to waste a lot of images taking multiple exposures, but that was a challenge. But after we knew roughly what the reflectivity of surfaces were and brightness and so on, on Cassini, we were much better prepared to put that information into models, put the models into our software, and figure out how to command the cameras. That's the stuff that went on in my shop at Cyclops. We developed all that software for commanding the cameras. You would think that as scientists, we would be so objective and almost cold about the whole thing. I would not, but many people do. And we were not.

Certainly, you know, I would look at a picture and just be so amazed that the beauty of it, that's what always would knock me for a loop, is just how beautiful it was and how detailed. We had a great camera system, and it just really served us well. Those images. and it just really served us well. Those images. We continue to get great science out of the images,

out of the data from that mission, but they are simply awe-inspiring. Well, okay, so we can't take all the credit for that because Saturn is the most beautiful system, the most beautiful planet. It's iconic. When do you see anyone like in science fiction trying to portray a planet in another stellar system and doing so without a ring? You know, it always has a ring around it because it's so supernatural looking. That ring,

it's so precise. It is mathematically precise. So it almost defies our concept of what Mother Nature is. Mother Nature is sort of around on Earth. It's sort of soft and fluffy. And, you know, things aren't, everything's on a continuum. You don't see things bounded to sharp precision, unless a human got in there and did it. Well, Mother Nature did this with Saturn's rings. And it's just beautiful that, you know, they dazzle from every angle, no matter how you look at them. And so surprising, you know, we did this deliberately. I planned this sequence to look at the rings as Cassini was passing through the ring plane. So you got to see them,

you're looking from above the rings, and you got to see them turn over, turn over, then you're in the ring plane, then you see them from below. That is one of my, it's simple as can be, but that's one of my most favorite video clips, because you just have a hard time believing that it's natural. At one angle, they're lit from the front, from behind Cassini. No, wait. No, at one angle, they're lit directly from the sun. Okay. And at the other angle, when you're below the ring plane, or when you're on the opposite side of the sun, then you see them only because light diffuses down through the ring plane.

It gets scattered among the ring particles and comes out. That's what I was getting at. Basically, they're backlit. But they're diffused because the ring itself is shaping the light. It's scattering it. And it's like looking through a screen in some parts of the rings. It's like looking through a screen. When you're in that geometry, if the ring is really thick so that not much light gets through, it can be hard to tell the difference

between a thick ring and empty space. That's when you really got to like put on your scientific hat to try to figure it all out. But what my point is before you even get there, it's just this smorgasbord of incredible, beautiful sights. And the public loves color. I'd like to tell a little anecdote about Voyager. Please, yeah. In Voyager days, and my days were post-Saturn, so it was Uranus and Neptune. So this was, you know, 1983, late 1983 to 1989. I had seen as a graduate student press conferences after the Voyager Saturn flybys. And there was a member of the press corps who was also an amateur astronomer. His name was Andrew Young. And he got on the case

of the Voyager imaging team for not producing the images in true color. And I agreed with him. I was kind of aghast as it was going on that the images were thrown together so sloppily. Of course, you have to understand this thing that we did, that I did with the Cassini cameras, and deliberately process images every day for a long period of time. My job was to get an image out every single day and a caption to it every single day. This was like running a news magazine, a daily news magazine. They didn't do that on Voyager. At Voyager, the images were processed solely for press conferences. So it was only during that brief period of time, like a week, 10 days, around flybys

that people were, and this, I think, the image processors in those days were at JPL. They were madly throwing it together. I know some stories about, in fact, I think, the image processors in those days were at JPL. They were madly throwing it together. I know some stories about that. In fact, I've met a couple of those people, some of them very young. Yeah, so they were thrown together images just so the scientists would have something to present at a press conference. But I remember Andrew Young. I remember his criticism.

I totally agreed with him that it could be done so much better. When I was chosen to be the imaging team leader for Cassini, that was one of my cardinal things. We were going to do a far better job processing images. I was going to take great care in that. I was going to produce them in true color to the extent possible, because that is an enormous challenge and you never could really get there. And I was going to take another one of my cardinal quests in the beginning is that we were going to take every opportunity we could to produce images just because they were beautiful and also to produce video clips. We were going to have, I mean, we're going to a dynamic system. I wanted to turn the camera as much as possible into a video recorder. And so we did that too. And all that stuff was immensely

popular. And that's still paying off. I mean, there is that feature film, which I think is out now, actually contributed to it, Through the Rings of Saturn, I think. I'll have to check the title. But using your images, they're all genuine. I cannot remember the guy of Saturn, I think. I'll have to check the title. But using your images. Well, who produced it? I cannot remember the guy's name, but I haven't been in touch with him for several years. Is this the one where it's just a sequence, a rapid sequence of raw images? No, I don't think so. That's pretty cool, too.

If you just look at a raw, even though the flaws in the camera were not removed. Like I said, it was a visual record of our travels. That's what I felt like we were doing. You mentioned just in passing, though you didn't refer to it this way, the image that is so iconic to all of us here and other people around the world, the pale blue dot. Yeah. Because you apparently had a part in that. Yeah, I know. It's not often mentioned, but that's why these days I'm making it clear that it was, Carl deserves absolutely full credit for making it happen. But I know that I, as soon as I was added to the imaging team in late 83, was starting to hawk around the idea that we should turn the spacecraft around

and take a picture of the Earth and the other planets, just because it would be a wonderful thing to see our planet from afar. And I also thought, wouldn't it be cool to show what our solar system would look like to an alien coming in from outside? You know, a new perspective. It's all about perspective. I remember vividly walking into Brad Smith's office, so this could have been late 83, early 84, and saying to him, you know, I think it would be really good to take a picture of the Earth and the other planets. And he said, well, if you go right away, right off the bat, it wasn't, oh, what a crazy idea. It wasn't, oh, I don't know that they'd let us do that. He said, well, if you go right away, right off the bat, it wasn't, oh, what a crazy idea. It wasn't, oh, I don't know that they'd let us do that. He said, right off the bat, he said, well, you know,

if you're going to do that, you have to turn the spacecraft so that you put the sun from the point of view of the cameras, you put the sun behind the high gain antenna so that you don't get any sunlight on the camera detector. Because if you're going to image the Earth from the outer solar system, the Earth is going to be very close to the sun. And you burn the cameras out. So as far as I'm concerned, he's the one who came up with that idea. And then I started probably in 84. You know, our imaging team meetings were three times a year. So it could have been early 84, like the next team meeting I went to, that I went around talking to people, seeing if this was possible.

