Antarctica: The Southernmost Continent
Antarctica is the coldest, windiest and driest continent. It contains 90 percent of all of the ice on Earth in an area just under 1.5 times the size of the United States. But the southernmost continent is much more than a big block of ice.
Lying in the Antarctic Circle that rings the southern part of the globe, Antarctica is the fifth largest continent. Its size varies through the seasons, as expanding sea ice along the coast nearly doubles the continent’s size in the winter. Almost all of Antarctica is covered with ice; less than half a percent of the vast wilderness is ice-free.
The continent is divided into two regions, known as East and West Antarctica. East Antarctica makes up two-thirds of the continent, and is about the size of Australia. Ice in this part of the continent averages 1.2 miles (2 kilometers) thick. West Antarctica, on the other hand, is a series of frozen islands stretching toward the southern tip of South America, forming an extension of the Andes Mountains. The two regions are separated by the Transantarctic Mountains, a range that stretches across the continent, and is sometimes completely covered by ice.
The ice of Antarctica is not a smooth sheet but a continuously changing expanse. Glaciers inch across the continent, cracking and breaking the ice. Crevasse fields with cracks hundreds of feet deep span the continent, hidden by only a shallow layer of snow. Icebergs fall along the coast, where shelves and glaciers break off into the sea.
Despite all its ice, Antarctica is classified as a desert because so little moisture falls from the sky. The inner regions of the continent receive an average of 2 inches (50 millimeters) of precipitation — primarily in the form of snow — each year. To put that into perspective, much of the Sahara desert gets twice as much rain each year. The coastal regions of Antarctica receive more falling moisture, but still average only 8 inches (200 mm) annually. Unlike most desert regions, however, the moisture doesn’t soak into the ground. Instead, the snow piles on top of itself.
Although little moisture falls from the sky, Antarctica is still battered by colossal blizzards. Like sandstorms in the desert, the wind picks snow up from the ground and blows vast white blankets. Winds can reach up to 200 mph (320 km/h).
Because it lies in the Southern Hemisphere, seasons in Antarctica are the opposite of seasons in the north. Summer runs from October to February and winter covers the remainder of the year. Antarctic summers average just above freezing, with the more mountainous East Antarctica colder than its western counterpart. The lowest temperature in the world, minus 89.6 degrees Celsius (minus 129.3 degrees Fahrenheit), was recorded at Vostok Station, a Russian research station in inland Antarctica.
The frozen southern continent wasn’t spotted until 1820. American seal hunter John Davis was the first to claim he landed on Antarctica in 1821, although some historians dispute his claim.
At the beginning of the 20th century, two groups of explorers set out across the desolate Antarctic landscape in a race to walk where no man had walked before. One team was led by Norwegian explorer Roald Amundsen, and the other by English naval officer Robert Scott. The groups spent 99 days racing one another to the South Pole, before Amundsen’s group claimed victory on Dec. 14, 1912. Scott and his crew made it to the pole four weeks later on Jan. 17, 1913, but did not make it back alive. A search party found Scott and his two remaining companions inside their sleeping bags in a small tent on the ice, 11 miles (17 kilometers) from the nearest cache of food and supplies.
In 1914, the Irish-born British explorer Ernest Shackleton set out to be the first to achieve an overland crossing of Antarctica through the South Pole — about an 1,800- mile (2,900 km) trek. Shackleton and his crew of 28 men faced incredible challenges and never made it across the continent, although they all eventually made it home alive, according to historical accounts.
Life below zero
The plant life on Antarctica is limited to a smattering of mosses, lichen and algae. Seasonal moss coverage on Antarctica, especially on it’s rapidly warming peninsula, has increased steadily over the last 50 years. Scientists expect the cold continent to become even more green as global temperatures continue to rise.
Despite the lack of lush greenery, and complete absence of amphibians, reptiles and terrestrial mammals, there remains an abundance of wildlife in and around Antarctica.
Large populations of penguins, whales, fish and invertebrates thrive along Antarctica’s coasts and frigid seas, especially in the summer. The male emperor penguin is the only warm-blooded animal to remain on the continent through the freezing winter while nesting on the single egg laid by its mate. (The female spends nine weeks at sea and returns in time for the egg to hatch.)
“You really see a complete spectrum of wildlife that you’ll see nowhere else in the world,” said Chuck Kennicutt, former president of the Scientific Committee on Antarctic Research. “It’s truly a beautiful and awe-inspiring location. A lot of people who go down early in their careers become dedicated to the Antarctic science for the rest of their lives,” Kennicutt said.
