NASA and the European Space Agency are in love with tardigrades that looks like an alien. That’s because they are known to be able to live for decades without food or water, to survive temperatures from near absolute zero to well above the boiling point of water, to survive pressures from near zero to well above that on ocean floors, and to direct exposure to dangerous radiations. Image © Nicole Ottawa & Oliver Meckes / Eye of Science / Science Source Images
Tardigrades (commonly known as waterbears or moss piglets) are small, water-dwelling, segmented animals with eight legs. They are notable for being one of the most complex of all known polyextremophiles. An extremophile is an organism that can thrive in a physically or geochemically extreme condition that would be harmful to most life on Earth.
The far-ranging survivability of these extremophiles was tested in 2011 outside an orbiting space shuttle. Tardigrades are so durable partly because they can repair their own DNA and reduce their body water content to a few percent.
Some of these miniature water-bears almost became extraterrestrials recently when they were launched toward to the Martian moon Phobos on board the Russian mission Fobos-Grunt, but stayed terrestrial when a rocket failed and the capsule remained in Earth orbit.
Tardigrades are more common than humans across most of the Earth.
Hank explains why NASA and the European Space Agency are in love with tardigrades and how these extremophiles are helping us study the panspermia hypothesis.