"Coral Reefs" on Mars; Why Is Uranus Sideways?

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1:00The last show with David Cooper. The planet Mars, if you look at it closely, it has landscapes that look bizarrely like coral reefs, except, of course, there's no coral and certainly no tropical vacation to be had there. These rippled layers on the surface of the planet may instead be a sort of geological diary of ancient Martian climate change. Let's talk about this here with Sarah Rue Kimer, an astrophysicist and astrobiologist and professor at the University of Edinburgh. Sarah, welcome to the show. Thanks for having me. So coral reef on Mars, should I pack my bags and head over there and enjoy the beach? Was there ancient life? What is this evidence of? What kind of parallels can we draw from what we see on the surface of Mars to hear on Earth? Yeah, so first off, it looks like a coral reef, but it's not a coral reef. Wait a minute, I'm not afraid. I know. It just has these wavy structures. It's really beautiful.

2:01I definitely recommend all listeners go check out High Rise. It's spelled H-I-R-I-S-E. High Rise. Images of Mars, they're beautiful. So we have on the Mars Reconnaissance Orbiter this really high resolution camera and it takes just stunning images of Mars and this is one of them that we can see. When you look at it, it looks blue, it almost looks ethereal and you might be like, wait, but I thought Mars is red and indeed you're correct. These are false color images. I know. Artists impression. Artists impression. Blue. Yeah, the structures are there, but they would be kind of more your darker brown. And they're just showing weathering patterns and they're colored this way so you can see the contrast more and you can kind of see the structures, but that's not a true color image. Okay, so I'm looking at them. They are absolutely gorgeous. Almost. It's not otherworldly, almost earth-like. Yeah.

3:02But why does this kind of layering, why does it interest climate scientists? What does it say about the history of the planet? Like, what are they, I guess, is what I'm asking. Yeah, so there are geological features that have been sculpted by dust storms, perhaps water interactions at some point or underground water erosion and these sorts of features we can kind of study to see how is the Martian surface evolving. And one thing that we're interested in is like how did early earth, or early Mars, excuse me, look like could it have had life, would it have been habitable? And so that links to another discovery that's been in the news about seeing the evidence of past water on Mars and indeed fairly warm water where you have some volcanic activity and you have this water rock interaction. And so some of what we see on Mars is kind of the remnants of seeming water features, rivers and lakes and things like that on the surface.

4:04And then some of the features are just sculpted by wind or maybe early volcanic turnover. And so we're trying to figure out what each of these features mean. And I think there's one important one to keep in mind. It was really big in the news a few years ago where they said they thought they saw liquid water on Mars today. I don't know if you were you're. I remember I was hoping you weren't going to say the face on Mars. That was the 90s, but I do remember this. The thing is you hear a big story like this. You get all excited and then it kind of quits down. And then when they actually get like a more revised answer and it's less sensational, we don't hear about it. I know. Well, indeed. And in fact, this is still kind of in the public conversation. I even heard Niels Gras Tyson speak. And he mentioned this liquid water on Mars. And it's like no, no, that's been kind of over proven. You know, it's it's just a nice watching Niels Gras Tyson talk and thinking to yourself, oh, he's operating on old news. He might not be right. He was offered. I emailed him the update because I was like, they're like, everything was great.

5:06But this was one fact that hasn't listed the test of time. And that is that these steep slopes have sand fall. And that's what seemingly was causing what looked to us like water flowing. But it was just the steepness of these, yeah, dunes that had sliding sand. And so these are the sorts of things we want to look at. We want to try to figure out, is this liquid water? How excited should we be versus is this wind? Is this falling sand? And that's just for today, let alone, you know, going back in history, trying to figure out with examining minerals and whatnot to see was there more definitive science of liquid water, which there are for the early history. So the takeaway from these, kind of a reef like structures, they give us insight into what the climate of the planet looked like a long time ago, likely. Yeah. So every rock and valley has its own story. And we're just trying to piece together what's happening on Mars now and also what happened

6:10before. If we zoom to now and we go to the Perseverance Rover, the water story on Mars, what's the current thinking with the knowledge that the thinking may change as we get new and different evidence? Yeah. So what we're seeing is, and this is not a controversial, we're just seeing evidence of past water on Mars. That's been known for a long time. But what's interesting about this is we're seeing its hot groundwater. So we're seeing some minerals that only form in these certain systems where it's hotter water and interacting with rock and through this molten material or volcanic activity. And so I think that's interesting where you're seeing, you know, this, this sort of mineral logical evidence of a type of water rock interaction. And that's really cool. It just is further evidence. We already have known this, but it's just further evidence that early Mars probably was

