From Man of Steel
[Jonathan shows Clark his ship
] We found you in this. We were sure the government was gonna show up at our doorstep, but no one ever came.
Clark Kent at 13
[Clark looks over the ship in puzzlement
[Jonathan shows Clark the command key
] This was in the chamber with you. We took it to a metallurgist at Kansas State. He said whatever it was made from didn't even... didn't even exist on the periodic table. It's another way of saying that it's not from this world, Clark... and neither are you. You're the answer, son. You're the answer to, "are we alone in the universe?"