So if it turned out that life on Earth came via some rogue asteroid with organic material in it - would we not be human beings anymore?
Imported aliens in fact, now let me explain. In the context of the Alien movies, it's not just natural panspermia (a rogue asteroid transporting the building blocks of life by accident) but directed panspermia
. I.e, the deliberate transport of microorganisms in space, sent to Earth to start the life here. However, in this particular case, we aren't only talking about the primordial life, as Prometheus went too far with such a concept by saying that human DNA fits perfectly with the Engineers. Now, that implies that such anthropomorphic blueprint (or human blueprint) is alien in its nature and origins.
Hell, even the flora/fauna of Planet 4 is almost identical to life on Earth. Perhaps the harvest of life on other planets in the life cycle of the Engineers, and they are more like space nomads traveling from planet to planet and creating colonies. The "humans" might be just one of the many space cultures of the Engineer race around the milky way, like in the neighborhood next door where we have different Predator clans traveling through the stars. Even Planet 4 might not be the world of origin of this species, because they have been doing this for eons and maybe they just forgot about their distant and utterly ancient origin. The difference between "Humans" and Engineers might be just a cultural thing, as they adopted a different lifestyle (minimalist and eco-friendly) in order to survive to universal great filters
(Xenomorphs and AI, both counts as great filters). That might be the very reason of why the last Engineer tried to kill David; he saw in the synthetic a dangerous great filter
like those the Engineers were facing before in order to survive in the cosmos. And he was right because David killed his entire civilization 10 years later and also he is the creator of the Alien. The search for our beginning (through a spaceship carrying a dangerous AI) could lead to our end (such AI created the final Alien).
That is one of the main reasons (besides the DNA match) of why they are us, they are everything
. After all, we'd not be here without these ancient "humans," who were successful in defeating an obstacle of cosmic scale to transcend as a very advanced civilization. Ok, maybe strictly speaking, we aren't extraterrestrial beings because we aren't been born and raised outside of Earth, but since the word human is a concept invented by us
; and the Engineers are those who came before
, we aren't (in the fictional context of course) entirely humans at all. We are more like an alien colony that was planted and harvested on Earth. So, if humans are actually imported aliens
; then the Xenomorph remains as an alien creation
as well, and makes the title of this universe (the word Alien
) even more meaningful.
We aliens now bro.