The Ancients - Origins of Water

Episode Date: June 22, 2023

When you envision what Earth was like 4.5 billion years ago, shortly after its creation, images of dust-filled air and raging volcanoes tend to come to mind. However, amidst all that chaos, hidden within the rocks and atmosphere, what if water was also present? Traveling back to the beginning of the Solar System and Earth's formation, it turns out that Earth was partially wet from the start. with water molecules clinging to the asteroids that would later form our planet. So, how do we go about proving the existence of primordial water? And why is it so important to scientists today?In today's episode, Tristan welcomes Dr. Lydia Hallis from the University of Glasgow to delve into the history of water's origins and explain why this research is game-changing. Drawing from research in NASA's Astrobiology archives and Dr. Hallis's own exploration in the Arctic Circle, where she scaled kilometer-high ice mountains with the help of a Red Bull athlete, we explore why the existence of primordial water on Earth is so significant and what implications it holds for the rest of the solar system.Discover the past on History Hit with ad-free original podcasts and documentaries released weekly presented by world renowned historians like Dan Snow, Suzannah Lipscomb, Lucy Worsely, Matt Lewis, Tristan Hughes and more. Get 50% off your first 3 months with code ANCIENTS. Download the app on your smart TV or in the app store or sign up here.You can take part in our listener survey here.For more Ancient's content, subscribe to our Ancient's newsletter here.

Hi, I'm Tristan Hughes, and if you would like the Ancient ad-free, get early access and bonus episodes, sign up to History Hit. With a History Hit subscription, you can also watch hundreds of hours of original documentaries, including my recent documentary all about Petra and the Nabataeans, and enjoy a new release every week. Sign up now by visiting historyhit.com slash subscribe. It's The Ancients on History Hit. I'm Tristan Hughes, your host, and in today's episode we're going further back in time than we've ever gone before on The Ancients. And that's saying something, given that we have done an episode in the past all about the origins of life on Earth. But this time, we're going back 4.5 billion years, roughly, to when the Earth formed from dust and rock. Because our subject today is the origins of water on earth and our guest the brilliant lecturer and

scientist at the University of Glasgow Dr Lydia Hallis. Well Lydia has been researching this topic and she believes that water is present on earth when the earth formed that there is primordial water. The science is astonishing and Lydia explains all so well in this interview. Included also is an expedition, an expedition which Lydia led to the Arctic, to an isolated uninhabited island in northern Canada where she and the team had to confront polar bears and then scale an unstable rock face to quarry, to extract samples of rock where she believed she could find evidence for this primordial water. The results? We're going to have to listen and find out. This was, dare I say, amazing.

It is left field for an ancients episode, but shout out to our producer Elena for suggesting for suggesting it. And it is well worth a listen. I really do hope you enjoy. And here's Lydia. Lydia, it is a pleasure to have you on the podcast today. It's nice to be here. Thank you for inviting me. You're more than welcome. You are the guest for something a little different on the ancients podcast. Now, we go quite far back. We have done an episode in the past on the origins of life on Earth, but this beats it. The origins of water. This feels mysterious, but we can go back almost to the whole creation of the Earth. Yeah, we really are talking the beginning of the

solar system here. Absolutely amazing. And you're the perfect guest for it. But I mean, one other background question before we really delve into it, which is sometimes we get in our mind that water is only found on Earth. Now, that's not quite true. No, it's not. And the more we explore our solar system with various space missions, the more we find water everywhere. It really is ubiquitous, not just in our solar system, but also increasingly with astronomy looking at other solar systems around other stars, we see that there's evidence for water in other solar systems as well. And you also mentioned this before we started recording.

For yourself as a scientist researching this area right now, how great a time is it to delve into this research with new scientific developments and so on and so forth? Yeah, I mean, I am so lucky that I landed up in this job at the right time, I feel, because there are so many, not just missions to other planets, like there are a lot of Martian missions, we have the possibility of Mars sample return within the next decade, but also new technologies that allow us to explore places on Earth that we know

incredibly little about, such as the deep oceans, you know, the highest mountains, the most remote places on Earth that really allow exploration and also scientific developments that mean that we can really explore on an atomic scale the Earth that's underneath our feet. And you also mentioned there, so Martian missions. So how can these missions to other planets, how can they help us in our knowledge about the origins of water, let's say on planet Earth? I always think it's a really good way of exploring the Earth to look at the different planets because they're alternate versions of Earth. Mars is a little bit further away from the Sun. It's a bit smaller. Venus is closer to the sun, it's relatively the

