Earth is a planet covered in habitable areas, but some of these places are a bit more hostile than others. In deserts, which are generally defined as areas that receive less than 10 inches (254 millimeters) of rain or snow per year, plants and animals must subsist on this scant rainfall.
The world's 10 largest deserts can be found on almost every continent, many of them forming in the shadow of massive mountain ranges that block moisture from nearby oceans or bodies of water. They are often the scene of unusual rock formations and, in some cases, amazing archaeological finds.
175,000 square miles (282,000 square kilometers)
The Chihuahuan desert on the US-Mexico border is larger than the state of California, according to New Mexico State University. Parts of it are found in the states of Texas, New Mexico and Arizona. Average rainfall is less than 9 inches (228 mm) per year, according to the Chihuahuan Desert Education Coalition.
Like many other deserts around the world, the Chihuahuan Desert formed in the rain shadow of both the Sierra Madre Occidental (to the west) and the Sierra Madre Oriental (to the east), both of which retain waters from the Pacific Ocean and the Gulf. from Mexico to flow inland.
Beneath the desert and Guadalupe Mountains in New Mexicoresides more than 300 caves. Those found in at least one of these regions, Carlsbad Caverns National Park, were created after sulfuric acid permeated the surrounding limestone.
Great Basin Wilderness
190,000 square miles (492,000 square kilometers)
Unlike any other desert in the United States, the Great Basin is a "cold" desert, where most of its precipitation falls as snow. Its geographic range includes most of Nevada, part of Utah, and parts of many neighboring states. Precipitation in the region ranges from 150 to 300 mm (6 to 12 in) per year.
The desert arose because it was in the desert.Rain shadows of the Sierra Nevada mountains in eastern California, according to the National Park Service. The desert, in turn, also affects the surrounding areas. The strong winds known asSanta Ana blows often in Southern Californiaafter forming in areas of high pressure in the Great Basin.
The Great Basin is also home to some unusual rocks, such as those found in central Nevada in 2009 and described asdripping like honey. The deformation occurs due to changes in the Earth's mantle, which is changing due to intense pressure and heat within the Earth's surface. The heavier material in the lithosphere sinks when the lighter mantle heats it, dragging material with it.
200,000 square miles (518,000 square kilometers)
Merriam-Webster describes the Syrian desert as a "barren wasteland." Covering much of Iraq, Jordan, Saudi Arabia and Syria, the region is made up of lava flows and was an "impenetrable barrier" to humans until recent decades. Now highways and pipelines crisscross the region, which receives less than 125mm of rain a year on average.
However, humans were able to reach parts of it in ancient times. An area now called "Stonehenge sirio”, was discovered in 2009. According to a 2012 Discovery News report, it contains stone circles and possibly tombs.
OIt is the Safa volcanic field near Damascus.It is the largest volcanic field in Arabia. The springs found in this area were active about 12,000 years ago, during the Holocene. More recently, a boiling lava lake was sighted in the region around 1850.
great victoria desert
250,000 square miles (647,000 square kilometers)
The Great Victorian Desert covers much of Australia and, according to one, consists mainly of parallel sand dunes and some salt lakes.Government Atlas of South Australia.The dunes are mostly red sand, originating from the Western Australian Shield, turning white further south as the sand washes in from the coast.
the australian governmentdescribes the regionthan one with "variable and unpredictable precipitation." Based on data between 1890 and 2005, precipitation is around 162 mm (6.4 in) per year. Due to the harsh environment, most of the desert is divided between aboriginal lands, wildlife sanctuaries, and crown lands, with no major cities.
One of the biggest ecological threats to the sertão comes from camels, whose ancestors were imported from India, Afghanistan and Arabia in the 19th century to work in the desert. A 2013 BBC report said thatabout 750,000 wild camelsDrink a recommended amount of water and damage the infrastructure. "Camels are almost exceptionally bright at surviving inland conditions," explorer Simon Reeve said in the report. "Introducing them was brilliant in the short term and a disaster in the long term."
260,000 square miles (673,000 square kilometers)
The Patagonian Desert is a large desert that covers much of Argentina. The desert and semi-desert zone stretches from the Atlantic Ocean to the Andes, with almost treeless plains, according to the Encyclopedia Britannica.
Like Death Valley in California, the Patagonian desert lies in the "rain shadow" of a high mountain range, in the case of Patagonia, the Andes. Some desert regions receive only 6 to 8 inches (160 to 200 mm) of rain a year, according to Dryland Climatology, a 2011 book by Florida State University meteorologist Sharon E. Nicholson.
"As air masses are forced over mountains and slopes, they warm up and their ability to hold water vapor increases," Susan Woodward, emeritus professor of geography at Radford University in Virginia, wrote of awebsite about deserts. On the leeward side of a mountain, he added, evaporation occurs faster than rainfall, creating a dry environment.
