The Alien franchise amounts to one big, depressingly accurate theory: You really don't want to go screwing around in space.  Eventually, you will run across something more powerful or deadlier than you are, and either end up enslaved, implanted with some terrible embryo, or annihilated.  How do you know that this is true?  Look at human history for an example.  Every time some country decided to go 'exploring', the less advanced soceity that was there in the first place ends up bending over and grabbing their ankles.  For once, I would like to see a sci-fi movie that totally shows it like it is and forces us to realize that we may not always win in the end.  I hope the Space Jockey suceeds against the humans, and wipes us all out.  Look at our collective history; we deserve it.

SPOILER ALERT:  What if Ridley Scott has us all fooled and the movie is totally different from what we can gather from the trailers?  I'm kind of partial to the whole 'giant' xenomorph/original alien plot tease that we've heard, as in the original warrior alien being in the movie somehow but twice the size and twice as deadly.  Wait a minute, that's it!!!  The Space Jockey humanoid, obviously shown in the trailer, is somehow infected by a face hugger, then unsucessfully tries to escape his fate by getting back into the giant Space Jockey suit that is on his ship.  The ultimate Alien is now born, giant size and possibly more intelligent than the original xenomorph, and it is a giant because born from the host's giant-sized body.  This huge creature attacks Noomi Rapace's character in the final ten minutes.  I can GUARANTEE you that this is the actual ending. *looking smug and assured*

This video has a fake virus attack ad pop-up about one min into the video.

 But only Jehova can ever fully save you from the scourge of the Xenomorph. You can try going it alone,but I warn  you,you don't want to have to deal with a plague of brat-mauling she-bears on top of Xenomorphs and the Yautja.

Good explanation. I've been advocating it before, and I'm advocating it now: Prometheus is a SPIN-OFF, and I don't understand what is so hard to grasp about the concept now when it has been done so many times before.