00:00This elegant and ultra-modern submarine, named RAN, was sent to explore the depths of Antarctica.
00:07However, shortly after its first discoveries, it mysteriously disappeared.
00:11So, what really happened?
00:14It all began when scientists wanted to explore one of the most remote and enigmatic places on our planet,
00:21the Dodson barrier, located in Western Antarctica.
00:25This silent colossus stretches over 50 kilometers wide,
00:29almost the length of New York,
00:31between two frozen promontories, the Martins and De Beers peninsulas.
00:35It contains an entire world of geological mysteries.
00:39If you think Antarctica is just a thick snow and ice desert, you are wrong.
00:44Real unknown landscapes are hidden under this frozen layer.
00:49The lower face of the Dodson barrier presents an accidental and dynamic terrain,
00:54shaped by the slow and relentless forces of nature.
00:57There are imposing ice formations, deep crevasses and strange structures,
01:02stretching over hundreds of meters.
01:04Scientists are extremely curious about this territory.
01:08However, as you can imagine, this environment is not an easy war to explore.
01:13To learn more about it, we would have to scan the region via satellites
01:18or try to pierce the ice to gather, piece by piece, the whole panorama.
01:23Unfortunately, these methods only offer vague and incomplete clues.
01:27The real breakthrough happened when scientists had the idea to send submarines
01:32to explore the Dodson barrier.
01:34Thanks to autonomous submersibles capable of diving under the ice,
01:38they are able to reveal what is really hidden in the depths.
01:42These robotic explorers are equipped with impressive sonar systems.
01:46This is what bats or dolphins do.
01:49They use sound to see the world.
01:52In short, they emit sound waves underwater,
01:55and when these waves hit an obstacle,
01:57such as the ice barrier above or the seabed below,
02:00they reintegrate the system.
02:02Animals feel the time that the sound waves take to return
02:06and the changes they undergo,
02:08which allows them to locate and interpret their environment.
02:12For example, the clicks that dolphins emit tell them where the fish are.
02:17We have reproduced this fascinating evolutionary trick
02:20and adapted it to our underwater exploration.
02:23However, our version is much more efficient,
02:26offering an increased level of precision
02:28that allows us to create detailed 3D maps of the environment.
02:32Submarine RAN was one of these robotic explorers.
02:36It owes its name to the Nordic deity of the sea.
02:39RAN had been meticulously programmed to navigate
02:42through the dangerous landscape of Antarctica.
02:45Despite its in-depth training,
02:47its mission ended unexpectedly and mysteriously.
02:51In 2019, RAN was sent to explore the depths under the Dodson barrier.
02:56It was a real hero,
02:58the first to undertake a mission of this type.
03:01The team described it as an expedition on the other side of the moon.
03:05For 27 consecutive days,
03:08it operated relentlessly,
03:10traveling 1,000 kilometers under the thick layer of ice,
03:13the equivalent of a trip from Paris to Berlin.
03:16RAN has crossed limits far beyond what anyone could have imagined.
03:21At one point, it reached more than 16 kilometers
03:24in the belly of the glacier.
03:26And what it discovered there was amazing.
03:29Scientists expected smooth and uniform ice surfaces.
03:34But RAN revealed an underground marked by vast cracks,
03:38crevices,
03:39formations resembling sand dunes frozen in time,
03:42Finally,
03:43he spotted mysterious patterns in the form of whirlpools and drops of water.
03:48Everything seemed more to belong to art than to geology.
03:51This actually tells the story of the ice platforms and the ocean around them.
03:56Hot water infiltrates under the ice and melts it below.
04:00Sometimes it smooths the ice,
04:02but other times it digs its strange and irregular shapes,
04:06resembling patterns or drawings.
04:08Some of these shapes are gigantic,
04:11more than 400 meters long.
04:13This is equivalent to three football fields and a half.
04:16The reason why they look like whirlpools
04:19is that the earth is spinning.
04:21This makes the water move in a particular way,
04:24bending the shapes and drawing its spirals.
04:27This effect is called the Coriolis effect.
04:30Imagine that you are driving and that you are throwing something,
04:34like a ball.
04:35It would follow a curve,
04:36and not a straight line.
04:38The same phenomenon occurs with water on earth.
04:41Later, scientists discovered similar patterns
04:44in other Antarctic ice platforms,
04:46although those under Dodson are much more spectacular.
04:49However,
04:50Ran also made a terrifying discovery.
