I’m a longtime fan of cosmic disaster scenarios. Not because I’m particularly gloomy (according to my friends and family, I’m actually more of a goof), but because they are fabulous ways to illustrate the workings of the universe. They are also great for making you appreciate the delicate set of contingencies that allow us to exist right now, right here on Earth. I wrote one of the first Armageddon-science articles, entitled “20 Ways the World Could End,” which was published for the 20