And I know there was tremendous skepticism. And I know... Resistance, right? Well, it wasn't at the level that... Resistance, yeah. I mean, just in a word, I'll say there was resistance to it. And I was surprised, but even Ed Stone said, in his very gentlemanly way, he said, well, you know, you're probably not going to be able to do that unless you could find any science in it.

You know, just to take a picture of Earth, they wouldn't allow that to happen. The project wouldn't allow that to happen. Now, let me just parenthetically say here, Voyager was one of those missions, and early enough that it was just absolutely sacred that you always kept the high-gain antenna pointing to the Earth and had a constant link with the Earth. Because if it was feared, the spacecraft was taken off Earth line, you might not be able to get it back. So it wasn't like we're going to take the spacecraft off Earth line just for something like this.

You better have a really good reason for it. I was a new team member, and I wasn't in the mode of, like, trying to be the little David to the big Goliath. So I went off and thought, well, I thought about science, taking a picture when I knew the Earth was going to be a pixel. Actually, now there could have been science in it, but I couldn't think of anything then. And so I went off and came up with the idea to try to capture the dust bands, the dust bands that had just been discovered in the asteroid belt by the IRAS spacecraft. And so that's what I ended up doing. That's the observation I ended up doing. But I guess it was the asteroid belt was far enough away from the sun that it wasn't a problem. All I'm saying is I had come up with this idea, tried to get people interested in it, and it didn't work. So sometime in 1988, I hear that Carl is hawking this idea

around too. He could have thought of it long before, but I'm hearing that he's pushing this idea now. I think I might have written him a letter that said, I learned that you're trying to do this. I tried to do this a while ago and didn't get anywhere. I really think this should be done. And he responded basically, great, help me. Why don't you come aboard and help? So he put me in charge of figuring out what the exposure times for the images should be. And I wrote him back. I did some calculations and wrote him back, sent them to him. It was a lot of work for him to do it.

He had the clout and he could maneuver politically to get it done. He had to go all the way to NASA headquarters. And I just learned recently that Ed Stone accompanied him. So he was successful convincing Ed Stone. And they went to NASA headquarters to basically get NASA to direct JPL to do it. But it was, you know, we waited until the whole entire planetary part of the mission was over. So this was, it happened in February of 1990. So the mission, Neptune Encounter, was over in August of 1989. And as you know, it became an incredibly popular image, even though it's not much of an image to look at. It was incredibly popular. And even the

phrase pale blue dot has become now synonymous with planetary brotherhood and protection of the environment. I use it all the time on this show. That phrase. Yeah. Well, you're not the only one. No. We've got much more of Carolyn Porco, including that time we all waved at Saturn. Stay with us.

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I had that other iconic image that you had even more to do with of Earth seen from Cassini. With the rings. The zoomed in version, I hope, which is a real beautiful one. Yes. And, I mean, for that matter, I was also at JPL waving at Saturn and smiling when you did that one.

Yeah. This stuff strikes a chord with pretty much everybody, whether they follow missions like this regularly or not. Well, I couldn't agree more, and I learned just how much a chord it strikes with people. I mean, I learned, of course, in Voyager, but when I was selected to be the team leader on Cassini, another one of those things on my to-do list right away was to redo the pale blue dot Voyager picture, only do it better. do the pale blue dot Voyager picture, only do it better. Now, it's not generally known that in the proposal that Carl wrote to the Voyager project, urging them to get this picture done, he wrote that the purpose of the picture was to take an image of Earth awash in a sea of stars. So the Voyager pale blue dot picture didn't quite turn out like that. You

can't see any stars. Actually, the earth is sitting on a beam of light that was scattered in the optics of the camera. So it's not the most beautiful picture. Of course, it's what Carl had to say about it and the way he romanced it that made it so iconic and really struck. People got it. They heard him say that and they got it, why this was an important image. So I wanted to redo it. So busy, never got a chance to work on it until about, I don't know, when we were in our second extension of the mission. I think I probably started thinking about it again, 2010, 2011, in figuring out where to put it in the timeline of images that we were going to take. And I had to piggyback on other scientific instruments.

Mind you, you can't just go and say, I want to do this just to do it. Maybe I was able to do that one or two or three times in the whole mission. It was really a difficult sell. I thought I'll piggyback on someone else's observation. And so there was going to be a mosaic made of Saturn when Cassini would be in eclipse. So instead of needing a high gain antenna to shield the sun, we had Saturn to shield the sun. That would be perfect. to shield the sun. We had Saturn to shield the sun. That would be perfect. I managed to convince the originators of that mosaic to let us piggyback. But while I'm doing this, you know how

good ideas just come. They just arise. And I just thought, wow, instead of doing what every mission has done since Voyager, and what, of course, Voyager did was take a picture of the Earth and then a week later, two weeks later, release it to the public and say, hey, world, while you weren't looking, guess what we did? I thought, wouldn't it be great if we told the people of the world ahead of time, at such and such a time, such and such a date, we are going to take your picture, take a picture of all of us from Saturn, and invite them to go out at that time. And as the picture taking window opens, and just contemplate this whole thing. Contemplate being on a planet, a small planet, and everyone else

on it, all living creatures, how connected we are to all of them, and think about their own existence. Think about how unique our planet is in its lushness and its life-giving properties. And just, you know, smile at the sheer joy of being alive on a pale blue dot. That kind of thing. And that's exactly what we did. Where were you at that moment? It's amazing to me. I was in Colorado, and I was being filmed by the BBC. They wanted to come out and capture me while the thing was going on. I have to say that while I was being recorded, I completely lost track of the fact that I was being recorded. You know, it can be very, I got completely swept up in the whole thing. Like, I just forgot I was being interviewed.

