Sunrise
190919
225681137
2008-07-14T21:41:17Z
68.46.70.48
{{otheruses}}
[[Image:HPIM0335.jpg|thumb|right| Sunrise in Virginia Beach, Virginia]]
'''Sunrise''' is the instant at which the upper edge of the [[Sun]] appears above the [[horizon]] in the [[east]]. Sunrise should not be confused with [[dawn]], which is the (variously defined) point at which the [[sky]] begins to lighten, some time before the sun itself appears, ending [[twilight]]. Because [[atmospheric refraction]] causes the sun to be seen while it is still below the horizon, both sunrise and sunset are, from one point of view, [[optical illusion]]s. The sun also appears larger on the horizon, but this is another optical illusion, similar to the [[moon illusion]].
The apparent [[west]]ward revolution of Sun around the [[earth]] after rising out of the horizon is due to the Earth's eastward rotation, a counter-clockwise revolution when viewed from above the North Pole. This illusion is so convincing that most cultures had mythologies and religions built around the [[geocentric model]]. This same effect can be seen with near-[[Geographical pole|polar]] [[satellite]]s as well.
As sunrise and [[sunset]] are calculated from the leading and trailing edges of the Sun, and not the center; this slightly increases the duration of "[[daylight|day]]" relative to "[[night]]." The [[sunrise equation]], however, is based on the center of the [[sun]].
The timing of sunrise varies with the time of year and the [[latitude]] of the location from which it is viewed. The precise time of day also varies in [[local time]] within a given time zone, determined by each location's precise [[longitude]]. Changes in timing of sunrise are driven by the [[axial tilt]] of Earth and the planet's movement in its annual orbit around the sun. Some apparent anomalies exist however. In the [[Northern Hemisphere]], the latest sunrise does not occur on the [[winter]] [[solstice]] around [[December 21]], but rather in early January. Likewise, the earliest sunrise does not fall on the [[summer]] solstice around [[June 21]], but occurs earlier in June in the Northern Hemisphere. As one travels farther from the equator, the times of sunrise and sunset change throughout the year. Even on the [[equator]], sunrise and sunset shift several minutes back and forth through the year, along with [[solar noon]]. These effects are plotted using an [[analemma]].
Due to Earth's axial tilt, whenever and wherever sunrise occurs, it is always in the northeast quadrant from the March equinox to the September equinox and in the southeast quadrant from the September equinox to the March equinox. Sunrises occur precisely due east on the March and September equinoxes for all viewers on Earth. The sunrise and sunset times for a 12 hr day and 12 hr night do not fall on the "equinox" (equal night), since the timing of sunrises and sunsets, and hence, the lengths of day and night vary with each viewer's particular latitude.
==Colors==
The [[red]] and orange [[hue]]s of the sky at sunrise and [[sunset]] are caused by scattering of sunlight off of dust particles, soot particles, other solid aerosols, and liquid aerosols in the earth's atmosphere. The enhanced red and orange colors at sunrise and sunset are mathematically explained by [[Mie theory]] or the [[discrete dipole approximation]]. The brilliance and intensity of the colors of sunrises are typically less than sunsets, since there are generally fewer particles in the morning air than in the evening air. Nightime air is usually cooler and less windy which allows the dust and soot particles to settle out of the atmosphere, reducing the amount of Mie Scattering and the amount of [[red]] and orange scattered light. Sunrise color intensities can however exceed sunset's intensities when there are nighttime fires, volcanic eruptions or emissions, or dust storms to the east of the viewer. A number of eruptions in recent times, such as those of [[Mount Pinatubo]] in 1991 and [[Krakatoa]] in 1883, have been sufficiently large to produce remarkable sunsets and sunrises all over the world.
Sometimes just before sunrise or after sunset a [[green flash]] can be seen.
<ref>
[http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html Red Sunset, Green Flash]
</ref>
<ref>
Selected Papers on Scattering in the Atmosphere, edited by Craig
Bohren ~SPIE Optical Engineering Press, Bellingham, WA, 1989
</ref>
<ref>
[http://ucsu.colorado.edu/~kuesterm/RTweb/startRT.html Science Made Simple]
</ref>
== See also ==
*[[Day]]
*[[Day length]]
*[[Daybreak (disambiguation)|Daybreak]] <!-- intentional link to dab page - uses redirect to emphasis same -->
*[[Sunrise equation]]
*[[Sunset]]
*[[Twilight]]
==References==
{{reflist}}
== External links ==
{{commonscat|Sunrise}}
* [http://destiny.xfiles.to/app/calendar/StarTrans Sunrise Sunset Moonrise Moonset Calculation , utilizing Google Maps.]
* [http://www.spectralcalc.com/ Rise/Set Calulator. Find sun position for any time/location.]
* [http://www.sunrisesunset.com/ Sunrise and sunset calculator]
* [http://www.chennaiiq.com/astrology/sunrise_sunset.asp Customized Sunset, Sunrise Calculator calendar]
* [http://aa.usno.navy.mil/data/docs/RS_OneYear.php Sun or Moon Rise/Set Table for one Year]
* [http://aa.usno.navy.mil/data/docs/RS_OneDay.php US Navy Sunrise and Sunset calculator]
* [http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html Full physical explanation of sky color, in simple terms]
* [http://www.ecy.wa.gov/programs/eap/models/twilight.zip An Excel workbook] with VBA functions for sunrise, sunset, solar noon, twilight (dawn and dusk), and solar position (azimuth and elevation); by [http://www.ecy.wa.gov/programs/eap/models.html Greg Pelletier], translated from NOAA's online calculators for [http://www.srrb.noaa.gov/highlights/sunrise/azel.html solar position] and [http://www.srrb.noaa.gov/highlights/sunrise/sunrise.html sunrise/sunset]
* [http://sun.exnatura.org sun.exnatura.org] Online sunrise/-set calendar with interactive location finder
*[http://herbert.gandraxa.com/herbert/lod.asp Formulas to calculate sunrise and sunset]
*[http://www.earthtools.org/ Provides sunrise/sunset times for location specified by Google Maps]
*[http://astroclub.tau.ac.il/ephem/Daily/ Daily almanac including Sun rise/set/twillight for every location on Earth]
*[http://wise-obs.tau.ac.il/~eran/Wise/wise_calen.html Monthly calendar with Sun/Moon rise/set times for every location on Earth]
[[Category:Solar phenomena]]
[[Category:Earth phenomena]]
[[Category:Symbols]]
[[Category:Parts of a day]]
[[ar:شروق]]
[[arc:ܕܢܚܐ]]
[[ay:Qhantati]]
[[bg:Изгрев]]
[[ca:Ortus]]
[[da:Solopgang]]
[[de:Sonnenaufgang]]
[[es:Orto]]
[[fr:Lever de soleil]]
[[ko:해돋이]]
[[iu:ᐅᓪᓛᖅ/ullaaq]]
[[it:Aurora (giorno)]]
[[he:זריחה]]
[[la:Sol oriens]]
[[lv:Lēkts]]
[[mr:सूर्योदय]]
[[nl:Zonsopgang]]
[[ja:天体の出没]]
[[no:Soloppgang]]
[[nn:Solrenning]]
[[pl:Świt]]
[[pt:Nascer do Sol]]
[[qu:Inti lluqsiy]]
[[ru:Восход]]
[[fi:Auringonnousu]]
[[sv:Soluppgång]]
[[bat-smg:Saulietekis]]
[[zh:日出]]