If there’s one place we’ve learned more about in the last 10 years, it’s Mars. Thanks to all those rovers, orbiters, landers which are flying overhead, crawling around the surface, and digging into the rich Martian regolith. What have we learned about Elon Musk’s future home?
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Mars NASA page
Mars Facts: Life, Water and Robots on the Red Planet
Mars’ Dark Streaks May Be Caused by Dry Landslides, Not Water
Valles Marineris, Mars: Wet debris flows and ground ice
Water on Mars
Scientists Discover Clean Water Ice Just Below Mars’ Surface
Mars life clues from methane and ‘sticks’
Mars Probe Poised to Solve Red Planet’s Methane Mystery
Valles Marineris, a Martian Rift Zone | Mars Odyssey Mission THEMIS
Mars mission: how increasing levels of space radiation may halt human visitors
Giant Impact May Have Created Mars’ Moons
Studying ground temperature with InSight
Podcast Transcription provided by GMR Transcription
Fraser: Astronomy Cast episode 493, updates about Mars. Welcome to Astronomy Cast our weekly facts-based journey through the Cosmos where we help you understand not only what we know but how we know what we know. I’m Fraser Cain, publisher of Universe Today, with me as always, Dr. Pamela Gay, the Director of Technology Citizen Science at the Astronomical Society of the Pacific and the Director of Cosmo Quest. Hey, Pamela how are you doing?
Pamela: I’m doing well, how are you doing Fraser?
Fraser: Great. I don’t know if I mentioned this last week but I’m going to mentioned this again which is that we have a book, The Universe Today’s Complete Guide of Viewing the Cosmos and we have a cover by Robert Gandler and we have a link on Amazon if you wanna pre-order the book.
Pamela: And I owe you a foreword.
Fraser: And it’s going to have a foreword from Dr. Pamela Gay. So, at some point that foreword will exist maybe that’s why I’m just announcing this, is that.
Pamela: I just wrote a note.
Fraser: There we go, that you remember to write your foreword but the publishing date is in October, October 23rd, I believe. So, I’m really excited and we’re still trying to sort of find space for more amateur astro photos to put in to the book, nagging all the photographers that we know. So, that’s the hope is it’s gonna be tons and tons of pictures that nobody’s ever since. Anyway, I know I probably mentioned this last week, I will mention this a few more times, pretty excited but definitely check it out. All right, so if there’s one place we’ve learned more about in the last ten years it’s Mars.
Thanks to all those rovers, orbiters, landers which are flying overhead crawling around the surface and digging in to that rich Martian regolith. What have we learned about Elon Musk’s future home? I love that you don’t know what my intros are gonna be and so you have to just kind of, you get this surprise just the audience. This is great, so another episode that we can definitely say new things have happened. Another place in the universe that we know a lot more about than we did ten years ago. Although, we have brought the listeners along with us as some of these have been discovered.
Pamela: And the number of things that we’re realizing we don’t know more than we knew before and we may be wrong both then and now is also kind of intriguing when it comes to Mars.
Fraser: But that’s how it works, right. Is that if you’re doing sciences job right, for every question that you answer you ask two new questions and the to do list of questions just keeps growing and growing faster than you can stay on top of them. So, I think that’s all fine. So, where do we wanna start. I think there are some big things that we should talk about some of the big, there’s obviously, the spirit and opportunity and then there’s curiosity and those have turned up some really big, let’s talk about the story of water then, the history of water and sort of where we’re at now with the discovery of sort of the history of water on the surface of Mars.
Pamela: And it’s not just the rovers, we need to remember XO Mars, Trace Gas Orbiter, we need to remember Maven. This is a world that is surrounded by spacecraft and crawling with a couple of spacecraft. So, all of these spacecrafts are working together to try and figure out the history of this world and because we’re kind of desperate to get there because he wants to stay on the planet earth because we’re all kind of desperate to get there. Each in their own way they’re kind of studying the history of water as they study the history of the planet.
So, when we first started this episode it was before Phoenix, it was –
Fraser: Before we started Astronomy Cast, yeah.
Pamela: Yeah, Phoenix was something we encountered midway through this show and we had to do updates with that little rover, reaching down pawing its way across the surface and revealing water ice. That then happily sublimated in to oblivion and I just love that image of it, basically reached out and scraped across the surface with its little paw which was a robot arm but in my head it’s a paw.
