Mars' Hidden Oceans, Sweat Shields & The Universe's Sudden End

Earth's atmosphere. Because up until now, we've used heat shields and tiles. Now they think they've come up with something completely different. It's called Sweat and the Universe RIP Yep, we're going to see it all end much sooner than we expected. We'll talk about all of that on this episode of space nuts.

Oh, it is a surprise to see you there. I mean, do you like my new background? I'm going to change the background every week on my studio. Professor Fred Watson: I think that's a good idea. Uh, and, um, I do like it. Uh, it's a, uh, place that's close to my heart as well as yours. It's a great place. Well, isn't that the saying, I left my heart in San Francisco. Professor Fred Watson: Yeah, you probably did. That's a photo I took after we crossed the

Golden Gate Bridge looking back to San Francisco. So thought I'd use that as my backdrop today. Professor Fred Watson: The, um, second line of that song is a good one as well. I left my knees in old Peru. Courtesy of the goons. Yes, of course. Yeah. Beautiful city. Really beautiful city. I think I told you about the driverless taxis they've got. But there's so much more going for it. Those cable, uh, cars are

fantastic. Um, we obviously did the tourist thing and did a ride on one of those and then, you know, did the walk down Lombard street, that, uh, zigzaggy street that, um, has become quite famous. And I don't know how many movies and TV shows it's been in, but, um. And it's like all of these things that when you see them on tv, you think, oh, wow, got to go see that. And then you get there and go, oh, it's. It's a lot smaller than

I thought. Ah. But yeah, um, I don't know what the price of a house is on Lombard street, but it's, uh, beautiful homes there. Professor Fred Watson: Yes. But overall, a beautiful city. Beautiful city. I'd go back there tomorrow. Uh, we better get into it, Fred Watson. And our first topic, uh, today is the water on Mars. Or in this case, according to a new theory inside Mars. And we're talking about massive amounts of water. Professor Fred Watson: Indeed. That's right, we are. It's not just a

few drips or drops. Uh, so the story, uh, the star of the story, Andrew, is NASA's InSight spacecraft, which it's almost. It's more than a decade ago now. I think that, uh, Insight landed, uh, you might remember it landed in the Arctic region, region of Mars. And, um, basically did one summer's worth of work. Because we knew that once it got into winter on Mars, the spacecraft would freeze and all the electronics would die and it would pass away, which it did.

Uh, it's still there, of course, but it's inactive. Um, so a great, uh, mission, uh, it had one little, um, hiccup in that the thermometer that they were trying to dig into the ground didn't get dug in. You might remember we covered that on Spacenauts. But what worked a treat was the seismometer. Because it had a very sensitive seismometer able, uh, to listen to Marsquakes. Uh, and, um, Marsquakes are caused by a number of things. Um, impacting, uh, meteorites actually cause a little

quake. And they also think there's some residual. Not exactly plate tectonics, but just slips and slides of fault lines and things of that sort, which also create seismic M data. Yeah. And so this is where the story really starts. Because, um, we know, uh, from other evidence that Mars, uh, Probably between about 4.1 and 3 billion years ago, was warm and wet. Uh, the evidence is in your face in many ways. You can see

evidence of beaches and river channels. And, you know, the northern hemisphere of Mars is much smoother and flatter than the southern hemisphere, which we think is because there was possibly an ocean there. So all the evidence, science, uh, is that during that early period in Mars's history. And just remember that all the planets are 4.6 billion years old or thereabouts. 4.7, something like that. 4, uh.1 billion years is only half a billion years after the

origin of Mars. But, uh, we think that that was more or less the start of when it was a warm and wet world and that lasted for nearly a billion years. A little bit more perhaps. So um, the atmosphere, uh, uh sorry the water on Mars is now no longer on the surface. And uh, that's pretty evident because it's as dry as dust and in fact it's got humidity effectively not quite but effectively of zero. Very, very low humidity. Um so the questions have