And I was as amazed myself at this whole thing as I'm sure everybody else who participated in this was. That I'm looking in that direction. It was daylight, but I knew where Saturn was. And I'm thinking, my God, there's a camera out there, and it's taking a picture of me, and it made the solar system so much smaller. I felt so connected to that thing, not only having been the originator of the idea, but just that that was something humankind had made. of the idea, but just that that was something humankind had made. A machine out there was taking our picture. So I was amazed by that. I really did feel what I wanted everybody else to feel, the sense of connection with everybody else, how important life is, how unique it is in our

solar system, how we have to protect our own planet. All those feelings just washed over me. And it was really a great, great moment. We had set up in my shop, Cyclops, had set up a website for people to write in and tell us what happened. And I got lots and lots of responses from people in Asia, in Canada, in South America, in Africa, I mean, just all over. And it worked just as I had wanted it to. People felt so, I don't know, inspired. And one woman called it transcendent. Another guy described how he and his 10-year-old daughter did this together. And it was, they loved it. Everybody just loved it.

So you say strike a chord. It was like the biggest piece of cosmic performance art. In fact, Brian Eno gave a talk after me. Brian Eno, the great musician, producer, composer, yeah. Yes. He gave a talk after me at this conference called Starmus. And I described this thing to him. And it's he who came up with this in saying, wow, that was a great talk.

And that must have been the greatest piece of performance art ever. I was so glad we did it. And it resulted in a beautiful picture of Earth. And there are stars in the picture. When I first released this picture to the public, I did so at the celebration for Carl Sagan at the Library of Congress that was held in concert with his papers being archived by the LOC. I am rereading about that right now because I'm talking, I'm reading for the second time Sasha Sagan's book because I'll be interviewing her, as I told you, in just a couple of days as we speak.

And she talks about that ceremony and how overwhelming it was. Oh, really? Does she mention the pale blue dot picture? I'm afraid not. But it does come up elsewhere in the book. Okay. So anyway, I mean, I'm sorry I'm talking so long about it, but it was a very, very— Obviously very meaningful to you, but it is to so many of us.

I mean, as I told you, I was standing heavily biased crowd, admittedly, but not so different at JPL. Oh, okay. I was standing on the patio with hundreds and hundreds of people who had all come out and doing the wave and smiling and laughing and listening to music. And it was glorious. Yeah, we were told when to look up and roughly where to look. And then, of course, to see that image later, it's thrilling still. It took us a long time to process that.

It was really a lot of work because it's a lot of images that had to be pieced together. But it turned out beautifully. Back to doing science out there at Saturn and why we should go back. I mean, I'm going to ignore Titan, and maybe I'll ask you a little bit later about the Dragonfly mission and what you think of that. Why else do we need to go back to Saturn? After being out there and seeing this amazing success of the Cassini mission for so many years? Well, that's actually a very reasonable question. And it really, no, it really gets to an issue that I've been thinking about a lot. And that is, you know, how much longer are

we going to continue to explore the solar system? I mean, how much do we really need to know? These are good questions, you know. Lots of resources go into this, and we need to have good reasons. I mean, I think there's lots to continue to do in the solar system. We have to go back to Neptune, for example, an ice giant, and do what we did at Cassini at a place like Neptune. But these are good questions. Why go back? And at Saturn, one of the most profound discoveries we made was this moon,

Enceladus. Enceladus is a small moon of Saturn that has, we found out from 13 years being there, has a global ocean with a salinity not too different from that of the earth. By flying through the plume, we also found it had, there's evidence for large organic compounds. We couldn't measure the organic compounds themselves. We didn't have instruments that could do that, but you could work backwards to show that the compounds that were detected actually came from larger compounds. And that's important because the compounds, the organic compounds of biology, like amino acids, they are relatively big. They're not like methane. They're not like acetylene. They're relatively big. So there are relatively big organic compounds in the material that is gushing out from Enceladus,

forming a plume of material. And that plume is fed by geysers, about 101 geysers on the surface. This was actually stuff that my research group and I did to figure out all those geysers on the surface. This was actually stuff that my research group and I did to figure out all those geysers and where they were and what connections they have to the other observations. And coming out of those tiger stripes. Great term. They're coming out of four fractures that cross the south polar terrain, so the south polar region.

I don't want to say it was a surprise. Anyone who says that scientists were so surprised to see this, that's not the correct historical story. The narrative really is that people knew there was something going on with Enceladus. Either charged particles were hitting its surface, releasing them to form the E ring of Saturn, which Enceladus is embedded in. That was the common wisdom, but there was a paper in 1984, post-Voyager 1984, that said the E-ring could possibly be produced by a geyser,

material that was in the form of a geyser coming from its interior. Wow. So we planned our observations from the beginning to look in the proper orientation so that we would see something like a geyser. And that's what we found. Early 2005, we discovered the plume. And other instruments, of course, confirmed later there was organic compounds in it or found later there was organic compounds in it. And they did the whole chemical analysis. found later. There was organic compounds in it, and they did the whole chemical analysis.

But the imaging team and the magnetometer were the instruments that first had anything to say about the existence of the plume. Do you wish, I mean, Europa Clipper seems to be on track for that other ocean moon, the one going around Jupiter. Do you wish there was an Enceladus Clipper, or maybe we should have gone to Enceladus instead of Europa? Clipper is going to do at Europa what we did with Cassini at Enceladus. That's what it's going to do. It's going to bring the knowledge of Europa up to the same level of our knowledge on Enceladus. A lot of what is said about Europa is actually speculation. They don't quite know. We do know on Enceladus because we spent 13 years studying it.

So I think the Clipper is going to do very important stuff. It needs to be done. I'm not – I was, you know, years ago I was saying we should go back to Enceladus because it's so urgent. I'm not really disappointed that they're going to go back to Europa with the Clipper mission. But next, we need to do a serious deep dive on Enceladus because Cassini didn't have the instrumentation that could tell you whether or not there was life in Enceladus. And that's the reason why Enceladus was so profoundly interesting and our results were so profound, period. And that is that it points to an ocean that could possibly support life. There was even

evidence of hydrothermal activity in the plume measured by one of the in situ instruments. So there's tantalizing clues. And how long has it been that NASA has set as its goal to find life in the solar system, to find habitable zones, and to determine if life got started? I'll tell you, it goes all the way back to the 1958 charter. and see if life got started anywhere else. So here we are, this incredible time when we now know there's a moon out there that, yes, has a subsurface ocean like many, not many, but several do, but it is unique in having that ocean being expressed into space and it's relatively trivial to just go sample it. We could next ask very pointed questions about whether or not there are any signatures of life in the plume of Enceladus if we had a mission that could go there and at least go into orbit

around Enceladus and even better land on the surface. And instruments that could do better than we could do with Cassini, like measure, detect directly, if possible, large molecules and determine what molecules those are, not, oh, this one is 250 atomic mass units. I mean, just really determine what those molecules are. We want to know chemically what's there. I've been the one pushing this idea for a long time. I think some people think I'm crazy, but I don't. And that is that there could be microbes in the frost particles that are in that plume. Why would that be crazy?

