IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, we explore the science of sleepiness, but first, in anticipation of the Oscars, Science Goes to the Movies.

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– The most spectacular science shocker ever filmed. Too real to be science fiction, now science fact. [PLAYBACK ENDS]

IRA FLATOW: Yes, and we have a triple feature. We’ll be talking about a new documentary on the mental health of astronauts and what 65, the film starring Adam Driver, got right and wrong about finding life on alien worlds. Our first feature, though, is the blockbuster Dune– Part Two, and as you may know from the book and the movie, the story takes place on a planet called Arrakis.

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– My lord duke, welcome to Arrakis.

IRA FLATOW: A scorching-hot world covered in, what else, but dunes that are homes to giant, deadly sandworms.

– You wouldn’t want to go down out there. It’s worm territory.

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IRA FLATOW: Could there be a real planet that resembles Arrakis? And if so, could it sustain life? Here to talk about that is Dr. Mike Wong, astrobiologist and planetary scientist at the Carnegie Institute for Science in Washington DC. Welcome back to Science Friday.

MICHAEL WONG: Hey, Ira. It’s great to be here.

IRA FLATOW: Nice to have you. Mike, when I watch sci-fi movies like Dune, I’m always thinking to myself, come on. Is there really any science behind here? Do you think like that also?

MICHAEL WONG: Yeah, it’s hard to shut it off as a professional scientist. Whenever I am watching the depictions of strange new worlds and I keep thinking to myself, huh, is that real? What exactly is right here? What are they getting slightly off? But it’s all in good fun, and I really enjoy watching science fiction.

I’m a huge fan of Star Trek myself, and that’s full of strange new worlds every single week. So yeah, I don’t turn it off. But I think it enhances the experience.

IRA FLATOW: Yeah. Yeah, all right. So let’s take Arrakis, please, and its famous giant, deadly worms. Could there be a planet like this and have those big worms on it?

MICHAEL WONG: Yeah, that’s a really good question. So I think the concept of a desert world isn’t too far fetched. After all, we know about worlds in our solar system that have less liquid water on them than Earth. Earth’s surface is covered in about 70% is covered by liquid water.

But you go to our next door neighbors. You look at Venus. Its water has long boiled off and escaped to space. And then you turn the other direction, and you look at Mars. And Mars is this cold, dry desert, where a lot of the water that still remains on Mars is in a frozen state, so it’s mostly ice.

So yeah, I think that the idea of a desert world is certainly valid. Whether or not it can host giant worms, that’s another issue. I see two things that I’d like to investigate and poke at with the hypothesis that you could have giant worms on a desert world. And the first is, what are they going to eat?

This world Arrakis, it’s said not to have any giant bodies of liquid water. If we think about the largest animals here on Earth, the whales, they’re able to sustain their huge biomasses because there are oceans full of krill, and plankton, and little critters that they can just gulp up and swallow. So what are these giant sandworms eating all day long? Are there smaller critters like in the sand dunes, too? We’re not sure about that kind of ecology from what is presented to us in Dune.

The other question is, what are they breathing? Where is all the oxygen in the air on Arrakis from? Because the oxygen on Earth is generated by photosynthetic life. We’ve got all these rainforests full of trees. We’ve got cyanobacteria, these blue-green algae in the oceans. They’re all doing photosynthesis, pumping oxygen into the air. And that’s the oxygen that we breathe. But Arrakis is just a desert world, so where did all of its oxygen come from?

IRA FLATOW: Yeah. Yeah, could you make oxygen?

MICHAEL WONG: Yeah. I think in the lore of dune, Arrakis once had large bodies of liquid water because we see these salt flats on the world. So perhaps there was an ocean that evaporated and left these salt flats, and maybe in that ocean there were photosynthetic life forms that produced a lot of oxygen. And the oxygen that is currently used by the giant sandworms today is left over from that.

Alternatively, you can also source oxygen from things that have nothing to do with life whatsoever. So you can split apart molecules in an atmosphere, molecules like water or carbon dioxide, that have oxygen in them. And then when you split those up using ultraviolet light from the star that Arrakis orbits, you can generate some amount of oxygen in the air.

IRA FLATOW: If it’s not worms that are living on that on our mythical planet, what kind of life could a super-dry planet, like Arrakis, sustain?

MICHAEL WONG: Luckily, we have really dry places here on Earth that we can look to for examples. So there are all sorts of really inventive critters, especially microscopic ones, that can survive in really dry environments. So in the Atacama Desert, there are some really inventive microbes that sort of live within the salt crystals.

And so I think that a desert world could still sustain some degree of microbial diversity on it. And indeed, when we go– we send rovers to Mars, that’s kind of the life that we’re looking for. We’re not really expecting to see any cheetahs prowling Mars’s surface, but we need really fancy instrumentation to try to spot evidence of microbial life in those soils.

IRA FLATOW: Let’s talk about all the sand, that where the worms live, there’s a huge amount of sand. Could that form on other worlds?

MICHAEL WONG: Yeah. Actually, one of the coolest examples of sand on another world– well, first of all, there is sand on Mars. But I’m going to go all the way out to the outer solar system and talk about Saturn’s moon Titan here.

