(SOUNDBITE OF MUSIC)
UNIDENTIFIED MAN: The alphabet has only 26 letters. With these 26 magic symbols, however, millions of words are written every day.
IRA FLATOW, HOST:
That music means it's time for Howard Markel to talk about our latest word of the week. Welcome to SCIENCE FRIDAY.
HOWARD MARKEL: Good afternoon, Ira.
FLATOW: Let's talk about what our word for today is. Moon, is it not?
MARKEL: The word is moon. And you know, it's not surprising if we look at the heavens. It's captured the imagination and the cosmology for centuries of people who looked at it. It comes from an Old English word, mona. But there are many other languages - Old Germanic, Old Saxon, Old Dutch, Old Nordic - that have similar words for it. But by the 15th century, English-speaking people began calling it the moon, although they often spelled it M-O-O-N-E.
FLATOW: And so I always thought it was like lunar (unintelligible).
MARKEL: Well, that's the Latin word for moon, of course. And Luna was the Roman goddess of the moon. And, now, they, of course, stole it from the Greeks. The Roman stole a lot of things from the Greeks. But the Greek goddess of the moon was named Selene, and that word - that comes from the word selas, which means brightness. But we still use lunar as an adjective all the time, you know. But in antiquity, it not only refered to things like insanity - a lunatic or a lunacy - but also a woman's menstrual cycle, which is 28 days just like the orbit of the moon around the Earth.
FLATOW: And so where did the man in the moon come from?
MARKEL: The man in the moon, well, you know, if you look at the moon, particularly when it's a full moon, you can imagine a face. Now, other people have said they can imagine a man carrying sticks or a man with a dog. My favorite is you can imagine a rabbit standing on its hind legs, but I don't know what those people are drinking. But - and you see it in a lot of the examples in literature, in the Bible and so on. But there actually was a book called "The Man in the Moone." It was written by a man named Francis Godwin. It was published in 1638. And Ira, it may be the first example of science fiction in English literature because it details a voyage to the moon.
FLATOW: All right. Howard Markel, we have an abbreviated version. We've run out of time. I want to thank you for joining us today.
MARKEL: Always a pleasure, Ira.
FLATOW: Howard Markel, professor of history of medicine at the University of Michigan in Ann Arbor. That's about all the time we have for today. I'm Ira Flatow. We'll see you next week. Transcript provided by NPR, Copyright NPR.