I mean, because it sounds crazy. Like it sounds maybe like it's stretching too far. But my argument is this, that on Earth, just about every frost particle you run into on Earth, even in the stratosphere, has a bacterium at its center. Bacteria nucleate ice particles, you know, frost particles. So they actually help to form the ice particles. they actually help to form the ice particles. They actually help to form the ice particles. So it's not crazy that you could have, and there's reasons why you could have microbes, if they exist at the hydrothermal vents on the seafloor of Enceladus, how they would get themselves attached to any bubbles that come up through the water column.

That's a common process here on Earth. It's called bubble scrubbing. So it's not out of the question that you could have microbes in the plume, probably at the center of the ice particles. So my thing is not only do you want to bring chemical instruments, I doubt they could give you a 100% confidence level that you'd found life, but also bring a microscope. Yeah. Because if you could get a picture of an organism, even better if they're still alive, a little video.

I mean, talk about knocking people's socks off. socks off. So we want to go back to Saturn because we want to go back to Enceladus to see if it is a moon that is forthcoming in telling us whether life got started in any other place. And it's not, I have to be honest, there's a camp of people who think you can't get life started in an ocean. But there's others who say, you know, that you could. Metabolism probably got started in the ocean. At least that's what they say. So who knows? But, you know, this is all about exploration. It's not like- We won't know until we look. Right. And if we knew the answer, maybe we wouldn't need to go back. But we don't know the answer. The clues, the hints are there. And it's just like, you know, running the program

now. Let's get back. I guess we should move on. Before we leave the Saturnian system, though, how do you feel about Dragonfly? Oh, I was very happy that Dragonfly got selected because it's a cool mission design. I had been criticizing the Titan people for, you know, when they talked about missions going back to Titan, like we were talking about missions going back to Enceladus, their mission seemed so ho-hum like it was just a redo of Cassini. But this group came up with a really cool idea,

which is this drone, basically, and putting it in the atmosphere, hopping like, you know, on the surface, sampling something. Oh, very cool. Very cool mission design. We talked to Zibby Turtle about it as well. Of course, she's very enthusiastic about her project. Yeah, of course. Of course. And it's good.

It's good that it's being done by APL. And so I liked it. I was a bit disappointed, though, that they're not going to get to the lakes and the seas in the north. though, that they're not going to get to the lakes and the seas in the north. You know, that's, I mean, to be able to sample the hydrocarbons that are ponded there in the north, well, there's some in the south too that we found early on in the mission. But, you know, that would have been really glorious. But I think already it's somewhat of a risky mission. So I don't think they thought they could pull it off. But they're going to sample

those areas, as I understand it, that in our pictures are dark. And we think that that's the hydrocarbon material in the atmosphere just raining down on the surface. So it'll be interesting to see, you know, what they find. They claim they're going to be going looking for life. At least I've heard some of them claim that. I think it's a stretch. I think it's a stretch because the temperatures on the surface are something like 350 degrees below zero Fahrenheit. They could have a major problem with kinetics getting biotic chemistry going on a place like that. Although I know there are people thinking about this, like what kinds of processes could drive biology in that kind of, it does seem far-fetched, but yeah. Well, why I'm excited about it, even though I think it's far-fetched, they'll find evidence of life. I think it's covered with native organic compounds, organic compounds that are native to

the Titan system. If it never got to life, they could just answer the question, what do organic compounds do in an environment like this? Even that would be extraordinary to know and very helpful for people to think about what happens in the run-up to life, prebiotic chemistry. So I was very excited about it. I can't wait to see the pictures. That's going to be absolutely fascinating. I hope they have a camera that will be able to take a picture of Saturn

through the atmosphere of Titan. Boy, oh boy. I've seen artist concepts like that. Oh, well, they're going back to Chesley Bonestell. Yeah. Yeah, right. Yeah. He didn't know the atmosphere of Titan was opaque.

I mean, not completely opaque, but very hard to see through. We're back to images, which have dominated so much of your life and the exploration that you've conducted. What's the right way to manage images? Because I know that you have strong feelings, or at least you used to, about the images that come back that you've worked so hard to create. You talked about some of these challenges with Cassini, but also with Voyager. There are, it seems now, a couple of camps, one that says, nope, put them out raw, send them all

out. And then another camp that says, no, these need to be studied. They need to be worked with before they are simply released. I mean, where do you come down in this? Well, this was a painful story in the development of Cassini because my team and I thought we were going to have a nine-month proprietary period like everybody else. Yeah, that's what I'd heard. And then I think it was 2003, we were told you're going to be releasing your all your images to the public. And so that came from on high. Oh, yeah. Okay. Well, again, let me maybe I should back up even more and say I had plans for, you know, releasing images, we were going to release images, I was going to, you know, turn them into true color. And we were going to release them. And I knew I'd be doing that, but I didn't know

then, knowing it came up with this crazy idea that we're going to release the raw images to the public. It really created a problem on my team that Europeans were the ones who were most upset. They felt that they had been promised a nine-month proprietary period. They were afraid people wouldn't get the images, and we're going to scoop them after they had put in all this work. Years of work in cases. Oh, are you kidding? By the time we got into orbit at Saturn, it was 14 years of work.

And the way this all was done was done in a very uncollegial way, I must say, just for us to be ordered to do this. So it did not go over well on my team. I personally was not worried about getting scooped from the outside. I was doing planetary rings then and I wasn't so much worried about getting scooped from the outside by members of the public or by outside scientists, because all my competitors were already on Cassini. I was just concerned that, everyone else on Cassini was going to have our images, and that would be a big problem for us. I had not anticipated that people from the outside would want to process our images just for the sake of processing them to make a nice picture. That came later, and that also surprised me. In the end, the public very much appreciated it. We managed to work out a scheduling so that

we did get to process things nicely. And I was very, very pleased that the press ended up being, either they were deliberately respectful or they didn't want to see or care about what the members of the public were processing. Before they actually made a big deal about any image from Saturn, they waited until we released it. So that was okay. And I was, as I said, I was happy to see in the end that it did engender a lot of affection

in members of the public for Cassini. But I will say this, that we did have enormous problems because those images were also available to our colleagues who used them to help them make discoveries that we, or claim they made discoveries. And there was no quid pro quo. There was no reciprocity in that. And that was a very bad thing. And I hope that other projects deal with it better than they dealt with it in our case.

