I don't think you mean the uncertainty principal - maybe relativity? That being said, that wasn't really what I was talking about (nor was Copernicus, seeing as how he came before Einstein). I was referring to the observable relationships between the Earth, Sun and other planets. With an Earth-centric model, the other planets seem to follow strange paths, sometimes reversing their direction. With a heliocentric model, those discrepancies are resolved to an incredibly precise degree, showing the planets to make perfectly elliptical orbits around the sun.