Well, it's still a sun no matter where you go, but it's not the same sun that's seen from Earth.

[ And there's the rub, the thing the Doctor's been skirting around until now. But he figures there's no reason to keep it hidden. ]

I'm what you might call a time traveler. Well, time and space traveler, I suppose, although I'm not much use for that here, since my ship got left behind.