Nobody likes the idea of panspermia, the idea that life on earth originated elsewhere in the solar system (or galaxy). It's unpalatable because it just kicks the can down the road, "if not here, then where did life originate?" "Why not here?" "That doesn't even answer the question of how life started" and I totally sympathize with all those sentiments.

But we're finding increasing evidence that life existed on Mars before it existed on Earth. And if that's true, then it becomes impossible to deny panspermia, because we already know some other key bits of information. First, we know chunks of Marian rock have crashed down onto earth after being ejected into space by asteroid strikes. Secondly, we know that some forms of carbon based life, bacteria and fungal spores can survive both the vacuum of space extended periods without moisture, and the heat of reentry into atmosphere if they're embedded into porous rock.

So 1, bits of Mars make it to earth every so often. 2, some life will survive a journey to earth. And now 3, there was life on Mars long before it was on Earth.

This unfortunately leaves many questions in its wake... Where did life actually first arise? If it didn't even start here, then how rare is life? Will we see the same kind of life everywhere we look? (Because apparently everything in the solar system is probably cross pollinated)

Exciting times.

[–] Naz@sh.itjust.works 1 points 10 minutes ago* (last edited 9 minutes ago)

A xenonaut sits in a bar with a glass of whiskey in one hand and a cigar in another.

A xenobiologist walks in and sits next to them.

"What was it today? Caustic gas? Acidic rain?"

"A fern."

The xenobiologist raises an eyebrow surprised by the despair in their tone.

"What's so bad about a fern?" She asked. "That's amazing evidence of convergent evolution!"

"Not just any fern. The same fern. Alpha, gamma, delta, epsilon quadrant, all of them have the same genetic blueprint." He continued putting his cigar out in his drink.

"That's.. amazing! Exciting news even! I mean, celebrate, live a little! You've found that the tree of life has roots!" She tried to cheer him up.

"The common... domesticated fern, from here." He says, getting up and departing, gesturing to the ferns growing on the campus green.

[–] skibidi@lemmy.world 9 points 1 day ago

IIRC we don't know when life started on earth because records of the early earth aren't available - geological activity recycled the surface. What evidence we do have is that life started pretty much as early as the records we have can show, meaning either it appeared very quickly once the planet cooled or was already present.

[–] P00ptart@lemmy.world 4 points 1 day ago

It wouldn't even necessarily need to be life, but the building blocks of life, to make it significant.