Excuse me for what I thought before. Mario's (obviously fictional) solar system is not our's.
Also, yeah, no Mario game (not counting the sport, party and puzzle spin-offes, their official websites, and the games Ninteod of Japan doesn't even know about like Mario is Missing) make references to Mario being from Earth. The only Earth reference is when Miyamoto said that he designed Mario Bros. thinking about a New York sewer system, but that doesn't mean it IS that. Only that he designed it while thinking of that.
Also, when someone here will have SMG2 could he/her re-draw on a paper the shape of the continents on Mario's planet (can be seen from the World selection and the Galaxy selection of World 1) and scan it, please ?