Landscape by Month. A month is a unit of time, used with calendars, which is approximately as long as a natural period related to the motion of the Moon; month and Moon are cognates.
The traditional concept arose with the cycle of Moon phases; such months are synodic months and last approximately 29.53 days. From excavated tally sticks, researchers have deduced that people counted days in relation to the Moon's phases as early as the Paleolithic age.
Synodic months, based on the Moon's orbital period with respect to the Earth-Sun line, are still the basis of many calendars today, and are used to divide the year. Main article: Lunar month The following types of months are mainly of significance in astronomy, most of them first recognized in Babylonian lunar astronomy.
The sidereal month is defined as the Moon's orbital period in a non-rotating frame of reference. It is about 27.32166 days.
It is closely equal to the time it takes the Moon to pass twice a fixed star. A synodic month is the most familiar lunar cycle, defined as the time interval between two consecutive occurrences of a particular phase as seen by an observer on Earth. The mean length of the synodic month is 29.53059 days. Due to the eccentricity of the lunar orbit around Earth, the length of a synodic month can vary by up to seven hours. The tropical month is the average time for the Moon to pass twice through the same equinox point
The traditional concept arose with the cycle of Moon phases; such months are synodic months and last approximately 29.53 days. From excavated tally sticks, researchers have deduced that people counted days in relation to the Moon's phases as early as the Paleolithic age.
Synodic months, based on the Moon's orbital period with respect to the Earth-Sun line, are still the basis of many calendars today, and are used to divide the year. Main article: Lunar month The following types of months are mainly of significance in astronomy, most of them first recognized in Babylonian lunar astronomy.
The sidereal month is defined as the Moon's orbital period in a non-rotating frame of reference. It is about 27.32166 days.
It is closely equal to the time it takes the Moon to pass twice a fixed star. A synodic month is the most familiar lunar cycle, defined as the time interval between two consecutive occurrences of a particular phase as seen by an observer on Earth. The mean length of the synodic month is 29.53059 days. Due to the eccentricity of the lunar orbit around Earth, the length of a synodic month can vary by up to seven hours. The tropical month is the average time for the Moon to pass twice through the same equinox point
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