Nature News online and print and television media report a new theory that the early Earth had two moons, and the small one pancaked into Luna, accounting for the remarkably rough texture of the far side compared to the near side. My eye was caught by a riff at the end of the article in the Houston Chronicle (from Associated Press with the byline of Seth Borenstein): The moon plays a big role in literature and song. And poet Todd Davis, a professor of literature at Penn State University, said this idea of two moons – one essentially swallowing the other – will capture the literary imagination. It long since did that in science fiction and fantasy! How many short stories, novels and comic books have put a second small moon in the sky to show that a world is Earth-but-not, or Earthlike-with-differences, or Earth-of-prehistoric-humanity-and something-eventually-happened-to-the-little-moon?