360,000 square miles (930,000 square kilometers)
The Kalahari desert covers much of South Africa, Botswana, and Namibia. According to the 1991 book The Kalahari Environment by David G. Thomas and Paul A. Shaw, it rains less than 20 inches (500 mm) per year on average, but some places receive less than 8 inches (200 mm) per year.
Described by the Encyclopedia Britannica as "featureless", the Kalahari is mostly covered by layers of sand that formed between 2.6 million and 11,700 years ago, probably due to the action of wind and rain. The sheets have remained largely unchanged ever since.
The Kalahari has also been a site of human activity for thousands of years. In one excavation area, Wonderwerk Cave in South Africa, archaeologists foundEvidence of fires lit approximately one million years ago.. A separate discovery of artifacts in the Tsodilo Hills in Botswana is implicated.Humans performed rituals 70,000 years ago.
800,000 square miles (1.3 million square kilometers)
The Gobi Desert, which includes large regions of China and Mongolia, is dry in some parts and more "monsonic" in others, meaning it has dry and wet seasons, according to the Encyclopedia Britannica. Precipitation ranges from about 2 to 8 inches per year (50 mm to 200 mm) depending on location. Especially in the eastern region, it rains a lot in summer, similar to the monsoon in the wetter regions.
In 2011, strange zigzag patterns appeared in the Gobi in Google images, leading to a host of conspiracy theories even involving aliens. But it probably took a while to get used to the lines.calibrate chinese spy satellitesto help the spacecraft orient itself in orbit, said Jonathon Hill, a research technician and mission planner at Arizona State University's Mars Space Flight Facility.
The Gobi is also a good place to hunt dinosaurs. A rare Tyrannosaurus Rex skeleton discovered in this region wasauctioned in 2012, which collected $1 million in a lawsuit.
900,000 square miles (2.3 million square kilometers)
The Arabian Desert includes Saudi Arabia and neighboring countries such as Oman and parts of Iraq. How dry and hot the desert is depends on where you are. The desert interior can reach an extremely dry 129 F (54 C). However, coastal and mountainous areas have more humidity, according to the Encyclopedia Britannica, and can also experience fog and dew during cooler periods of the day.
Average annual precipitation is less than 100 mm (4 in), but can vary from 0 to 20 in (0 to 500 mm) depending on the region. But human activities have artificially irrigated and greened parts of the desert.
Crop circles have exploded in abundance in Saudi Arabia over the past three decades, according to a series of Landsat images. This is possible because engineers have drilled into a "fossil" water source that is more than 20,000 years old, according to NASA. It is estimated that at current usage rates, the water will dry up in 50 years.
Make it happen
3.3 million square miles (8.6 million square kilometers)
OMake it happenit is distinguished not only by its enormous size, but also by the lack of precipitation. Annual rainfall in the world's second largest desert is less than 25mm per year. On the eastern side of the desert, precipitation can be as low as 0.2 inches (5 mm) per year, according to NASA.
Although water doesn't fall to the ground very often, it is common for raindrops to float over the desert as mist. There isn't much vegetation in the Sahara to contain the heat after the sun goes down, so temperatures can be quite cool at night. The sudden change between daytime and nighttime temperatures can cause fog.
The desert also offers avolcan alto, Emi Koussi, which is located in Chad, at the southeastern end of the Tibesti Range. At an altitude of 3,415 meters above sea level, there are lava flows and other volcanic features that appear to be two million years old. There is also an active thermal region on the southern flank of the volcano.
5.5 million square miles (14.2 million square kilometers)
Located around the South Pole, where thecoldest temperature on earthrecorded and without months of sunlight each year, it is sometimes hard to imagine frigid Antarctica as a desert. But it is the largest in the world because it receives very little rain, on average less than 50 millimeters a year, mainly in the form of snow.
Despite little snow, huge glaciers cover 99% of the surface of Antarctica. This is because the average temperature (minus 54 degrees Fahrenheit or minus 48 degrees Celsius) slows down evaporation. According to Discovering Antarctica, a project of Britain's Royal Geographical Society, snowfall is accumulating faster than Antarctica ablates over long periods of time.
parts ofAntarcticahowever, they are showing strong signs of warming along with global climate change. Temperatures on the Antarctic Peninsula have risen 2.5 degrees Celsius in the last 50 years, five times faster than on the rest of the planet. And scientists believe warm ocean water could melt Antarctic glaciers as they flow beneath floating ice tongues.
Elizabeth Howell is a regular contributor to Live Science and Space.com, along with other scientific publications. She is one of the few Canadian reporters specializing in space reporting. Elizabeth has a Bachelor of Journalism, Major in Science from Carleton University (Canada) and an M.Sc. Spatial Studies (distance learning) at the University of North Dakota. Elizabeth became a full-time freelancer after earning her M.Sc. in 2012. She has personally reported on three space shuttle launches and once spent two weeks at a remote facility in Utah where she pretended to be a Martian.