
Description


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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 cesium133 atom (13th CGPM, 1967).

•

Maple knows the units of time listed in the following table.

Name

Symbols

Context

Alternate Spellings

Prefixes






wink


standard *

winks


flick


time

flicks

SI

shake


standard *

shakes


svedberg


standard *

svedbergs


blink


standard *

blinks







second

s

SI *

seconds

SI



sidereal


SI



Atomic


SI

minute

min

SI *

minutes




sidereal



hour

h

SI *

hours




sidereal



day

d

SI *

days




sidereal








pentad


standard *

pentads


week

wk

standard *

weeks


fortnight


standard *

fortnight







month

mo

lunar *

months




sidereal





anomalistic





nodical








lune


lunar *

lunes


lunour


lunar *

lunours







year

yr

tropical *

years




anomalistic





ellipse





standard





leap





Julian





Gregorian





Orthodox





galactic





sidereal








biennium


tropical *

biennia




Gregorian



triennium


tropical *

triennia




Gregorian



quadrennium


tropical *

quadrennia




Gregorian



quinquennium


tropical *

quinquennia




Gregorian



decade


tropical *

decades




Gregorian



century


tropical *

centuries




Gregorian



millennium


tropical *

millennia




Gregorian



eon


tropical *

eons, aeon, aeons


planck_time


planck *

planck_times





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 $\frac{1}{3}$ nanosecond.


A flick is defined as $\frac{1}{705600}$ millisecond.


A shake is defined as $1.\times {10}^{\mathrm{8}}$ second.


A svedberg is defined as $1.\times {10}^{\mathrm{13}}$ 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 $\frac{1}{24}$, $\frac{1}{1440}$, 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 $\mathrm{\pi}$ times the speed of light to the fifth power.


The Month



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 $\frac{1}{30}$ lunar month.


A lunour is defined as $\frac{1}{24}$ 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.



The Year



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 $2.25\times {10}^{8}$ years.



Multiple Years


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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 $1.\times {10}^{9}$ years.




Examples


>

$\mathrm{convert}\left('s'\,'\mathrm{dimensions}'\,'\mathrm{base}'=\mathrm{true}\right)$

>

$\mathrm{convert}\left(1.0\,'\mathrm{units}'\,'\mathrm{year}\left[\mathrm{tropical}\right]'\,'\mathrm{year}\left[\mathrm{standard}\right]'\right)$

>

$\mathrm{convert}\left(1.0\,'\mathrm{units}'\,'\mathrm{year}\left[\mathrm{tropical}\right]'\,'\mathrm{year}\left[\mathrm{Julian}\right]'\right)$

>

$\mathrm{convert}\left(1.0\,'\mathrm{units}'\,'\mathrm{year}\left[\mathrm{tropical}\right]'\,'\mathrm{year}\left[\mathrm{Gregorian}\right]'\right)$

>

$\mathrm{convert}\left(1.0\,'\mathrm{units}'\,'\mathrm{year}\left[\mathrm{tropical}\right]'\,'\mathrm{year}\left[\mathrm{Orthodox}\right]'\right)$

>

$\mathrm{convert}\left(1.0\,'\mathrm{units}'\,'\mathrm{year}\left[\mathrm{tropical}\right]'\,'\mathrm{year}\left[\mathrm{sidereal}\right]'\right)$

>

$\mathrm{convert}\left(1\,'\mathrm{units}'\,\frac{'\mathrm{centimeters}'}{'\mathrm{minute}'}\,\frac{'\mathrm{furlong}'}{'\mathrm{fortnight}'}\right)$

$\frac{{1400}}{{1397}}$
 (7) 
>

$\mathrm{evalf}\left(\right)$



