In the first scenes on the moon, we hear the sounds of the 1899 receipt being removed from its site; sounds can't be heard in the vacuum of the moon! And the paper couldn't have aged on the airless moon! Also, Bedford and Cavor's hands shouldn't have been exposed. Worse of all, the Selenites are shown to be air-breathers, so going outside their caverns to drag in the anti-gravity sphere would be fatal to them! And how did they discover it anyway?