Welcome to StarTalk. You're a place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk, Neil deGrasse Tyson, your personal astrophysicist. Today we're going to talk about ocean worlds. We've got with us a previous guest on StarTalk, Kevin Hand. Kevin, welcome back. Hey, my pleasure and welcome to JPL. Oh, yeah, this is not my office, is it?
You made a great trip out of here? It's not my office. Yeah, yeah. Yeah. In your turf that Pasadena, California, the Jet Propulsion Labs, I don't ever presume that everyone knows what those three letters stand for. But you can take it for granted if you work here. Everybody knows. I don't think everybody knows. Jet Propulsion Labs and water worlds is your thing. It is. My God, just at the dawn of COVID, you had a book by that title. That's right, Alien
Oceans. Alien Oceans. There it is. Typically, when people think about an ocean world other than Earth, they go straight to Europa at the top of everybody's list. I don't know if it has a better PR agent. But if you abstract that idea and go to any place that might have liquid in the world doing anything, that list goes up. It does, absolutely. And these ocean worlds, Europa is sort of the mother of ocean worlds. Europa, again, a moon of Jupiter. Correct.
And even back in the late 70s, we could see with the Voyager data that something curious was going on with Europa. And over the course of the past several decades, we've now come to learn and appreciate that the outer solar system has got a small fleet of ice-covered worlds. And beneath the icy shells, these moons of the outer solar system have liquid water oceans. And of course, the big picture for me is the search for life beyond Earth. That's your guiding star.
I would love life on Mars, exoplanets, you know, SETI, etc. But these ocean worlds like Europa, and Seltis, and Titan, these are worlds where life could be alive today, extant lives. Because when you look at Mars, no one really thinks anything's going to be calling around on its surface. Whatever might have been happening billions of years ago. But there's no active water activity on Mars. Well, at least not on the surface. Exactly. Not on the surface.
There could be on the subsurface. Who knows? Maybe there's life in the subsurface on Mars. But our search for life on Mars is a search for past life. And the molecules of life don't last long. So like DNA, RNA proteins, you know, the stuff that makes our biochemistry. But bones last pretty long. Well, bones too last long. And it's not inconceivable. We didn't find life. Yeah. We would have back to different. And as you appreciate, you know, back in the Viking days,
Carl Sagan wanted to leave, put some lights on the Viking lander. So what if there's a Martian mouse, right? So, you know, a Martian mouse would leave bones behind. Bones do last for a long time. But for the most part, we're talking about the search for microbial life. And microbes do actually leave behind minerals. By the way, if a microbe had bones, I don't want to meet it. I don't know. What the hell that microbe is doing?
Well, some of the most beautiful, you know, if you ever see like, Travertine or some of the beautiful rock structures that are used. Or the Burgess shale. Yeah. Yeah. Is that in Canada? I think. Yeah. Burgess shale has got animals. But, you know, there are... Because that was after the Cambrian explosion, if I remember correctly, where you were during it in that time frame. In that time. So they took on very
interesting shapes, but they got preserved. That's the point of that. Yeah, exactly. Whereas microbes, microbes can mediate rock structures. And if we see sort of a weird, wavy rock form, sometimes referred to as a microbial light or a stromatolite, that is a form of an inorganic biosignature for microbes, kind of like bones for microbes in some of them. It's more of like knowledge. It's more of a frozen apartment building for microbes. And you knew somebody lived there
because it's an apartment building. It's an apartment building. But you want to couple that observation of the strange rock structure with some detection of organic compounds or other
things. But that's all for Mars, right? Looking at life in the past, billions of years ago on Mars, when it comes to a separate independent origin of life and a separate tree of life, we're going to be kind of constrained on Mars because those large biomolecules of, if life on Mars utilized DNA, DNA only lasts like maybe 10 million or at best, tens of millions of years in the rock record. So we're not going to get like Martian DNA from samples returned from
Mars. On a world like Europa, on a world like Enceladus, these are worlds where if we find indications of life on the surface of the IC shells, that's most likely, I would argue, an indication that life is currently alive in the oceans below. And that's extraordinary because then we can actually study it and see, does it run on DNA, RNA, and proteins, or is there a different ballgame? mechanism altogether. Yeah, contingent versus cleavage. That was completely transformed
everything we know of biology. Exactly. Contingent evolution versus convergence in terms of what is contingent evolution? The impact that caused the dinosaurs to go extinct is perhaps somewhat useful, though mildly flawed contingent example. You could say that humans would not be here if it weren't for the impact that wiped out the dinosaurs. Definitely the case. Well, but you might argue that at some point, something else would have wiped out the dinosaurs, but you get my point.
