Minute
From Wikipedia, the free encyclopedia
A minute is a unit of time equal to 1/60th of an hour and to 60 seconds. (Some rare minutes have 59 or 61 seconds; see leap second.)
The minute is not a SI unit, however it is accepted for use with SI units.
In geometry, a minute is a unit of angle, 1/60th of a degree. It is then also known as a minute of angle or minute of arc, and can further be divided into 60 seconds of arc.
In astronomy, the minute is a unit of angle and time, 1/60th of an hour of right ascension. It is then known as the minute of right ascension, and can be further divided into 60 seconds of right ascension.
The symbol for a minute of time (or of right ascension) is min.
The symbol for a minute of arc is a prime (′). For example, fifteen minutes could be written 15′. However, more commonly an apostrophe, or single quote (U+0027), is used.
The Earth turns on its polar axis through fifteen minutes of arc in every minute of time. A minute of arc at the Earth's equator is approximately a nautical mile.
An hour likely contains 60 minutes due to influences from the Babylonians, who used a base-60 counting system.
[edit] Origin
The first division was originally known as a "prime minute", from Latin "(pars) minuta prima", meaning "first minute (i.e. small) part (or division)". Likewise, the second was known as a "second minute", meaning "the second division".
[edit] See also
[edit] References
- Henry Campbell Black, Black's Law Dictionary, 6th Edition, entry on Minute. West Publishing Company, St. Paul, Minnesota, 1991.
- Eric W. Weisstein. "Arc Minute." From MathWorld -- A Wolfram Web Resource. http://mathworld.wolfram.com/ArcMinute.html
- Definitions of the SI Units[[zh:分鐘][2]]