same size, but it's very different from Earth. And these alternate Earths give us an example of what could have happened to Earth if we weren't in exactly the right place, if we didn't have so much water, if the composition of the Earth was slightly different, we would have ended up in a very different place and probably life might not have developed especially if we were closer to the sun there's no one is questioning the fact that there's life on venus we that would be very unlikely well therefore let's delve into earth itself lydia take it away This feels like the ultimate background question to this topic. Talk to us about how we believe the Earth forms. Okay, so we're starting with the small questions. Okay, I'll give you the short version. So our solar system really began as a big ball of gas and dust and the earth formed after the sun formed and after what we call the gas giant planets so planets such as jupiter saturn uranus and neptune so those are the outer planets

that are very gas rich they formed first and then they did this strange thing of moving in towards the sun because the sun is huge. So it has a lot of gravitational attraction and it began to attract these gas giants towards it. Jupiter being the first planet that was attracted, then Saturn. And what makes our solar system special is that we have four of these gas giants. We see a lot of solar systems via telescopes around other stars where there's a star and there is a supersized gas giant very close to its star. So that seems to be quite a common model for extra solar systems, where you have a central sun and then a huge big gas giant that's kind of collected up a lot of the remaining gas and dust that wasn't incorporated into that star. What happened with our solar system was that Jupiter formed and it began to move towards the sun. But then Saturn formed.

So we have two really big gas giants. And as Jupiter rolled in towards our sun, it kind of caused chaos in the inner solar system where there was a lot of the heavier elements making up rocky asteroids and what we call planetesimals, which are essentially large asteroids. It caused chaos, it kind of just steamrolled through this area of rocky material, caused lots of collisions, and yeah, essentially caused chaos. But then because Saturn formed, it pulled Jupiter back out, which is the unusual thing. So normally that wouldn't happen. But because we have Saturn, it kind of pulled Jupiter away from colliding into our star eventually. So as Jupiter

moved back out, it left behind these four larger planets, Mercury, Venus, Earth and Mars, because it didn't steamroller all the way into the Sun, it kind of stopped at around one astronomical unit, which is actually where the Earth is right now. It never got too close to the Sun. And the fact that it moved back out and that we have Saturn is really what makes our solar system really special. Can you therefore explain how Earth forms in the wake of that almost with theced and stuck together from just particles of dust and gas incorporated into that. Towards the outer area of that there may be ice but in the inner solar system we're talking about quite a hot environment. So these are sort of dry particles of dust that have stuck together to form kind of what we would call rubble pile asteroids.

dust that have stuck together to form kind of what we would call rubble pile asteroids. They're not very solid. They're not circular like you think of as planets. They really are just bits of dust and rock stuck together. And as Jupiter moves in towards the sun, it causes lots and lots of these things to smash into each other. And so eventually, the gravity of these collisions would mean that you get bigger and bigger bodies forming more kilometre sized, more things that would be recognisable as large asteroids or smaller planets. moves out again that chaotic rubble pile area has more or less coalesced into four planets so we have more order in that inner solar system environment because jupiter caused that chaos right so it's almost like building blocks and the blocks are being added together and then you get that as you said the dust and rock i mean how far back are we talking when we think that these events occur? So this is the first five to 10 million years of solar system history.

So five to 10 million years sounds like a lot. But if we think that the solar system is more than four and a half billion years old, it's really the first few sort of snapshots of solar system history where chaos happens and then we have relative order after that and the planets kind of stabilize into their orbits that we see today there are a few knocks and bumps along the way but in terms of the inner solar system we go from absolute chaos in the beginning to kind of relative order of things not moving around so much. There is an exception to that, and that's the formation of our moon, which the inner solar system and collided with Earth and actually caused one of the biggest impacts in the history of the solar system and stripped off the top mantle of Earth, was kind of stripped away.

