Tardigrades Might Be The Sole Survivors Of The Apocalypse

Geronimo Vena
Luglio 14, 2017

Earth's designated heir is the tardigrade, a microscopic, grub-like, eight-legged animal that can live in water or on land, in extreme pressure high or low.

"Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the universe". They've survived the frozen vacuum of space and even can bring themselves back to life. Well, scientists say yes and believe it will survive until the death of the Sun.

Normal natural disasters that are fatal for humans - volcanoes, tsunamis, and the like - weren't even considered in the study: This is the mind-blowing endurance of the tardigrade, here; the suggestion that those events could be hazardous is nearly insulting. But researchers wanted to know what it would take to annihilate one of the world's most resilient creatures, so they turned to tardigrades.

Scientists scored the survival of the species over three rounds of tests which simulated a large asteroid impact, a blast from an exploding supernova star and a gamma ray burst, which is a huge explosion thought to be caused by a star collapsing.

There are only a dozen known asteroids and dwarf planets with enough mass to boil the oceans (2x10 kg), these include (Vesta 2x10 kg) and Pluto (10 kg), however none of these objects will intersect the Earth's orbit and pose a threat to tardigrades.

Supernovae, the expanding balls of gas that form when stars explode, would need to occur no more than 0.14 light-years away from Earth in order to boil away our oceans.

In comparison, humans could be wiped out pretty easily.

But, he added, if the tardigrades were the only survivors, they would face a struggle. Even subtle changes to our environment can have a drastic effect on our health. In the next seven billion years, the sun will swell into a red giant star, potentially engulfing Earth and surely sizzling away its water. "As we are now entering a stage of astronomy where we have seen exoplanets and are hoping to soon perform spectroscopy [on those planets], looking for signatures of life, we should try to see just how fragile this hardiest life is".

"Although nearby supernovae or asteroid impacts would be catastrophic for people, tardigrades could be unaffected". Therefore it seems that life, once it gets going, is hard to wipe out entirely.

Boffins have named a super-hardy, water-dwelling lifeform only half a millimetre in size as the Earth's toughest species.

"In this context there is a real case for looking for life on Mars and in other areas of the solar system in general", said Dr. Alves Batista said. Life on this planet can continue long after humans are gone.

"Organisms with similar tolerances to radiation and temperature as tardigrades could survive long-term below the surface in these conditions", said Prof Loeb.

Similarly, the subsurface oceans on Saturn's moon Enceladus and Jupiter's moon Europa may feature volcanic vents that provide heat, similar to the locations where tardigrades can thrive deep under Earth's sea, he said.

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