What happened at the end of Prometheus Movie? [closed]

Prometheus did pose some interesting questions, so here goes:

1. What makes you think the holograms take a lot of energy? They're on a ship that's travelled "billions of miles" from Earth; running a few holographic generators (small ones at that) shouldn't pose a problem.

2. Shaw took David's head and used it to commandeer another ship, heading out to find more answers (presumably the Engineer's homeworld).

3. A single vial of the "black liquid" virus would probably be enough to wipe out all life on Earth. See this answer for a thorough look at the Engineer's motivation.

There were some scenes that picture holographic images. I don't get from where they were getting that much energy to create holographs.

David inspects writing on the wall, and rubs off some kind of gel with his fingers. When he inspects the gel he sees glowing specks of organic life in the gel. A kind of living digital storage that lines the walls of the cave.

He activates the writing on the wall and the specks in the gel turn on to play back the old recording that we see as the hologram. It's not really a holographic image as much as it is a recording saved into the living gel that lines the walls. This is why the images are made up on glowing dots that look a lot like the dots in the gel.

1) When you have a ship blasting an interstellar quad engine layout I'd imagine hololithics would be relatively easy from a power consumption point of view.

2) She wasn't going back to earth, in fact she explicitly states she intends to find the Engineer home world and then you see her take off in another spacecraft.

3) a) Welcome to a main plot thread of the whole movie. b) Are you sure you watched this? The cargo hold is packed with canisters of the virulent evolutionary biological weapon.