It formed a ring like we see rings around Saturn, a ring of debris around our planet. And then slowly that formed into the moon that we see rings around Saturn, a ring of debris around our planet. And then slowly that formed into the moon that we see today. So the moon is actually at least partially formed from earth material. And the earth is at least partially formed from the material of this Mars-sized planet that came and smacked into us. Well, there you go. It is all absolutely mind-blowing and I'm loving every moment of it and learning so much it also sounds therefore lidia from what you were saying that at this conception stage of earth that the planet it's super hot did that lead many people to believe therefore if you're therefore

thinking of water and evaporation that water came at a later stage? Yes. So because not only the Earth is really hot, but the whole inner solar system environment is really hot during the early solar system, it's difficult to envision that water can really be in its liquid or its ice form, which you would imagine if it's going to sort of condense onto a rocky surface, you need it to be liquid or ice. If it's gas, it's kind of difficult to imagine that it would stick to those early rocky rubble pile style asteroids. And also because even if that did happen, we would have the moon coming and forming

and that whole event, what we call the giant impact moon forming event even if there was liquid water on earth before that would completely vaporize any water that was present on the surface because the whole earth then forms into a molten environment again so we wouldn't have any solid rocky crust at that point. The moon would kind of obliterate any of that. And it's thought that the atmosphere at that time is up to 3000 degrees Celsius. So really hot. If we keep on that argument for a bit, therefore, Lydia, what theories have been put forwards, if water, let's say, did come later as to how water originated on Earth? Yeah, this is the big question. And for planetary scientists, this is really one

of the key questions to try to figure out how our solar system formed and also how rocky planets form in general. There are two main theories. The first is that water was delivered later, after the Earth formed, from the kind of outer part of the solar system where it was cooler and where ice would have been able to form, so beyond what we call the snow line in the solar system. This would have come from outer solar system bodies, maybe such as comets, but more predominantly from water-rich asteroids. And these would have been delivered by collisions during the early solar system, but after the Earth essentially formed dry. The second theory, which is now gaining a bit more ground

and which is the one that kind of I'm more in agreement with, is that Earth was at least partially wet when it formed, in that the building blocks of Earth, even though they did come from the inner solar system, did contain some water and the Earth didn't form completely dry. This is what I've been looking forward to getting to in this episode. So Lydia, if we follow this belief, this theory that there is water at Earth in its primordial stage, how would you go about finding evidence for that? Searching for, I can't believe I'm saying these words, primordial water.

Yeah, it's difficult. The cool thing about water, the molecule H2O, is that it's very sticky. So it tends to stick in secret places within rocks and within minerals. It forms inside. If you think of a crystal, a crystal is never perfect. There are always voids and dislocations in the crystal structure that can fit a tiny water molecule because H2O is a tiny molecule. And what we find is the more that we look at any minerals that we thought were anhydrous, so don't contain any water within their

known crystal structure, the more we do find that there's sneaky water in there. And whether it be only a few parts per million or a few hundred parts per million, if you then add that up to the size of a planet, that's actually a lot of water. And it tends to escape when you reheat those minerals. So if we imagine that Earth formed from these rubble pile asteroids, and that every mineral in those rubble pile asteroids contains a tiny amount of water, when you then put those rubble pile asteroids together into a planet, that planet then what we call differentiates, which means that it remelts. So the reason that planets are spherical is that you add asteroids together and eventually they reach a critical mass where they start to melt under their own friction, under radioactive decay from certain elements.

And heat can't escape from a certain size. And so the whole planet will melt and it will form a liquid magma ocean on the surface. And the interior will form an iron rich core, we get a mantle, and then eventually it'll cool down slightly and we get the crust, which is what we stand on on the earth today, the solid part. But the solid part is only an outer shell. Actually, most of Earth is still molten. And so when you melt those original rubble pile asteroids, the minerals release their sort of secret sneaky water. And actually, we end up with a lot of water just kind of hanging around in the mantle. It gets hot, it forms steam, it wants to escape, we get volcanoes. And then eventually that water will coalesce into an atmosphere. And in the case of Earth, we get liquid oceans.

