What’s hiding under the Antarctic ice?
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We all started looking out that window.

On his first trip to Antarctica, John Priskew couldn't stop staring out that little oval porthole at the cargo plane. This is a whole continent, right? It's covered with ice. It's just white. Most people who've seen all that endless white, they figured it was basically empty. They painted this picture of this awful place for life.

I mean, we all know about the stuff around the coast, right? Penguins, seals, shorebirds. But everybody thought that the rest of the continent was just a big benign block of ice. Which makes sense. Like, it's Antarctica. It's really harsh at the surface. I mean, the average temperature of Antarctica is about minus 60 centigrade. And it's really dry, dark, more than half the year. That's a tough place.

But John's used to tough environments. He's a microbiologist. He studies life that can survive in some of the most extreme places. And when he looked out that window, it didn't seem impossible. You can't have this much real estate on our planet that's lifeless. John knew that if there actually was a ton of life in the middle of Antarctica,

It wouldn't be on the surface. It would probably be somewhere way deeper. Somewhere no one's ever been before. We know more about the surface of Mars than we know about the subsurface of the ice in Antarctica. I'm Noam Hassenfeld, and this week on Unexplainable, is there life miles beneath the Antarctic ice? And if there is, where else might life be hiding? ♪

So, John, intuitively, I would think if you went deep under the ground of an already inhospitable place, it would get more inhospitable. I wonder, how is it possible that life can survive?

In a place that is that cold and no sunlight. Let's go right to the bottom. Some of the largest lakes on our planet are under the Antarctic ice sheet. There's lakes under the ice sheet? Like fresh, like liquid water? Liquid water lakes. Over 600 have been identified. One of the lakes, I think it's the crown jewel of lakes, is Lake Vostok.

It's over in East Antarctica, and that lake is under two miles of ice. The lake is 3,000 feet deep, and it's the size of Lake Ontario. So this lake has been ice covered for more than 15 million years. So it hasn't seen a ray of light or a wisp of wind for 15 million years. And how is it liquid down there? Yeah, now that's the question I was waiting for. How?

How do you get liquid water when the average temperature at the top is like minus 60 centigrade? First of all, you get about a couple miles of ice. Ice is a really good insulator, right? So if you look at the temperature profile in the ice sheet, it starts out really cold and then it warms up, warms up until you get to about zero centigrade or the melting temperature of ice.

Secondly, we have a lot of pressure. So when you put pressure on the system, the freezing point changes a little. So water doesn't freeze at zero centigrade. It freezes like minus one. And then the third and the most important ingredient is just heat flux from the earth. We know there's always heat coming up out of the earth everywhere. Because we have this molten core on a planet in conduction. So we have a little bit of heat.

We have a great insulator from the cold, and we have a little bit of a freezing point depression. It's really a precise system. So how did you get all the way down there and actually study these lakes? Our first expedition was into subglacial Lake Willans under the Willans Ice Stream.

Also, the ice was only like 3,000 feet thick. If we want to go under the Antarctic ice sheet, we get there by melting. So we had to develop a clean drill. It's like a big steam cleaner, a big hot water hose. We had to develop sleds that we could pull and buy tractors. We had to buy like seven tractors.

and get them all the way from the United States to Antarctica, and then drive them for two to three weeks to get out to our field sites, pulling all the loads out, and then make a runway to bring aircraft in. So it was a big effort. So we get out there right at the end of December 2012 and started drilling. The drilling took about a week to get a hole that's about three feet diameter to get our tools in.

And then the drillers popped through and we got into liquid and everyone was just like, this is awesome. There was elation. I mean, you could hear roars from all the tents and everybody in our field camp. There were 52 of us. But then all of a sudden the work started, right? The drillers pulled the drill out, turned it over to us, and we started sampling. The first thing we did was put down cameras to make sure, you know, you got to see something.

And we could see the ice, we could see the sediment on the bottom of the ice sheet. And then we got into the water column and saw the bottom of the lake. So the water was a little off-color, it was a little turbid. The bottom of the ice was very dirty. I remember people said, "Wow, this is not at all what we expected." I mean, we didn't know what to expect, so let's put it in a big frame where it's like, this is all exploration.

And then we sent down a sampling bottle, I guess you can call it, a system. So we brought water up. First thing we did was put it under a microscope, stained it with the water sample with a DNA stain, and we saw cells.

I mean, you're seeing something that, I guess, tell me if I'm wrong, but you're seeing something that no one in human history has ever seen before. That's true. Yeah. Being a polar scientist, it was like the highlight of my career, right? But what surprised me was how much and how diverse it was. It's a thriving ecosystem that lives without sun.