always been where did the surface water go? We know that uh because Mars does not have a strong magnetic field it's bombarded intensely by the solar wind, uh and that tends to separate any water uh, vapour uh into its component atoms, hydrogen and oxygen and they then basically waft off into space. And we know that's happening because there's uh, a spacecraft called Marvin or Maven, uh which is still active in uh, orbit around Mars and that can see this stuff all leaking away. So we

know that was part of the story. But um, the planetary scientists who look at Mars in detail say that's not enough. We can't actually account for, for all the water that must have been there by it just disappearing into space. Um, we know some of it's frozen in the polar caps uh of Mars. Um, and probably you know, hydrolyzed minerals. There have been minerals on Mars surface have been affected by water. Uh that's still the case however uh, there must

be more. And there was a calculation done um, I think by the research group that's uh, done this work with the Insights, um, lander which estimates that the water that's gone missing was uh, enough to cover the planet in an Ocean between 700 and 900 metres deep. So that just blowed me away. Professor Fred Watson: Yeah, uh, it's gone um, where. And that's not an

insignificant amount of water. Remember Mars is only half the diameter of Earth so it's not like uh, an earthly amount but it's a lot of water, 700 to 900 metres deep across the whole planet. So uh, where's it gone? Uh and you know, if we can find it, what, what might it be like? So uh, now enter uh insight. Uh and actually I was wrong. It's not a decade ago. It was 2018 when Insight landed uh and uh, did all that super work with its sensitive

seismometer. Uh these scientists looked at the vibrations that come from um, any sort of marsquake caused by as I mentioned before, either slippage in the rock or uh, a meteorite. Uh but you can look very accurately at ah, the um, essentially the types of waves that you're getting because, uh, there are pressure waves and shear waves. I think they're called S waves and P waves in the, um. Uh, in the

jargon of seismometry. But these waves, seismographic waves, tell you something about the material that they are passing through. And that is where this, uh, story has gone. Because these scientists estimate, uh, what they call a significant underground anomaly exists, uh, in a layer between five and a half and eight kilometres below the surface. Because they find that these shear waves move more slowly, uh, in that region. And the most likely

explanation. And remember, that's. That's a layer that's, you know, it's two and a half kilometres, two and a half kilometres thick. Um, that layer they think is likely to be porous rock, uh, like we've got here on planet Earth, uh, filled with liquid water, just a little bit like the aquifers. And we've got a great one here in Australia, the great Artesian Basin, uh, which is. I'm sitting on it, right?

Professor Fred Watson: You're sitting on it. That's right. You are. Are your feet wet, Andrew, or. No, no. We do have, as you know, several bores all over the city here because, uh, we can tap the Great Artesian basin and, and get that water for domestic use. So we. We kind of, um, take water from that source as well as from river. The river is fed by a huge dam upstream which is bigger than Sydney Harbour. Professor Fred Watson: Uh.

And. Yes, that's right, Farendom Dam. So, uh, yeah, we, uh, definitely use the aquifer water from the great artesian basin to supplement the city supply. We are actually drought proof. As a consequence of that, we will never run out of water because we sit on the Great Artesian basin, which basically stretches north to south across the entire continent down, um, this sort of central, um, eastern section. Professor Fred Watson: That's correct, yeah.

Yeah. It's massive. Professor Fred Watson: It is massive. It's like an underground ocean, basically. And that's what we're talking about with Mars. Professor Fred Watson: That's exactly right. And so it's a really nice, um, you know, connection that we have here in Eastern Australia with Mars. Uh, this sort of, you know, um. It's almost. The rock itself is sponge, like in the sense that it holds the water, the liquid water.

