The Derelict has already left the building

i think you're right about the derelict from Alien having happened long before the events in Promo. why it landed there is tricky, because he sure didnt get very far.

I like that idea. Quick question: If the SJ died, then who's the other SJ in the traillers next to David?

The other SJ is part of the video, it is not real, if you look at the cast there are only 3 Engineers, which means the rest were wiped out. One of the wall sculptures show an engineer with something bursting out of him.

yeah I noticed friend. Yet another question: Could there be more SJ portrayed by the same guy/actor? [thus having only one entry as a cast member?]

Maybe there is some sort of cloning mechanism at play here, Ridley Scott could be paying homage to Alien: Ressurection to some degree and indeed he may be paying homage to all alien-based themes throughout Prometheus: (i.e) First and for-most Alien as in the derilict and the SJ's, Aliens with the Exo-Walk Loaders. I'm not sure about Alien 3 but there may be some reference either directly or indirectly to that film as well. He may be just in a frame of mind (Ridley Scott that is) to be 'paying his respects' to the entire franchise in the form of subtle 'Easter-Eggs.' Or Silo-Eggs even! lol!

Thats why the 'man' in the Blue suit colud look similar to others.

I have just watched the new origins video and it seems the Engineer did get quite far as it turns out the planet prometheus lands on is near Io in our solar system. Also I have just seen something on another forum that indicates that there are hardly any engineers left.

Well what you said is near enough exactly what i thought was going on, and posted my idea a while back. With the Cast List and Hologram scenes this pretty much made me conclude as such. It seems one Engineer Survived, and you have to look at it like this. If your race was the Gods or as Gods (no Gods exist) and you seeded and terraformed many worlds, you have your Technology that can be used to Teraform worlds, a Bio Former that can create and manipulate life and DNA. Then if you are the last survivor and your creations had found out the location of where your from and uncover your secrets to creating and modifying life etc... Then you would know as a argogant race and as its only survivour that you just cant see your race die out "king has its reign" and then see your creations come and take yout technology and thus become the new Gods. This would make Mankind almost on same playing field as the Engineers, they dont have the Tech as far as Space Travel or Live as Long but they are in their Billions while you are just one and if/when you die. They will take and use your PROMETHEUS FIRE Mankind would then become the new Gods, they would be playing with Fire and not know the damage it could cause and they could end up destroying other planets life as much as create. For the above you would have to put a stop to them, and if you destroy the Prometheus and its crew, well how long before Earth sets off another Mission. Thats one posibility the other is the Surviving Engineer played some part in the downfall of his race and has not every good plans for us.

Yes the Engineers are to look pretty much the same. While there may be 3 actors that dont mean your limited to only 3 of them in the movie. Look at the AVPs one bloke played more than one Predator and the same actor plays most of the Engineer scenes in this movie when he is interacting with the crew. Their is one Actor who is average and only 5ft10" but they use his likeness for the Satue, and he will play the face of all Engineers in scenes where we see any close ups, he also plays the Water Fall scene guy. As far as LV223 and LV426 well the System is about 40 Light Years away thats pretty far, but yes not much in the scale of the Galaxy. The distance between LV223 and LV426 could be like from Jupiter to Saturn or closer.

Wouldn't it be a whole lot easier to destroy the derelict that's really close by and kind of small than to make this epic journey to wipe out an entire planet?