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medieval world in search of the stories you haven't heard and to get under the skins of the ones you have. Gone Medieval from History Hit, twice a week, every week. Listen and follow on Apple, Spotify or wherever you get your podcasts. okay oceans that feels like almost near the end of it it feels like you said that's the ultimate end isn't it i want to hear more though about this whole research trip that you did, this adventure you did and I know the paper was published quite a few years back in this search for primordial water but it's just so fascinating. I mean talk me through that whole process of therefore searching for evidence of this, you know 4.5 billion years old primordial water in the modern

landscape. Well I first became interested in this when I was working at the University of Hawaii in what was called the NASA Centre for Astrobiology there. So it was really a great bunch of people that were all working together, astronomers, chemists, biologists, and me as a geologist. And we were looking for the origins of life and how the planet formed. And particularly, I was looking at how water came to be on our planet. I got interested in a group of samples that I knew had been collected in 1985. They were chemically a bit strange. So people had determined the different chemical compositions within these rocks and they'd figured out that they were probably from the deep mantle and that there

were signatures of chemicals in there that suggested that they were from a source in the deep mantle that had lain undisturbed for four and a half billion years. So really since Earth's early history. And that really got me excited because at the time I was looking for signs of water in Martian meteorites. And, you know, how did Mars get its water? And I thought, wow, this is actually an opportunity to figure out how Earth got its water, which previous to this I had thought wasn't possible because we live on such a dynamic planet that we have plate tectonics, we have oceans at the surface, we have interactions with our atmosphere that would wipe out any signature of Earth's

original water. But I thought maybe these rocks have kind of trapped and preserved a little bit of Earth's original water. So back in 2015, I made some measurements of these rocks. I only had five rocks. And they showed really promising signs in terms of their water chemistry. So if I explain a little bit about the chemistry, there are two types of hydrogen. There's normal hydrogen, and then there's something called deuterium, which we may be most familiar as heavy water. It's a hydrogen atom, but it's twice as heavy. So it has a proton and a neutron in its elemental structure. And tracing deuterium actually helps us to trace where a water molecule came from in the solar system. So we know that comets have a lot of deuterium, for example.

So if I was looking for original water in these samples and I found a lot of deuterium, the heavy hydrogen, then I would think, ah, well, Earth's original water came from comets. And that wasn't the case. In fact, it was the opposite. There was not very much of this heavy hydrogen in Earth's original water at all. And really, that only points to one source in the solar system, and that's the sun. So it's pointing towards the sun having kicked out things like solar wind and incorporated that into the original building blocks for earth but as I said I only had five samples so what I wanted to do was to go back to the place they were collected and get some more samples. But the place they were collected was very, very remote. It's a place called Palavik Island, which is in the Inuit territories of

Northern Canada. It's an island off of Baffin Island. So it's not even on Baffin Island. It's an uninhabited island that's a few miles across that you have to charter a boat to within the Arctic Circle. And if that wasn't difficult enough, it's riddled with polar bears and the cliffs are almost a kilometre high. So it would involve some very niche skills to get me to the rocks. Okay go on keep going this is a great adventure I mean so what skills did you need to just get to the rocks? So you've charted the boat, you've got to this uninhabited island, you survived the polar bears, you're north of the arctic circle, what are the next steps? Luckily when my paper was published in 2015, I did an interview for a Canadian newspaper and a professional ice climber known as Will Gad, who is a Red Bull athlete.

He's a real professional climber. He read my article and he thought, wow, that sounds cool. So he actually sent me an email in 2020. It may have been 2019. It was pre-pandemic. And he said, hi, I'm Will Gad, would you like to go to Baffin Island with me? And I thought it was a joke at first, because I am a rock climber. And I thought one of my friends was playing a prank on me,

because I knew who Will Gad was. And I thought, this is not real. But it was. And he had kind of read into the science of it. And he was really interested to go on this adventure, but not just for adventure's sake, to actually collect these samples to try and figure out where Earth got its water from. That was what fascinated him. contacts, we really were able to mount an expedition and get to the very difficult places that we managed to get to on Baffin Island. We were also able to get in touch with some locals who were our guides and knew about polar bears and how to avoid interactions and what to do if there were interactions. And there were many interactions with polar bears. So the first day that we were planning on landing on the island in the area that I had suggested, we took the boat around from the base camp, which was on a nice beach. We took the

boat around the headland and we planned to land in an area of sort of rocky terrain and hike up to these cliffs so that I could sample directly from the cliffs because it's important that I get fresh samples so they're not weathered in any way because I want to avoid any ingress of surface water into these rocks. So I was really aiming for the cliff faces and obviously that meant that I had to go to the difficult places. Billy, the boat captain, as we were landing on this beach, he sort of pointed up to the cliffs above to the left of us. And he said, oh, there's polar bears up there. Three polar bears. It's a mum and two cubs. And what he called cubs, they weren't tiny

