An anomalistic month is a term used in astronomy to describe the time it takes for the moon to complete one full orbit around the Earth, measured from one perigee (the point at which the moon is closest to the Earth) to the next. This period is slightly longer than the period of a synodic month, which is the time it takes for the moon to return to the same phase (e.g. full moon to full moon).
Definitions
An anomalistic month is defined as the period of time it takes for the moon to complete one orbit around the Earth, measured from one perigee to the next. It is approximately 27.55455 days long.
Origin
The term “anomalistic month” comes from the Greek word “anomalos,” which means “irregular” or “deviating from the norm.” This refers to the fact that the period of an anomalistic month is not constant, but varies slightly due to the elliptical shape of the moon’s orbit around the Earth.
Meaning in different dictionaries
According to the Oxford English Dictionary, an anomalistic month is “the period of time between two successive passages of the moon through perigee.” Merriam-Webster defines it as “the period of time required for the moon to return to the same position in its elliptical orbit with respect to the perigee.”
Associations
Anomalistic months are important in astronomy because they affect the moon’s apparent size and brightness in the sky. When the moon is at perigee, it appears larger and brighter than when it is at apogee (the point at which it is farthest from the Earth).
Synonyms
There are no commonly used synonyms for anomalistic month.
Antonyms
The antonym of anomalistic month is synodic month, which is the time it takes for the moon to return to the same phase (e.g. full moon to full moon).
The same root words
The root word of “anomalistic” is “anomaly,” which means “something that deviates from what is standard, normal, or expected.”
Example Sentences
- The anomalistic month is approximately 27.55455 days long.
- The moon appears larger and brighter when it is at perigee, which occurs once every anomalistic month.
- The difference in the length of the anomalistic month and the synodic month is due to the elliptical shape of the moon’s orbit around the Earth.