And the thinking is, uh, that because it's at a depth, as I said, a few kilometres, between five and a half and eight kilometres, um, the temperature there is warmer than it is on the surface by quite a long way because of just the internal heat of the planet. Uh, and so they think it is actually liquid, uh, and that fits the bill in terms of the seismic waves that they've detected, uh, that you've actually got this liquid water in porous

rock. Um, and what's really nice about this story is, uh, that if that is, um, a global, uh, layer of rock, and it may well be, um, they calculate how much water is in it, uh, and sure enough, it's enough to cover Mars in a global ocean between. Well, the figures they quote is between 520 and 780 metres deep. Just about the same as what they think is the missing water mass on Mars. So this is sense. Yeah, I mean, this is still a maybe, not a definite, but the numbers certainly support it.

That's what's really interesting about this story. Excuse me. And, uh, yeah, the question is, if we go to Mars, and I know you don't like this, but they will probably establish colonies there. If one man has his way, um, will they be able to access it? Could it. Could it actually hold microbial life and could you drink it? Professor Fred Watson: Uh, yes, that's right. I mean, the middle question there, the. The fact that there might be life in it, that's the one

that's so intriguing. Uh, I think, I suspect at that depth you'd struggle to get it. But we do know. And again, this comes from Insight. Um. Uh, no, it wasn't. Insight was. It was Phoenix. Yes, Phoenix was a spacecraft like Insight, uh, which was actually, uh, the one that was in the Arctic. And so. I beg your pardon, I said something incorrect before. The INSIGHT was in the Arctic. Martian Arctic. But it wasn't. It was Phoenix 2 spacecraft which was very similar. Uh, one was for

seismometry. INSIGHT was basically giving us sight of the inside of Mars and M. Phoenix was all about, uh, basically, um, sampling the surface rock. Uh, and, um, we remember those classic pictures, they scraped away the top layer. Of soil and there was ice. Professor Fred Watson: There's ice underneath it. Yeah, yeah, yeah. Um, it was like a kid had been up there with his Tonka tractor and he scraped the top of the dirt and turned white.

Professor Fred Watson: That's right. So, uh, that is in the Arctic region, but that's telling you there's a permafrost of water and there is a huge amount there as well. Uh, but, you know, to find liquid water now, um, whether that's drinkable, probably if you purify it, might have minerals in it that you'd like to get rid of. But, uh, I think it will be drinkable.

Um, but yes, the intriguing thing is, as you said, is whether it could harbour Martian Biology that's uh, really, really interesting. Uh, and, and in that regard, um, you know we've talked about the planetary protection rules before and uh, um, how much of spacecraft has to be sterilised before it's sent to Mars. If it's going anywhere where liquid water could exist,

what it would do. This would mean that we would have to be doubly careful sort of no matter where you're going on Mars because deep under the surface there might well be Martian microbes that wouldn't like earthly microbes if they found their way down through the rocks, so. Oh, uh, absolutely. And, and we've got evidence on Earth of that kind of contamination when like the Spanish went to South America and the South American people um, were exposed to diseases that just didn't exist in there.

Professor Fred Watson: Wipe them out. Wipe them out. Professor Fred Watson: Almost completely similar things happened in our own country. Andrew as well. Yep, absolutely. Professor Fred Watson: Smallpox and things like that. And I should just talking about our country, I should mention that some of this work has been carried out by Australian investigators at the Australian National University

as well as um, uh, scientists at the Chinese Academy of Sciences. Well hopefully there'll be some follow up to um, maybe confirm what they think. As I said, the numbers are stacking up in that favour and it will mean that if uh, that's true, um, Mars is not a dry dead planet. It's probably a water world, but a different kind of water. And we're seeing more and more of that throughout the solar system. Professor Fred Watson: We are indeed. That's right.

Very exciting indeed. All right, if you'd like to read up on that you can uh, see that@the conversation.com website. This is Space Nuts Andrew Dunkley with Professor Fred Watson Watson. Space Nuts. Professor Fred Watson: Speaking of water.