No, it's contingent. Definitely the case. We're in a natural history museum. We got bones everywhere. Yeah. Okay. I'm telling you, here's the argument for that. Just hear me out. If you didn't otherwise know this. Yeah. Do you know when T-Rex went extinct 65 million years ago, do you realize more time had elapsed between the extinction, the stegosaurus and T-Rex than the extinction of T-Rex and today?
So dinosaurs thrive. Oh, hundreds of millions of years. If you say, well, something might have still taken them out in the last 65 million years, I don't think so because it would have taken out a whole lot of other things and we would have known about it. Dinosaurs were a highly successful phenotype. Phenotype? Is that the right word? No. But highly successful branch in the tree of life,
the collective things we call dinosaurs. So I think they would have been here and we'd still be scurrying underfoot, not trying to get as a snack by whatever the version of T-Rex is that survived today. Exactly. So I'll remove any nuance. Give me. That's saying that that was contingent. Okay. And then convergent is something like eyes. Oh, yeah. No, I got convergent. Yeah, yeah. That one where a highly useful feature evolves completely independently. Right. And to serve the same purpose.
Exactly. So something that I find fascinating is when it comes to the origin of life, is the polymerization of amino acids or nucleobases, et cetera. Is that something that we're going to find is convergent? So life on Europa or insoluose evolved to use DNA also. Is it inevitable? Right. Or is there some other way to get that biochemistry done? Now, the best argument I've heard for DNA, otherwise it took me part of the way there, but I'm still
skeptical because of the complexity of a DNA molecule. It's kind of a geologist said, look, when we go to other planets, the geology is familiar. Right. A rock crystal of these atoms crystallizes the same way of giving the right temperatures and pressures here as in there. Right. And so if the geology repeats itself, no matter what planet we're on, maybe biology will repeat itself. Exactly. And I thought, okay, I threw a bone to that and I said, all right,
let me hang with that for a bit. But speaking of bones, I got a bone to pick with you. You lumped Titan in with insolidus and Europa. And Europa. How dare you? You're motivated by the search for life. Life on earth everywhere has needs, uses liquid water. There's no liquid water on Titan. Well, to be clear, there is. We do think that beneath the ice shell of Titan, there is an ocean trapped beneath that thick ice shell. But I think you're referring to the fact that on the surface,
we got these liquid methane and... If you have liquid methane, you don't have liquid water. That's right. Just to be clear about that. But it's not just a given that every moon is going to have a heated interior from Titan, forces. Now, I didn't do my homework on Titan before this interview, but is it subject to the same title stressing of its physical body as Europa and as a insolidus? It's a bit of a more complicated story, specifically at Saturn. And this is... The story is
complicated. Titan, Moon of Saturn. So Titan and insolidus and the moons of Saturn, when it comes to the tides and how much tidal energy they have now and have had in the past, it's a bit complicated because the various moons go through resonances. Kids on a swing set, kind of pumping each other up to swing in harmony or out of phase. In the Jovian system, with... Jupiter system. In the Jupiter system. With I.O. Europa and Ganymede, those three moons
are right now in a beautiful resonance we call the Laplace resonance. So for every two times, I.O. goes around Europa. I.O. goes around Jupiter. Europa goes around Jupiter once. For every two times, Europa goes around Jupiter. Ganymede goes around Jupiter once. I did not know they were in resonance. Yeah. And so that's what keeps their orbits, basically. The system evolves to that because the dynamical forces favor it. Exactly. So gradually the
orbits widen out and then I.O. starts tugging on Europa and Europa on Ganymede. Perhaps someday Colistone will be part of the party but right now it's not. So that would complete the big four. I.O. Europa Ganymede closed up. The four that Galileo discovered. That's right. Yeah. We got to call them Galilean moons. In fact, he called them stars. I think the Medici and stars. He was nowhere. He knew where the paycheck was. Because they were just points of light.