Titan is a really fascinating world because, in many ways, it’s kind of Earthlike. It’s got sand dunes. It’s got mountains. It’s got rivers. And it’s got precipitation, too, but it’s made of a completely different material.

So Titan’s out in the outer solar system. It’s super frigid there. The bedrock on Titan is solid water ice, and it sort of like snows these organic, carbon-rich fractal-like compounds out of its atmosphere. And so the sand dunes on titan might be some combination of eroded water ice and this fluffy kind of organic rich material that is sedimenting out of its atmosphere. So there’s lots of possibilities for sand across different types of worlds.

IRA FLATOW: We’re always looking for water, and you mentioned Titan. We might not have to go way out into outer space to find life because it seems like it may be possible in our own solar system.

MICHAEL WONG: That’s right, yeah. We’ve got lots of really tantalizing environments in our solar system that we’re really curious about in terms of its astrobiological potential, its potential for alien life. And so anything from the clouds of Venus, perhaps, all the way to ancient life living on Mars when it was more warm, and wet, and habitable to the outer solar system, the moons of Jupiter and Saturn, namely Europa and Enceladus, respectively. These are moons that have liquid-water oceans hidden beneath icy crusts.

They’re maintained in their liquid water state by tidal forces, the gravitational pull of Jupiter and Saturn flexing the interior of those moons, keeping them warm. And then, of course, Titan, that really enigmatic world orbiting Saturn, with this organic-rich atmosphere, bodies of liquid, hydrocarbons, methane and ethane, on its surface that could potentially host weird forms of life that don’t use liquid water at all. The possibilities are really endless, and I’m so excited for this next phase of planetary exploration that really starts later this year with the launch of the Europa Clipper Mission to go out to the outer solar system, return there, and try to find evidence for habitability and potentially life.

IRA FLATOW: From the way you’re speaking, I’m thinking that you would think that there’s more chance of finding life than not finding life.

MICHAEL WONG: [LAUGHS] I guess– I guess as an astrobiologist, I have to be inherently fundamentally hopeful that there is something out there to try to find. As a scientist, I try to say, I don’t know. I don’t know if there’s life elsewhere in the universe. I’m going to let the data speak for themselves.

When we go out there, when we sample these environments, when we take our microscopes and our other instruments and try to look for evidence of life, then I will say what the probability might be. But right now, we haven’t really done a really good job of looking yet.

We’ve tried a few times, the Viking missions in the ’70s on Mars, and Curiosity and Perseverance are doing their thing these days. But we haven’t really investigated many of these worlds, Europa Enceladus, Titan, in the kinds of way that could actually find life. And so once we do that, then I’ll be more confident about saying, oh yeah, there is this probability of finding life versus that probability.

As a scientist, I’ve got to say the data will speak for themselves. And we just have to go and do our jobs to the best of our ability to see what’s out there.

IRA FLATOW: Yeah. You mentioned the moons of Saturn and the moons of Jupiter that are full of water or might be places that we could find life there because of that. Would you like to see them represented in films instead of just a dry, rocky place like in Dune?

MICHAEL WONG: [LAUGHS] Yeah, yeah, I think planetary science, if it’s taught us anything, it’s that we’ve got to expect the unexpected when we explore outer space. These surprising ocean worlds, again, that was completely mind blowing when people discovered them. And with the whole exoplanet revolution, we’re discovering all sorts of new kinds of planets out there that, I hope, work their way into science fiction one day.

I love this idea, Ira, of depicting icy ocean worlds more in science fiction. I think there could be some really fun adventure exploring the hydrothermal vents in the bottom of a Europa-like planet. That would be great.

IRA FLATOW: So if I put you in charge of making the next Hollywood blockbuster, you might put us on a watery planet.

MICHAEL WONG: Yeah. I think it would be really fun to explore a super-watery planet. Let me tell you about this type of world that we’re currently investigating called a hycean planet. That’s kind of a weird name, hycean. What does that mean?

So this is a type of planet that we think we may have discovered a few of them outside of our solar system, orbiting other stars. These are planets that are somewhere in between the size of Earth and Neptune. And so they have one quality that is kind of like Earth in that they have a surface that is covered in an ocean of water, but the atmosphere is more like that of a giant planet, so full of hydrogen.

And so if you smush the word hydrogen and ocean together, you get the word hycean.

IRA FLATOW: Wow.

MICHAEL WONG: And so that’s what a hycean world looks like. And so the idea here is that maybe there is life swimming in that kind of ocean under a hydrogen-rich atmosphere, which I’ll just emphasize that, again, our atmosphere is made up of nitrogen and oxygen, not hydrogen. So it would be very different kind of environment with a very different kind of life, and it would be really fun to try to investigate or dream up, in a Hollywood sense, what life might look like on such a planet.

IRA FLATOW: Wow. That’s a great idea. Mike, thank you for taking time to be with us today.

MICHAEL WONG: Yeah, no problem. This was real fun.

IRA FLATOW: It was fun. Dr. Mike Wong, astrobiologist and planetary scientist at the Carnegie Institution for Science based in Washington.

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