Well not quite but uh, we, we've seen over the entire space ah, race to date, um, which began way back in the middle of the last century, uh, that if you wanted to get a spacecraft back into the atmosphere you had to be prepared for it to potentially burn up uh, unless you put a heat shield on

it. And later those heat uh, absorbent tiles that were made famous by the space shuttle and my son has actually got one of those tiles at his place because he got it as a secret Santa through um, one of the uh, social media websites when they used to do that um, and the warning came do not lick the tile. Well apparently it's very toxic. Um, so um, that's how it's been done to date. But now they've come up with a new idea that basically involves spacecraft sweating to Stay cool as they come back

into the atmosphere. This is really fascinating. Professor Fred Watson: Uh, it's extraordinary. Yeah. And what you've said is absolutely right. Um, uh, the traditional uh, heat shield is called an ablative shield because it ablates the heat, takes it away. Uh, and that means that you only use them once. So um, that's an issue for example with the Orion capsule which is um, going to be reused. Uh, this is the one that will take astronauts to the moon.

Um, uh, and um, it's a pretty large piece of kit and every time you reuse it you've got to replace that ablative shield that's on there. Or ablative shield, however you pronounce it. It's on the back of the spacecraft. That's the bit that burns away, uh, as the spacecraft re enters. Uh, so, um, could you find a way of doing this, uh, which was essentially reusable something else, uh, that would actually protect the spacecraft from the intense heat of

reentry. And it's a team at Texas A and M University, uh, partnering with a private concern called Canopy Aerospace. And they've basically developed uh, a 3D printed substance, um, that releases gas when you've got the heat of re entry. Uh and the reason that's interesting is that gas ah, has a very low conductivity of heat. Uh unlike you know, a piece of metal or something like that which conducts heat very, very well. Gas is pretty poor at conducting heat.

Uh, and it's actually, you know, you've got a lot of uh, you know, why put it. Putting, putting air in the space between your inner and outside walls provides a bit of heat insulation and things of that sort. Uh, it's um, a um,

good heat insulator. So if you can make something that will release gas as it enters the space, uh, as the spacecraft enters the atmosphere, then you might well find that you've got the situation where you've got uh, something that's effect reusable and that you don't have to replace every

time. And it, and the material itself is a, it's a 3D printed silicon carbide, uh, and it is strong and I'm quoting here from the um, Space.com article about this, which is a very nice description, uh, written by Samantha Mathewson a few days ago or a day or so ago. Uh, uh, it's designed to be strong enough to withstand extreme atmospheric pressures, yet poor enough

for the coolant to sweat through. Uh, and uh, she says prototypes are being tested at the university to evaluate the material's ability to sweat and how well, the gas that is released insulates a spacecraft. Uh, so it is. Yeah, um, it's a really interesting step. You know, um, what struck me about this is we've been using these ablative shields since, well, the Mercury capsule back in 1960, whenever it was 62, I think, Mercury, maybe 63. Um, and

they're still being used. They're still on the Orion capsule, which is just a giant version of Mercury in some ways. Uh, and it's great to see people thinking outside the box as to whether we can find better ways to do this and actually create, um, you know, create new materials, given where we've got to today in things like 3D printing, uh, create new materials that can do the job better.

Yeah, I suppose the only way to really test this would be to create this, this new form of shielding and send one up and bring it back and see if it survives, basically. And you wouldn't want to sort of, um, go up there unchecked and go, okay, we're going to test this new. Professor Fred Watson: Yeah, no, you wouldn't, you wouldn't want that. Um, uh, they've used hypersonic, uh, uh, wind tunnels to test it. So, and these are things that blow the wind along at

several times the speed of sound. And so they've got a good idea that this is going to work, I think. Yeah. As we've seen though, with the space shuttle, all it takes is a tiny little crack in a tile to cause a major catastrophe. I'll never forget that. Um, but, but, um, I would imagine with a heat shield type of approach like this, the gas that too could be exposed if one of the vents or whatever it is they use to release the gas fails. Professor Fred Watson: Yes, I guess that's right.

