Polarnatt
Polarnatt eller midvintermörker innebär att solen aldrig går upp under dygnet; det vill säga att den befinner sig under horisonten under hela dygnet. Under polarnatten är solen nere även mitt på dagen, vilket kallas middagsmörker. Polarnatt förekommer närmast polarområdena, det vill säga norr om norra polcirkeln och söder om södra polcirkeln.[1][2]
Vid Nordpolen varar polarnatten från höstdagjämning till vårdagjämning. Strax norr om norra polcirkeln varar polarnatten några dagar kring vintersolståndet. Här är dock solen så nära under horisonten att det rör sig om skymnings/gryningsljus mitt på dagen. Man måste komma norr om ungefär 72:a breddgraden för att det ska upplevas som mörkt mitt på dagen.[3]
I södra polarområdet råder motsvarande förhållanden, men under motsatt halvår och med maximal utsträckning vid norra halvklotets sommarsolstånd (som inträffar under södra halvklotets vinter).
Polardag och midnattssol är motsatser till polarnatt och middagsmörker.
Bildgalleri
Polarnatt vid Amundsen–Scott-basen på Antarktis.
Polarnatt i Narjan-Mar i Ryssland den 23 december 2014, 11:27 (67° nord).
Polarnatt i Nordkinnhalvøya, det europeiska fastlandets nordligaste halvö.
Polarnatt i Adventdalen i Svalbard i Norge.
Se även
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Källor
- ^ ”Solens upp- och nedgång”. SMHI. https://www.smhi.se/kunskapsbanken/meteorologi/solens-upp-och-nedgang/solens-upp-och-nedgang-1.4179. Läst 28 december 2023.
- ^ ”What is polar night?”. Timeanddate.com. https://www.timeanddate.com/astronomy/polar-night.html. Läst 28 december 2023.
- ^ ”Polarnatten når Sverige”. Astroinfo.se. https://www.astroinfo.se/2023-12-01-polarnatten-nar-sverige/. Läst 28 december 2023.
Media som används på denna webbplats
Mehamn-polarnight-newsyearsday.jpg
Författare/Upphovsman: Algkalv (talk), Licens: CC BY 3.0
Mehamn, Nordkinnhalvøya, Finnmark, Norway.
Författare/Upphovsman: Algkalv (talk), Licens: CC BY 3.0
Mehamn, Nordkinnhalvøya, Finnmark, Norway.
Polar night in Naryan-Mar.jpg
Författare/Upphovsman: Lsnmar, Licens: CC BY-SA 4.0
Polar night in Naryan-Mar, Russia. December 23, 2014, 11:27 (noon). The altitude of the sun is –0.4° at this moment.
Författare/Upphovsman: Lsnmar, Licens: CC BY-SA 4.0
Polar night in Naryan-Mar, Russia. December 23, 2014, 11:27 (noon). The altitude of the sun is –0.4° at this moment.
Sun920607.jpg
Solen och några solfläckar. De två små fläckarna i mitten har ungefär samma diameter som jorden.
Solen och några solfläckar. De två små fläckarna i mitten har ungefär samma diameter som jorden.
Amundsen-Scott marsstation ray h.jpg
A full moon and 25 second exposure allowed sufficient light into this photo taken at Amundsen-Scott South Pole Station during the long Antarctic night. The new station can be seen at far left, power plant in the center and the old mechanic's garage in the lower right. Red lights are used outside during the winter darkness as their spectrum does not pollute the sky, allowing scientists to conduct astrophysical studies without artificial light interference. There is a background of green light. This is the Aurora Australis, which dances thorugh the sky virtually all the time during the long Antarctic night (winter).The photo's surreal appearance makes the station look like a futuristic Mars Station.
A full moon and 25 second exposure allowed sufficient light into this photo taken at Amundsen-Scott South Pole Station during the long Antarctic night. The new station can be seen at far left, power plant in the center and the old mechanic's garage in the lower right. Red lights are used outside during the winter darkness as their spectrum does not pollute the sky, allowing scientists to conduct astrophysical studies without artificial light interference. There is a background of green light. This is the Aurora Australis, which dances thorugh the sky virtually all the time during the long Antarctic night (winter).The photo's surreal appearance makes the station look like a futuristic Mars Station.
The Earth seen from Apollo 17.jpg
"The Blue Marble" is a famous photograph of the Earth taken on December 7, 1972, by the crew of the Apollo 17 spacecraft en route to the Moon at a distance of about 29,400 kilometres (18,300 mi). It shows Africa, Antarctica, and the Arabian Peninsula.
"The Blue Marble" is a famous photograph of the Earth taken on December 7, 1972, by the crew of the Apollo 17 spacecraft en route to the Moon at a distance of about 29,400 kilometres (18,300 mi). It shows Africa, Antarctica, and the Arabian Peninsula.
High Moon.jpg
Författare/Upphovsman: PaterMcFly, Licens: CC BY 3.0
High Moon in Adventdalen, Svalbard: Full Moon at Noon over Adventdalen, South of Longyearbyen, Svalbard
Författare/Upphovsman: PaterMcFly, Licens: CC BY 3.0
High Moon in Adventdalen, Svalbard: Full Moon at Noon over Adventdalen, South of Longyearbyen, Svalbard
Morketidettermiddag.JPG
Författare/Upphovsman: Osopolar, Licens: CC BY-SA 3.0
Early afternoon during the Polar Night, viewed from the upper reaches of Tromsø centre towards the mainland side.
Författare/Upphovsman: Osopolar, Licens: CC BY-SA 3.0
Early afternoon during the Polar Night, viewed from the upper reaches of Tromsø centre towards the mainland side.
Nordkinnhalvoya-polar-night.jpg
Författare/Upphovsman: Algkalv (talk), Licens: CC BY 3.0
Nordkinnhalvøya, Finnmark, Norway. Midday during polar night, 2 January.
Författare/Upphovsman: Algkalv (talk), Licens: CC BY 3.0
Nordkinnhalvøya, Finnmark, Norway. Midday during polar night, 2 January.
Polar-Night Longyearbyen.jpg
Författare/Upphovsman: Bjørn Christian Tørrissen, Licens: CC BY-SA 3.0
The polar night in Nybyen, Svalbard, looks like on this photo. While the Sun doesn't rise above the horizon, it does come close to doing so. Instead of the pitch black many imagine it to be like, you get a blue light much of the time during the days of the polar night.
Författare/Upphovsman: Bjørn Christian Tørrissen, Licens: CC BY-SA 3.0
The polar night in Nybyen, Svalbard, looks like on this photo. While the Sun doesn't rise above the horizon, it does come close to doing so. Instead of the pitch black many imagine it to be like, you get a blue light much of the time during the days of the polar night.
Note: the photo wasn’t actually taken during polar night.