So it's much like a deep sea vent in a way, except it's a cold system. What did the scientific community think? I mean, did people question the findings? Did they think it was impossible that life could live down there? Yeah. For any new discovery, you've got to have extraordinary data.

Think of it as going to Mars and reporting life. You better have your act together. So we wore Tyvek suits. We sampled all of our drill water every day. Is this because you're worried about contamination or something? Yeah, exactly. Like bringing down life from the surface. That's right. Or life from us. So samples went into a clean lab. Everyone's Tyveked up, masked up. And we had to convince the world that it wasn't contamination. But I think we did.

Tell me about the actual life you found down there. What kinds of microbes you found, what they look like. Yeah. So it probably took a month after we brought samples back to really do the hardcore testing

deep sequencing of DNA to really find out who they are and how they made a living. There's no solar radiation down there. There's no energy coming in from the sun, but there is energy in the rocks. Now, plants on the surface of the earth, they use CO2, but they get their energy from the sun. The organisms in the dark

use CO2, but they get their energy from minerals. Okay. So they're just using the chemicals that are already down there instead of sunlight. Yep, exactly. Got it. Like ammonium, methane, iron, sulfur. So they can break those chemical bonds and take energy from them. So what they're doing is then they're mobilizing nutrients. And as these lakes flush to the ocean,

It's actually fertilizing the continental shelf in Antarctica. Are you saying then that there's sub-ice rivers that take this lake water to the ocean? Oh, yeah. In the area where we sampled, in West Antarctica, we're under ice streams where these lakes fill and drain about every decade, and that water flows right out to the ocean.

I teach a lot of biology courses and geology courses, and Earth's biosphere, the definition of the biosphere, never included Antarctica. It took 20 years to

of my life as well as others to convince the people to fund us to do this. And now we showed it. Instead of being a big benign block of ice, we could say that it is a thriving biological community. And it's part of the Earth system. It transforms nutrients to the ocean. It's hosting this whole biodiversity that we don't know about. So now we're finding a whole group of viruses that are unique.

We have bacteria that are quite unique from all the surrounding oceans. So we're just starting to unravel it. But you're saying there's essentially this enormous, hidden,

ecosystem that is shaping the rest of the planet because it is filtering into the rest of the planet and we're just kind of starting to understand and that's the key thing it's it's part of the earth system it's this deep biosphere under the ice sheet and as we're losing our ice we may lose it too so you know it's it's got a lot of ramifications we're just starting uh

John's work has transformed the way we see Antarctica. It's gone from a seemingly lifeless place to one that we know is teeming with life.

But understanding what's down there in one of the most extreme environments on Earth, it might help us understand something way bigger. What life could look like beyond Earth. So now that we understand the life under the ice sheet, it has opened huge doors for me to be part of the NASA exploration to ocean worlds. That's in a minute. Support for Unexplainable comes from 1Password. If you work in cybersecurity or IT,

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Around the same time John started exploring lakes deep under the Antarctic ice, NASA made this groundbreaking discovery. There might be liquid water hiding deep under ice on other planets and moons in our solar system. Like entire oceans worth of sub-ice liquid water. Which means there might, might be life there.

One of the most promising spots is Jupiter's moon Europa. And a few months ago, NASA launched the Europa Clipper probe to figure out just how habitable it might be. Three, two, one, ignition.

And liftoff. Liftoff of Falcon Heavy with Europa Clipper. Clipper took off Monday from the Kennedy Space Center in Florida. Arriving in 2030, Clipper will make 49 orbital flybys of Europa to search for the basic ingredients of life. But NASA needed someone who really knows their way around subsurface ice. So they teamed up with John. And over the last few years, they've been working on a way to figure out if there might be extraterrestrial life.

right here in our own solar system. So tell me about Europa. What do scientists think it's like there? Firstly, it's got an ice shell, a full ice shell. So that ice moves around just like our Antarctic ice sheets do.

The ice is maybe 10,000 feet thick, and then it's got a liquid water ocean under it. You have an iron core at the bottom of that moon that generates heat, right? And at the surface of Europa, there's a huge amount of radiation coming from Jupiter's magnetosphere. It'd be really hard to live there.

But you got this nice, clement environment under the ice, nice, thick, insulating blanket, a heat source in the bottom, some pressure to lower that freezing point a little bit. And there's no sunlight under that much ice. So our subglacial work under the deep ice sheets is a perfect earthly analog to what we would see in the ocean worlds beyond Earth.

I'm curious, you know, what we've learned from the kind of subglacial Antarctic microbes you've studied that could help us find or maybe understand life on Europa. Well, first, we've defined a habitat. That's really important. That could support liquid water in a place you'd never think it would be. We've defined in Antarctica organisms that can survive in this habitat, that eat minerals for energy.

