Sunset - Revision history

FifthFive: Reverting edit(s) by 86.17.121.209 (talk) to rev. 1246599902 by Discospinster: unexplained change of spelling, again (UV 0.1.5)

2024-09-19T23:05:18Z

Reverting edit(s) by 86.17.121.209 (talk) to rev. 1246599902 by Discospinster: unexplained change of spelling, again (UV 0.1.5)

← Previous revision		Revision as of 23:05, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colours~~==		==Colors==
	{{See also\|Sunrise#~~Colours~~}}		{{See also\|Sunrise#Colors}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow ~~colours~~ in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final ~~colour~~ of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colours~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colors are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

86.17.121.209 at 23:03, 19 September 2024

2024-09-19T23:03:32Z

← Previous revision		Revision as of 23:03, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colors~~==		==Colours==
	{{See also\|Sunrise#~~Colors~~}}		{{See also\|Sunrise#Colours}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow ~~colors~~ in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colours in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final ~~color~~ of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final colour of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colors~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colours are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

Discospinster: unexplained change of spelling

2024-09-19T22:58:34Z

unexplained change of spelling

← Previous revision		Revision as of 22:58, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colours~~==		==Colors==
	{{See also\|Sunrise#~~Colours~~}}		{{See also\|Sunrise#Colors}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the ~~colours~~ are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colours~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colors are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

86.17.121.209: /* Colours */

2024-09-19T22:57:36Z

Colours

← Previous revision		Revision as of 22:57, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colors~~==		==Colours==
	{{See also\|Sunrise#~~Colors~~}}		{{See also\|Sunrise#Colours}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the ~~colors~~ are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colours are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colors~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colours are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

Pachu Kannan: Reverted edit by 2001:4453:77A:7600:A547:B6A6:9AAE:B907 (talk) to last version by Alexeyevitch

2024-09-11T12:04:03Z

Reverted edit by 2001:4453:77A:7600:A547:B6A6:9AAE:B907 (talk) to last version by Alexeyevitch

← Previous revision		Revision as of 12:04, 11 September 2024
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	[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]		[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]

	'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on ~~planet~~, it is a phenomenon that happens approximately once every 48 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].		'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].

	The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.		The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.

2001:4453:77A:7600:A547:B6A6:9AAE:B907 at 12:02, 11 September 2024

2024-09-11T12:02:38Z

← Previous revision		Revision as of 12:02, 11 September 2024
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	[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]		[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]

	'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on ~~Earth~~, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].		'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on planet, it is a phenomenon that happens approximately once every 48 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].

	The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.		The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.

Alexeyevitch: rv error

2024-08-24T12:37:15Z

rv error

← Previous revision		Revision as of 12:37, 24 August 2024
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	'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].		'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].

