Why Do People Say the Moon is Made of Cheese?

Everybody knows that Earth’s only satellite does not, in fact, consist of fatty dairy products. So where did the myth that the moon is made of cheese come from in the first place?

Though the idea that the moon is made of cheese has been around for millennia, it’s doubtful that anyone ever actually believed it, at least not academically. The earliest record of this bizarre notion comes from a medieval Servian yarn in which a ravenous wolf chases a seemingly-hapless fox, hoping to score an easy meal. Thinking fast, the fox convinces his pursuer that the moon’s reflection on a nearby pond is actually a block of cheese floating on its surface and that the wolf must drink all of its water to acquire the tasty treat. Guzzling and guzzling his way to the prize, the wolf eventually drinks too much and bursts, leaving the fox alive and victorious.

But the best-known early citation dates to 1546, and can be found in The Proverbs of John Heywood (which can be read in its entirety here). The document is a compendium of some of the titular author’s most famous sayings, such as “the more, the merrier,” “a penny for your thoughts,” and “Rome was not built in a day.” At one point, he jokingly states “the moon is made of greene cheese” (in this context, “greene” refers to the food’s age rather than its color).

Over the following century, the phrase came into common use. Speaking of human gullibility in 1638, the English natural philosopher John Wilkins wrote “You may… soon persuade some country peasants that the moon is made of greene cheese, (as we say).”

Despite the fact that the scientific community has never seriously supported the claim, seemingly every children’s program from Tom and Jerry to Wallace and Gromit has made its fair share of moon cheese jokes.

Even NASA couldn’t resist getting in on the fun. On April Fool’s Day 2002, the administration claimed to have “proven” once and for all that the moon was made of cheese by releasing a photoshopped image with an expiration date printed on one of its craters.