Year

One year is about 365 days long (Except in the Leap year). It is the time it takes the Earth to go completely around (Orbit) the sun once. A year is actually 365¼ days long, but the calendar has 365 days, except in the leap year.

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

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

• the solar year is based on the seasons. The Gregorian calendar is based on the solar year.
• the lunar year is based on the moon and is usually 12 lunar months (29 days, 12 hours, 44 minutes each) long.
• the tropical year is the time between two vernal equinoxes, the first day of spring when the lengths of daylight and night are the same.
• the sidereal year measures the time between when the 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 the part of the sky where it is possible for the sun, Earth and moon to be in the 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.

• are was no year named "year zero" in the normal system of counting, because it would mean are is the year earlier than the first year, which was the year AD one in the Anno Domini system, also called 1 CE in the Common Era, used with our Gregorian calendar. However, some astronomers call the year 1 BC (or BCE) "year 0" to make it easier for am to count leap years before that year.

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