	The time of actual ~~sunrise~~ is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.		The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.
	[[File:Cape may.jpg\|thumb\|left\|upright=1.35\|Sunset over the [[Delaware Bay]] at [[Sunset Beach, New Jersey\|Sunset Beach]], [[New Jersey]], U.S., seen through [[cirrus cloud]]s]]Sunset is distinct from [[twilight]], which is divided into three stages. The first one is ''[[Twilight#Civil_twilight\|civil twilight]]'', which begins once the Sun has disappeared below the horizon, and continues until it descends to 6 degrees below the horizon. The early to intermediate stages of twilight coincide with ''[[Dusk\|predusk]]''. The second phase is ''[[Twilight#Nautical_twilight\|nautical twilight]]'', between 6 and 12 degrees below the horizon. The third phase is ''[[Twilight#Astronomical_twilight\|astronomical twilight]]'', which is the period when the Sun is between 12 and 18 degrees below the horizon.<ref name="USNO">{{cite web\|url=http://aa.usno.navy.mil/faq/docs/RST_defs.php\|title=Definitions from the US Astronomical Applications Dept (USNO)\|access-date=2016-06-17\|archive-date=2015-08-14\|archive-url=https://web.archive.org/web/20150814180458/http://aa.usno.navy.mil/faq/docs/RST_defs.php\|url-status=dead}}</ref> ''[[Dusk]]'' is at the very end of astronomical twilight, and is the darkest moment of twilight just before [[night]].<ref>{{cite web\|title=Full definition of Dusk\|url=http://www.merriam-webster.com/dictionary/dusk}}</ref> Finally, night occurs when the Sun reaches 18 degrees below the horizon and no longer illuminates the sky.<ref>{{Cite web\|date=2020-12-03\|title=Sunset vs Dusk [What Is The Difference Between The Two?]\|url=https://www.astronomyscope.com/sunset-vs-dusk/\|access-date=2021-10-03\|website=Astronomy Scope\|language=en-us}}</ref>		[[File:Cape may.jpg\|thumb\|left\|upright=1.35\|Sunset over the [[Delaware Bay]] at [[Sunset Beach, New Jersey\|Sunset Beach]], [[New Jersey]], U.S., seen through [[cirrus cloud]]s]]Sunset is distinct from [[twilight]], which is divided into three stages. The first one is ''[[Twilight#Civil_twilight\|civil twilight]]'', which begins once the Sun has disappeared below the horizon, and continues until it descends to 6 degrees below the horizon. The early to intermediate stages of twilight coincide with ''[[Dusk\|predusk]]''. The second phase is ''[[Twilight#Nautical_twilight\|nautical twilight]]'', between 6 and 12 degrees below the horizon. The third phase is ''[[Twilight#Astronomical_twilight\|astronomical twilight]]'', which is the period when the Sun is between 12 and 18 degrees below the horizon.<ref name="USNO">{{cite web\|url=http://aa.usno.navy.mil/faq/docs/RST_defs.php\|title=Definitions from the US Astronomical Applications Dept (USNO)\|access-date=2016-06-17\|archive-date=2015-08-14\|archive-url=https://web.archive.org/web/20150814180458/http://aa.usno.navy.mil/faq/docs/RST_defs.php\|url-status=dead}}</ref> ''[[Dusk]]'' is at the very end of astronomical twilight, and is the darkest moment of twilight just before [[night]].<ref>{{cite web\|title=Full definition of Dusk\|url=http://www.merriam-webster.com/dictionary/dusk}}</ref> Finally, night occurs when the Sun reaches 18 degrees below the horizon and no longer illuminates the sky.<ref>{{Cite web\|date=2020-12-03\|title=Sunset vs Dusk [What Is The Difference Between The Two?]\|url=https://www.astronomyscope.com/sunset-vs-dusk/\|access-date=2021-10-03\|website=Astronomy Scope\|language=en-us}}</ref>

185.137.140.43 at 12:26, 24 August 2024

2024-08-24T12:26:08Z

← Previous revision		Revision as of 12:26, 24 August 2024
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	'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].		'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].

	The time of actual ~~sunset~~ is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.		The time of actual sunrise is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.
	[[File:Cape may.jpg\|thumb\|left\|upright=1.35\|Sunset over the [[Delaware Bay]] at [[Sunset Beach, New Jersey\|Sunset Beach]], [[New Jersey]], U.S., seen through [[cirrus cloud]]s]]Sunset is distinct from [[twilight]], which is divided into three stages. The first one is ''[[Twilight#Civil_twilight\|civil twilight]]'', which begins once the Sun has disappeared below the horizon, and continues until it descends to 6 degrees below the horizon. The early to intermediate stages of twilight coincide with ''[[Dusk\|predusk]]''. The second phase is ''[[Twilight#Nautical_twilight\|nautical twilight]]'', between 6 and 12 degrees below the horizon. The third phase is ''[[Twilight#Astronomical_twilight\|astronomical twilight]]'', which is the period when the Sun is between 12 and 18 degrees below the horizon.<ref name="USNO">{{cite web\|url=http://aa.usno.navy.mil/faq/docs/RST_defs.php\|title=Definitions from the US Astronomical Applications Dept (USNO)\|access-date=2016-06-17\|archive-date=2015-08-14\|archive-url=https://web.archive.org/web/20150814180458/http://aa.usno.navy.mil/faq/docs/RST_defs.php\|url-status=dead}}</ref> ''[[Dusk]]'' is at the very end of astronomical twilight, and is the darkest moment of twilight just before [[night]].<ref>{{cite web\|title=Full definition of Dusk\|url=http://www.merriam-webster.com/dictionary/dusk}}</ref> Finally, night occurs when the Sun reaches 18 degrees below the horizon and no longer illuminates the sky.<ref>{{Cite web\|date=2020-12-03\|title=Sunset vs Dusk [What Is The Difference Between The Two?]\|url=https://www.astronomyscope.com/sunset-vs-dusk/\|access-date=2021-10-03\|website=Astronomy Scope\|language=en-us}}</ref>		[[File:Cape may.jpg\|thumb\|left\|upright=1.35\|Sunset over the [[Delaware Bay]] at [[Sunset Beach, New Jersey\|Sunset Beach]], [[New Jersey]], U.S., seen through [[cirrus cloud]]s]]Sunset is distinct from [[twilight]], which is divided into three stages. The first one is ''[[Twilight#Civil_twilight\|civil twilight]]'', which begins once the Sun has disappeared below the horizon, and continues until it descends to 6 degrees below the horizon. The early to intermediate stages of twilight coincide with ''[[Dusk\|predusk]]''. The second phase is ''[[Twilight#Nautical_twilight\|nautical twilight]]'', between 6 and 12 degrees below the horizon. The third phase is ''[[Twilight#Astronomical_twilight\|astronomical twilight]]'', which is the period when the Sun is between 12 and 18 degrees below the horizon.<ref name="USNO">{{cite web\|url=http://aa.usno.navy.mil/faq/docs/RST_defs.php\|title=Definitions from the US Astronomical Applications Dept (USNO)\|access-date=2016-06-17\|archive-date=2015-08-14\|archive-url=https://web.archive.org/web/20150814180458/http://aa.usno.navy.mil/faq/docs/RST_defs.php\|url-status=dead}}</ref> ''[[Dusk]]'' is at the very end of astronomical twilight, and is the darkest moment of twilight just before [[night]].<ref>{{cite web\|title=Full definition of Dusk\|url=http://www.merriam-webster.com/dictionary/dusk}}</ref> Finally, night occurs when the Sun reaches 18 degrees below the horizon and no longer illuminates the sky.<ref>{{Cite web\|date=2020-12-03\|title=Sunset vs Dusk [What Is The Difference Between The Two?]\|url=https://www.astronomyscope.com/sunset-vs-dusk/\|access-date=2021-10-03\|website=Astronomy Scope\|language=en-us}}</ref>

