New Scientist is carrying this article on the six "great" unknowns of the solar system. Some of the answers (such as the one re: relative sizes of the Moon and Sun) seem to rely on some awfully convenient coincidences.

Hey, man, don't look at me. I live on a planet where one of the greatest empires in history originated on an isthmus shaped like a human boot, complete with heel and calf bulge, that's kicking a football. It's all sitting at nearly the middle of a giant lake, which ensures it's even visible from space. If a planet like that had been put in a science fiction movie, nobody'd believe it. And that's just the start of the coincidences of this place. Don't even ask me about the triple alpha process.

Why, thank you, but you see I already have this foil hat of my own that fits just fine. I will keep it for an extra, though...