They moved around Jupiter and I think it's a moon. If it's just a dot of light, it looks like a star. So he started off really well with naming the stars. The stars of Medici. The Medici family was all happy. And he was like, oh no. These things go around Jupiter. Next thing you know he's under house arrest. I'm Nicholas Castella and I'm a proud supporter of Star Talk on Patreon. This is Star Talk with Neil deGrasse Tyson.
Why not call I.O. an ocean world? Let's zoom out and think about kind of a golden lock scenario. In the early days of astronomy and planetary science, conceptualization for habitability was kind of framed around this gold-delock scenario Venus, Earth, and Mars. Venus is too hot. Mars is too cold. Earth is just right. That's all mediated by the energy that the planets receive from the Sun from the central star.
Just that the energy that reaches the surface can reflect away some energy and that doesn't participate in the energy equation. And so the thinking back then and still today is that in order to have an Earth-like habitable planet, you have to have you have to be at that right star planet distance. So it's to maintain a sustained liquid water on the surface of your world. Whereas what these ocean worlds of the outer solar system are teaching us is that there's a new
gold-elox in town. It's a gold-elox where the energy for maintaining and sustaining liquid water comes not through your parent star, but rather through the tug and pole and mechanical deformation and friction and internal heating of tides of getting stretched by Jupiter, which is some 318 times as massive as the Earth. And so back to your question about I.O.
In this analogy with a new gold-elox, I was kind of like Venus. Billings of years ago, I may have had water, but I.O. is the most volcanicly active body in the solar system, and it has since lost any water that it perhaps had in the early days. Oh, you misunderstood my point. Go on. You misunderstood. No, I didn't make myself clear. Your book is titled Alien Oceans. Yeah. We're talking about ocean worlds. You didn't specify water ocean. So you want to qualify a magma ocean on I.O.
Well, I told you the beginning. If it's the most volcanicly active object. No. You find life forms in a magma ocean that's, that's... I don't know. I guess it's fair enough. But you're right. It was hot enough to melt rock. Probably there's no life hanging out. Yeah. Doing a backstroke. But you are correct. There have been some nice papers on a magma ocean in I.O. Because that tidal energy dissipation is so extreme. From the ability standpoint, it's got to gain more.
Okay. But also, I wanted to think very freely because you guys make me do this. If we go to Titan, where it has enough atmospheric pressure to sustain a liquid state of methane, because without pressure, then you lose your liquid, the range of temperatures where you can keep a liquid. Right. So, maybe life does not require liquid water. Maybe it just requires a liquid. Can you imagine a life form where it is liquid methane coursing through its veins, or whatever circulatory system it has?
Yeah. So, I really hope that kind of weird life exists on Titan. The challenge is I actually have a bit of a hard time formulating an hypothesis that it could exist. So, for example, Europa and Enceladus, we can say- Why should nature care what you have a hard time figuring out? So, are you the metric that exists in the universe? I know you wrote a book on it and everything. But I get that. But still. Right.
But when we do experiments, obviously with a scientific method, you formulate an hypothesis. So, I can formulate an hypothesis that life on Earth is based on liquid water, a suite of elements, and some energy to power life. I can then look at worlds like Mars and Europa and Enceladus and say, check, check, check. Now, there's a fourth element there of time and stability that we can come back to, and there's some differentiation.
