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The length of polar night varies by latitude from 24 hours just inside the polar circles to 179 days at the poles. As there are various kinds of twilight, there also exist various kinds of polar twilight that progress towards true polar night. Each kind of polar night is defined as when it is darker than the corresponding kind of twilight.
Olbers's paradox says that because the night sky is dark, at least one of these three assumptions must be false. Olbers's paradox , also known as the dark night paradox or Olbers and Cheseaux's paradox , is an argument in astrophysics and physical cosmology that says the darkness of the night sky conflicts with the assumption of an infinite and ...
Relationship of Earth's axial tilt (ε) to the tropical and polar circles. The Arctic Circle is the southernmost latitude in the Northern Hemisphere at which the centre of the Sun can remain continuously above or below the horizon for twenty-four hours; as a result, at least once each year at any location within the Arctic Circle the centre of the Sun is visible at local midnight, and at least ...
The night sky is the nighttime appearance of 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 night sky include moonlight , starlight , and airglow , depending on location and timing.
Videos of eerie noises erupting from the skies have recently surfaced on YouTube, sending people into a panic around the world. The video above shows a particularly frightening episode of this ...
A map of the Arctic. The red line is the 10 °C isotherm in July, commonly used to define the Arctic region; also shown is the Arctic Circle. The white area shows the average minimum extent of sea ice in summer as of 1975. [1] The climate of the Arctic is characterized by long, cold winters
Here's a breakdown of how and why it all happens. But the science behind a blue sky isn't that easy. For starters, it involves something called the Rayleigh effect, or Rayleigh scattering.
Noctilucent clouds during arctic dawn seen from high altitude. Data from the Aeronomy of Ice in the Mesosphere satellite suggests that noctilucent clouds require water vapour, dust, and very cold temperatures to form. [9] The sources of both the dust and the water vapour in the upper atmosphere are not known with certainty.