There are no indigenous people on the frozen continent. Today, human habitation exists at a variety of scientific research stations managed by more than 20 countries, including the United States, China, Russia, Japan, France and Germany.
The harsh weather and remote location does little to keep scientists away from the southern continent.
As many as 4,000 visiting scientists, spread out across 70 research stations, inhabit the continent during the summer, according to the Norwegian Polar Institute. The number of people drops to 1,000 during winter.
“There is so much we don’t know about all aspects of Antarctic research that the chance of a significant discovery is great,” said Dr. Alexandra Isern, acting section head of the National Science Foundation’s program director for Antarctic sciences division.
“I think, in part, it is the exploratory nature of Antarctic science that makes it so exciting for students and researchers,” said Isern.
Science on ice
Although Antarctica is largely a hub for climatologists, oceanographers and marine biologists, the frozen desert also attracts astronomers from across the globe. Thanks to its dry climate and the absence of light pollution, Antarctica is one of the best places on Earth to observe space.
Built in 2010, the IceCube is the first observatory of its kind. The facility houses a detector designed to identify high-energy neutrinos (subatomic particles as small as electrons) that originate within our galaxy and beyond. This ultra-sensitive device, which is buried about a mile into the Antarctic ice sheet, is the first gigaton neutrino detector ever built.
In recent decades, scientists using radar and satellite technology have discovered a system of rivers and lakes beneath Antarctica’s thick ice sheets. Studying these subglacial lakes, some of which are as large as North America’s Great Lakes, will help scientists refine their predictions of future, long-term ice sheet changes, according to a press release published by the National Science Foundation in 2016.
The vast, mostly vegetation-free expanse makes an excellent place to search for meteorites; the dark rocks stand out easily against the white backdrop, with few growing plants to obscure them. In 2013, a team of Belgian and Japanese scientists found a 40-pound (18 kilogram) meteorite on the East Antarctic plateau.
Antarctica’s freezing weather also makes it an ideal location to study how plants and animals adapt to extreme environmental conditions. For example, in 2013, scientists discovered that emperor penguins keep their feet from freezing using a handy adaptation known as countercurrent heat exchange. The blood vessels in their webbed, unprotected feet are wrapped around one another to minimize the amount of heat that is lost to the ground. Penguins also have the ability to adjust blood flow to their feet in response to changes in foot temperature — allowing just enough warm blood in to keep their feet from freezing.
Finding microbial life in some of the most desolate regions of Antarctica has given scientists hope of finding life on relatively inhospitable planets. In 2014, scientists identified Antarctic microbes capable of sustaining themselves on air alone.
Fun facts about Antarctica
In 1959, 12 countries with scientists stationed in and around Antarctica signed a agreement that “Antarctica shall continue forever to be used exclusively for peaceful purposes and shall not become the scene or object of international discord.” Since then, more than 38 countries have signed what is now known as the Antarctic Treaty.
Catherine Mikkelson, the wife of a Norwegian whaling captain, became the first woman to visit Antarctica in 1935.
As part of its effort to claim a portion of Antarctica, Argentina sent a pregnant woman to the continent. In January 1979, Emile Marco Palma became the first child born on the southernmost continent.
The area of Antarctica is approximately 5.4 million square miles (14 million square km). The continental U.S. is 3.6 million square miles (9.36 million square km).
There are no huskies pulling sleds in Antarctica. As of 1994, no non-native species may be taken to Antarctica. Motor vehicles are the primary method of transportation across the ice.
There at least two active volcanoes in Antarctica. The highest, Mount Erebus (12,448 feet; 3,794 meters), boasts a permanent lake. The other lies on Deception Island, off the Antarctic Peninsula. Although eruptions in 1967 and 1969 damaged science stations there, the island remains popular with tourists, who can bathe in the water warmed by the volcano while surrounded by ice.
If you throw boiling water into the air in Antarctica, it will instantly vaporize. Most of the particles will turn into steam, while others are instantly converted to small pieces of ice.
Millions of years ago, Antarctica had a much warmer climate and boasted evergreen forests and a variety of animals. Fossils from this earlier period provide scientists with clues about life before Antarctica became a vast icy shelf.
Melting Antarctica’s ice sheets would raise oceans around the world by 200 feet to 210 feet (60 to 65 m).
In 2000, the largest recorded icebergs broke free from the Ross Ice Shelf, a region the size of Texas. With a surface area of 4,250 square miles (11,000 square km) above water and 10 times the size beneath, the iceberg was approximately as large as Connecticut.
Additional reporting by Traci Pedersen, Live Science contributor. This article was updated on Sept. 21, 2018, by Live Science contributor Annie Roth.