7:13habitable and a place where microbial life could have flourished. Okay. And why hot underwater groundwater, underwater groundwater? Why hot underground groundwater? I'm still not making sense. Why is this of such interest? And where does this heat come from? Is it from the core of the planet? Yeah. So when Mars formed, of course, it had more heat from formation. And when it had a molten core before it froze out, that happened pretty quickly. But it was just a warmer place as it's, you know, planet formation is a fairly violent process, right? It's a bunch of collisions of objects. And when you have these collisions, you get a lot of heat and molten rock and magma and that slowly cools over time. So Mars has remained cold for billions of years. But the first, you know, half billion year. So it was, you know, at first, very hot. And then a period probably a more temperate climates.

8:14And so what we're seeing is these mineral veins that contain features that seemingly show us that hot water circulated through these volcanic rocks. And that's pretty cool because that's where we think, you know, perhaps life evolved on Earth is in these hydrothermal systems that you have water, rock, and heat and the sort of chemical gradients that could give you energy for kick-starting life and metabolism. So I just think it's more evidence that we need to go to Mars, look for either fossilized evidence of life or current life in the deep subsurface and check it out. The most important question on this story though, did Neil deGrasse Tyson email you back? And thank you. No, he did not. No, he did not. Root. Root. Okay. I want to zoom away from Mars as we go to our next topic, which we'll cover after the break here with Sarah Rueheimer, a professor of astrophysics from the University of Edinburgh in the UK or in Scotland, depending on, you know, we won't go there.

9:16But the planets, they all kind of rotate about their axis the right way up, so to speak, but there is one that is tilted on its side. And I'm curious as to why it's Uranus and when we come back, we'll tell you why and I promise I won't make any off-color jokes. Let me let you in on something I learned after 15 years working as a software engineer in Silicon Valley. You'd be surprised how little information anyone needs to start finding a lot about you online. I'm David Cooper, host of The Last Show. Just typing in your name can lead to your phone number, old addresses, your relatives, even where you live now. And a lot of that information can end up on data broker sites and other sites that publish your personal and private information where you never even asked to be listed. That's why I use in Cogni. In Cogni finds companies holding your personal information, asks them to remove it and keeps going back when that information shows up again. As just knowing your name should not come with a complimentary map to your front door.

10:17You should use in Cogni too, and you can get 60% off their annual plan at incogni.com-couper. Make yourself a little harder to find online. That's INC-O-G-N-I-N-Cogni.com-slash-couper for 60% off their annual plan. Parenting unlocks some pretty impressive skills, like carrying grocery bags, a soccer ball, and a sleepy kid all at once. Good thing the newly designed Chrysler Pacifica has a few tricks of its own, hands-free power-sliding doors and lift gate, rear seat entertainment, and still-en-go seating and storage that adapts faster than your family's weekend plans. Visit Chrysler.com to learn more. Chrysler is a registered trademark of FCAUS LLC. Most planets spin more or less upright in our solar system. But there's one that is completely tilted on its side, Uranus. And it looked at that arrangement and just said, no, I don't want to do it the way the other planets are.

11:17Why is it this outlier? And why do the other planets seem to be upright? Not knocked over. Let's talk about this here with Sarah Rue Kimer, a professor of astrophysics, and an astrobiologist at the University of Edinburgh in Scotland. Check out her audible- no, not the audible thing. Let's talk about the great courses thing. Experience James Webb, experiencing James Webb, the Invisible Universe Revealed. You can check that out on the great courses. Okay, Sarah, welcome in. Why is Uranus like this? Why is it on its side? I mean, the short answer is we don't know for sure. This is a, we're trying to do modeling of the system and how different gravitational interactions could have basically caused Uranus to be completely tilted on its side. And it's kind of rolling around its axis as it orbits its side. It's got a wobble. It's very strange. It's so cool though, because it means that like a year on the dark side of Uranus would

12:22last like 21 years. You'd be in darkness. And so it's a weird place to think about. Yeah, like if Earth were like that, let's say the South Pole was kind of mostly facing to the sun. That area would be hot. It would not really experience nightfall much. And then the other pole would just be like a dark, frigid, very, very strange place to live indeed. Yeah. So I think it's just interesting also from like how this whole planet is experiencing, yeah, heat from the sun. And it's partly due to this very weird orbit. And you said something that maybe listeners are not aware, but most planets are rotating more or less kind of in the way we would expect. And that's because if you think about how a planetary system forms, it's from a giant cloud of gas. And that gas is slowly rotating in one direction or the other. And whatever direction it's rotating as it collapses due to gravity and the star in the