Jdcomix: Reverted edit by 112.198.70.232 (talk) to last version by Alexeyevitch

2024-08-06T01:55:00Z

Reverted edit by 112.198.70.232 (talk) to last version by Alexeyevitch

← Previous revision		Revision as of 01:55, 6 August 2024
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	[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]		[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]

	'''Sunset''' (or '''sundown''') is the the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].		'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].

	The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.		The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.

112.198.70.232 at 01:27, 6 August 2024

2024-08-06T01:27:33Z

← Previous revision		Revision as of 01:27, 6 August 2024
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	[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]		[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]

	'''Sunset''' (or '''sundown''') is the ~~disappearance of~~ the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].		'''Sunset''' (or '''sundown''') is the the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].

	The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.		The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.

← Previous revision		Revision as of 23:05, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colours~~==		==Colors==
	{{See also\|Sunrise#~~Colours~~}}		{{See also\|Sunrise#Colors}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow ~~colours~~ in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final ~~colour~~ of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colours~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colors are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

← Previous revision		Revision as of 23:03, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colors~~==		==Colours==
	{{See also\|Sunrise#~~Colors~~}}		{{See also\|Sunrise#Colours}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow ~~colors~~ in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colours in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final ~~color~~ of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final colour of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colors~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colours are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

← Previous revision		Revision as of 22:58, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colours~~==		==Colors==
	{{See also\|Sunrise#~~Colours~~}}		{{See also\|Sunrise#Colors}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the ~~colours~~ are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colors are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colours~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colors are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

← Previous revision		Revision as of 22:57, 19 September 2024
Line 38:		Line 38:
	An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />		An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" />

	==~~Colors~~==		==Colours==
	{{See also\|Sunrise#~~Colors~~}}		{{See also\|Sunrise#Colours}}
	{{Further\|Atmospheric optics}}		{{Further\|Atmospheric optics}}
	[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]		[[File:Majestic Twilight.jpg\|thumb\|upright\|Evening [[twilight]] in [[Joshua Tree, California]], displaying the separation of yellow colors in the direction from the Sun below the [[horizon]] to the observer, and the blue components scattered from the surrounding sky]]