Fraser: See, I just imagine like one of those, you know, those kids sit on this kind of like little shovel and they’ve got these little, you know what I mean?
Fraser: And it’s got this sort of little arm that reaches out and sort of digs on the regolith, that’s what I imagine Phoenix looked like.
Pamela: And this was our first clear indisputable, this is water right here discovery and from there we have simply been debating the details. And the details refuse to clarify themselves. So, I think my personal greatest frustration is the, are they, aren’t they identity of the dark streaks on Mars. Do you have a favorite are they, aren’t they, water story?
Fraser: Well, that, but I think that’s a great example by us being patient and only sort of covering this now, we’ve been able to miss the water’s been found on Mars, oh, probably not water. So, we sort of passed through the whole cycle. Well, let’s explain that, just to give people sort of an idea of what those, are they, aren’t they dark streaks.
Pamela: They’re in a variety of locations on Mars there are these seasonal dark streaks that appear across the surface of the edges of crater, the edges of hills. And because they’re seasonal and because they often appear in repeating places but not exactly the same every year, it was thought, and this was work done by an under grad and a grad student that was really quite solid. It was thought that this might indicate there was seasonal melting and flowing of water across the surface, and there was much rejoicing. But because it’s Mars no-one let such a discovery stay for very long.
So, more researchers came along and found other ways to explain the dark streaks as essentially seasonal avalanches. Little tiny ones, not very exciting ones but it appears that there is not water seeping across the surface creating these dark streaks if you belong one camp and this is water seeping across the surface if you belong to another camp
Fraser: But the evidence now is that it’s just little landslides on the side of these craters that are sort of, they’re at the perfect angle that sand would crumble and fall down to slope. And that’s what they are finding, you get this seasonal change, the temperatures change and it sort of kicks up a little bit of the sand and it falls down in to the crater. And that does seem to kind of nicely explain what’s happening here and it’s not some weird elaborate water pouring out the sides of these craters or maybe there’s some kind of liquid carbon dioxide that’s rushing out and causing these flows, it really does look like it’s just sand.
Pamela: But there are those remaining in the it is water camp. And this won’t be completely sorted out until we can send something to explore the dark streaks. But due to the fact that we have not done a good job sterilizing curiosity or opportunity which are two current rovers on the surface nor could opportunity get to one. Well, yeah, they’re not getting explored anytime soon, so the debate shall continue.
Fraser: Yes. But one thing that is not debate is that there was water on the surface of Mars a long time ago, that was what we found from spirit and opportunity and curiosity showed that that water was on the surface for a long time, in several different ways.
Pamela: And what’s really amazing is looking at all of the different kinds of sediments, the different kinds of soil textures, soil formations that curiosity is observing on the surface of Mars. It looks like a whole bunch of dried out riverbeds. It has that same baked dry cracked mud that anyone who has explored the American south west after the monsoons have seen before. And it’s amazing to think that Mars had these oceans and we’d had hints previously, you look at a lot of the craters on mars and you see what looks like outflow canals. Places where water filled up a crater and then broke through the edge and created a gushing stream or river let out of the crater. So, we’d seen that.
And we wanted to believe this was formed by water but with Mars in situ it suddenly becomes clear, yes, yes, the only way to get these particular structures is with water.
Fraser: yeah, and so they’ve found multiple lines of evidence at this point. They’ve found rocks which can only form with the present of water, the minerals in the rocks. They’ve found structures called concretions which are these little balls that have rolled around and those can only form through sort of water-based processes. And I don’t know if I’ve mentioned this in the past, we have concretion sin the rivers by my house.
Pamela: Oh, that’s cool.
Fraser: But they’re big, like these concretions are sort of basketball sized and so if you find one of them, mostly they’re broken but each one contains a fossil in the middle. And so, the concretion formed around some ancient object, a fossil or something and you take one of these concretions and you smash it and you find a fish inside or you find an ancient leaf or a fern or something like that. And we have a dinosaur, actually it was a plesiosaur here and it was found because the head was in one of these concretions that had rolled out of the side of the bank.
