00:00Of all the creatures on our planet, this one could well be the only one capable of surviving in the extreme conditions of Mars.
00:06The Tardigrade.
00:08These little creatures are also called water bears or foam pigs because of their unique appearance.
00:14They are literally found everywhere on Earth.
00:16Coastal dunes in the mountains.
00:18Luxurious Amazonian tropical forests in the arid landscapes of Antarctica.
00:23Although some Tardigrades live on Earth,
00:26these creatures need a thin layer of water around their bodies to ensure gaseous exchanges and maintain their hydration.
00:32This is why they prefer moist soils, moss or water-covered foliage.
00:36As aquatic animals, they generally prefer soft water environments such as lakes, rivers and ponds.
00:43You have probably never met these incredible animals before
00:47because they are only just half a millimeter long, they are barely visible to the naked eye.
00:52But being practically immortal, they have also developed exceptional survival techniques.
00:58If we embarked them on a small spaceship to send them to Mars, they would first be somewhat opposed by the temperature.
01:06Of course, they can survive in an extremely large thermal fork, ranging from less than 272 degrees Celsius to 150 degrees Celsius.
01:14Yet, Mars may seem hot in the picture, but in reality, it is much colder than Earth.
01:20Indeed, the temperatures there are extremely low, because Mars is further away from the Sun and has a fine atmosphere,
01:27which means that they can go down to minus 129 and climb up to 21 degrees Celsius.
01:33For comparison, on Earth, the lowest temperature was recorded in Antarctica with minus 89 degrees Celsius,
01:40while the highest was recorded in California, in the state of Indio, at 56 degrees.
01:47Tardigrades are also very resistant to high pressures.
01:50They can withstand a pressure six times higher than that found at the bottom of the ocean.
01:54Indeed, for every 10 meters traveled under the surface, the pressure doubles.
01:59Thus, at a depth of 3,800 meters, the pressure is 383 times stronger than at the surface.
02:07In the deepest areas of the ocean, it can even reach 1,100 times that of the surface.
02:13The pressure on the Red Planet is about six times higher than that of the ocean abysses.
02:18This would not facilitate the adaptation of these little creatures.
02:22They should evolve over the next generations to become even more resistant and thus be able to survive under the conditions of the planet Mars.
02:31Food would also be a major problem for them.
02:34Some tardigrades feed mainly on plants such as moss, algae, or some flowering plants, accompanied by some bacteria.
02:42Others are carnivores, and consume smaller tardigrades or other microscopic organisms.
02:48However, they would not find anything like that on Mars.
02:51They would therefore need to equip their small spaceships with sufficient food reserves
02:56that they could suck through their tubular mouths.
02:59Another challenge would be water.
03:01The Red Planet is now a dry and dusty desert.
03:04Although the dried-up reefs and deltas testify to a past where water flowed to its surface,
03:10we have long sought to understand where this water could have disappeared.
03:13But it is likely that a large part of this ancient water was trapped in the minerals of the Martian crust.
03:20Previous studies suggested that most of this water escaped into space
03:25when solar radiation had disintegrated the atmosphere of Mars.
03:29However, more recent research has shown that only a small amount of water escaped,
03:34while the bulk was still present, concealed, and waiting to be discovered.
03:39A few years ago, researchers discovered traces of hydrated minerals on the slopes of Mars,
03:44where they observed strange dark trails that seemed to flow down.
03:49This phenomenon occurs mainly during the hot seasons, and disappears when temperatures drop.
03:54These seasonal flows on Mars, also called equatorial dark flows, or RSL,
04:00could be proof of the presence of liquid water on Mars.
04:04Scientists have found some minerals that reinforce this hypothesis.
04:08They can lower the freezing point of water, a bit like salt on icy roads.
04:13This is why they think that a shallow underground water flow could be responsible for these trails.
04:18Tardigrades, presumably endowed with exceptional instincts,
04:22could detect the presence of water on Mars well before us.
04:25And even if they did not reach it immediately, they would have strategies to survive for a while.
04:31For example, when they lose 99% of their water content,
04:36they can put most of their vital functions on hold and remain in this state for several years.
04:42These creatures can absorb extremely powerful impacts that would crush other animals, including humans.
04:49They also resist levels of radiation so high that it would be fatal to anyone.
04:53If one day we send tardigrades to Mars, it will not be their first space adventure.
04:59In 2019, a probe named Beresheet was sent to the Moon, carrying thousands of tardigrades,
05:05the first lunar library, samples of human DNA,
05:09and an archive the size of a DVD containing 30 million pages of information.
05:13The goal was to create an archive of all the knowledge accumulated by humanity.
05:18But a few seconds before the landing,
05:20the mission control center lost contact with its ship, which crashed on the lunar surface.
05:26The team wondered about the fate of its cargo.
05:28After many debates and analysis, it was assumed that the library had survived.
05:34And even more incredible, that the tardigrades had perhaps also survived.
05:39In this state of dehydration, a kind of dormancy,
05:42the tardigrades hatch in small balls.
05:45They reduce their metabolism and expel most of the water from their bodies,
05:50waiting for a more favorable environment to become active again.
05:54These creatures can remain like this for decades and survive in extremely harsh conditions.
05:59And it was not the first space adventure of the tardigrades.
06:03In 2007, a team of scientists had sent a group of these little water bears,
06:07orbiting the Earth, outside the photon M3 rocket, for about ten days.
06:13They showed remarkable resilience,
06:15given that 68% of them survived the return to Earth.
06:20Scientists do not focus only on tardigrades.
06:23They also test other forms of life likely to survive on Mars.
06:27An experiment called Biomex was conducted on the International Space Station.
06:32Tiny organisms, such as algae, bacteria, and other similar creatures,
06:38were continuously exposed to extreme space conditions for 18 months.
06:43This included enormous temperature variations, intense radiation, and space vacuum.
06:49Surprisingly, many small forms of life survived these conditions,
06:54and came back to Earth as true heroes of space.
06:57They could therefore probably face the challenges of Martian life.
07:01Scientists have also studied the arches of ancient microorganisms
07:05present in saltwater for more than 3.5 billion years.
07:09Some of their Arctic cousins have survived similar conditions to those of space.
07:14But life on Mars may not be anything new in itself.
07:18Billions of years ago, the red planet probably looked like Earth,
07:22with the presence of water, an essential ingredient in life.
07:26Scientists believe that small organisms called methanogens could have thrived there.
07:33These organisms hid under the surface to protect themselves from severe radiation.
07:37They breathed hydrogen and carbon dioxide, expelling methane.
07:41By consuming hydrogen, a powerful greenhouse gas at the time,
07:45they could have excessively cooled the planet.
07:49It is therefore possible that these ancient microbes are still prisoners of ice,
07:53deeply buried under the surface.
07:55They could be plunged into a deep sleep,
07:57waiting for more favorable conditions to wake up,
08:00or maybe new friends from Earth.
