A complete and utter myth, where did this absurd saying actually come from?
The most likely source is from the Proverbs of John Hayward a 1546 collection by the English writer where one of the proverbs is:’the moon is made of greene cheese’. A popular and enduring book, the saying presumably originates from here. It has also been used throughout history and folklore as a sign of gullibility or stupidity.
The legend has been used jokingly since then. Cultural references are made to it in TV programs and films such as in Wallace and Gromit’s A Grand Day Out
Recently, even NASA decided to get in on the act by claiming they had proved that the moon was indeed made of cheese on April Fool’s Day 2002. The hoax can be seen here.
In reality, the moon is a celestial body primarily made of the rock regolith. It is covered with impact craters which look similar(isn) to cheese holes but are actually from collisions with asteroids and other matter.