Hello, I just heard a guy talking about the Michelson-Morley experiment as evidence that the earth is still. It is true that the MM experiment basically showed that the earth was at rest with respect to "the ether" (but we know that the earth moves around the sun, so the notion of ether starts looking a bit flimsy). This guy basically said that this showed that the earth was completely stationary and used it to defend geocentrism. How do you show that the earth is indeed moving around the sun? I've read about stellar aberration, but can you guys suggest some less complicated arguments that I can give to people like this (I haven't studied astrophysics, so I'd be cool if you explain this stuff to me as well)? I guess that if you could repeat the MM experiment on Mars, it would also show that Mars is "stationary", but we know that it is in relative motion to the earth. I guess no one has done that experiment on Mars though.