Month
Month
A month is a unit of time, used with calendars, which is approximately as long as a natural period known as the lunar month. In the Gregorian calendar, introduced in 1582 and now used almost universally, a month is a period of 28, 30, or 31 days.
Etymology[edit | edit source]
The word month is derived from Old English monað, which is ultimately from Proto-Germanic *mēnōths.
Length[edit | edit source]
The mean month length of the Gregorian calendar is 30.436875 days.
Types of months in astronomy[edit | edit source]
In astronomy, the month is principally used to refer to the period of the Earth's moon's orbital period.
Sidereal month[edit | edit source]
The sidereal month is the time the Moon takes to complete one full revolution around the Earth with respect to the background stars.
Synodic month[edit | edit source]
The synodic month is the period of the Moon's phases, because the Moon's appearance depends on the position of the Earth and the Sun.
Tropical month[edit | edit source]
The tropical month is the average time for the Moon to pass twice through the same equinox point of the sky.
Anomalistic month[edit | edit source]
The anomalistic month is the average time the Moon takes to go from perigee to perigee - the point in the Moon's orbit when it is closest to Earth.
Draconic month[edit | edit source]
The draconic month is also known as the nodical month or nodal period. It is the period in which the Moon returns to the same node of its orbit; the nodes are the two points where the Moon's orbit crosses the plane of the Earth's orbit.
See also[edit | edit source]
Month Resources | ||
---|---|---|
|
|
Translate to: East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
Urdu,
বাংলা,
తెలుగు,
தமிழ்,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
European
español,
Deutsch,
français,
русский,
português do Brasil,
Italian,
polski
Navigation: Wellness - Encyclopedia - Health topics - Disease Index - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro) available.
Advertise on WikiMD
WikiMD is not a substitute for professional medical advice. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Admin, Prab R. Tumpati, MD