Definition

Noun: 1. A specific type of lunar month: The anomalistic month is the time it takes for the Moon to complete one full orbit around the Earth, measured from one point of closest approach (perigee) to the next. Its average duration is approximately 27.5546 days.

Usage

• The anomalistic month is a key concept in astronomy for calculating the Moon's varying speed and apparent size in its elliptical orbit.
• It is slightly longer than the sidereal month because the point of perigee itself slowly advances in the direction of the Moon's orbit.

Examples

• Noun:
  • The length of an anomalistic month is about 27.55 days.
  • Astronomers track the anomalistic month to predict supermoons, which occur when a full moon coincides with perigee.
  • The difference between the anomalistic month and the synodic month explains variations in tidal forces.

Advanced Usage

• "Cycle of the anomalistic month": Refers to the repeating pattern of the Moon's distance from Earth.
  • The tidal range is influenced by the cycle of the anomalistic month.

Variants and Related Words

• Anomalistic year (n): The time it takes for the Earth to orbit the Sun from one perihelion (closest approach to the Sun) to the next.
• Sidereal month (n): The time it takes for the Moon to complete one orbit relative to the distant stars (~27.32 days).
• Synodic month (n): The time between two successive new moons, or full moons (~29.53 days). This is the basis for the lunar calendar.
• Draconic month (n): The time it takes for the Moon to return to the same node in its orbit (~27.21 days), important for eclipse prediction.

Synonyms

• Perigee-to-perigee month: A descriptive synonym emphasizing the defining start and end points of the cycle.

Related Concepts (Not Phrasal Verbs or Idioms)

• Perigee (n): The point in the Moon's (or any orbiting body's) orbit where it is closest to Earth.
• Apogee (n): The point in the Moon's orbit where it is farthest from Earth.
• Orbital period (n): The general term for the time taken to complete one orbit.

Noun

1. period between successive perigees; approximately 27.5546 days