00:00It is a place of absolute silence, uh, you know.
00:04Down here, deep beneath the ice of Antarctica, there is no wind to howl across the plains.
00:10There is no sunlight to cast a shadow.
00:13No birds call out across the frozen expanse.
00:16There is only the immense crushing weight of ice, a solid blue-white ceiling that can be miles thick.
00:23For millions of years this world has remained hidden from our view.
00:26A secret locked away in the deepest freeze on our planet.
00:32We once thought it utterly lifeless, a sterile desert of unimaginable cold.
00:37But we were wrong.
00:39Beneath all that ice, something stirs.
00:42There are vast, hidden lakes, and within them, the possibility of life.
00:47This is a realm unlike any other on Earth.
00:50Imagine a landscape buried so deep that the sky is just a distant memory.
00:55The pressure is immense, hundreds of times greater than at sea level.
01:00The darkness is total, an eternal night that has persisted for geological ages.
01:05So, what exactly are these extraordinary hidden features?
01:09A subglacial lake is a body of liquid water trapped between the bedrock of the continent,
01:15trapped beneath the vast ice sheet that covers it.
01:18Think of it as a lake with a roof made of solid ice, a roof that can be over two miles thick.
01:24The enormous weight of ice acts like a giant insulating blanket.
01:29Antarctica's surface is the coldest place on Earth yet the ice traps, geothermal heat rising from the planet's core.
01:37That gentle warmth melts the very bottom of the ice sheet, creating and sustaining these hidden bodies of water.
01:44They are the result of a dance between cold from above and warmth from below.
01:50These lakes are not small ponds.
01:53Some are truly colossal.
01:55Lake Vostok is one of the largest lakes on Earth comparable in surface area to Lake Ontario.
02:01How do we find something that is buried under miles of impenetrable ice?
02:05We cannot see these lakes, so we must find other ways to sense their presence.
02:10The primary tool for this detective work is radar.
02:14Scientists in specially equipped aircraft fly in precise grids over the ice sheet, sending radio waves down into its depths.
02:22Ice and rock reflect these waves differently than liquid water does.
02:27When the radar signal passes through the ice and hits a body of water, the returning echo is flat, bright, and strong.
02:35This tells the researchers below that they have found a lake, and they can even map its shape and depth.
02:42Another ingenious method involves using satellites orbiting high above the Earth.
02:48These satellites can measure the height of the ice surface with incredible precision, down to a fraction of an inch.
02:54When a large subglacial lake fills or drains the ice sheet above it, will rise or fall by a tiny amount.
03:01By tracking these subtle movements over time, scientists can watch the plumbing system of Antarctica in action.
03:09They can see water moving from lake to lake, revealing the hidden connections that link this underground world together.
03:16It is like detecting the faint breathing of a sleeping giant.
03:20If life exists in these dark, cold lakes, it must be a very particular kind of life.
03:25It cannot be like the plants and animals we know.
03:28Without sunlight, there can be no photosynthesis.
03:31The entire food web must be built on a different foundation.
03:35The life forms that could survive here are microbes, tiny, single-celled organisms.
03:41Many are what we call extremophiles, a word that simply means, uh, lovers of extremes.
03:48These are the hardiest life forms on our planet, bacteria and archaea, that thrive in conditions that would be instantly fatal to us,
03:57from the boiling water of volcanic vents, to the high salt brines of desert ponds.
04:03So how do they get their energy?
04:06Instead of using sunlight, these microbes may perform chemosynthesis.
04:10This is a remarkable process where an organism gets its energy by breaking down chemical compounds found in its environment.
04:18They essentially, you know, eat rocks.
04:21The discovery of life in Antarctica's hidden lakes would be a monumental achievement for science,
04:26but its implications reach far beyond our own planet.
04:30These lakes are a remarkable analog for environments we believe exist elsewhere in our solar system.
04:36The conditions here, a liquid water ocean trapped beneath a thick protective shell of ice,
04:43are precisely what we expect to find on several distant moons.
04:48Jupiter's moon, Europa Saturn's moon, Enceladus, are both thought to harbor vast global oceans of liquid water,
04:57warmed by tidal forces and hidden beneath miles of ice.
05:01They are, in essence, scaled-up versions of Lake Vostok.
05:06This connection is the driving force behind a field of science known as astrobiology,
05:12the study of the potential for life beyond Earth.
05:16If we can prove that life can arise and sustain itself in the dark, cold, high-pressure environment of a subglacial Antarctic lake,
05:24it dramatically increases the probability that life could also exist in the hidden oceans of Europa, or Enceladus.
05:31Finding microbes under the Antarctic ice would provide a powerful proof of concept,
05:37and that wherever we find liquid water, even in the darkest corners of the cosmos, we should look for it.
