The West is the home to many popular myths and legends about the moon. The Chinese have the story of Chang’e and Wu Gang, who was banished to the moon for delinquency (过错，过失；不端行为). But people in Europe have their own stories about the man on the moon.
Many people believe the story came into being because the suce of a full moon sometimes resembles the face of a man. However, the truth of the legend is more complex.
A German version of the myth suggests the man was banished to the moon because he refused to stop working on Sunday, a traditional day of rest.
Other myths say the moon has an effect on people’s behavior, causing them to lose their mind when there is a full moon. This is the origin of the word "lunatic".
Lunatics in the U.K. sometimes "pull a moony". This is the practice of pulling your pants down and waving your bottom at people as an insult.
Of course, the moon is also a popular romantic symbol. American singer Frank Sinatra’s song Fly Me to the Moon is perhaps the world’s most famous love ballad. This association may also be the source of the idiom "to be over the moon".
Another popular idiom is the phrase "once in a blue moon". This means that something is as likely to happen as the moon turning blue.
However, it might not be such a good idea to take your loved one walking by moonlight, because wolves are supposed to change from human to animal form under a full moon.
There is one final idiom about the moon that’s often used. When someone "asks for the moon", he or she is asking for the impossible.
This expression originated long ago, but perhaps now it will begin to lose its meaning. In the coming years, space tourists may very well be able to travel to the moon and have their wish granted, as long as they have enough money.
The idiom "once in a blue moon" means ______.