Have you ever stopped to wonder how far the planets are from one another? In a textbook space doesn’t look like that big a deal, does it? Only it is a big deal, and just within our solar system space is just that: space. Vast distances of absolute nothingness.
PS: Do you know what’s really scary? The fact that despite all that emptiness asteroid still pass incredibly close to Earth – indeed just last night one shot by so close it was actually closer to us than the Moon was.
Also, obligatory Carl Sagan video: