Photo provided by the magazine Nature of a tardigrade, nicknamed the water bear, September 20, 2016
(AFP/HO)
Not even hurt! The tardigrade, a microscopic animal known for its resistance, would be able to survive the consequences of a collision of the Earth with a giant asteroid, unlike Man, ensures a study.
Nicknamed the Water Bear, this strange, claw-clawed, eight-legged animal, measuring about half a millimeter in length, "will survive until the Sun dies," scientists said Friday. Reports.
Thus, the tardigrade can still hope to live for at least 10 billion years - much longer than the human race, the team of researchers from the University of Oxford (UK) and the University of Oxford Harvard University (United States).
On Earth, we find this superchamp almost everywhere, including on some peaks of the Himalayas and in the depths of the ocean.
Considered the most indestructible animal on the planet, the tardigrade - whose name means "the one who walks slowly" - is able to survive for 30 years without eating or drinking. It can endure extreme temperatures, ranging from -272 degrees Celsius to 150 degrees Celsius, for a few minutes.
It supports all kinds of extreme pressures, and can live in the deep sea as in the icy vacuum of space.
It also has good radiation resistance, unlike humans.
Suffice to say that it is a virtual guinea pig ideal to test on computer the ability of life to resist disasters coming from the sky.
"Without our technology that protects us, man is a very fragile species. Small changes in our environment can have dramatic consequences for us," says Rafael Alves Batista of Oxford University, co-author of 'study. "There are many more resistant species on Earth. Life is likely to continue well after our disappearance," he said.
The researchers studied the chances of survival of the tardigrade (Milnesium tardigradum) to several disasters coming from the sky, using several mathematical models.
- Life elsewhere in the Universe? -
A collision between the Earth and a large asteroid should obscure the sky, triggering a kind of brutal "winter", with a sharp drop in brightness and a drop in temperatures. This could be catastrophic for species dependent on light but life will continue near the volcanic chimneys at the bottom of the oceans that will provide heat, according to the researchers.
Only truly massive asteroids, likely to boil the oceans, could threaten the tardigrades. But none is likely to cross the Earth's orbit, the researchers said.
The cataclysmic explosion of a star (supernova) and the bursts of gamma rays (short jets of matter very energetic) would result in intense radiation that would destroy the protective ozone layer. "But life could continue underground," says the study.
And the probability that a massive star explodes close enough to Earth to kill all life forms on the planet is "negligible," she said. Same for gamma ray bursts.
The resistance of lateigrades to cosmic events "seems to demonstrate that life, once it has started, is difficult to eliminate completely," says David Sloan of Oxford University, co-author of the study.
An observation that feeds the hope of finding a day of life elsewhere than on our planet. "It is possible that there are other resistant species elsewhere in the universe," said Rafael Alves Batista.
On Mars, "organisms with tolerance to radiation and temperature similar to that of tardigrades could survive long under the surface," says Abraham Loeb of the Harvard Astronomy Department and co-author of the study.
The probable oceans beneath the surface of Europe, the natural satellite of Jupiter, could also have similar conditions to those of the deep terrestrial oceans where lateigrades.
Le tardigrade, un superchampion qui n'a rien à craindre des astéroïdes
