A solar term is any of 24 points in traditional East Asian lunisolar calendars that matches a particular astronomical event or signifies some natural phenomenon. The points are spaced 15° apart along the ecliptic and are used by lunisolar calendars to stay synchronized with the seasons, which is crucial for agrarian societies. The solar terms are also used to calculate intercalary months in East Asian calendars; which month is repeated depends on the position of the sun at the time.
Solar terms originated in China, then spread to Korea, Vietnam, and Japan. This is exhibited by the fact that traditional Chinese, Hanja, and Kanji characters for most of the solar terms are identical.
Because the Sun's speed along the ecliptic varies depending on the Earth-Sun distance, the number of days that it takes the Sun to travel between each pair of solar terms varies slightly throughout the year. Each solar term is divided into three pentads (候 hou), so there are 72 pentads in a year. Each pentad consists of five, rarely six, days, and are mostly named after biological or botanical phenomena corresponding to the pentad.
Read more about Solar Term: List of Solar Terms, Regional Note
Famous quotes containing the words solar and/or term:
“Senta: These boats, sir, what are they for?
Hamar: They are solar boats for Pharaoh to use after his death. They’re the means by which Pharaoh will journey across the skies with the sun, with the god Horus. Each day they will sail from east to west, and each night Pharaoh will return to the east by the river which runs underneath the earth.”
—William Faulkner (1897–1962)
“The developments in the North were those loosely embraced in the term modernization and included urbanization, industrialization, and mechanization. While those changes went forward apace, the antebellum South changed comparatively little, clinging to its rural, agricultural, labor-intensive economy and its traditional folk culture.”
—C. Vann Woodward (b. 1908)