Hi, I have a question that and I am unable to come up with a consistent and simple answer to. If we consider a coordinate system centered at the earth, then all planets, the sun and indeed the rest of the universe is rotating around the earth in a very complicated way (as measured in this system). Now if we instead consider a coordinate system centered at the Sun, then the planets move in nice elliptical paths (as measured in this system). Now, my question is: Is these descriptions in fact equivalent, but we prefer the latter because of its simplicity or is the latter the right description and the former the wrong? I know that the question of acceleration (because of the rotation around the sun) should settle the argument in favor of the Copernican view, but is there a more "direct" method? What if I took a trip from Earth to outerspace and looked down at the planets orbiting the Sun - what would that actually prove?