13:26center forms, it would follow that the axis sort of is a, if that cloud is like a disc, it would follow that the axis of the planet forming from stuff in the disc would be aligned with the disc, which would be about, you know, exactly. So as it's collapsing just like a figure skater bringing in their hands, it's spinning faster and it's all in this line. And so this is why we tend to have planets mostly in a line. They're all rotating in the direction that we're traveling, except for Venus and in this case, also Uranus is weirdly tilted on its axis. This is rotating the other way, odd, you know, and Uranus is just totally tilted on its side. And so something happened to make that happen. The obvious explanation, and I'm an armchair, you might even call me an astrologer. No, we won't go there. The obvious explanation and the thing that I think that I learned way back when is that just something likely hit it, like an asteroid and knocked it out of its kind of correct spin, if you will, into this bizarre spin.

14:28Is the case closed on that one? Is there a good evidence for that or is it just a hypothesis and we don't really know? Yeah, so these are hypotheses of how it happened and what this recent research showed is, maybe you don't need these collisions. Maybe it's just moons that are kind of gravitationally pulling it in different ways and causing it's tilt to change. So, you know, if there, even if there was a collision, they, you know, it could have happened, and it may not have done the tilt that we thought. And so there's kind of, I guess, competing models at this point. I wouldn't say we definitely have an answer as to Uranus' history and hopefully more modeling will figure out if there are observables we can see now that will determine one of these ways or the other. But what they did is they're looking at these ancient moons of a, enough size and where they're located could just cause this extreme tilt due to gravitational interactions.

15:31And that would have happened before the collision. Oh, interesting. Well, let's talk about moons a little bit more. Moons can have water on them. Europa is the one that sort of famously has a lot of water on it or ice. Yeah, absolutely. Water and ice both. And when I think of moons or even larger objects, planets, when I think of like, I don't be smashed by an asteroid, I think, okay, that's enough to just get rid of its ocean. Just kind of vaporize the ocean, kill the ocean. If a rock hit earth, I'd assume we look more like Mars after something like that. I'm not right in this based on some new modeling. Is this a good setup for what we're about to talk about here? Absolutely. So definitely giant collisions happen all the time again, especially at the formation of a system where you have a lot of material flying around. I saw on the get-in. I saw what happened with Bruce Willis. I'm aware that asteroids can hit objects. Yes. Absolutely. And when they're big, they can really catastrophically disrupt the system.

16:33So, you know, earth's moon formed from a giant collision. And so earth was actually collided with a Mars-sized object early in its history. And then some of it coalesced into now what we call earth and the rest of it became the moon. So you can have these really catastrophic collisions. And it is a surprising result to me as well when I read this that you would retain your ocean. And I'm not sure like retain the ocean is quite what we think it means. The ocean could still be kind of temporarily obliterated. It's just that water is still there. And so when it all comes back and differentiates again, you still have water. Basically, the water's not like blown out into space. It's in the gravitational pull of this system. And so even if it's vaporized or disrupted, it'll still form back together and have an ocean. Which is pretty cool. It's very raiding for a time as well.

17:34Pretty cool. Yeah. And maybe some rain and other weird things. But I think what's interesting here is these moons are some of the longest classically habitable places outside earth in the solar system. So going back to our previous conversation on Mars, Mars doesn't have liquid water on the surface. So today, maybe did in the past and when it did in the past, it wasn't very long, you know, on terms of billions of years. So these moons, however, Europa has had a liquid water ocean for four billion years. Right. So long time. There is a problem there. It's pretty cold on Europa. It's cold. And it's under an ice layer and the ice layer is pretty thick. So you have like this big thick ice layer, like 10, maybe even 100 kilometers thick and then you have this ocean under it. But still you have liquid water ocean. And because of the moon being around Jupiter, for example, causing tidal flexion.

18:35So it's basically like if you bend your credit card back and forth a bunch of times and it heats up, that's what's happening to the moon. And the gravitational pull on the rock actually creates heat. It's tidal heating and so you can have these hydrothermal systems and heat and water and rock all interacting, which are the conditions for life as we know it. So in many ways Europa represents a very traditionally classics habitable system. Well, Sarah, it was a joy discussing these topics with you. I might even say that our conversation was out of this moon. I don't know. I've attempted to joke. It's been a long day. But thank you for being here. Thanks for having me. When fall comes back around, there's a sense of a reset. And new pieces from Lululemon's fall drop are an inspiration to push your goals and elevate your routines. As your calendar fills, easy to layer styles meet the demands of your day. And as you challenge yourself to try even more, versatile sets transition with you.

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