04:53It turns out that these hot waters,
04:55in addition to being of great artists,
04:57also represent a serious danger.
04:59The Dodson barrier does not float peacefully on the sea.
05:02It is part of a very delicate system
05:05and acts as a protective barrier,
05:07held by vast glaciers in Western Antarctica.
05:11Although floating on the ocean,
05:13it remains connected to the earth.
05:15When hot water infiltrates and melts the ice,
05:18the platform can no longer hold its anchor to the earth
05:21in such a firm way.
05:23The protective barrier then begins to weaken,
05:26which allows the glaciers located behind
05:28to flow faster towards the ocean.
05:30When these glaciers reach the sea,
05:32they add water to it,
05:34which could lead to an elevation of the sea level
05:37and potentially redraw our coasts.
05:39Ran came across vast pockets
05:41where the ice melted at an alarming rate,
05:44due to powerful underwater currents.
05:47It was like seeing a clock ticking inside the glacier.
05:50The stakes were high,
05:52but fortunately, the submarine was ready.
05:55This time, he managed to return safe and sound.
05:58Then, he continued to operate for five additional years,
06:02helping scientists with an impressive amount of precious data.
06:06These missions were perilous.
06:08Ran could sink into the dark cavities under the glacier,
06:13spending 24 hours without communication.
06:16But he mapped each summit and each valley,
06:19and he accumulated experience
06:21thanks to more than 40 missions under the ice.
06:24Then, at the beginning of 2024,
06:26Ran undertook a mission to the Thwaites Glacier.
06:29These objectives were bold from the start.
06:32This place is also sadly nicknamed
06:34the Glacier of the Apocalypse.
06:36It is called that because it melts slowly
06:38and could cause an ascent of the oceans of the globe
06:41if it collapsed,
06:42leading to large-scale disasters.
06:44This is why Ran was rushed to explore these depths,
06:48a place that had never been mapped
06:50with so much detail before.
06:52The goal was to discover the secrets of the glacier,
06:55to study its rapid melting
06:57and to understand why it was degrading so much.
07:00It was the second time that Ran explored the Thwaites Glacier.
07:03During the previous visit,
07:05he had become the first submersible to map the below.
07:09Ran ventured to depths ranging from 2 to 500 meters,
07:13and he transmitted numerous data
07:15on how the Glacier of the Apocalypse
07:17melted slowly due to hot ocean currents.
07:20But as he ventured into these icy depths,
07:23something happened.
07:25Without warning, Ran disappeared from the radars.
07:28He left no trace.
07:30For a moment, he sent crucial data,
07:33and the next moment he had plunged into the abyss.
07:36No distress signal,
07:38no final transmission,
07:40and he never returned to the planned point.
07:42Intensive research has been launched.
07:45Helicopters were hovering above,
07:48while drones were hovering in the icy sky.
07:51But no sign of the submersible
07:53manifested itself under the ice.
07:56After a while,
07:58Ran's batteries were probably exhausted.
08:00At this stage,
08:02he had certainly been swallowed by the abyss
08:04under 450 meters of ice.
08:06It was a great and sad loss
08:08for the scientific team.
08:10Researchers at the University of Gothenburg
08:12are now trying to replace Ran
08:14and continue their research under the Thwaites Glacier.
08:16To this day,
08:18scientists have no certainty
08:20about what really happened.
08:22Some think he could have been trapped under the ice,
08:24while others believe he was carried away
08:26by an invisible current.
08:28It could also be that
08:30something unexpected happened to him.
08:32Whatever the circumstances of his disappearance,
08:34it left scientists stunned.
08:37And it seems that the ice barrier
08:39will continue to keep its secrets for a while.
08:41At least,
08:43we have accumulated a treasure of knowledge
08:45thanks to Ran's journey.
08:47Scientists continue to explore Antarctica,
08:49looking for the history hidden under the snow.
08:51They have thus discovered
08:53that about 90 million years ago,
08:55a luxurious temperate forest
08:57flourished near the South Pole.
08:59They have revealed an ancient world
09:01much warmer than they imagined.
09:03In the depths of Antarctica,
09:05they have exhumed fossilized roots,
09:07pollen and spores
09:09preserved in the soil.
09:11This shows that a rainforest flourished
09:13despite months of polar night.
09:15And all these discoveries
09:17benefit our understanding of the Earth's climate,
09:19past and future.
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