little cute polar bears. They were almost as big as their mum and then I thought oh okay well we won't be landing there we're gonna go somewhere else and he just kind of went okay bye and he just left us there and I was thinking okay there are I think there were 10 of us and we have three rifles and I thought okay we don't want any interactions with these polar bears we've got f bears we've got flares we've got bear gas but maybe with the guides we'll be okay with three where we outnumber them by the end of the day I think we'd seen 11 polar bears and there was no fence between us and the bears and they were just staring at us from up high we were sort of in the lowlands and every

time we went over a ridge I was thinking oh god what if there's a bear there but I was in very good hands and thankfully we didn't have any scary interactions with them they just had their beady eyes on us quite a lot of the time. So you've got these interesting spectators therefore as you're going about on the mission with your posse of 10 people, getting to that cliff face and then, I guess mining is the wrong word, but extracting those samples. How do you go about extracting the samples themselves? It's difficult in such a remote area because you can't bring anything like a JCB or an electrically powered drill, for example, everything has to be by hand.

So all we had was manpower and some rock hammers. And the difficult thing with these cliffs is they were very high, but they're actually, and what Will would say is probably the most difficult thing, they were rotten. So they're not secure cliffs. They're more like a Jenga pile of huge big blocks that are very unstable. And for a climber, that's an absolute no-go area. Because if you pull on something as you're climbing, it could just come off in your hand. So we had to be really careful about climbing up the cliffs. And then the thing that kind of scared me the most was that I knew I

had to hammer when I was sort of underneath or on the cliffs is the hammering because you could feel the whole cliff kind of vibrating. And so I was sort of hammering a little bit gingerly, bit gently, and nothing was happening because they're quite solid big blocks but they're not really connected to each other and then Will said oh let me have a go and he really started whacking and I just sort of put my hands over my head and thought this is where I die but thankfully we were okay we didn't have any big rockfall events I think Will's very he's a real professional at knowing when to push things and knowing when things are not safe. My mind, I know it's wrong, but my mind immediately goes to like climbing the wall in Game of Thrones or something like that, you know, that kind of

extreme to acquire these samples. I mean, it really does sound like an adventure and a half and it's absolutely brilliant listening. By end of the trip how many rock samples were you able to collect from this you know really difficult to access point of the world so we sampled 27 different locations and i probably have around 30 kilos of rock so we got a relatively sort of big fist-sized chunk from every location. And it was important to sample as many different locations as possible because the original samples that I have, they were collected from the scree slopes at the bottom of these cliffs. So they weren't what we would say in situ in the cliff face. So I don't know which layer of rock the interesting samples came from. So all I had was

my visual knowledge as a geologist, kind of, well this looks like the interesting one that I've got you know back home and really I made a map of the area, a geological map and so I was kind of suggesting places to go where the interesting rocks might be and we were collecting from every different layer which meant that I had to go up and up in the cliff section to get the interesting rocks and sometimes that involved climbing the cliffs. I mean yes in regards to these interesting rocks as a geologist how can you have a look at a cliff face and the rock types and at a place like that and try to deduce right okay this rock that i'm looking at in front of me there's great potential here that it's been undisturbed that this is a

rock that originally formed 4.5 billion years ago you can't you can tell that something is a lava flow that erupted under the water something is a lava flow that erupted under the water. Something is a lava flow that erupted into the air just from the texture and the different minerals that are in there. But really, you can't tell anything about the geochemistry until you get it back to the lab, which is why I had to sample so many locations, because realistically, not all of those locations will have the chemical signature that I want. And there's no way to tell that in the field. We had a field laboratory, which was really useful to give us some idea of the major elements that are in those rocks. So the fact that I'm kind of in the right ballpark, but it wouldn't tell me this has got primordial water in it or this hasn't. For that, you need instruments that are

the size of whole rooms and that cost millions of pounds well we'll get on to that very quickly but last question on the expedition itself how many days in total roughly did you and the team spend up there north of the arctic circle i mean that's in itself i can presume requires quite a lot of training to endure we were there for somewhere between three and two weeks. On the island itself, I think around seven days because just travelling there took three days. So the flight to get to Nunavut, which is the Northern Territories of Canada, and Kikitaravik, which is the town that we stayed in,

was a three-day journey. And shipping in all of the gear And Kikitarovik, which is the town that we stayed in, was a three day journey. And shipping in all of the gear for that, all the tents, all the cameras for the film, all of the geological equipment, that was a mission in itself. We spent around a week on the island at base camp, which is totally uninhabited. So we had to take in all of our food. We had to take in all of our shelter. We had a very sophisticated wooden toilet that was an earth toilet that was built before I arrived, which was great, but was also very scary because it was outside of the bear tent. So when you went to the loo, you felt very exposed. It's something out of a horror movie, isn't it?