But Mars Europa and Enceladus, I think we can check the box on liquid water and the other key stones for life with the liquid methane on Titan. It's hard for me to say, like, based on what I know of life on Earth, or even oil fields on Earth, that a hydrocarbon liquid could give rise to life. And here's the sort of key chemical difference. Liquid water is a polar solvent. Right. So, in liquid water, we can dissolve other polar molecules. This is the shape of the molecule, right? That's right.
It gives a little plus minus. Yeah. It's got hydrogen and oxygen and two hydrogens coming off at an angle there. Yeah. Yeah. Yeah. And so, the electrons get sort of preferentially positioned, such that you end up with a plus and a minus with a wall. So, just correct my chemistry if I get it right. So, if the two oxygen were sticking straight out on either side, then the molecule itself would have no polarity in that sense, correct?
And that is, there would be no difference between one orientation and another. And water would lose all of its really cool properties that we cherish. Well, the problem is that my thinking is that my thinking is that it comes a little more from the hydrogen and oxygen differentiation, right? Well, so it's not the angle that they're coming down. The angle plays a little bit, but the... Okay, that's a problem. Chemistry. It's a feeling in my chemistry, yeah.
Yeah, just put it down the middle like the oxygen is on one side of the V and the hydrogen is on the other. Yeah, and so if you flatten it out, you would definitely affect the charge distribution. Yeah, that's what I thought. It wouldn't be as effective at things we care about. Yeah. And certainly, you know, coming when it comes to ice, you wouldn't get that beautiful hexagon. That's right.
In part due to the V shape of water, I think it's like 109 degrees and then 107 depending on liquid and solid form. But liquid water, great at dissolving other polar compounds. Liquid universal solvent. Universal solvent for life on earth, right? But you go to Titan and now you've got this, these, cold by our standards, liquid methane lakes and seas. And liquid methane is non-polar. And so you're talking about life arising and thriving in a non-polar solvent.
And that just makes me scratch my head. It's like, could that work? I sure hope it does. I sure hope that nature is. I'm just saying, if you go back 100 and whatever years, and when evolution was first a thing that people discussed, the effect Darwin himself might have called for. This is what we need is a 72 degree tide pool. Yeah. So it's just right for life to form. And then the more we looked, it was like, no, you don't need that. You can do it this way.
In fact, you don't even need sunlight. I'm old enough. I'm old man here. My textbook said, life requires sunlight. All right, that's before we had the undersea vents. I know, that's what's got geochemical energy, thermal energy down there. So and now even in modern astrophysics, the planetary astronomy, the Goldilocks zone is insufficient to get it all. All the places where you'd have liquid water.
So this is an exercise in broadening any definition we previously laid down for what we'd expect of life. Yeah. And I think there's one thing I'd be curious to hear your thoughts on this. Life is just a biology is a layer on top of geology. Okay. And as such, what life does is, well, wait, just to be clear, we would later learn even that some significant fraction of earth's biomass lives underground as a participant in the geology that's there.
So it's not just life on earth and then hand over to the geologist. There's this, there's this zone where the two have to make nice in the coffee lounge. Right? Okay. And so life's job in the universe is to accelerate our production of entropy and heat, abiding by, if you will, the second law of thermodynamics.
And so when it comes to Titan and say, weird life on Titan in a non-polar solvent, yeah, I think as long as there is some energy that needs to be dissipated in some way, okay, perhaps biology will fill that energetic niche, even if it requires going way out of the box of what we're able to conceive of. I'm reminded in the movie 2010 where we learn where the life form that made the monolith came from from 2001. And do you remember where it came from? I did remind it.
It's Europa. Well, I'll give, but the actual came from. But that was the solar system's outpost of this life was Europa. That's right. And I think they found chlorophyll on the surface of Europa. Right. So back then there was the thinking that in the movie that I show, the sort of a green underneath the ice. A green, yeah, yeah. And that would require a very thin ice shell at Europa. So yeah, that's where the sort of monolith stuff originates, but then it goes back to some distant places.
