abordoliJune 18, 2012[i]It looks to me like there was already some forms of life on Earth when the sacraficial engineer did his thing. I think the goo just made humans.[/i]
The first debate is whether or not that was Earth in the opening sequence.
I believe it is.
-Ridley says "it could be Earth doesn't have to be".
-SFX Technician called it Earth in a video.
-It looks like Earth
The second debate is "when?".
I believe that it is slightly prior to the Cambrian explosion around 800 million years ago (yes, that is around 2.6 Billion years before plant life).
-We see moss
-The engineers have human-like physiology
-They need to breathe on the planet that are "messing with" else they'd need to be in their "space-suits" to get the plant life started first
-They need protection from radiation (the planet has to have an ozone layer). Earth's didn't form until around 1.3 billion years ago +/-. It tool over 2 billion years of oxygen-producing plants to create the atmosphere and develop our ozone layer.
Earth ain't no "shake-n-bake colony". It has taken us a long time to get to where we are over our 4.5 billions years on this planet (yes, in some form our atoms are THAT old....older if you consider the 14-17 billions of years we've been in the "universe"...some say the universe might be considerably older since we can only see 14.5 billion light years away at the moment).