Sidereal month

Definition

A sidereal month is the time it takes for the Moon to complete one full orbit around Earth relative to the background stars. It lasts approximately 27.3 days.

5 Must Know Facts For Your Next Test

1. The duration of a sidereal month is about 27.3 days.
2. It is different from a synodic month, which measures the time between successive new moons.
3. A sidereal month allows astronomers to track the Moon's position relative to distant stars.
4. During a sidereal month, the Moon completes one orbit around Earth.
5. The term 'sidereal' comes from the Latin word 'sidus,' meaning star.

Review Questions

• What is the duration of a sidereal month?
• How does a sidereal month differ from a synodic month?
• Why is tracking the Moon's position relative to stars important in astronomy?

Related terms

synodicMonth: The time it takes for the Moon to return to the same phase, approximately 29.5 days.

orbitalPeriod: The time taken for a given astronomical object to complete one orbit around another object.

eclipticPlane: The imaginary plane that contains Earth's orbit around the Sun.