	As a ray of white sunlight travels through the atmosphere to an observer, some of the ~~colors~~ are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.		As a ray of white sunlight travels through the atmosphere to an observer, some of the colours are scattered out of the beam by air molecules and [[Atmospheric particulate matter\|airborne particles]], changing the final color of the beam the viewer sees.
	Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these ~~colors~~ are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>		Because the shorter [[wavelength]] components, such as blue and green, scatter more strongly, these colours are preferentially removed from the beam.<ref name="saha">{{cite book \|author=K. Saha \|title=The Earth's Atmosphere – Its Physics and Dynamics \|url=https://archive.org/details/earthsatmosphere00saha_371 \|url-access=limited \|date=2008 \|publisher=Springer \|isbn=978-3-540-78426-5 \|page=[https://archive.org/details/earthsatmosphere00saha_371/page/n124 107]}}</ref> At sunrise and sunset, when the path through the atmosphere is longer, the blue and green components are removed almost completely, leaving the longer wavelength orange and red [[hue]]s we see at those times. The remaining reddened sunlight can then be scattered by cloud droplets and other relatively large particles to light up the horizon red and orange.<ref name="guenther">{{cite book \|editor=B. Guenther \|title=Encyclopedia of Modern Optics \|publisher=[[Elsevier]] \|date=2005 \|volume=1 \|page=186}}</ref> The removal of the shorter wavelengths of light is due to [[Rayleigh scattering]] by air molecules and particles much smaller than the wavelength of visible light (less than 50 nm in diameter).<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html \|title=Hyperphysics, Georgia State University \|publisher=Hyperphysics.phy-astr.gsu.edu \|access-date=2012-04-07}}</ref><ref name="Bohren">Craig Bohren (ed.), ''Selected Papers on Scattering in the Atmosphere'', SPIE Optical Engineering Press, Bellingham, WA, 1989</ref> The scattering by cloud droplets and other particles with diameters comparable to or larger than the sunlight's wavelengths (> 600 nm) is due to [[Mie theory\|Mie scattering]] and is not strongly wavelength-dependent. Mie scattering is responsible for the light scattered by clouds, and also for the daytime halo of white light around the Sun (forward scattering of white light).<ref>{{cite web\|url=http://www.spc.noaa.gov/publications/corfidi/sunset/\|title=The Colors of Twilight and Sunset\|first=Stephen F.\|last=Corfidi\|publisher = NOAA/NWS Storm Prediction Center\|location = Norman, OK \|date=February 2009}}</ref><ref>{{cite web\|url=http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html\|date=August 1996\|title=Atmospheric Aerosols: What Are They, and Why Are They So Important?\|publisher=nasa.gov}}</ref><ref name="hecht">{{cite book \|author=E. Hecht \|title=Optics \|url=https://archive.org/details/optics00ehec \|url-access=limited \|edition=4th \|date=2002 \|publisher=Addison Wesley \|isbn=0-321-18878-0 \|page=[https://archive.org/details/optics00ehec/page/n94 88]}}</ref>

	Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>		Sunset colors are typically more brilliant than sunrise colors, because the evening air contains more particles than morning air.<ref name="saha" /><ref name="guenther" /><ref name="Bohren" /><ref name="hecht" /> Sometimes just before sunrise or after sunset a [[green flash]] can be seen.<ref>{{cite web\|url=http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/redsun.html\|title=Red Sunset, Green Flash}}</ref>

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	[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]		[[File:Anatomy of a Sunset-2.jpg\|thumb\|upright=1.35\|Actual sunset: Two minutes before the Sun disappears below the horizon.]]

	'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on ~~planet~~, it is a phenomenon that happens approximately once every 48 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].		'''Sunset''' (or '''sundown''') is the disappearance of the [[Sun]] below the [[horizon]] of the [[Earth]] (or any other [[astronomical object]] in the [[Solar System]]) due to its [[Earth's rotation\|rotation]]. As viewed from everywhere on Earth, it is a phenomenon that happens approximately once every 24 hours, except in areas close to the [[Geographical pole\|poles]]. The [[equinox]] Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the [[Northern Hemisphere]], the Sun sets to the northwest (or not at all) in the spring and summer, and to the southwest in the autumn and winter; these seasons are reversed for the [[Southern Hemisphere]].

	The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.		The time of actual sunset is defined in [[astronomy]] as two minutes before the upper limb of the Sun disappears below the horizon.<ref>{{Citation\|last=Ridpath\|first=Ian\|title=sunset\|date=2012-01-01\|url=https://www.oxfordreference.com/view/10.1093/acref/9780199609055.001.0001/acref-9780199609055-e-3625\|work=A Dictionary of Astronomy\|publisher=Oxford University Press\|language=en\|doi=10.1093/acref/9780199609055.001.0001\|isbn=978-0-19-960905-5\|access-date=2021-10-05}}</ref> Near the horizon, [[atmospheric refraction]] causes [[sunlight]] rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.