This eight-legged ‘freak’ animal will survive on Earth until Sun dies

Paris: The eight-legged animal is the world's most indestructible creature after scientists discovered that the creature will be alive on the Earth until the Sun dies.

According to a study published on Friday, the tiny tardigrade will continue to survive for at least another 10 billion years.

Also known as a water bear or moss piglet, the eight-legged animal can live in water or on land and in extreme pressure high or low. It can withstand sizzling heat, freezing cold, and high radiation, 30 years without food, and even being dried to a crisp.

It is considered the world’s toughest animal, despite its diminutive size which is under a millimetre (0.04 inches).

Researchers from Oxford and Harvard said that the tardigrade will survive all foreseeable astrophysical catastrophes -- asteroid strikes, exploding stars (supernovae) or gamma ray bursts -- and “be around for at least 10 billion years.”

That is far better than the diagnosis for our own species.

Rafael Alves Batista of Oxford University, a co-author of the study in the journal Scientific Reports said, “Without our technology protecting us, humans are a very sensitive species. Subtle changes in our environment impact us dramatically.”

“There are many more resilient species on Earth. Life on this planet can continue long after humans are gone.”

Batista and a team set out to determine what kind of a catastrophe would be required to wipe Earth clear of all life.

And they found it would be nigh impossible -- once life takes root, it is surprisingly difficult to eradicate.

Supernovae or gamma-ray bursts, electromagnetic explosions that happen in other galaxies, could deplete the Earth’s protective ozone layer which protects us from radiation. But life could continue below ground, and deep under water.

And on Mars?

Even a complete loss of atmosphere would not affect species on the ocean floor.

A large asteroid strike could cover the Earth in a cloud of Sunlight-blocking dust, causing temperatures to drop and a so-called “impact winter”.

Creatures dependent on light would die off, but in volcanic vents in the deep ocean, life would continue.

No space rock big enough to cause a complete species annihilation is on a collision course with our planet, the team found.

 

Nor are there massive stars or potential gamma ray sources near enough to boil Earth’s oceans if they erupted.

The only event that would kill even the tardigrades, is when the Sun eventually burns out.

Co-author David Sloan said,“Although near supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected.”

Tardigrades have a body divided into four segments, each with a pair of legs ending in sharp claws.

They live in moss, on plants, in sand, in fresh water or in the sea.

Water bears can survive temperatures as high as 150 degrees Celsius (302 degrees Fahrenheit) and as low as minus 270 degrees Celsius (-454 Fahrenheit).

They can come back from being dried out to a lifeless husk for decades, and withstand near-zero pressure in outer space as well as the crushing depths of the Mariana Trench, 11 kilometres (seven miles) below sea level.

They can survive radiation up to 6,200 gray (Gy). A dose of 6 Gy can kill a human.

The tardigrade’s extreme resilience points to another tantalising possibility -- the existence of life elsewhere in our Solar System in places once thought too hostile.

If a tardigrade can survive these extreme conditions, then so may other creatures beyond Earth’s atmosphere.

Subsurface oceans believed to exist on Jupiter’s moon Europa and Saturn’s Enceladus, “would have conditions similar to the deep oceans of Earth where tardigrades are found,” said the authors.

(With Agency inputs)