Quite something. But you all survived and it sounds like an amazing adventure just to go to that part of the world. But let's keep moving on. Therefore, you've gathered all of these samples. You're back from this expedition. You go to the lab and you've got all of this really expensive equipment and you're looking at these samples. What did the results reveal about them? So we're still developing the results, but I had a really great master's student, Ryan,

who did all of the initial classifications and really looked into the chemistry of the rocks. And it turns out that around half of them are really the chemical signatures that we were looking for. Now the difficult part begins because this is where we have to start looking at their internal water composition and the really parts per million abundances of water that are present within the minerals inside these rocks. That's something that I'm still working on. But in parallel to looking at the water, I'm also looking at the nitrogen content of the rocks. Because if I'm correct, and some of this water comes from the sun, then the sun also has a very specific nitrogen chemical signature. And that should also be evident in these rocks.

Can you explain to us therefore this potential link with the sun because for us it might be feeling a bit confusing because when we think of the sun we think of something super super hot and yet from your research and looking at nitrogen and these other gases you can start to deduce whether actually the sun plays an important role in the origins of water on our planet. Yeah, there's a lot of recent evidence to suggest that the solar wind, which is the hydrogen that the sun is kicking out every day, and that is thrown out into the solar system, the solar wind actually interacts with mineral particles in space. So missions such as the Hayabusa Japanese Space Agency mission to the asteroid Itokawa collected particles of minerals that have been present on the surface of that asteroid for a very long time and have been

exposed to the solar wind. And when those particles were looked at on the atomic scale, it was found that water was actually produced in the rims of these particles purely by the mineral interacting with hydrogen. The mineral contains oxygen. The hydrogen comes in. It's very high energy. Hydrogen atom collides with the mineral and actually produces water on the outside surface of these mineral grains. What's unknown is how long that process takes, how much water it can produce on kind of an asteroidal or a planetary scale. That's still being investigated. But we do know that the sun can interact with these minerals and produce water. It is all so extraordinary. So with these samples, and as you say, the tests are still ongoing, by looking at the nitrogen and you and your students really delving into the detail and using all this equipment to find out as much as you can

with modern technology about these samples, what are you hoping to find out in the years ahead, I guess in regards to water and I guess more generally in regards to these samples? What I'm really interested in is finding out how much water can really be produced by this mechanism of potential solar wind interaction or just the stickiness of water being inside minerals as they form in the solar system, in the early solar system. How much water can we really say is from this solar source on Earth? Is that enough water to produce our oceans or do we need an additional source of water? My feeling is that for Earth, there's so much water here that we probably have had a lot of interactions with water rich asteroids and comets within our solar system because we just know that there are a lot of them hanging around. And it would be counterintuitive to say that none of those asteroids have hit Earth. I'm sure they have. But what I'm interested in is what percentage of water was actually there to begin with. And that's

important when we start to look at planets outside of our solar system. Because if we think about an Earth-like planet in a different solar system, maybe it isn't surrounded by an asteroid belt, as we are with a lot of water-rich asteroids. Maybe there aren't so many comets in that solar system. And maybe it hasn't been so lucky in its interactions with water-rich bodies. So we can't rely on this kind of lottery of delivery of water-rich bodies after the planet formed. But if we can say, oh, well, you know, 50, 60% of Earth's water was actually formed when the planet formed by interactions with our sun, then we know that that other planet in another solar system has a star, it has its own sun. And this mechanism must be going on with that rocky planet in this different solar system. So we

can say, this planet can have X amount of water. Is that enough water for oceans? water is that enough water for oceans and is that enough water for the planet to be habitable and to have life right so this whole study of water can look at potentially how likely it is that there is life on other planets that's absolutely fascinating and i guess that's why this must be such an exciting area of research at the moment lydia because there will be more information coming to light in the years ahead thanks to the research of yourself and others and the development of science. Yeah, absolutely. There are so many space missions at the moment that are looking specifically at Mars as the potential for Mars to be a habitable planet.