It created a lot of resentment, a lot of resentment. And it was not a way to treat a major team on a spacecraft mission. The team that was shouldering a lot more work and certainly shouldering a lot more of the responsibility of keeping the mission in the eyes of the public, that was like a big slap in the face. Very understandable. A big jump back in toward the center of the solar system to Mars. Lots of great stuff happening there. Lots more to come, including plans to send people there. We talk every now and then on this show about Elon Musk building his big spaceship and wanting to establish a human community, a colony, if you will, on that planet. You have strong feelings about this. Oh, you know I have strong feelings about this. Have you heard me express my strong feelings? Yeah, I think the

guy's on drugs. Well, that's a proven fact in at least one case. No, seriously. I think maybe he can't afford fact checkers, but he's not going to terraform Mars. It's not possible. Well, you agree with our boss about that, Bill Nye. I have a bet with him. I said, you don't think terraforming, maybe within 10,000 years? Let's just get to the facts. And I have been informed by people who are on Mars orbiting

missions, recent results show that there is an insufficient amount of CO2 in reservoirs that are not atmospheric to ever get the atmosphere to the point where terraforming would even be possible. So you've got CO2 already in the atmosphere. We know that's insufficient. But even if you could take the CO2 in the reservoirs under the ground or on the surface in, I guess, the ice caps and put them into the atmosphere, it still wouldn't work. So you can't terraform Mars.

And besides, why would you want to? Here's where I'm becoming very critical of commercial space. I hear things like, mining asteroids will save the Earth. Or we need to go to Mars because we're in danger here on Earth. We've screwed things up. We're going to get hit by asteroids. We need another place to go. And of course, the same motives are given for this even crazier notion that we're going to actually colonize another stellar system. It's not going to happen. These are lovely thoughts. I empathize with the people who put them forth because they, some of them are younger than me, but some of them are about my age. I grew up in the 60s.

I was a Star Trek fan. I love the whole concept of us being a space-faring civilization, being on the Starship Enterprise. I love the whole thing. It's wonderful fantasy. It's inspiring. But let's get real. It can't happen. It can't happen. But we're hearing things like, again, Elon saying terraforming Mars, and people are going

to be living on Mars. People will live on Mars in the same way people live on Antarctica now. There is an outpost there. It's continuously inhabited. It's not continuously inhabited by the same people. People aren't living there. They're not giving birth to the same people. People aren't living there. They're not giving birth to the next generation. It's not going to be a multi-generational thing in the Antarctic.

And that's the way we will make our way across the solar system. There will be outposts. I had been calling them colonies. I think now it's better. So you don't get confused with the idea of a colony where people live out their lives and they don't make their living there or they don't get confused with the idea of a colony where people live out their lives and, you know, they don't make their living there or they don't give birth to the next generation. We will see outposts. We could. On the moon, maybe on Mars, I could see it for reasons of scientific research. But to have this idea that humans are going to move off the planet and that's the remaining 4 billion people onto the internet, why don't you spend those resources down here? Because we are at a crossroads with regard to our own planet. We are in really very serious trouble. And we could use a little love.

I don't see why those people have to make even more money. Anything they do, they want to have it be profitable. It's time to give back. Going to Mars for research purposes, going there because I come to the Apollo 11, the Apollo program, how inspirational it was. Humans still, in addition to complementing robots, go into these places and establishing perhaps these outposts that you've talked about. Much better word because colony also has political and cultural connotations. Oh, good, yeah. That a lot of people don't like.

But you do believe that humans have a place out there. I think they have a place out, certainly scientifically. You know, the point has been made by others. We have tremendously capable robotics. They'll get better and better with AI. But, you know, there's something about having a human there to pick up a rock and say, oh, I see this. I think there's place for it. But I would even say say before we do that,

let's make sure the earth is secure. It may be time to just rethink this whole thing and just clean up our act at home first. You know, there's no planet B. The idea that there's a planet B is just, you know, it's fantasy. We are part of our planet. It is part of us. We evolved here.

We are intimately woven into the web of life that is here. And to even undertake, physically undertake, physiologically undertake any of these things we're talking about is a strain on the human body. Here's another thing that I laugh at. I just went on and on about true color and how important it was to me to process our images in true color to give people a sense of what it was really like. Even in doing that, by the way, you have to cheat a little. But I'll put that aside for the moment. I'm wondering if Elon Musk thinks it would be great to go to Mars

because he's seen the pictures that people have produced of Mars, and they are extremely processed. The contrast is enhanced. The colors are enhanced. They look like Sedona. If you were really there on Mars, it would be very low contrast. Even on a good day, the atmosphere would be very hazy. You know, Elon might not like it so much. So let's get real about this. And please, you know, love your fellow Earthlings. Love the

Earth. That's my motto these days. Love the Earth. I couldn't agree more. I just hope that we can continue to explore the solar system as we fix the terrible things that are happening down here on this planet. And what you said, I think, made me think of your friend, your colleague, maybe even your mentor, Carl Sagan. I want to come back to him in a second, but I got one more before we bring it all the way back home to Carl. You think Pluto is a planet? Ha ha, no. Oh yeah, we're going there. You'll want to stay for Pluto and Carolyn Porco's view of the great planet debate, along with her memories of Carl Sagan.

I know you're a fan of space because you're listening to Planetary Radio right now. But if you want to take that extra step to be not just a fan, but an advocate, I hope you'll join me, Casey Dreyer, the chief advocate here at the Planetary Society, at our annual Day of Action this February 9th and 10th in Washington, D.C. That's when members from across the country come to D.C. and meet with members of Congress face-to-face and advocate for space. To learn more, go to planetary.org slash dayofaction.

