Year

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Year_2000 :: Year_of_the_Dragon :: Yeargin :: Year_of_the_Rabbit :: Yearbooks :: Year_of_Living_Dangerously,_The :: Year_After_Year :: Year_Round_Education :: Yearwood,_Trisha :: Yearly_Meetings

One year is about 365.25 days long (see Leap year). It is the time it takes the Earth to go completely around the sun once.

The year starts on January 1 in the Gregorian calendar, but a fiscal year or a school year can start on a different day of the year.

There are several ways used to measure the length of a year.

a solar year is based on the seasons. The Gregorian calendar is based on the solar year.
a lunar year is based on the moon and is usually 12 lunar months (29 days, 12 hours, 44 minutes each) long.
a tropical year is the time between two vernal equinoxes, the first day of spring when the lengths of daylight and night are the same.
a sidereal year measures the time between when a selected fixed star is highest in the night sky.
an anomalistic year is the difference between the times when the Earth gets closest to the sun.
an eclipse year is the time between node passages. This is when the sun moves through a part of the sky where it is possible for the sun, Earth and moon to be in a line. It is also when solar eclipses can happen.

Solar and lunar years are used by different societies in daily life. The other measurements are used by astronomers.

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