But you're not landing there. You're heating the warnings of the aliens in 2010. No, not at all. There's a cadence. Of course, that's what you'd have to say. It's just what you should say. But let's talk about Europa Clipper. Yeah. A six-year mission there. Six years to get there. Yeah. And then you hang out there a bit or being Jupiter, but doing some close flybys of Europa. That's right. And it's very exciting. Oh, it's tremendously exciting.
And when we say flybys, oh, normally when we think about a spacecraft flying by a world, it's thousands of kilometers away. The engineers here at JPL, the pinball wizards are able to get the Clipper spacecraft. But pinball wizards because you have multiple gravity of all. Europa Clipper is getting a gravity assist from what? It's from Earth and Mars and then once it's in the Jovian system. Wait, so this is a two-cushion pull shot? Yep. To get to get to Jupiter. To get to Jupiter and Dan.
Once it's at Jupiter, then we go off the cushions of Ganymede and Clisto a bit. Oh, so you get more gravity assist from the moons. That's right. Very query. By that time, it's gravity assist to slow us down. Yeah, because you people forget that you can gravity assist in either way for your energetics.
Yeah. Yeah, and so Ganymede and Clisto, it's a beautiful thing about the Jovian system, the Jupiter system, where those larger moons can actually help out the spacecraft engineers to get into all sorts of different orbits. And so we'll pinball around. And so the pinball wizards. Yeah, great title for them. Wait, are they okay with the title? Yeah, I use this endearingly with my engineering colleagues all the time and they like it. They like it, okay.
And so we pinball around Jupiter and then we start going into these roughly 14-day pedals, orbiting Jupiter and making these close flybyes of Europa. Like pedals of a flower. Pedals of a flower. Exactly. Or I think about like those spiral graph. I've had one, yeah. Yeah, that's right. And so we'll orbit Jupiter, but make these flybyes of Europa and the close approaches. How close you're going to get? 25 kilometers. What's my closest ones?
And that's as close as any object has ever swung by anything. It's going to be extraordinary. And the images have a meter per pixel. And the Galileo images. So think about how extraordinary the images from the... Galileo this spacecraft. Yeah, okay. Because he was an astronaut. He never told us to go. And he did look at Jupiter. So it makes sure I'm right. Galileo did not have to have a meter per pixel. So Galileo, the astronomer, point of light. Galileo, the spacecraft.
We get beautiful pictures at, you know, kilometer scale. Suppose you could just tell Galileo what you're about to do. What a privilege that would be. Oh, absolutely. I mean, and that's 400 years ago. 400 plus years ago. That's not even... That's nothing. That's nothing. In the history of our species. Yeah. Just say, you know, one day we're going to go there. Yeah. One of your Medici-in. Oh, my God. Yeah. So you're going to close view of the surface ice. But you're not looking at the water below.
And that's what you really care about. Right. And so what Clipper has on board are cameras to give us pictures of the surface, spectrometers to tell us about the surface composition. And by looking at the surface ice, we know from Galileo spacecraft, from telescopes. And Hubble helps out. Hubble, yeah. Yeah. And the ice of Europa serves as a window into the ocean below. So using the spectrometers and looking at the ice, we will get a bit of a fingerprint of the ocean chemistry.
But that's only because there are cracks that might fill in with the water. Knowledge free. That's right. And subduction, subsumption. Oh, subsumption. It's... It's... it shouldn't even be a word. Just my opinion here. Yeah. Sub-sub-sub-sumption. Yeah. As a term, I coined by some colleagues of mine. Oh, you're all just made up the word. No. As we do, right? Because I know there's subduction. Right. As when a continental plate goes under. That's right. And then there's...
Yeah. And so, subsumption is kind of thinking about how that might occur on an icy shell. Did it really need another word? Yeah. Yeah. Debatable. But so with Clipper, we've got these cameras and spectrometers and then mass spectrometers that will allow us to taste any plume material coming out of Europa. Well, we can taste any organic compounds, carbon compounds. So taste, you mean almost literally taste.