No, Pluto is not a planet. It never was a planet. It just was, you know, it suffered a mistaken identity for a very long period of time. And people got so attached to the idea that it caused this big commotion. But no, it's not a planet. And that doesn't make it any less interesting than it is, or it should be. Here's the thing about this whole debate. The word planet, as shown by several people, but the latest really detailed work, the one that really kind of cleaned up the slightly misbegotten IAU attempt at this topic, was work done by Jean-Luc Margot at UCLA. He showed that the bodies that we call the planets now, the eight of them in our solar system, are the ones that have sculpted our solar system. They're the ones that have cleaned out their orbital corridors. And that's

why we see eight distinct objects and not a disk of debris. He also showed and and the exoplanet people were waiting for something like this. He has shown that if you use the same criterion that produces shows that eight of our planets are those sculptors you take that same criterion and you apply it to other stellar systems, you show that some large, very large number, 95, 99, I forget, percent of the exoplanets also fit that criterion. So here's the thing. What this really means is that when the Greeks, thousands of years ago, looked up at the sky and they saw these wandering, stellar-looking things, and they called them planets, what they really were seeing were bodies that were dominant in the chronology of the solar system. And that's why they saw only eight of them.

And now we are like the Greeks, looking out at the exoplanets. All we see are little planets. We don't have any detail on them yet. So we're equally ignorant about them as the Greeks were about our planets. And what we're seeing are those objects that have sculpted out their solar systems. So even if there was no word for this class of bodies that has been dominant, dynamically dominant in their solar systems, even if there was no word, we'd have to invent a word for them. Because whenever anybody on a computer tries to simulate the evolution of a solar system or a stellar system, this concept of a body that clears out its orbital corridor is central. So we would need a word anyway. Well, we have that word. It's called planet. So there's no sense

in trying to extend planet to other criteria like roundness or anything. This category needs to remain the same. What about the sort of compromise term that a lot of people have adopted of dwarf planet, not just for Pluto, but Ceres and some of those other objects that have been found in the Kuiper Belt? Well, dwarf planet makes no sense when you think about it, because how can anything be a dwarf of a category that it is not a member of, right? Another word needs to be created. But here's another thing. I don't think the roundness is a sensible criterion

because you never really know if it's round. And whether it's round, whether it's in hydrostatic equilibrium will depend on its composition. There's other ways to look at categorizing bodies according to their geophysical properties. And I think someone I know is going to be working on this. I won't make any mention of it yet. On one hand, I'm sort of sympathetic that people want to be able to talk about large-ish bodies, but I'm not sympathetic to a lot of justifications that I've heard. Some of them go

like, look at Pluto. Look how complex its surface is. Well, complexity is not something that you can use to categorize anything because there's complexity on every spatial scale. Complexity is an outcome of our universe. It's everywhere to be found. So it's scale invariant. You can't use that. Another is, oh, look at Pluto. It's got satellites. It looks like a miniature solar system.

Well, asteroids have satellites. That's another scale invariant process. So you can't use that to say it's got to be a planet. So I just think if this group of people interested in natural or inherent geophysical characteristics wants a word, they just should invent another word. But planet is taken, and it's already well justified. So you know I'm going to hear from people, of course, and I suspect the debate will continue here and elsewhere with excellent people on both sides. But I know that you, in spite of all of this, have marveled at those gorgeous images of Pluto returned by New Horizons. Oh, I love them. I mean, it really was. I was, of course, eager to see, was it going to look like

Triton? Because they're kind of kissing cousins. Triton was captured from the outer solar system into orbit around Neptune, excuse me, from a heliocentric orbit into orbit around Neptune. So I was expecting that it would look like what I was half hoping it wouldn't, because then it would be more exciting. And it kind of like split the difference, because there are ways in which it looks like Triton. There are, of course, because it's also an icy body. It's in a cold place. It's got nitrogen on the surface. It has things in common with Triton, but it also had a lot of really, really unusual features like the convective pattern. And I don't know the terminology, but there was a big flat area. It had these things that look like the top of convection cells.

It's really the convection of the ice. And the pictures were just really, really beautiful. They did a beautiful job with the instrumentation and so on. Gorgeous. Yeah. So I get it. But you don't look at something like that and say, oh, it's so beautiful. It's so complex.

It should be called a planet. That is not the way we do things in science. We don't base it on, oh, it's so complex, it should be called a planet. That is not the way we do things in science. We don't base it on, oh, it's so beautiful. Then I hear these inane things. I'm sorry, I'm on my roll now. Like, oh, we don't want to disappoint the members of the public. Well, as you know, I am all about informing the public of what we do and getting them inspired and to feel a part of it. But the members of the public should not be telling scientists how to do their science any more than a member of the public should stand behind your dentist while she's drilling in your mouth and say, I think you should go a half inch back and three inches down. They shouldn't be telling us how to categorize things.

We love them. We want them to, you know, to enjoy what we do. But when push comes to shove, scientists are scientists for a reason. You got to let us do our job. Keep those cards and letters coming, everybody. And you have done more than your share of communicating what our boss calls the passion, beauty, and joy, the wonder of our solar system. We opened this conversation talking about you doing stuff with StarTalk. You clearly believe very strongly in this. And you also said Carl

Sagan was a pioneer in doing this as a scientist who cared about communicating the passion he felt to the public. You were a friend, a colleague. What were the most important things that you got out of your relationship with Carl? Well, out of my relationship with Carl, I was somewhat of a mentory of his. I wasn't a student of his. I never did any research with him. But I felt we were on the Voyager imaging team together. Actually, I first met him when I was an undergraduate,

and he came through our university, the Stony Brook University, to give a talk about Mariner 9. And the students got to meet him. I got to meet him then. But then, of course, I met him later on when I was a graduate student at Caltech. And I met him at conferences. And then, of course, we ended up on the imaging team together. And I felt that the man had my back. There were times when I think he felt someone was rude to me or said something to me that was really inappropriate. This is at a meeting.

In his very Carl way, you know, very gracious, very maybe even witty, very calm, very measured way. But he would defend me and basically not tell the guy, oh, you're being such a jerk. You know, that's something I might do. You know, that's something I might do. He would just, you know, make it clear that that was, you know, not an appropriate statement, wasn't even accurate. So that was wonderful. And he would also compliment me when, you know, he thought I had done something well. So that was lovely to know that Carl Sagan's looking out for you. I also learned, I just watched the way that he conducted himself as a scientist in combat, sitting around a table when there's like heated discussion. He was always very measured there and very calm. And he would be the guy that would, I don't know if it was his voice, his bearing. I don't know. But he just had that thing. He could bring tempers down. He just was very principled in the way he conducted himself.

