The Qur'an doesn't say that God created life on earth only, it doesn't say humans are so special, it doesn't tell us of what's on other planets or in the core of earth even
this doesn't prove or show anything related to religion, it's like hundreds of years ago 'hey we discovered life between europe and asia, and we'll call it America.. now let's kill those aliens and build colonies to steal their gold!"
bring proofs of what you assume then, quote God or a prophet saying that he created life on earth only.
you really believe that life just existed on its own? one day there were a few microogranisms and now there's planets? seriously? if anything this is the dumbest theory ever.. who created those organisms and where did they come from?