Trisolarian thread!

pheelix: I'm damn near convinced if someone scoops up a cup of Martian regolith, thaws it out, and adds a little water they'll find tardigrades swimming around in there.

I'm sure that there are some on Mars waiting for water that will never come because asteroids colliding with Earth and tossing stuff into space. But this will be only in spots were Earth stuff fell from the sky because Mars' surface was dry before these guys evolved.

pheelix: TheMysteriousStranger: I'm sure that there are some on Mars waiting for water that will never come because asteroids colliding with Earth and tossing stuff into space. But this will be only in spots were Earth stuff fell from the sky because Mars' surface was dry before these guys evolved.

How do we know these guys didn't originate on Mars when it was habitable and hitched a ride here after an asteroid collision?

it is possible that Earth life originated on Mars. But this is before animals and plants evolved. Indeed. It is before eukaryotic organisms evolved.  And be clear, there is no real reason to say we are martians other than it would mean life had more than a chance to originate on two planets than it did on just one.

But tartigrades  evolved on Earth. I can say this with near certainty like I can say Earth is a globe. They, like all other known life forms have a common ancestor. Their DNA and anatomy make it indisputable that they are part of the animal clade. Their evolution was a fairly recent few hundred million years ago. Mars was already uninhabitable by the time they evolved.