[quote=@Arawak]
...Than again, Flagg's not running things.

Maybe we can just say some point millennia ago there was some earth and martians that existed and no one remembers it because the houses purged all history at some point for whatever reason.  Than you get your martians.
[/quote]It's a safe bet actually. Given the backdrop is some ancient galactic empire.
Earth is nothing special and thanks to mankind's abuse I bet it'd be long worthless by now. Earth could be even a barren lifeless rock which nobody visits nowadays.