I know exactly why the Earth is beautiful :). God created a perfect creation and we are only glimpsing the endless possibilities before us. It is understandable and very mature to say that we don't know, but it is simply not true. God says in Romans 1:20 that his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So all nonbelievers are without excuse.