There'll always be, um, some sort of failure, uh, possibility, uh, and the trick is to reduce those as much as possible. Indeed. Uh, well, uh, it will be really interesting to see how this develops. It could, could be one of the, um, the big leaps forward in terms of getting spacecraft back into Earth without having to constantly regenerate, um, shields. Because, uh, that's what happens at the moment. Once a heat shield has been used, you can't

use it again. It's the same with the tiles on the space shuttle. You, you have to replace them after every mission. Apparently, uh, this could be a renewable resource, a renewable approach to the whole thing, which obviously would reduce costs ultimately. And it's still very expensive to get up there, send out your payload or whatever, and then get the hardware back to Earth. So, um, uh, it's Been a long time coming.

We're coming up on 100 years of space flight and it's taken three quarters of that time to come up with a new idea. So fingers crossed that this is actually the answer and who knows what else they might figure out down the track that could do the job. So um, I suppose a question that pops to mind and this is sort of a very dumb question I suppose, um, why can't they just re, enter slowly to avoid the heat? I'm guessing you wouldn't get back in.

Professor Fred Watson: Um, you're limited by, you know, the mechanics of space flight. So um, anything in space that's you know, that's not coming back to Earth is orbiting at uh, nearly eight kilometres per second. And uh, that's why you need such a big rocket to put things into orbit. Because you've got to not only get the height, uh, to two or 300 kilometres, but also to push it into this high velocity with respect to the Earth's surface. And when you come back

you've somehow got to dump that velocity. You've got to kill it somehow. Now you know, I do remember when I used to read Dundeere, the uh, pilot of the future in the Eagle. They, they used um, what they called reactor rockets. So you had uh, the spacecraft was in orbit and then uh, the command that Captain Dan Dare said was blower reactors and that was forward firing rockets that slowed the spacecraft down. And that's what they still do. They fire forward firing rockets

to slow the spacecraft down. But unless you've got the same amount of fuel as you used to put it up there, you can't use that forward firing rocket to gently land it on the planet's surface. You've got to have something else. And uh, that something else is aero braking which is using the atmosphere to slow the spacecraft down. That's traditionally what

has been used. It's the only way we have available at the moment until somebody invents something that doesn't need as much fuel to slow you down as uh, it takes you up there. Well that time will probably come. But for now making your spacecraft sweat could be uh, the new approach. And if you uh, are interested in that story, uh, as Fred Watson said, it'[email protected]. okay, we checked all four systems and team with a go Space Nats.

Okay Fred Watson, our final ah, story today is a very scary one because um, we might not be here next week or maybe it's a billion years. I always get the two mixed up. Uh, but um, on a serious note, uh, some Dutch scientists have come up with a new theory as to when the universe will end. And it is a heck of a lot sooner than we originally thought if they are right. Professor Fred Watson: Indeed it is. Uh, so here are the numbers, okay. Uh, because we might as well start with

that. We used to think

that the universe would die in 10 to the power 1100 years. So that is a one with 1100 zeros after it. It, that's how long we thought it would take to die. The new calculation uh, is only. It's a mere 10 to the power 78 years. And that's 10 followed by, sorry one followed by 78 zeros. Look, that's ah, one heck of a difference, isn't it? It's a factor of more than 10 different uh, uh, it's a factor of more than 10 in exponent, which means that it's a

very much different different. Um, so yes, the universe has only got really a brief period of 10 to the 78 years to last. Um but let's cut to the reason why these scientists are ah, uh, making these calculations. They're um, scientists actually in the Netherlands. Uh, and what they've done is they've looked at Hawking radiation. And that is the, the trick to this, this whole calculation. Hawking radiation is uh, as we know, the rad that

leaks from a black hole. Uh which is a quantum physics effect because uh, relativity says nothing can come out of a black hole. But quantum mechanics says well they can evaporate very, very slowly. And they do. Uh, there's all the evidence suggests that Hawking radiation is a real thing. And so what these calculations are about is how long it takes everything in the universe to come to an end by Hawking radiation. Um, and they don't just cover black holes. They cover everything.