Pamela: So, people just like walk around cracking these open and now I want to have the rovers on Mars like –
Fraser: Cracking open, but there are these little blueberries, these little tiny ones but here like I said, and you don’t find fully spherical ones anymore, they’re almost all cracked open. And it’s not because people have done it, it’s just the weathering process have just cracked them all. So, you very rarely see them in any kind of form. But yeah, absolutely, the next rover should crack open concretions and find fossils inside that would be awesome. And there have been other lines of evidence for water as well and it’s just it’s piling up and piling up. And now, they’re sort of really getting a sense of when and how long and where and so on.
Let’s talk about back in to the mystery area, let’s talk about methane.
Pamela: So, there has been various detections and lack of detections of methane on Mars where it was thought that we were detecting it, some of the orbiting spacecraft saw signs that they were detecting it. But as far as I know the rovers haven’t detected methane, so we don’t know where it may be coming from, we don’t know if it’s geological origins because this is supposed to be a geologically dead world. We don’t know if it had biological origins but this is supposed to be a biologically dead world. So, our dead planet is less dead than we thought and the question is are the rocks alive or are there critters?
Fraser: And both are absolutely fascinating possibilities, right? The fact that Mars still has volcanism going on inside of it and that volcanism is reaching the surface and out gassing is an absolutely fascinating thing. And people thought that Mars was dead for a long time. All right, that’s second to the more interesting possibility that there’s life there that there’s bacteria there. And the really fascinating idea is that it is seasonal, so the curiosity rover detected the stuff rising and falling over the course of the seasons.
Pamela: And that is information I didn’t have.
Fraser: Oh, you didn’t know that, yeah. But it’s not a slam dunk and the other possibility as the temperature rises, it could be that something is thawing and it’s releasing this material. And another possibility is that the rover itself is giving off the methane, that it’s out gassing.
Pamela: We have a farty rover.
Fraser: Yeah, exactly. So, we need a second rover and so on.
Pamela: And what we’ve learned about the volcanos, one of the most amazing things that I saw, was people are now starting to think that valles marineris may have formed when the planet cracked open as a result of how much lava outpoured from those three main volcanos that you can see, even from a backyard telescope. And so, the debate of, was the valles formed with water? Was the valles formed with wind? It turns out, no it’s just the planet cracked open and this is something we see on our own planet. We see in Ethiopia the rift valleys that are actively forming. Now, the reasons are different but this idea of a planet cracking open, well, now we know it happens more than just here.
Fraser: One of the other detections that the curiosity rover made was a very accurate measure of the radiation falling on the surface of Mars. And that’s kind of bad news for people who wanna live on Mars.
Pamela: Yeah. So, we’ve talked about this a lot on this show, one of the biggest issues with trying to get to Mars is all the solar activity that you’re going to be exposed to on the way there. Well, now it turns out that just being there could kill you. And so, our prediction that when humans do get to Mars you’re gonna have to live beneath the surface, well, that’s still true. So, it’s not the world that Elon Musk is going to live on, it’s the world Elon Musk is going to live under the surface of.
Fraser: Right, as long as he and his friends are willing to live in lava tubes or bunkers underground it should all work out okay. And I forget the number, the exact numbers but the curiosity rover when it made its journey to Mars it was equipped with radiation sensors. The RAD experiment and now that it’s on the surface of Mars it’s continuing to measure the radiation and it’s this ongoing galactic cosmic radiation that is streaming in. Not to mention the radiation that’s coming from the sun and we really have no way to prevent either of those. And a solar flare is even worse and there’s just no protection, there is some protection from the atmosphere on Mars but apart from that it’s not as good as being here on earth.
Pamela: Yeah, so, we’re kind of out of luck there. We’re really looking at something that’s kind of the equivalent of 24 CAT scans per 180 days which adds up.
Fraser: You’ll want that, no. And so, this is one of the issues when you think about the astronauts in the future who are gonna be asked to go to Mars and explore. They’re gonna take nine months to get there if they wanna time their return they’re probably gonna have to stay a year on Mars and they’re gonna have to take nine months to come back. Like a journey to Mars and back is a multi-year commitment and it is an increased risk of radiation to go through that. So, people are gonna have to decide if that’s the risk that they’re gonna wanna take. Of course, they’re gonna say yes but I think they need to at least be informed.
Pamela: The way I always look at it, is this is the perfect last journey for your elder astronauts.
Fraser: Send the John Glenns and I’m sure Buzz Aldrin would go back.
