Carbon dating is also correct only if the "engineers" ate food that was grown in that planet's original atmosphere.Even now, many Earth greenhouses add extra carbon dioxide gas for quicker plant growth.
But considering that the entire spaceship had just violently crashed, shouldn't the parts of his body been tossed all over the chamber? Located near each other is coincidence but not impossible. Besides the rooms in the Lifeboat are sealed; so oxygen can flow even with any breach in another room.Organic carbon in living items is "fixed" when and organism like a tree dies or when an animal metabolizes the carbon it consumes, carbon dioxide is not consumed or metabolized by the body but expelled by the body as waste.We have zero idea of how much the Engineers grow as they age.By the end of the movie, the squid-like alien that was surgically removed from Elizabeth grows to a creature at least 10 times the size of the original.This happens inside of the lab where there is no organic matter present.Teru_Kage David's head and body were initially on the deck of the big cannon. The Engineers most likely did not need a suit on that planet, as shown by the free roaming Engineer at the start of the movie. It is common practice in spacesuit design to blow fresh oxygen from the back of the helmet so that it flows down over the astronaut's face. Because of constant motion of the stars in a galaxy is visible, constellations change their shape over the time.
But all old civilizations' star maps and future maps are the same in the movie, even they are separated from each other by several (tens of) thousands of years.
Carbon dating relies on the differences in the ratio of elemental carbon isotopes, specifically carbon12 and carbon14 which is radioactive and decays over time.
By comparing a sample of known age's ratios to those of an unknown and using the fixed, constant decay rate of carbon14 the age of the unknown can be determined.
Earlier in the movie, Shaw had no problems carrying the helmet, still with the head in it, in a bag, with one arm and still held on to it in the storm.
Shaw and Ford carried the head together, hanging straight down between them in a bag with handles.
Temp when the ship is on the surface is listed for the atmosphere as 2.724 K which is -454.7628 F.