Antarctic in the context of "Fortress of Solitude"

Polar deserts are the regions of Earth that fall under an ice cap climate (EF under the Köppen classification). Despite rainfall totals low enough to normally classify as a desert, polar deserts are distinguished from true deserts (BWh or BWk under the Köppen classification) by low annual temperatures and evapotranspiration. Most polar deserts are covered in ice sheets, ice fields, or ice caps, and they are also called white deserts.

Polar deserts are one of two polar biomes, the other being Arctic tundra. These biomes are located at the poles of Earth, covering much of the Antarctic in the southern hemisphere, and in the northern hemisphere extending from the Arctic into North America, Europe and Asia. Unlike the tundra that can support plant and animal life in the summer, polar deserts are largely barren environments, comprising permanent, flat layers of ice; due to the scarcity of liquid water, the same is also true of the few ice-free areas. However, there is evidence of some life in this seemingly inhospitable landscape: sediments of organic and inorganic substances in the thick ice hosting microbial organisms closely related to cyanobacteria, able to fix carbon dioxide from the melting water.

Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately 35 grams (1.2 oz) of dissolved salts (predominantly sodium (Na) and chloride (Cl) ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at 4 °C (39 °F)) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about −2 °C (28 °F). The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was −2.6 °C (27.3 °F).

Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurements based on different reference scales may be up to 0.14 units.

Livingston Island (Russian name Smolensk, 62°36′S 60°30′W / 62.600°S 60.500°W / -62.600; -60.500) is an Antarctic island in the Southern Ocean, part of the South Shetlands Archipelago, a group of Antarctic islands north of the Antarctic Peninsula. It was the first land discovered south of 60° south latitude in 1819, a historic event that marked the end of a centuries-long pursuit of the mythical Terra Australis Incognita and the beginning of the exploration and utilization of real Antarctica. The name Livingston, although of unknown derivation, has been well established in international usage since the early 1820s.

The history of exploration by citizens or subjects of the Russian Federation, the Soviet Union, the Russian Empire, the Tsardom of Russia and other Russian predecessor states forms a significant part of the history of Russia as well as the history of the world. At 17,075,400 square kilometres (6,592,850 sq mi), Russia is the largest country in the world, covering more than a ninth of Earth's landmass. In the times of the Soviet Union and the Russian Empire, the country's share in the world's landmass reached 1/6. Most of these territories were first discovered by Russian explorers (if indigenous peoples of inhabited territories are not counted). Contiguous exploration in Eurasia and the building of overseas colonies in Russian America were some of the primary factors in Russian territorial expansion.

Apart from their discoveries in Alaska, Central Asia, Siberia, and the northern areas surrounding the North Pole, Russian explorers have made significant contributions to the exploration of the Antarctic, Arctic, and the Pacific islands, as well as deep-sea and space explorations.

The Antarctic Circle is the most southerly of the five major circles of latitude that mark maps of Earth. The region south of this circle is known as the Antarctic, and the zone immediately to the north is called the Southern Temperate Zone. South of the Antarctic Circle, the Sun is above the horizon for 24 continuous hours at least once per year (and therefore visible at solar midnight) and the centre of the Sun (ignoring refraction) is below the horizon for 24 continuous hours at least once per year (and therefore not visible at solar noon); this is also true within the Arctic Circle, the Antarctic Circle’s counterpart in the Northern Hemisphere.

The position of the Antarctic Circle is not fixed and, not taking account of the nutation, currently runs 66°33′50.7″ south of the Equator. This figure may be slightly inaccurate because it does not allow for the effects of astronomical nutation, which can be up to 10″. Its latitude depends on the Earth's axial tilt, which fluctuates within a margin of more than 2° over a 41,000-year period, due to tidal forces resulting from the orbit of the Moon. Consequently, the Antarctic Circle is currently drifting southwards at a speed of about 14.5 m (48 ft) per year.

Tardigrades (/ˈtɑːrdɪɡreɪdz/ ), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them Kleiner Wasserbär 'little water bear'. In 1776, the Italian biologist Lazzaro Spallanzani named them Tardigrada, which means 'slow walkers'.

They live in diverse regions of Earth's biosphere – mountaintops, the deep sea, tropical rainforests, and the Antarctic. Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions – such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation – that would quickly kill most other forms of life. Tardigrades have survived exposure to outer space.

The sub-Antarctic zone is a physiographic region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Atlantic, Indian, and Pacific oceans, especially those situated north of the Antarctic Convergence. Subantarctic glaciers are, by definition, located on islands within the subantarctic region. All glaciers located on the continent of Antarctica are by definition considered to be Antarctic glaciers.

Peter I Island (Norwegian: Peter I Øy) is an uninhabited volcanic island in the Bellingshausen Sea, 450 kilometres (240 nmi) from continental Antarctica. It is claimed as a dependency of Norway and, along with Bouvet Island and Queen Maud Land, composes one of the three Norwegian dependent territories in the Antarctic and Subantarctic. The island measures approximately 11 by 19 kilometres (7 by 12 mi), with an area of 156 km (60 sq mi); its highest point is the ultra-prominent, 1,640-metre-tall (5,380 ft) Lars Christensen Peak. Nearly all the island is covered by a glacier, and it is surrounded most of the year by pack ice, making it inaccessible during these times. There is little vertebrate animal life on the island, apart from some seabirds and seals.

The island was first sighted by Fabian Gottlieb von Bellingshausen on 21 January 1821 and was named after Peter I of Russia. Not until 2 February 1929 did anyone set foot on the island, when Nils Larsen and Ola Olstad's Second Norvegia Expedition, financed by Lars Christensen, was successful. They claimed it for Norway, which annexed it in 1931 and made it a dependency in 1933. The next landing occurred in 1948, and the island has been subject to some scientific research and a limited amount of tourism. The island became subject to the Antarctic Treaty in 1961. Since 1987, there has been an automated meteorological station on the island. Three amateur radio DX-peditions have visited the island, and there are sporadic landings by tourists.

The five main latitude regions of Earth's surface comprise geographical zones, divided by the major circles of latitude. The differences between them relate to climate. They are as follows:

1. The North Frigid Zone, between the North Pole at 90° N and the Arctic Circle at 66°33′50.7″ N, covers 4.12% of Earth's surface.
2. The North Temperate Zone, between the Arctic Circle at 66°33′50.7″ N and the Tropic of Cancer at 23°26′09.3″ N, covers 25.99% of Earth's surface.
3. The Torrid Zone, between the Tropic of Cancer at 23°26′09.3″ N and the Tropic of Capricorn at 23°26′09.3″ S, covers 39.78% of Earth's surface.
4. The South Temperate Zone, between the Tropic of Capricorn at 23°26′09.3″ S and the Antarctic Circle at 66°33′50.7″ S, covers 25.99% of Earth's surface.
5. The South Frigid Zone, from the Antarctic Circle at 66°33′50.7″ S and the South Pole at 90° S, covers 4.12% of Earth's surface.

On the basis of latitudinal extent, the globe is divided into three broad heat zones.