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Characteristic polar night blue twilight in Longyearbyen, Svalbard, Norway.
Polar night and Aurora australis at the South Pole, Antarctica.
Polar night in Naryan-Mar, Russia.
Polar night is a phenomenon in the northernmost and southernmost regions of Earth where night lasts for more than 24 hours. This occurs only inside the polar circles.[1] The opposite phenomenon, polar day, or midnight sun, occurs when the Sun remains above the horizon for more than 24 hours.
"Night" is understood as the center of the Sun being below a free horizon. Since the atmosphere refracts sunlight, polar day is longer than polar night, and the area that is affected by polar night is somewhat smaller than the area of midnight sun. The polar circle is located at a latitude between these two areas, at approximately 66.5°. While it is day in the Arctic Circle, it is night in the Antarctic Circle, and vice versa.
Any planet or moon with a sufficient axial tilt that rotates with respect to its star significantly more frequently than it orbits the star (and with no tidal locking between the two) will experience the same phenomenon (a nighttime lasting more than one rotation period).
^Burn, Chris. The Polar Night(PDF). The Aurora Research Institute. Retrieved 28 September 2015.
Polarnight is a phenomenon in the northernmost and southernmost regions of Earth where night lasts for more than 24 hours. This occurs only inside the...
or the Antarctic Circle, due to refraction. The opposite phenomenon, polarnight, occurs in winter, when the Sun stays below the horizon throughout the...
create the polarnight jets, that race eastward at an altitude of about 48 kilometres (30 mi). The polar vortex is circled by the polarnight jet. The warmer...
at least a day a year when it is always below the horizon – a polar day and a polarnight as is the case for longer, within the circles. Up to and including...
sunset or sunrise on at least one day of the year, when the polar day or the polarnight persists continuously for 24 hours. At latitudes greater than...
Astrophysics. 51 (1): 127–135. Bibcode:1976A&A....51..127B. Burn, Chris. The PolarNight (PDF). The Aurora Research Institute. Archived (PDF) from the original...
and night. At the 45th parallel, the longest winter night is roughly twice as long as the shortest summer night. Within the polar circles, night will...
Circle, the latitude affects the view of the night sky, especially the fact that during winter polarnight may occur for multiple months and the midnight...
causes the vortex to spin up. The stratospheric polar vortex breaks down in Spring as the polarnight ends. A sudden stratospheric warming (SSW) is an...
experiences midnight sun in summer and polarnight in winter. At 74° north, the midnight sun lasts 99 days and polarnight 84 days, while the respective figures...
PolarNight Halfmarathon is an annual half marathon running competition in Tromsø, Norway. It takes place in the beginning of January, during the Polar...
clouds, or night shining clouds, are tenuous cloud-like phenomena in the upper atmosphere of Earth. When viewed from space, they are called polar mesospheric...
as the seasons change, reaching particularly low temperatures in the polarnight (winter). Winds in the stratosphere can far exceed those in the troposphere...
sun or polarnight should follow the timetable of Mecca, it is common practice to follow the timetable of the closest country in which night can be distinguished...
astronomical twilight during a polarnight: between about 78°34' and 84°34' north or south. Solar noon at night during a polarnight: between approximately 84°34'...
in a polar climate characterized by persistent cold and relatively narrow annual temperature ranges. Winters are characterized by the polarnight, extreme...
The polar bear (Ursus maritimus) is a large bear native to the Arctic and nearby areas. It is closely related to the brown bear, and the two species can...
sunlight (midnight sun) or shade (polarnight) 24 hours a day because of the earth's tilt. Plants and animals in the polar regions are able to withstand living...
Muslims do not segregate themselves. In areas where the midnight sun or polarnight renders the five daily prayers impossible to tie to dusk and dawn, congregants...
between 18 April and 23 August (127 days), polarnight from 27 October to 15 February (111 days) and civil polarnight from 13 November to 29 January. However...
axial parallelism of Earth's tilted orbit around the Sun. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight...
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