Life would be trivial to introduce to Mars.

What counts as life? E.g., organic molecules, RNA, self-replicating systems using biological molecules?

It has to be able to replicate on some level. Viruses, loose RNA, organic molecules, etc would not count.

Cellular life, even as simple as non-colony bacteria, would count. This would include if it didn't use DNA/RNA, but used some clear analog to it.

Beyond that, I want to defer that to the broader community. It's always possible we will find something unexpected.

@LivInTheLookingGlass Viruses can definitely replicate "on some level". I assume you mean that it has to be able to replicate in the absence of a separate organism?

Note that RNA and even proteins can replicate without direct assistance, they just need to be in the right environment.

https://en.wikipedia.org/wiki/RNA_world#Prebiotic_RNA_synthesis

https://en.wikipedia.org/wiki/Prion

My suggestion would be to pick some general definition of life so we know how broad you're being, and then you can defer to the community for the details if it ends up mattering.

https://en.wikipedia.org/wiki/Life#Definitions

If humans land on the moon and notice a patch of mold inside their spacecraft, does that count?

What if we settle mars and the humans are actively cultivating plants there?

It has to be outside of any station, habitat, etc. and still alive without human assistance

@LivInTheLookingGlass So if we take bacteria to Mars and leave them outside as an experiment, and it turns out they can grow there without assistance, that counts?

@IsaacKing yes

@LivInTheLookingGlass title is misleading in that case

I don't see how anyone could claim to have 'discovered' the lifeform in that scenario. It shouldn't count. What the unusual formulation of the question seems to be pushing at is the idea that we might have already accidentally introduced life to Mars or another body on a lander. Would it count if the life form was living on the outer surface of a lander?

You spelled Enceladus wrong.

And that's what I get for trusting speech to text lol