Pamela: Oh, totally.
Fraser: And John Glenn went back to space after being a senator and I’m sure if we asked Buzz Aldrin he would totally do it.
Pamela: And what’s kind of interesting is here in the United States we have regulations on exactly how much radiation you’re allowed to encounter within the workplace. And they already have special exemptions for the astronauts, wo it may be that we just need to have more special exemptions for whoever goes to Mars. Because let’s face it workplace safety is gonna have to have slightly different definitions on the red planet.
Fraser: Yeah, what else have we learned about Mars?
Pamela: So, one of the interesting things that’s just come out in the past week actually, is there’s different scientists who are trying to understand the formation of various objects in our solar system from Pluto to Mars to Earth. And a paper that came out just yesterday, talked about how it looks like Mars is made up with a combination of two different kinds of chondroid asteroids that hit and merged and hit and merged. And so, it’s possible that Mars was built up during the age of heavy bombardment. There is another paper that then looked at the formation and this is an older paper.
It looked at the formation of Phobos and Deimos, the two moons of Mars. And that paper said that these aren’t captured asteroids which is what we thought when we first talked about Mars. Instead it’s now considered that just like our own moon Phobos and Deimos were formed when some large object hit Mars, sent a large splash of material in to outer space and it coalesced in to these two potatoes in orbit.
Fraser: That sounds familiar, sounds like something that happened to us.
Pamela: Yeah, we just ended up with a sphere instead of a potato.
Fraser: Yeah, well, because more material, we got hit by a bigger object.
Pamela: Well, we were hit by a Mars sized object.
Fraser: Right and Mars probably wasn’t.
Pamela: Would not have survived that, no.
Fraser: And another fairly interesting piece of research, again, fairly recent, is this idea that Mars is as big as it could have been thanks to Jupiter and Saturn. That they’re influence in the solar system prevented and scattered any additional material from crating in and joining the mass of Mars. So, thanks to Jupiter, Mars isn’t a more habitable planet.
Pamela: And this all comes down to that terrible period where it’s theorized that Jupiter and Saturn were in a two to three residence with Jupiter going around three times for every two times Saturn went around. And during this terrible residence it wasn’t that Jupiter was protecting us it’s that Jupiter and Saturn were sending object in all random directions and destroying things haphazardly as they did this.
Fraser: What else you got?
Pamela: So, at the end of the day I think all that we’re getting out of the atmospheric studies is most intriguing, we’re starting to really understand the mass loss rates that are going on, thanks to Maven, ExoMars is continuing this research helping us realize that without that magnetic field, Mars I continuing and continuing to lose its atmosphere which is both interesting to study and also terrible when you start thinking about we’d like to terraform it and we probably shouldn’t try.
Fraser: Yeah, the most reasonable strategy that I’ve heard explained for how you might do this, is that you would set up like a shield at the Mars Sun L1 Lagrange point, that would block the solar radiation coming from the sun. And then what that would do is that would stop the atmosphere from leaving Mars and you would actually warm up the planet enough that the poles would melt, you’d get a thickening of the atmosphere. But can you imagine the megastructure, but Jim Green the Head of Planetary Science at NASA.
Pamela: He’s actually, the new NASA Chief Scientist.
Fraser: Right. And he pitched that at one of the NASA Planetary meetings and I thought it was great to see that even, normally so, the folks working at NASA, especially in the higher end of the bureaucracy tend to be a lot more conservative about some of their ideas. And it was great to have him putting out one of these, like clearly, it’s like a crazy megastructure to build. But if you want to terraform and make Mars a habitable place, building that alone would take you a lot of the way to getting there. It would prevent the atmosphere loss, make the place a lot better.
Let’s talk a little bit about what people can expect shortly because there is a ton of stuff still making its way to Mars right now, we’re only just getting started.
Pamela: Yeah, the thing that has me most excited is the insight mission which is a lander currently on its way to the red planet. It has two different primary science components. One is a seismometer that is going to look for tectonic activity and for asteroid impacts that cause Mars to shake. There are two different kinds of waves that move through planets they’re called P waves and S waves, name doesn’t really matter. What matters is one of these will pass happily through liquid, changing a bit as it goes, travel times differ. The other will bend around a liquid core, so you can get different arrival times from these two different kinds of waves that are both generated at the exact same place.
