Units of Time
Time is a base dimension in the International System of Units. The SI unit of time is the second, defined as the time interval equal to 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom (13th CGPM, 1967).
Maple knows the units of time listed in the following table.
eons, aeon, aeons
An asterisk ( * ) indicates the default context, an at sign (@) indicates an abbreviation, and under the prefixes column, SI indicates that the unit takes all SI prefixes, IEC indicates that the unit takes IEC prefixes, and SI+ and SI- indicate that the unit takes only positive and negative SI prefixes, respectively. Refer to a unit in the Units package by indexing the name or symbol with the context, for example, second[SI] or h[SI]; or, if the context is indicated as the default, by using only the unit name or symbol, for example, second or h.
The units of time are defined as follows. Unless otherwise stated, conversions refer to SI units.
A wink is defined as 13 nanosecond.
A flick is defined as 1705600 millisecond.
A shake is defined as 1.×10−8 second.
A svedberg is defined as 1.×10−13 second.
A blink is defined as 0.00001 day.
An SI minute is defined as 60 seconds.
An SI hour is defined as 60 minutes.
An SI day is defined as 24 hours.
A sidereal day, which varies daily, is approximately 23 hours, 56 minutes, and 4.1 seconds.
The sidereal hour, minute and second are defined as fractions of the sidereal day with factors of 124, 11440, and 0.00001157407407, respectively.
A standard pentad is defined as 5 days.
A standard week is defined as 7 days.
A standard fortnight is defined as 14 days.
A planck time is defined as the square root of: the planck constant times the Newtonian gravitational constant, divided by twice π times the speed of light to the fifth power.
A lunar month, which has also been called the lunation and synodic month, is approximately 29 days, 12 hours, 44 minutes, and 2.8 seconds.
A lune is defined as 130 lunar month.
A lunour is defined as 124 lunar day.
A nodical month, which has also been called the dracontic month, is approximately 27 days, 5 hours, 5 minutes, and 35.8 seconds.
An anomalistic month is approximately 27 days, 13 hours, 18 minutes, and 33.1 seconds.
A sidereal month is approximately 27 days, 7 hours, 43 minutes, and 11.6 seconds.
A standard year is defined as 365 days.
A leap year is defined as 366 days.
A sidereal year is approximately 365 days, 6 hours, 9 minutes, and 9.7632 seconds.
An ellipse year is approximately 365 days, 14 hours, 52 minutes, and 54.48 seconds.
A tropical year is approximately 365 days, 5 hours, 48 minutes, and 45.216 seconds.
An anomalistic year is approximately 365 days, 6 hours, 13 minutes, and 52.464 seconds.
The Julian calendar includes a leap year every fourth year. Therefore, a Julian year is defined as 365.25 days.
The Gregorian calendar includes a leap year every fourth year unless the year is a multiple of 100 and not a multiple of 400. Therefore, a Gregorian year is defined as 365.2425 days.
The proposed Orthodox calendar includes a leap year every fourth year, leaving out 7 leap years every 900 years. Therefore, a Orthodox year is defined as 366.2424222... days.
A galactic year is approximately 2.25×108 years.
For the following units the Gregorian context is based on the Gregorian year and the tropical context is based on the tropical year. An exception is the eon, which has only a tropical context that is based on the tropical year.
A biennium is defined as 2 years.
A triennium is defined as 3 years.
A quadrennium is defined as 4 years.
A quinquennium is defined as 5 years.
A decade is defined as 10 years.
A century is defined as 100 years.
A millennium is defined as 1000 years.
An eon is defined as 1.×109 years.
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