Because if you have the molecules and you have something to detect the molecule, you basically taste it, the molecule. That's right. Exactly. And so on your machine. I'm a co-investigator on the Suda instrument, which is a dust analyzer, mass detector. Surface analyzer for dust at Europa. Okay. So we have acronyms these days are... Okay, I'll give you that. I'll give you a hall pass on that one. So I don't necessarily go by the first letter of the word anymore.
Okay, so that's more of a passive experiment. Because you're not aiming for those. It has to sort of come to you if it happens to be spewed forth from the surface. Exactly. Think about a kid with a bucket running through a snow storm. It's much more muted than that at Europa, but we will be getting those compounds in the bucket and passing them through a mass detector. No, no, no, no. And these aren't big plumes like you find on cello discs, but there is certainly upward movement.
Yeah, so I've been on a team that's used the Hubble Space Telescope and the James Webb Space Telescope to look for plumes on Europa. It's great. We have telescopes that can see the edge of the universe. It's extraordinary. And then right in front of our nose as well. That's... This is good. This is a good people. We can get amazing things going on when that's a people. We got some people. People are good folks. Not just the astronomers, but of course the engineers that actually make it happen.
That's right. Shout out to the engineers here. Okay, they get the hard stuff done. So, in Telugu, this is a tiny moon. It's only 500 kilometers in diameter and very low gravity. And so plumes on in Telugu, go out for hundreds of kilometers. Europa is about the size of our moon. And Europa's gravity is about one-seventh. So Europa is way bigger. Way bigger. 3,000 kilometers. I didn't even think about that. Yeah. So 500 kilometers in American speak, that's like 300 miles across. All right.
It's still a nice object, but it's not like Europa. Right. And... So what are the chances of you seeing sort of macroscopic life that might have bubbled up and landed on the surface? Like fish is flopping. You asking if our bucket's going to catch a squid? And you reminded me. You advised on the movie, the sci-fi movie, low budget, but still carefully conceived and executed movie, the Europa robot. That's correct. And I have a tiny cameo. You do? I do a tiny little cameo. I think it was on CNN.
They used actual footage of me on actual news. Commenting, I said, I want to go ice fishing on Europa. Cut a hole. Laura's submersible and see what's there. Yep. And expressing my enthusiasm for this. You and I, that, uh, if we could fish on Europa. Oh, man. So you were an advisor to that film. That's right. And they did a fantastic job. That's why it was so good. Not because I was in it. Because they thought about the science.
Well, one of the really cool things, you know, I've done some consulting on various movies. And I was like, hey, team, if we're going to do Europa, we got to do Europa, right? And so they didn't know that much about the radiation environment of Europa. From Jupiter. From Jupiter, exactly. And so that's factored into the movie and become sort of central to the story. And on Europa, that irradiation of the surface would kill an astronaut.
But coming back to habitability, one of the things that we're looking for with Europa, Clipper, is how some of the radiation driven chemistry on the surface of Europa could positively affect the chemistry of the ocean and the habitability of the ocean. Let me give you an example. Sulphur comes from volcanoes on Io. The eruptions on Io exude sulfur and some of that sulfur actually lands on Europa. This is sulfur that has been spewed forth from volcanoes faster than the escape velocity of Io.
That's right. thereby contributing to the general orbital environment of Jupiter. That's right. It gets spun up in Jupiter's magnetic field. Next thing, you know, that sulfur ion is slamming. What's an ion? So it responds to the very strong magnetic field. That's right. But then so some of that sulfur impacts Europa and then gets radiologically processed into sulfate and other forms of sulfur, which then if mixed into the ocean. sulfate. sulfate. Microsanurth, sulfate. That's a fact.
And then get that, get this. So what happens when you split apart H2O water? You get OH and H. Some of that H escapes the space. Some of the OH recombines with another OH forming H2O2. H2O2 is hydrogen peroxide. We have observed. Which is the same thing as what anyone would call peroxide. Exactly. That's the pharmacy. The pharmacy. Yeah. And so that's that old joke. You know the old joke. No, what's that? Someone goes to the bar and said, I like some H2O and then they hand them a glass of water.
