“Scientists have, in fact, assembled long lists of scores of such “happy cosmic accidents.” When faced with this imposing list, it’s shocking to find how many of the familiar constants of the universe lie within a very narrow band that makes life possible. If a single one of these accidents were altered, stars would never form, the universe would fly apart, DNA would not exist, life as we know it would be impossible, Earth would flip over or freeze, and so on.”