They cover um, neutron stars which are kind of failed black holes. They cover white dwarf stars which are kind of failed neutron stars. Um, and these all have um, a Hawking age. And I think actually um, the original calculation of 10 to the 1100 years was um, um, basically coming from just the lifetime of white dwarf stars does, but uh, the new calculation have uh, have um, essentially said uh, the, the decay time for white dwarfs is uh, sooner than we

thought. Uh, I think actually the white dwarf decay time originally didn't include Hawking radiation. I think it was just how long it takes to cool down to a completely inert object. So um, the new calculation takes into account uh, the basics of Hawking radiation. Um, they've got some nice other figures as well because uh, they can Work out how long neutron stars take to decay. That's 10 to the power 67 years. Um, they can work out how long. Long the moon will take to evaporate by human.

Uh, Sorry, By Hawking radiation. And how long it will take a human to evaporate. And those figures are respectively. Well, they're the same 10 to the power 90. So you and I, as we sit here, Andrew. Yeah. Professor Fred Watson: Uh, we will evaporate in 10 to the power 90 years, which means we actually outlast the universe because the universe is going to evaporate in. In 10 to the 78 years. Uh, so we're, we're doing well there. How can we

outlast the universe? I'm not sure what the answer to that is. Yeah, well, nothing, um, could. If the universe comes to a grinding halt, that's the end of everything, isn't it? Ah, to qualify this, you've got to accept that, um, they're talking about the, the, uh, fading out of everything. That's correct. But the universe will still be there. It'll just be dead.

Professor Fred Watson: Unless, uh, the, you know, the accelerated expansion of the universe results in the Big Rip, which could come a lot sooner than those evaporation times. So you're quite right. This is assuming nothing else happens in the universe. The universe is as boring as anything. Uh, and things just evaporate by Hawking radiation. That's the numbers that you get.

Yeah. And there was one other thing we left out of that, and that was the, um, um, evaporation of brown dwarfs, um, because they're failed Disney actors, so got to take that into account too. And that only takes 88 years. Professor Fred Watson: Okay. Very good. That's a neat calculation. I think you should write. That's up to the conversation, Andrew. It's terrible, Jack. Horrible. Yeah. Um, no, but it is, uh, rather fascinating. Um, so do we

know. I don't know if you said it in number of years, what 10 to the 78 actually means for the universe. Professor Fred Watson: Yeah, well, yes, uh, just means one followed by 78 zeros. It's a long time. Still a long time. Professor Fred Watson: Yeah. And, um, we should be right to. Pay the, the water rates next week then. Professor Fred Watson: That's right. I mean, you know, put it in perspective. Uh, the Earth is probably going to get melted within maybe 4 billion years.

What's that? 4 times 10 to 9 years. So. Yeah, yeah, yeah, that's, uh. That's. That's going to be a much more immediate problem, uh, for us than the evaporation of everything by Hawking radius. That's assuming humanity has actually survived that long, which is totally different. Professor Fred Watson: Yes, we might. Argument, theory, whatever you like. Professor Fred Watson: M yeah. All right. Uh, that story available through fizz.org p h y s.org

if you want to read up on it. It's really, really interesting. Uh, and that brings us to the end. Fred, thank you very much. Professor Fred Watson: Pleasure, Andrew, as always. And we'll speak again soon. I'm sure we will. And, uh, looking forward to it. And don't forget to visit us online at our website and visit the shop while you're there or just have a look around. And that's at, uh, spacenutspodcast.com or

spacenuts IO. Uh, I would have said thanks to Huw in the studio, but he couldn't be with us today because he reached the age of 10 to the 78. And that was the end of that from me, Andrew Dunkley. Thanks for your company. We'll see you on the next episode of Space Nuts. Bye. Bye.