Time for your daily mind-blow. In this four-minute video (tsk tsk!), Minute Physics explains why the night sky is dark, and in turn tackles the more interesting question of why space itself is dark. It's a truly puzzling question, largely because space is full of stars -- we can see those little points of light. My puny human brain thinks "Gee whiz, the Sun produces a bunch of light...so why wouldn't all those other stars produce just as much light, turning the inky black of outer space into a sunny cosmic playground?"
Without ruining the answer, it involves the universe having no edge, as well as our old friend infrared light. (At least IR is my friend because I have a collection of remote controls. They are my totems.)