And so I use him as an example of what a scientist really should and could be. Kind of like there's this phrase, the beau ideal, like the beautiful ideal, you know, that shiny thing that, you know, you aspire to or that's what Carl was like. And he wasn't, he was pretty much that way personally, too. Like what you saw on television is what you got. Not that I didn't see him like, you know, get irritated with his daughter or whatever. So he was human, but he was also just a wonderful, wonderful man. or whatever. So he was human, but he was also just a wonderful, wonderful man. And I think he deserves all the affection and accolades that he's received during his life and since because he was, he was it. He was, he was the, the real McCoy. So it must have been quite an honor when you

were asked to help out with the production of the movie Contact based on his book, on the character of Ellie Arroway, the central character in the story. Oh, it was a complete surprise. I didn't realize it until later that I was at Cornell for an imaging team meeting that I was holding there, because I had team members at Cornell, and he invited me to have dinner with him and Annie at their house. Androian, of course. Androian. In fact, oh, gosh, Carl wanted me to meet Annie. You know, he said, I think you two are going to like each other.

And it turned out we're still friends. It was great. He was very, very right about that. So we were having dinner. And as you can imagine, the conversation was very wide ranging. Everything from, you know, SETI and the pale blue dot and women in science and so many things. It wasn't until after he had invited me to be a consultant on the main character, Ellie Arroway, in the movie that I realized it was probably being interviewed at that dinner.

He probably wanted to know, you know, would she be good at this? And I'll never forget, he called me up and he said, out of all the people we know, out of all the women scientists we know, we think that you come closest to being what we want to portray on the screen. So I was, of course, delighted. It didn't take me a microsecond to agree to that. So I read the book again because I had read it long ago. And then I went to this meeting of the director at the time.

They ended up getting a different director, but the director at the time, George Miller, the executive producer, Linda Obst, and Carl and Annie and someone to take notes. It was great. They just peppered me with questions. You know, if you were in this kind of a situation, how would you feel? What was your life like? Why did you get into science?

Why do you have long hair when all of the women have cut their hair? did you get into science? Why do you have long hair when all of the women have cut their hair? Obviously, what they were trying to do was just lend authenticity to what they were making, this film that they were making. So everyone had a great time. I was told it really inspired them. And the plan was for me to meet with Jodie Foster. She was going to kind of shadow me for a day or two and talk to her. She was going to pick my shadow me for a day or two and talk to her. She was going to pick my brains. And so there was about a year when the people at Warner Brothers would call me up and say, oh, quick, give us your schedule for the next two months, because we want to find a time when we can hook you up with Jodie. And so I'd do it. And then two months would go by,

nothing would happen. And then they'd call me again, same thing. And this went on about three or four times. And I remember calling Carl up and saying, Carl, what's going on here? And here's another thing I'll never forget. He'll say, how did he put this? It was just so Carl and just hysterical. The section of the American Astronomical Society that's devoted to planetary scientists is called the Division of Planetary Sciences, the DPS. He said to me, Hollywood makes the DPS look like the paradigm of fascist order. So anyway, I never got to meet with Jodie Foster, but I was told by Linda Opes that she, in the end, used Carl as her role model.

And they did a fabulous job. I thought so. I can certainly see some elements of your character in what Jodie Foster brought to that wonderful character at the center of that movie? Okay, so you tell me what, what characteristics? Oh, her independence, the enormous curiosity, the passion that she brought to her work. Her feistiness. Her feistiness, absolutely. Yeah, yeah.

So I think that's probably what they wanted. I love that film so much. It wasn't, of course, it didn't capture everything that was in Carl's book. As far as a story, what's in Carl's book was better. But, and I regretted that they didn't, we talked about this. I asked them, are you going to, how are you going to deal with the pie? The, you know. At the end of the book. At the end of the book, pie in the message. Please, you got to put that in the movie. And they said, we just don't think anyone will get it. So they didn't put that in

the movie. I love the end of the book with that. And I won't give it away because I'm sure there are a lot of people out there who've seen the movie but not read the book. So read the book. Oh, read the book. Really read the book. And it's so obviously Carl. I asked Carl directly, like twice. No, once he offered. And another time I asked him, who is this character based on, you know? And he said, well, it's really based on me, meaning himself. You know, the voice of Ellie is Carl's voice in talking about the approach to science or the conflict between religion and science. And all that stuff that is said in, that she says or what she espouses is all Carl. That's his voice. But I think what he did was he just pulled together like, you know,

bits and pieces of various people. Little Jill Tarter, little you, a lot of his own voice, some of Ann as well, Annie. Oh, I think it's mostly Annie. I think it's mostly Annie. But I think the, I don't know what you would call it, the accoutrements, you know, like I went to graduate school at Caltech and had long hair and feisty. Jill's father died when she was young, apparently. I think he got that from her. I know there are scenes in the book that come out of Andy's life, you know. And I think the relationship between the two in the book, they took a lot of their own relationship and put it in the book. So I think of Ellie as kind of a composite character.

But really, if you're hell-bent on thinking of Ellie Arroway as a single person, then she's Carl Sagan in drag. That's great. This conversation has been more fun and every bit as feisty, maybe more so than I had hoped. Thank you. You need to hit the road. I know you're headed up north here in California. I'm headed up north. Yeah, but this was fun. I'm glad I did it.

Oh, me too. It's true. I haven't— Come back. I've come back. Thank you, Carolyn. Well, thank you, Matt. This was fun.

It is time for What's Up on Planetary Radio, and we are joined by the chief scientist of the Planetary Society. Bruce Betts is in the parking lot of the Planetary Society. Hey there, there's a little black spot on the sun today. There is a little black spot on the sun. Sorry, sorry, I told people I wouldn't sing on, okay. Especially on the phone. Yeah, we're out here looking at the Mercury transit using our proper safety filters with some great Planetary Society volunteers,

and we've checked out that indeed there is a little black spot on the sun today, and it is moving across the sun as Mercury moves between, oh, there's a bus. It's not in front of the sun, though. As Mercury moves across our vision as we look over to the sun from Earth. Glad to hear that you're out there joined by other folks taking a look at this. And it's no wonder I couldn't see it in my solar binoculars, because it's really tiny. It is. It's very tiny. I've been trying to take pictures just with my camera with a proper solar filter. And it's right on the edge.

