Everything explained

A lot of people found the movie frustrating because there are so many unanswered questions, but I really liked that aspect of it. One of the main screenwriters was the guy who did Lost, so teasing mysteries are his stock in trade. The movie is a kind of riddle, and this is the answer I have come up with: The "engineers" are a highly advanced life form who have developed the ability to create life and accelerate evolution. They do this with the black goo. In the opening scene we see an engineer drinking some, which destroys him, reconstitutes his dna and seeds the earth with life. They only do this on planets which are sterile, but have the right conditions for life. They use their own pure DNA because it will lead eventually lead to an intelligent, benign life form. They return to their seeded planets and plan eventually to let the new life forms understand their origins. Hence the cave paintings. However, there is a downside to the process in that in certain circumstances it can lead to the creation of the ultimate survival-of-the-fittest predatory life form - the xenomorph of the first Alien movie. Perhaps it happens when the planet that they seed is not completely sterile. The engineers have come across this creature before, because in the temple on LV-233 there are murals etc depicting it. Perhaps they think they have managed to defeat it or eliminate it. The engineers realise that there is a problem or contamination on earth, which will lead eventually to xenomorphs, so they realise that they have to either destroy all life on earth, or apply some sort of corrective measure, it is not clear which. This is why they have earth as a destination on their star map, and perhaps why David says "in order to create, you first have to destroy". My theory is that they had a corrective plan, because when David goes into the cargo hold of the engineer ship, the jars contain not black goo, but a clearer looking substance packed in ampules with slime. They choose LV-233 as a barren planet for their goo factory and seeding project. The temple with the giant head is the heart of the goo factory, and depends on minute adjustments of humidity and temperature. However, something goes wrong and they are all killed by a vicious predatory creature which bursts out of their chests. This is not yet the xeno, but something very dangerous. Only the engineer who is in deep sleep survives. This is why Earth has not been visited for 2000 years. When Prometheus comes to LV-233 and they open up the temple, it sets off a change in humidity, which makes the black goo come out of the urns. There is brief shot which shows that there are worms in the soil. These react with the goo and become the cobra/vagina snakes. One of these snakes kills Millburn by going into his mouth and coming out of his chest. So presumably this is how all the engineers were killed. They had not realised that there was a tiny life form on this planet that would react with the goo. When the last engineer wakes up he is horrified to find humans with him, which is why he kills them and immediately tries to set off for earth. There is a brief but interesting moment when he picks up David and realises that it is a robot. He is touched that humans have learned to recreate themselves, like engineers, but then saddened that it has to be destroyed. David gets Holloway to drink some goo. Why? Perhaps just as an experiment. It seems to be having the same effect on him as on the engineer in the first scene, but there is one interesting glimpse of a little worm in the corner of his eye. Perhaps this is some tiny parasitic bacterium transformed by the goo. He is burned before we can find out any more. Fitfield, whose helmet is dissolved by acid, falls face forward into the goo. He ends up as some kind of malevolent super strong monster. Perhaps he is a kind of zombie operated by super-evolved bacteria and bugs inside him. Holloway has sex with Shaw and she is impregnated with a super squid. After she cuts it out of her, it ends up going into the mouth of the last engineer. In the last scene, what bursts out of the engineer is recognisably a xeno, and probably a queen. My theory is that this is exactly what the engineers were afraid of. It is the human reproductive system (engineers don't do sex) which allows the xeno to come into being. Before that they were unable to lay eggs. They could only burrow in and burst out. So the sex between Holloway and Shaw was a crucial step in its creation, a creature with ultimate survival skills, but also engineer intelligence. The intriguing question is whether David knew this and planned it. There is a horrible irony in the fact that Shaw, who is infertile, gets to be the mother of such a malignant life form. If you want to make a connection between Prometheus and the first Alien movie, maybe the newly created Xeno goes and lays eggs in the other ships which David mentioned are on LV-233, possibly with other sleeping engineers. Or maybe the xeno in the first Alien movie is from a completely different xeno incarnation. If there is a sequel, what will Shaw find when she gets to the engineer home world? The motivation of the robot is very mysterious. If he is simply programmed to provide Weyland with a meeting with the engineers, why does he meddle in the way that he does? Why does he give Holloway the black goo and not the clear goo?