And then someone sees that. I want some H2O2. That's how they go. Get a glass of water. And then they drink it. That'd be a very chemically literate bartender. Right. And I'm not a very tasty drink. So get this. That radiation processing of the ice of the H2 of the water ice on Europa leads to the formation of hydrogen peroxide H2O2. Which then that also gets radiologically processed or decays to O2 oxygen. And telescopically we see hydrogen peroxide and oxygen in the surface.
You have to be very clever to go from one step to the other to see this through. The game of dominoes and you don't know where the dominoes are, but you think you do and maybe it is. And if it is, this leads to that, this leads to that, and then you have what you need. Right. Except we actually observe it. So to be clear, we see condensed phase oxygen on the surface of your water. And you think that's how you get it. Right. We get it radiologically. I do that in my lab.
And I love when you say that. I do it in my lab. I need somebody to hack my lab. And that's the fun of like lab and spacecraft. I know it's great. It's great. And they go hand in hand. Right. Yeah. So we can make predictions and it's a lot of fun. But so of course we know that oxygen is very useful for life on Earth, not just for microbes, but for Well for our kind of life. For mycophonus. An aerobic life does not like oxygen. That's right. That's right.
And they love sulfur and methane, and all sorts of other things. But so here you are, the radiation environment on the surface of Europa could produce compounds, which then if delivered to the ocean through subduction, subsumption, whatever you want to use could help provide rich chemistry to the ocean to sustain a biosphere within Europa's. And this will give you some of the chemical gradient. The chemical disguise that you need.
So you got hydrothermal vents on the bottom of the ocean, spewing out things like methane and hydrogen and sulfide. And then from the ice shell, you might have things like oxygen and sulfate. So you can connect the battery, the biochemical. And that's how you make Godzilla. At least that's the recipe for Godzilla. So we got to wrap this up. Just one point I care a lot about words and what they mean and have they're received. Europa has water underneath ice.
Yet you name this mission Europa Clipper. And a Clipper ship from the 19th century floats on water swiftly. So who came up with the word Clipper? Because that's a little, you're not floating anywhere. Right, yeah, you're still. So in the early days, remember that during the Gold Rush, Clipper ships were used to very quickly get people from New York City to San Francisco. Yeah, there's some of the fastest ships made. There are narrower, a lot of sales.
The wind can take you before steam ships, of course. That's right. Yeah. And so... By the way, I think the phrase, let's get there on a good clip. Yeah. I think the company Clipper ships. Yeah, Clipper is swiftly. Yeah. The Clipper ship gets you there fast. Yeah. So I know you're getting there fast because you strip down the Falcon Heavy. The Falcon Heavy doesn't even have return stages. Because that uses weight that you could put in your payload. Right. Right.
So you strip it down, put it all in the payload, get it out of this fast as you can, get you to, get your to gravity assists, you're there in six years. That's right. So in that sense, it was a Clipper, but not in the sense that it's floating anywhere. I just got to get that off my chest. 100%. Yeah, and some of that Clipper terminology goes back to variation in launch vehicles and stuff. Okay, so... All right. Well, Kevin, great to have you back.
Thanks so much, Neil. My pleasure and the hard to see you. And it's exciting to... So if something bad or good happens to the Clipper mission, we've got to get you back on to talk about it. Okay. When good life will cry. When all the good things happen, we've got to get you back on. We won't do it while you're busily receiving the data, but if there's a break in there, you'd have to come back on. Anytime. And we can find your book Alien Oceans. Alien Oceans, I love the assinance there.
Alien Oceans. Search for life in the depths of space. Yes. There you go. All right, good luck with that. Thanks a lot for you. Sure. This has been StarTalk, or JPL edition. Oh, yeah. Neil deGrasse Tyson bidding you, as always, as they do here to keep looking up.