They can transform nutrients. They can live in cold environments. So we've defined a habitat.

What's the actual work you're doing with NASA? What's the research? We're putting robots under ice in lakes that are frozen. We call that rover BRUEY, it's a buoyant rover for under ice exploration. This was developed at JPL with NASA funding. It's positively buoyant and has big wheels on it. It has lights, it can do 360s, and it crawls along on the bottom of the ice. Now what we're doing is putting instruments on a little tail.

to collect data. Because I would hope the follow-up mission to Europa after Clipper will be a lander. Got it. So the Clipper is going to give you a lot of data on the surface so that we can then plan a lander. And then eventually a drill...

to get into the ocean and then to put under ice rovers in and let them collect data. There's no way we're going to make it. A human is not going to walk around on the surface of Europa any time in our lifetime. But we're going to have to have some kind of rover that has like a 10,000 foot drill attached to it? There are many concepts. I've been to many think tanks on how to drill through it. You can't do it like we do in Antarctica with hot water. And, uh,

They'll have to go down and the hole will seal behind them. It'll free shot. And when they break through, they're going to have to open up a little bay. Out comes a little rover, right? You know, and I mean, something's going to go around and swim around. Yeah. So that's what we were doing a concept of in the Arctic with our rover called BRUIE. That's BRUIE. Yeah. Do you have any sense of when...

if something like that could be possible in our lifetime? - Yeah, I do. I think it will be in your lifetime, maybe not mine, but. - Do you think there's life down there? - I do. - Do you think we're gonna find something down there? - I'd be in denial if I said no. Yeah, why not? - You really think there's life down there? - Yeah, so I don't think we're alone. And I don't mean higher life forms.

You know, these ocean worlds beyond Earth have been around since the beginning of our solar system. So to get life to originate, you need time for all these molecules to come together and make complex molecules like DNA and RNA and proteins. You need liquid water. You need nutrients. We think the Europan ocean has nutrients from this satellite imagery, the salts.

I mean, yeah, why would it not? I mean, I'm taking off any metaphysical hats or anything. I'm just looking at pure chemistry and physics. You've got everything to support life out there. And do you think life on Europa could potentially look like the life in the Antarctic lakes? I do, because the environment that we defined in Antarctica looks like it's pretty similar to the environment in the Europan Ocean.

Yeah, it's got all the ingredients. I don't know, just the idea of...

Antarctica being an analog for a moon of Jupiter. Pretty cool, huh? It makes me feel like there are parts of Earth that are as unknown as Europa, that are as alien as Europa, that there's so many parts of this planet that we still don't know. I mean, you're talking about a completely hidden ecosystem that is shaping our biosphere. I wonder if the connection between your research here at home

and the search for alien life, does that make you think about Earth differently? For sure it does. Now, when I'm out in the deep field and I'm walking in the same area where Robert Falcon Scott walked, I've been there walking, you know, and I just know that under my feet, it's teeming with life, just huge amounts of life. Maybe I feel a little more at home by that. It's a little more habitable.

I would have not thought that before. And if we found life beyond Earth, not little green man, not the purple blob, but a whole microbial system that's with organisms similar to Earth or even different, I would hope that the human population would be humbled for at least 10 minutes by the fact that we're not alone.

This episode was produced by Mandine Nguyen. It was edited by Meredith Hodnot, who runs the show, mixing and sound design from Christian Ayala, music from me, and fact-checking from Anouk Douceau. Thomas Liu is working on a universal translator. Bird Pinkerton is making her way back to the octopus hospital. And we're always grateful to Brian Resnick for co-founding the show.

We've also got some news this week. This was Mandy Nguyen's last episode on the show. She's been with us almost since the very beginning, and we couldn't have made this show what it is without her curiosity, her incisiveness, and above all, her empathy. When I think of Mandy's contributions to our show, I always think back to the time she flew to Texas to search for a lost species of salamander. She went swimming in an underground cave in

And afterwards, she sat down and collected her thoughts. Pure darkness. All I can hear is our breath and the light splashing of water. I stop feeling cold. I don't notice my own short breath. I can't register anything. For a moment, I feel myself disappear, dissolving into the dark world of water and salamanders. Mandy is an adventurer at heart.

And she cares so deeply about understanding the world around her. Everything from mushrooms to the Mariana Trench. But most of all, she cares about people and their stories. Thanks for everything, Mandy. If you want to tell us how much you love Mandy, or if you have any other thoughts about the show, email us. We're at unexplainable at vox.com. You can also support this show and all of Vox's journalism by joining our membership program today. You can go to vox.com slash members to sign up.

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