You can't prove that god ever visited earth aside from what you read in your so called divinely inspired texts. Your believing these texts is an act of faith in and of itself. Just because we thought of describing the unknown as some form of superior being or intelligence does not make it true. Everything people claim to know about god and his nature is invalid since it comes from men just as fallible as we are. Regarding the words of the bible being divinely inspired because they can't be bettered I beg to differ. There are many works that are superior to anything written in the bible.
There is nothing people will not maintain when they are slaves to superstition
http://chatpilot-godisamyth.blogspot.com/
http://chatpilot-godisamyth.blogspot.com/