Did Mars have an ocean in its early history? Did Mars have life? But also, if we look further out in the solar system, there are missions planned for Europa, which is one of the icy moons of Jupiter. Is there life there? Because we know that there's a lot of water on that moon. Is it capable of being a habitable environment and really looking for habitable environments in places where we wouldn't have thought 20 years ago could possibly be habitable it's so cool and i must admit although my background is humanities and ancient history i'm becoming more and more just enthralled by science the more and more we have a look at it and the more i get older and something like this is just you can't help but just be fascinated by it lydia a couple of things just before we completely wrap up if it is therefore that we have

water at the formation of the earth you know within these minerals in the rock but also as you say because the amount of water that we have that there is probably very much a likelihood of meteorites crashing in and comets which were rich in water contributing contributing to it. How, therefore, do we think water, I guess, almost evolves from that non-liquid state into becoming liquid and then ultimately, you know, oceans and rivers and so on? This is where volcanoes really become important, because the early Earth would have had a lot of volcanoes. And volcanoes are capable of kicking out a lot of gas, a lot of ash, a lot of dust. But mostly things like water would be present as a gas in a pressurized environment in the

mantle and it wants to get out. It really, it builds up pressure. And if you imagine a steaming kettle, that's really what a volcano is. Eventually the pressure of those gas molecules would build so much that they kind of punch through the surface of earth and they form volcanoes. So a lot of gas would escape through volcanic activity during the early earth and that would start to form our atmosphere. So we know there's a lot of water vapour in our atmosphere, oxygen and carbon dioxide, this all comes from volcanic activity. But eventually that water starts to condense when the Earth becomes a more manageable temperature at its surface. Things sort of calm down and then we start to get liquid water.

It's under debate as to how early the Earth's oceans formed, but more or less once you have a solid crust, so you have rock at the surface of the Earth and things start to cool down a little bit, then you would start to condense water into ponds, eventually oceans. And the interesting thing about Earth is that at some point after that, we got plate tectonics. So we have plates that slide and move around next to each other. No other planet that we know of has plate tectonics. Every other planet in our solar system is what's called a static lid, which means it has a crust. That crust doesn't move very much and it stays static and actually we think that water is the big driver there it's kind of the lubricant that makes the plates move and then the water is

dragged down into the mantle recycled and we get thousands of different types of minerals on earth because of that because of this plate tectonic recycling, because of the process of weathering of the crust. And that's all related to water, flowing water, water in the atmosphere. Mars, for example, is a very boring planet geologically. It probably has 10, 15 minerals maximum on the whole planet. We have thousands. And that's purely because we have plate tectonics. And that's probably purely because we have so much water. Well, there we go. As you say, and now two thirds of the planet is covered by water,

which is absolutely insane to consider its origins. And, you know, the work of yourself and your colleagues on this amazing area of research. Lydia, lastly, any expeditions planned in the future? Anything that can beat the isolated, remote, uninhabited island off of Baffin Island in the Arctic? I don't know if I can beat that. Interestingly, but also quite depressingly, there are areas of Greenland that are becoming exposed.

So rock areas of Greenland are becoming exposed because they're no longer covered in ice. Eastern Greenland in particular is connected to that place on Baffin Island where I visited. So it may be that some of these geochemically interesting rocks are actually newly being exposed there. So Eastern Greenland would be a good place for me to visit. There are also a lot of polar bears there though. I need to pick somewhere with less bears. Well best of luck with all of that Lydia, it sounds insane. That's all I can say and it just goes for me to say thank you so much for taking the time to come on the podcast today. No thank you very much for inviting me. It's always good to talk about my research, it helps me reflect on why I'm doing this weird job.

Well, there you go. There was Dr. Lydia Hallis talking all things, the origins of water on earth. I hope you enjoyed today's episode. As mentioned at the start, it is slightly left field for an ancients podcast episode. However, it is absolutely extraordinary. And I hope you enjoyed listening to that as much as I did recording it. Now, last things for me, you know what I'm going to say, but if you've been enjoying the Ancients episodes recently, well, you know what you can do.

You can leave us a lovely rating on Apple Podcasts, on Spotify, wherever you get your podcasts from. podcast on Spotify, wherever you get your podcasts from. It greatly helps us as we continue to grow the podcast and to share these extraordinary stories from our distant past with you and with as many people as possible. But that's enough from me. I will see you in the next episode.