Corrected entry: In the beginning, we are shown a sort of picture of the alien ship and all the coral that covers it, that's how they know how old it is, but when we see the ship for real, there's hardly any coral on it. Yes, the coral was supposed to have been blown away, so they can get in and out, but they wouldn't have blown all the other coral away - they could have damaged the ship. And yet, there is the enormous ship, clean of coral.
kh1616
1st Oct 2013
Correction: The cleaned the coral off the entire ship, careful not to damage it, so that they could get an unobstructed visual of the exterior.
Phixius ★