And by mapping out a whole bunch of quakes they are either generated by the internal activity of the world or stuff hitting it externally. This will allow us to once and for all answer the question is there any liquid core left in Mars and that’s kinda cool. But what is even more interesting and are I say hot, is the insight mission also has a thermal probe that is going to dig itself under the surface. And I can’t remember a planetary conference that I’ve gone to where there hasn’t been at least one scientist speculating about sub-surface temperatures and where it will be warm enough to support water of this acidity or that saltiness.
And it’s only been speculation because we don’t know the exact thermal properties of the Mars soil. And with insight we’re going to finally get direct measurements. Now, it’s only measurements in one place, it’s gonna land, dig, stay put but it’s one measurement which is still greater than zero. And one of the tantalizing things that occurred to me when we were talking about the Galileo discoveries of ice plumes. Is you can actually sense when you fly through different water by how other things suddenly change and it’s possible that if this little probe digs itself down through water variations in its readings will allow us to detect that.
And I don’t think that’s going to happen but it’s just kinda cool to think about its possibility of happening.
Fraser: And in sort of together with the insight lander, NASA sent two adorable cube sats as well and we got a great sort of pale blue dot and moon image from those which was wonderful. But I love this idea and we’ve talked about this a few times on different platforms in the last couple of weeks. That there’s so much infrastructure built up at Mars now in terms of communication and relaying, that you can start sending the small inexpensive spacecraft all the way to Mars. So, these two cube sats, they would not be able to communicate anything they find back to Earth, but they’re gonna be testing a whole bunch of sort of micro technologies at Mars.
And then use this existing relay network to get that data back to Earth. So, there’s a real value in infrastructure that’s happening at Mars. All right, before we close this up, the big piece of exploration coming soon is gonna be the Mars 2020 rover. Which is gonna be this not exactly a carbon copy of curiosity but it’s gonna be searching for the holy grail, it’s gonna be looking for life.
Pamela: It’s not looking for life it’s looking for complex organic materials consistent with life. But, yes, and it’s going to be picking up and collecting rocks and theoretically some day we’re gonna send another space craft to gather those rocks from the Mars 2020 and bring them back so that we have a cool distribution of different samples that we can study. Now, along with the Mars 2020 rover they are now also looking at sending a helicopter to Mars. I think helicopter may be a strong word, I’m more comfortable saying drone, it’s not a quadcopter or anything cool like that but it is tiny.
And it’s solar electric and one of the amazing things to think about how hard this is going to be, is helicopters that we have here on Earth are really on capable of flying up to 40,000 feet. Whereas the surface atmosphere on Mars is the equivalent of going 100,000 feet up.
Fraser: Right. The rotors on this is gonna turn 3,000 rpm.
Fraser: And it’s got two rotor and they go in opposite directions which is cool. It’s gonna have its own solar panels so it’s gonna be able to recharge itself and be completely independent from the rover. And in theory it’s gonna fly around and scout out the area around the rover and then give operators back on Earth a whole other set of eyes on whether they should be going and what they should be looking at.
Pamela: And one of the use cases for it that deeply amused me, is if there aren’t enough gusts of wind it will be able to use its rotors to clean off the solar panels on Mars 2020. And all of these different things are made possible because of this fleet of aged spacecraft orbiting Mars. The 2001 Mars Odyssey Mission is still there, we still have Mars Express, we still have Mars Reconnaissance Orbiter and all of these satellites –
Fraser: MOM, India’s MOM mission, the European Space Agency, there’s so many.
Pamela: Yeah, and so we have Mars Orbiter Mission, MOM, we have ExoMars which is Europe; we have another mission called Maven from the United States. And all of these missions have that capacity to become satellites for the rovers crawling around on the surface. So, the rover doesn’t have to carry all the capabilities to call back to Earth instead they just call up to orbit and these higher power spacecrafts in orbit are what call home.
Fraser: Yeah, I would love to see more spacecraft, more communications relay satellites at more places in the solar system because then you could send these smaller simpler spacecrafts that don’t need all that big electronic just to be able to communicate. That’s one of, I think, gonna be a really exciting progression shortly. All right, well I think we’ve wrapped up another episode, thanks as always, Pamela. We’ll see you next week.
Pamela: Bye bye.
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Duration: 29 minutes