Since it's a theoretical question I can only assume you're not in a vacuum (where S.O.L is a constant) otherwise both yourself and the SD would be on your backs gasping...Soooo the light would travel slightly ahead of the bike, because it's relative..Aaaand, of course a falling tree makes a noise if there is no one there to hear it; the sound of one hand clapping is a slap; the egg came before the chicken because of reptiles and the Pope definitely at one time shat in the woods 'cos he was Hitler bloody Youth. Oh yeah..and all bears are Catholic...