Book 8, Question 45
Why Can the Moon Occult (Cover) a Star or Planet?
The Moon can occult, or cover, a star or planet because it drifts east among the stars! As it moves, it can slide in front of a star or planet and briefly hide it, like a sky eclipse of a pinpoint. Occultation means the Moon is a sky curtain!
More fun facts
- In an occultation, a big object, usually the Moon, passes in front of something that looks much smaller, like a star.
- The Moon passes every planet in the sky about once a month, but because its orbit is tipped, it usually misses them.
- It takes about 30 to 45 seconds for the Moon to cover Mars completely, like slowly drawing a curtain across a window.
- A bright planet can slip behind the Moon, vanish for about an hour, and then reappear on the other side.
- Some of the most useful occultations for scientists happen when the Moon passes in front of distant stars.
- In November 2001, a photographer caught the Moon covering the planet Saturn.
Sources: Science News Explores, Scientific American, NASA
Questions kids ask
What is an occultation?
It is when a big object, like the Moon, passes in front of a smaller-looking one, like a star or planet.