Yes, it'd be scary to learn that they could be among us without us knowing. Scientifically speaking, this would be extremely unlikely (I'm assuming by being human you mean not only sharing with us appearance, but also genome and reproducible with us), so it would certainly raise big questions in the science community.

Funnily, this is how I usually imagine aliens, as portrayed in some sci-fi movies and comics.

Convergent evolution causing creatures to look near identical to humans? Probable. The universe repeats. You got the same boring suns, planets, planetary properties, and material/building blocks. DNA can only be configured in so many ways as it is bound by the constrains of physics so ecological niches should remain somewhat the same assuming the planet share most of our settings (size, gravity, moon, sun distance, oxygen events, water, etc).

Literal humans? Highly unlikely. The evolutionary trajectory of a planet would need to be near identical to ours, with historic events coinciding with our own. One random meteor out of match and everything would change.

Yeah, if that happened, that would be new data that would need explaining, in the context of evolution.

I see you like Caulifla from Universe 6. Or is it Kale?

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