I get a black smudge. But with our bigger telescopes, it's quite clear. Could you see it through your telescope? Yeah, I could. I could. It's just really tiny. Small planet, really far away. What else is up in the night sky or the day sky? We've got in the night sky, in the early evening, we're getting super bright Venus starting to rise low in the west shortly after sunset.

And above it is bright Jupiter. They will be closing in on each other. And we've also got Saturn still to the upper left of those. And then in the morning sky, in the east, we've got Mars looking reddish but not super bright. Mercury's hard to see in the middle of the night right now because it's right in front of the sun, Matt. I'm going to wait for that Mars transit. When's that happening again? Well, first, you're going to have to go to someplace farther out than Mars.

And so you can do that. Well, first, you're going to have to go to someplace farther out than Mars. And so you can do that. You can go to Ceres or out towards Jupiter, and then it's not happening. No. Sorry. So we move on, actually, to this week in space history. And it was 50 years ago that Apollo 12 launched and landed on the moon, becoming the second mission to land humans on the moon. We heard from Jason Davis about that last week.

And you can check out his webpage on our website at planetary.org on the Apollo 12 mission. So we've got a gang in the parking lot ready to help me out. Here we go. One, two, three. Remember Jason! Oh, that was good. That was really good. Thank you. One, two, three. Mercury Transit! Oh, that was good. That was really good. Thank you. Tell everybody I say hi. Matt says hi.

Hey, Matt. So the next Mercury Transit is 2032. The next one visible from the U.S.? 2049. Wow. All right. It's a date. There's about 13 or 14 per century, but they come kind of clumped.

But hey, it's better than the next Venus transit being, you know, like 2117. We move on to the contest, and I asked you, what comet did Mariner 10 return data about in 1973? How did we do, Matt? 10 return data about in 1973. How'd we do, Matt? We did great, I think, because that Sasha Sagan interview of a couple of weeks ago was so popular. We heard from a lot of first-time listeners and first-time entrants as well, and what a lot of them told us was that you were off by a little bit. Apparently that data came back a month later. People often say I'm off, but usually by more than a little bit, so I'll take it as a victory. I don't know. I trust our listeners. So I was using the Trajan calendar. Oh, of course.

Trajan calendar. Yeah, which is why it's so hard to make an appointment with you. No, that's not why, Matt. So I bet you want to hear about our winner. Yeah, what else did we learn? Chosen by Random.org, our winner, and he's a first-time winner, first time entering the contest, too, Eric Robertson in Cleveland, Ohio, where the Cuyahoga River burned slowly to the sea.

Indeed, said that it was Comet C-1973E1 Kahootek. Yep, Kahootek. Yeah, and it was the first, as our listeners may have also said, it was the first comet a spacecraft returned the data about. spacecraft returned the data about. Hey, we did hear that from a lot of people, and a big disappointment to a whole lot of people who were alive and looking up at the time, because it was supposed to be put on this big show, and it just did not.

Yes, I was one of the ones disappointed, but it helped him teach an important lesson, not to overhype things when you really don't know what's happening, and I'm guessing it was not the astronomers who did that. Yeah. Eric, you are going to receive that copy of Sasha Sagan's book for small creatures such as we. It's a terrific book, along with a 200-point itelescope.net astronomy account.

So congratulations, Eric. Daniel Sorkin in New York. Comet Kahootek may have disappointed, but planetary radio never does. Ad Astra. Mark Little. Mariner 10 discovered that Mercury has a helium atmosphere, but he really wants me to say it like this. Mariner 10 has a helium atmosphere. I don't think it's thick enough to really alter your voice, but okay. I'd be lucky if it sounded that way. Zachary Lupin, last week's winner, he mentioned what you did a couple of weeks ago when you put this question out there. I think you did anyway. Don't forget to mention the science team was led by Planetary Society co-founder Bruce Murray. Indeed. He was behind particularly the imaging on Mariner 10,

as he had been on some of the Mars missions. Your mentor, we should add, also at Caltech. Yeah, my PhD advisor. Yeah. From our poet laureate, Dave Fairchild, he's back. Comet Kohutek was touted to be a comet of brilliance. It wasn't, you see. But Mariner 10 thought it still pretty grand and watched it in the Ultraviolet Band.

Ultraviolet Band, that was my favorite rock group of the 70s as well. Pure coincidence, of course. All right, we're done, unless you've got a new question for us. You know, I do, Matt. This time I do have a new question, and we're going to talk about planetary transits. What spacecraft observed a planetary transit from the surface of another planet? Go to planetary.org slash radio contest. Wow. Okay, that is extra cool. We have a very special prize this time. Our friends at the Ugin tribe

who make this terrific cosmic jewelry are now selling that jewelry through another of our partners, Chop Shop, chopshopstore.com. And isn't this perfect? Just at the start of the Christmas or holiday shopping season, we're going to give away a necklace and earring set from Eugen with interchangeable images of LightSail, of LightSail 2.

So pretty thrilling. Yeah, isn't that great? So that's the prize this time around. Well, yeah, you can if you go to chopshopstore.com and put in your credit card. But anyway, we're going to have a free set for somebody out there just in time. You have this time until the 20th. That'll be November 20 at 8 a.m. Pacific time to get us your answer. All right, Bruce, it's still going on, right?

It is. It is for a few more minutes, time to get us your answer. All right, Bruce, it's still going on, right? It is. It is for a few more minutes. Still in front of the sun. So I want to go watch it some more. Yeah, enjoy. All right, everybody, go out there, look up in the night sky or the day sky if you're using appropriate filters. And think about whether you prefer a mercury transit or public transit.

Thank you and good night. whether you prefer a mercury transit or public transit. Thank you, and good night. That's an easy question to answer, but I'll leave it to the listeners. That's our friend, chief scientist of the Planetary Society, Bruce Betts. He's in transit as he joins us here on What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its members who love every world in the galaxy, large or small. Learn how to become a member of the Society at planetary.org membership. And please leave us a rating or review on iTunes, Apple Podcasts. Mark Hilverde is our associate producer.

Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. I'm Matt Kaplan at Astro.