Antarctica is famous for one thing: [Off

Screen:] Penguins! Well, yes. But I was going  for “It’s covered in ice!” [Off

Screen:] Ice! Thank you. But it hasn’t always been this way. It was only about 38 million years ago that Antarctica’s glaciers started to form.

And it was only six million years ago that everything looked pretty much like it does today. All that ice… which averages  over two kilometers thick… covered up a continent’s worth  of stuff for us to discover. But how the heck do we know what’s down there?

Science has got us covered. [♪INTRO] For starters, you have to know a little bit about what you’re dealing with. Unlike the arctic, where all  that ice is just floating on top of a bunch of ocean, Antarctica  has a lot of land down there. It’s one big old continent,  which split off from the supercontinent Gondwana hundreds  of millions of years ago.

Eventually, Antarctica settled  into its current south pole spot. And there it has chilled, pun intended, undisturbed for about 65 million years. Until, that is, scientists came  along with their trusty… radios?

Well, radio waves, anyway. If  you want to see through stuff, radio waves are one of the best  tools you have at your disposal. More specifically, a radio-wave-based technique called radio echo sounding, or RES.

To use RES, scientists beam  radio waves down through the ice and wait for them to hit the ground below. When they do, they bounce back  up to detectors on the surface. And those bounces, or echoes,  give experts a lot of infomation.

For example, if the waves take  a long time to bounce back after traveling through a bunch of  Antarctic ice, you’ve found a valley. If they come back real fast,  you’ve found yourself a mountain. So by scanning a really large  area, you can create a whole topographical map of a continent buried under ice, and read the history of the land itself.

One map published in 2023 revealed that, back when the buried part of Antarctica  was still the surface, it was riddled with rivers that  carved valleys between mountains. Much like the Colorado River  carved the Grand Canyon, Antarctic rivers were making their paths known. But as things started cooling down, glaciers started to grow on the mountaintops.

And they slowly worked their  way down into the valleys. Over time, these glaciers grew into  the entire ice sheet we see today. In some cases, they’ve actually  preserved the land underneath.

It looks basically like it did  all those millions of years ago. Complete, wildly enough, with liquid water. Yeah, RES doesn’t only find  land.

It also helped scientists find massive amounts of water  beneath the Antarctic ice. And it comes in liquid form  partly because ice is heavy. In some places, the pressure  put on this water is around 350 times the atmospheric pressure at sea level.

That’s more than enough to  keep water from freezing, even when it’s around -22 degrees Celsius. But when RES wasn’t quite good enough to identify all the water they thought might be down there, researchers turned to other  techniques like seismological surveys. In a seismological survey, scientists  track the movements, speeds, and reflections of vibrations traveling  through our planet called seismic waves to measure densities of and  distances to underground areas.

Researchers also made use of  satellite imagery and laser altimetry, where you bounce a laser off of a  surface to measure how tall stuff is. Using all of those techniques  together, scientists have found entire freshwater rivers, some of  which do fun things like flow uphill, and even carve whole caverns  out of the ice above them. They’ve also uncovered  nearly 700 lakes down there!

Both freshwater lakes which  are created by meltwater from all the ice and glaciers and stuff and saltwater lakes made from trapped ocean water. Finding all of that stuff is certainly  cool–pun once again intended– but scientists aren’t content to stop there. They wanted to see what’s inside  all that hidden land and water.

And that requires sampling. Now, truth be told, we haven’t actually managed to sample all that much of Antarctica. A treaty known as the Madrid Protocol of 1991 declared all of Antarctica  to be a nature sanctuary.

If you want to know what’s down there, it can only be for pure scientific reasons. Companies are not allowed to  do the typical invasive surveys to prospect for, let alone extract,  any of Antarctica’s resources. As a result, direct under-ice sampling  is rare.

It does happen, though. Like with Lake Vostok, Antarctica’s  largest underground lake, which is around 240 kilometers  long and 50 kilometers wide, and sits four kilometers under the ice. To get a look at what was in there,  scientists sampled it directly by drilling deep enough to  puncture the pressurized reservoir.

Thanks to the crazy amount of  pressure the water was under, the second the team punctured the lake, water shot up through the  hole and froze into a plug. And eventually, an ice core from that “plug” was able to be taken and analyzed. So, sometimes we can get a direct sample.

But most times, the samples come  from one of two indirect places. The first is the less-than-1% of Antarctica’s surface that isn’t covered in ice. In these exposed rocks, scientists  have found ores for metals like iron, copper, and silver, and even kimberlite, which is the rock that you can find diamonds in.

And if you venture over to Mount Erebus, the southernmost active volcano in the world, you’ll find it spewing gold dust!  Like, over $8000 worth per day! Although researchers have noted  that the rate it spews out gold is lower than other  volcanoes around the world. So if you’re looking to strike it  rich, you might want to look elsewhere.

The second place we can get indirect  samples are formations around the world that used to be connected  to what is now Antarctica. For instance, parts of the  Transantarctic Mountain Range butt right up against where  Antarctica and Australia used to touch during those Gondwana years. As a result, the Flinders Ranges  in Australia are basically made from the same rocks as  the Transantarctic Mountains.

And in the Flinders Ranges, we’ve  found gold, silver, uranium, rare earth minerals…barium…You  name it, it’s probably there. Which means it’s probably in Antarctica, too. But what about when it comes to finding life?

After all, Antarctica is not, and has never been, the “devoid of life except for penguins” hellscape that it’s sometimes portrayed as. It’s gonna depend on how alive you want your life. If we’re talking fossils, the  digging-in-the-exposed-dirt route has certainly borne fruit.

Before their untimely demise coming back from the South Pole in 1912, Robert  Scott and his team found rocks that contained the long  preserved remnants of seed ferns. And back in the 1990s, scientists  started finding dino fossils, too. But if we’re talking living life, we could also go with cameras and robots.

Over the past several decades, a  few different teams of researchers have sent remote control submarines  down through holes in various Antarctic ice shelves to see what was hanging out in the ocean water underneath. Our favorite of these robots  had a jerry-rigged vacuum with a coffee filter over it that scientists used to suck up samples of the life they found. And they found a lot!

Like weird  dangling anemones! And even fish! But non-robot cameras work too,  and they can work even better for exploring the more  constrictive regions of water found inland and disconnected from the ocean.

Down there, researchers have  found thriving critters. And not just a bunch of microbes! There’s macroscopic life, like weird little crustaceans called amphipods!

Researchers have floated a few ideas as to how these communities can sustain themselves. After all, there’s so much  ice sitting on top of them, there isn’t a whole lot of light to fuel the organisms at the base of the food web. For the inland lakes, scientists  still aren’t sure what’s going on.

But for the sub-ice-shelf  neighborhoods, there are a few theories. One hypothesis posits that currents  might be drawing nutrients in from the ocean and distributing  them via those subglacial rivers. Meanwhile, another…perhaps way  weirder…concept, proposes that the underside of the ice sheet might  be leaking rotten organic goo from long-dead organisms that the  now-living organisms could be eating!

That sounds delicious! It certainly doesn’t make  itself easy to understand, but Antarctica is a vibrant, fascinating place with geology and ecosystems. And we’ve barely scratched the  surface!

That icy, icy surface. But understanding what’s going on down there gets more important every day. Because as Antarctica’s ice  sheets melt due to climate change, we need to know what may  happen not just to Antarctica, but to the rest of the world.

The better we understand this alien landscape, the more prepared we can be,  and the better we can try to save this magnificent,  more-than-penguin-populated, place. [♪OUTRO]