"That's no moon, it's a spacestation!"
"It can't be a spacestation, it will take the Empire ... wait a second ..."
So he knew that it was no moon, if you look at the next scene, you must be a Jedi to see that he is correct, you don't see the lines or the place were the green beans are located. So it must be an evidence that he has special powers, let's say Jedi-powers because he is a Jedi