and picture in your mind the toughest animal on earth

whatever you think it is

and now imagine what that animal would do in the most inhospitable environment that you can imagine

so for example if you thought of a grizzly bear on top of Mount Everest

being attacked by a swarm of silverback gorillas

you would be wrong

that is neither the toughest animal, nor is it the most inhospitable environment

but I thank you for the visual image, that was a good one

do you wanna what he toughest animal on earth is?

well voilà, there you have it

my friends, it is the Tardigrade

also called a water bear or a moss piglet

because they're plump and waddly and they like to suck on moss

and you may have noticed they're actually kinda cute

they're what scientists call "Extremophiles"

which means they don't give a crap about where they live

the Tardigrades secret is that, when the environment gets to tough

they just shrivel up and die for a while

with the option of reviving when conditions improve

and that is the weird thing about Tardigrades, they're so extravagantly tough

like for no real reason, they're just supposed to like waddle around on moss and suck up water

that's their job

and yet in their dormant state, they can withstand temperatures close to absolute zero

and up to 300°F

they can survive being exposed to 1000 times the radiation that would kill an elephant

they can withstand pressures up to 6 times what you find in the deepest oceans on earth

what, what is the point of that, there's no ways that that would be useful on earth

and you had better believe, that we've been sending these little waddlers into outer space

because what is the most inhospitable environment? yes, it's space

in fact, scientists think that Tardigrades may be the key to understanding how life began on earth

back in 2007, NASA put a bunch of Tardigrades on the Space Shuttle

then they opened up an air locked door and left them outside in the vacuum of space for 10 days

being exposed to crazy amounts of UV radiation

then they brought them back to earth and when they got there, the Tardigrades were like: What's up?

they were happy and healthy and some of them laid Tardigrade eggs

and had little Tardigrade babies, that were completely normal and we keep doing it

earlier this year on the very last mission of the Space Shuttle Endeavour we send some Tardigrades up

and the European Space Agency send some Tardigrades into space

as part of a mission called "Tardigrades in Space"

uhm, which isn't clever until you realize that they shortened it to "TARDIS"

so the question is: why do we keep shoving these adorable little beasts uhm into the vacuum of space

it doesn't seem like a very nice thing to do

well, one: because we want to understand how Tardigrades work, just scientificly

how they can possibly survive these intense, horrible, inhospitable environments

and two: because we're interested in proving the Panspermia hypothesis

that is right "Panspermia" a word I'm not going to make a joke about

so imagine for a moment a meteorite slamming into our planet

and this meteorite is so large, that it actually ejects pieces of the earth into outer space

now imagine on those pieces of earth that got ejected into outer space, there are Tardigrades

if that little organism could survive the vacuum of space long enough to then fall down onto another planet

it could seed that planet with life, if life can be transmitted in that way

then it becomes much more likely, that life is a very very common thing in our universe

Panspermia hypothesis has been around for a long time, but thanks to Tardigrades it's starting to look a lot more credible

so we can already thank these beasts for being a great proof of concept for us

bot of course they will never now, that we are so in their dept

they're just going to keep walking around on mars, sucking water off and occasionally visiting other planets

I'm Hank Green, that was today's SciShow dose, we hope you learned something