Tardigrades are microscopic, but they can survive just about every disaster

Pablo Tucker
July 15, 2017

The tardigrade, also known as a "water bear", "space bear" or "moss piglet", is a micro-animal with eight legs which looks a little like a pig, hippopotamus or bear, and usually lives in moss or lichen. Scientists have known for some time that tardigrades are almost impossible to kill - although they dwell in water, they can be without it for 30 years - but research published Friday in Scientific Reports takes that notion a step further: The species will live through every disaster until the sun itself explodes. Their hardiness means they can endure deadly radiation, temperatures ranging from 212 degrees Fahrenheit to 459 degrees below zero, deep pressures below the ocean, being dried out for a decade, and even the vacuum of space. Specimens have been observed to exist without food or water for more than 30 years.

Most previous studies of apocalyptic astronomical events - like asteroid impacts, neighboring stars going supernova or insanely energetic explosions called gamma-ray bursts - focused on their threat to humankind.

A study published Friday in a journal called Scientific Reports says tardigrades can survive pretty much anything. There are few asteroids in our Solar System large enough that they would boil away Earth's water if they struck our planet, reports Giorgia Guglielmi for Science, and none of them are heading anywhere Earth.

Now, a team of Oxford and Harvard researchers has found that tardigrades survive all astrophysical calamities, such as an asteroid, since they will never be strong enough to boil off the world's oceans.

"To our surprise we found that although nearby supernovae or large 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.

"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", said lead author Dr. Rafael Alves Batista, postdoctoral research associate in the Department of Physics at Oxford University.

Oxford University boffins said tardigrades, or "water bears", are as "indestructible as it gets on Earth".

In highlighting the resilience of life in general, the research broadens the scope of life beyond Earth, within and outside of this solar system.

"There are many more resilient species' on earth".

Moreover, the animal's ability to survive in extreme conditions suggests that alien life could be a lot more common than previously believed.

Scientists found only one way the tardigrades could be killed off - if our oceans boil away and we are left without any water. These explosions occur when enormous stars collapse or neutron stars collide; they're even rarer than supernovae, and astronomers have only seen them in distant galaxies. "Organisms with similar tolerances to radiation and temperature as tardigrades could survive long-term below the surface in these conditions".

Measuring no more than half a millimetre, the creature has the reputation of being the toughest and most resilient critter on the planet. "Subtle changes in our environment impact us dramatically", Dr. Batista said.

Batista emphasized that humanity is considerably less resilient than tardigrades. "The history of Mars indicates that it once had an atmosphere that could have supported life, albeit under extreme conditions". If life that developed on planets like Mars is anything like tardigrades, it would stick around despite the planet's current inhospitable conditions, the researchers said.

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