Dusk occurs at the darkest stage of

twilight Twilight is light produced by sunlight scattering in the upper atmosphere, when the Sun is below the horizon, which illuminates the lower atmosphere and the Earth's surface. The word twilight can also refer to the periods of time when this i ...

, or at the very end of astronomical twilight after sunset and just before nightfall.''The Random House College Dictionary'', "dusk". At predusk, during early to intermediate stages of twilight, enough light in the sky under clear conditions may occur to read outdoors without artificial illumination; however, at the end of civil twilight (when Earth rotates to a point at which the center of the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

's disk is 6° below the local horizon), such lighting is required to read outside. The term ''dusk'' usually refers to astronomical dusk, or the darkest part of twilight before night begins.

Technical definitions

The time of dusk is the moment at the very end of astronomical twilight, just before the minimum brightness of the

night sky The night sky is the nighttime appearance of astronomical object, celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon. Natural light sources in a ...

sets in, or may be thought of as ''the darkest part of evening twilight''. However, technically, the three stages of dusk are as follows: *At civil dusk, the center of the Sun's disc goes 6° below the horizon in the evening. It marks the end of civil twilight, which begins at sunset. At this time objects are still distinguishable and depending on weather conditions some stars and planets may start to become visible to the naked eye. The sky has many colors at this time, such as orange and red. Beyond this point artificial light may be needed to carry out outdoor activities, depending on atmospheric conditions and location. *At nautical dusk, the Sun apparently moves to 12° below the horizon in the evening. It marks the end of nautical twilight, which begins at civil dusk. At this time, objects are less distinguishable, and stars and planets appear to brighten. *At astronomical dusk, the Sun's position is 18° below the horizon in the evening. It marks the end of astronomical twilight, which begins at nautical dusk. After this time the Sun no longer illuminates the sky, and thus no longer interferes with astronomical observations.

Media

Dusk can be used to create an ominous tone and has been used as a title for many projects. One instance of this is the 2018 first person shooter Dusk (video game) by New Blood Interactive whose setting is in a similar lighting as the actual time of day.

Gallery

File:Seattle 3.jpg,

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

during Nautical twilight File:PortoCovo February 2008-4.jpg, Civil twilight in

Porto Covo Porto Covo is one of the two civil parishes in the municipality of Sines, located along the western Alentejo coast of Portugal, about south of Lisbon. The population in 2011 was 1,038,Magere Brug, Amsterdam – astronomical twilight File:IbirapueraDusk.jpg, View from

Ibirapuera Park Ibirapuera Park ( pt, Parque Ibirapuera) is an urban park in São Paulo. It comprises 158 hectares between Av. República do Líbano, Av. Pedro Alvares Cabral, and Av. IV Centenário, and is the most visited park in South America, with 14.4 milli ...

São Paulo São Paulo (, ; Portuguese for ' Saint Paul') is the most populous city in Brazil, and is the capital of the state of São Paulo, the most populous and wealthiest Brazilian state, located in the country's Southeast Region. Listed by the Ga ...

, Brazil, at civil twilight File:Deep blue sky in twilight with trees and garage.JPG, Trees' silhouettes against dusk sky File:Albi at dusk - 2014-02-22.jpg, Civil twilight in

Albi Albi (; oc, Albi ) is a commune in southern France. It is the prefecture of the Tarn department, on the river Tarn, 85 km northeast of Toulouse. Its inhabitants are called ''Albigensians'' (french: Albigeois, Albigeoise(s), oc, albig ...

, France File:Amoudi Bay at Dusk.jpg, Amoudi Bay, Santorini, at dusk File:Dusk at Hakaniemenranta in Siltasaari, Helsinki, Finland, 2021 July.jpg, Dusk in

Siltasaari Siltasaari (Finnish), or Broholmen (Swedish), is a central neighborhood of Helsinki, Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders ...

Helsinki Helsinki ( or ; ; sv, Helsingfors, ) is the capital, primate, and most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of Uusimaa in southern Finland, and has a population of . The city ...

, Finland File:VancouverConventionCenter.JPG, Nautical twilight in

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

, British Columbia, Canada

References

{{Parts of a day Earth phenomena Parts of a day Night

Technical definitions

Media

Gallery

See also

References