Polar night is a natural phenomenon where the sun remains entirely below the horizon for extended periods, ranging from days to several months, depending on latitude. While often described as “no sunlight,” it’s not a complete absence of light, as various forms of twilight can still provide ambient illumination.
The Phenomenon of Polar Night
Polar night is an astronomical event directly resulting from the Earth’s axial tilt and its orbit around the sun. The Earth is tilted on its axis by approximately 23.5 degrees relative to its orbital plane. As the Earth revolves around the sun, this tilt causes one of the poles to be angled away from the sun during its respective winter, preventing direct sunlight from reaching areas within the polar circles. While the sun is continuously below the horizon, the level of darkness varies. Civil twilight, for instance, occurs when the sun is between 0 and 6 degrees below the horizon, allowing enough light for outdoor activities without artificial illumination. As the sun dips further below, nautical and astronomical twilight follow, with the latter being dark enough for stargazing.
Countries Experiencing Extended Darkness
The phenomenon of polar night occurs in regions situated above the Arctic Circle in the Northern Hemisphere and within the Antarctic Circle in the Southern Hemisphere. It is important to note that entire countries do not experience this, but rather specific northern territories or settlements.
In Europe, Norway, Finland, and Sweden have areas that undergo polar night. Norwegian cities like Tromsø experience polar night from late November to late January. The Svalbard archipelago experiences even longer periods, with Longyearbyen seeing civil polar night from November to January. In Finland, the Lapland region, including towns like Rovaniemi and Utsjoki, and northern Sweden, with cities such as Kiruna, also have these periods.
Large parts of Russia, such as Murmansk, experience approximately six weeks without sunrise. In North America, northern Canada and Alaska, including Utqiaġvik (formerly Barrow), also experience polar night, lasting about 65 days in the latter. Greenland’s northern towns, such as Qaanaaq, also experience prolonged periods without sunlight.
While Antarctica is not a country, it is a continent where research stations endure a prolonged polar night during the Southern Hemisphere’s winter.
Living in Prolonged Night
Life in areas experiencing polar night requires various adaptations for humans. Communities rely on artificial lighting to mimic daylight, which aids in maintaining a sense of normalcy and regulating circadian rhythms. Light therapy lamps are often used to combat Seasonal Affective Disorder (SAD). Despite the extended darkness, residents engage in outdoor activities, such as skiing and dog sledding, often under the ambient light of the moon and stars, or the brief “blue hour” twilight around midday.
Wildlife in these regions also exhibits remarkable adaptations to survive the long, dark winters. Some animals, like Arctic ground squirrels, hibernate to conserve energy during periods of scarce food. Others, such as reindeer, have specialized eyes that utilize more UV light to navigate in low-light conditions. Many species develop thick fur, feathers, or blubber for insulation, and some, like emperor penguins, huddle together to share body heat. Marine life, including zooplankton, continues to be active, sometimes responding to lunar light cycles rather than solar ones.