Chances are about 50–50 that in any night sky there is at least one visible comet that has not been discovered. This keeps amateur astronomers busy looking night after night because the discoverer of...

Chances are about 50–50 that in any night sky there is at least one visible comet that has not been discovered. This keeps amateur astronomers busy looking night after night because the discoverer of a comet gets the honor of having it named for him or her. With this high probability of comets in the sky, why aren’t more of them found?