Sahara desert interesting facts. Sahara Desert: secrets, riddles, facts
The Sahara Desert is one of the largest deserts in the world. The Sahara stretches across much of North Africa, covering 9 million square kilometers. In fact, the Sahara Desert covers 30% of the entire African continent. It is the hottest and hottest place in the world with summer temperatures that often exceed 57 degrees Celsius. The desert experiences annual rainfall and very powerful sandstorms, lifting sand 1000 meters into the air and moving the dunes.
We continue the topic of the deserts of Africa. In previous issues of LifeGlobe we told you about the White Desert in Egypt and the Namib Desert, now it’s the turn to tell you about the Sahara. Some say that the Sahara Desert was much larger before the first ice age, and some say that the Sahara Desert appeared 4,000 years ago. For example, German scientists, using methods of computer modeling of the Earth's climate, found that the Sahara became a desert 4,000 years ago. 10 thousand years ago, the world's largest desert was covered with grass and low bushes, but then the summer became hotter and the rains almost stopped. Naturally, many ancient civilizations disappeared, and all living things left the Sahara. According to scientists from the Potsdam Institute for Climate Research, the transformation of the Sahara into a desert was one of the most dramatic climate events on Earth in the foreseeable millennia. Why is the climate so variable? It turns out that the inclination of the earth's axis to the Sun is gradually changing: approximately 9 thousand years ago it was 24.14 degrees, now it is 23.45 degrees. Today the Earth comes closest to the Sun in January, ten thousand years ago - at the end of July. Subtle changes in the Earth's orbit around the Sun, amplified by interactions with the atmosphere, ocean and land, change the climate beyond recognition.
The climate of the Sahara is extraordinary. The humid factor is the wide position of the Sahara north and south of the Tropic of the North. This explains the fact that most of the desert is influenced by the northeast trade wind throughout the year. An additional influence on the climate is exerted by the Atlas mountain barrier located in the north, stretching from west to east and preventing the bulk of humid Mediterranean air from penetrating into the desert. In the south, from the Gulf of Guinea, wet masses freely enter the Sahara in summer, which, gradually drying out, reach its central parts. Extreme dryness of the air, a huge moisture deficit and, accordingly, extremely high evaporation are characteristic of the entire Sahara. According to the precipitation regime in the Sahara, three zones can be distinguished: northern, central and southern.
In the northern zone, precipitation falls in winter and its amount does not exceed 200 mm per year. To the south their number decreases, and in the central zone they fall sporadically. Their average size does not exceed 20 mm. Sometimes there is no precipitation at all for 2-3 years. However, such areas may experience unexpected downpours, causing severe flooding. The aridity of the Sahara also varies in the latitudinal direction, from west to east. On the Atlantic coast, heavy precipitation does not occur, since rare westerly winds are cooled by the Canary Current passing along the coast. There are frequent fogs here. At the tops of mountain ranges and highlands, the amount of precipitation increases slightly due to the condensation of water vapor. Sugar has a high degree of volatility. Its total annual value varies from 2500 to 5500 mm, which is more than 70 times the amount of precipitation.
The Sahara is characterized by high, one might say record-breaking, air temperatures. The average temperature of the coldest month, January, in almost the entire Sahara does not fall below 10 ° C. The average temperature of July in the central part of the desert is 35 ° C. In many places in the Sahara, temperatures above 50 ° C are recorded. Nights in the Sahara are cool, the temperature drops to 10 -15° C. On the plains, the temperature drop rarely reaches minus 5° C. Frosts are frequent in the mountains. The daily amplitudes of air temperatures are very large - up to 30 ° C, and on the soil surface - up to 70 ° C. At the beginning of summer, hot sirocco winds blow in the north of the Sahara, which come from the central part of the desert. Strong winds cause dust and sand storms; wind speeds during a storm reach 50 m/s. Masses of sand and small stones rise into the air, which have a very strong effect on people and animals. Storms arise as suddenly as they end, leaving behind clouds of slowly settling dry dusty “fog.” Tornadoes are also common in the Sahara.
The Sahara Desert consists of one quarter volcanic mountains, one quarter sand, rock and gravel plains, and small areas of permanent vegetation. Vegetation includes bushes, grasses and trees in the highlands and in the oases located along the river beds. Some of the plants are well adapted to this climate and grow within three days after rain and sow their seeds within two weeks afterwards. Only a small part of the Sahara Desert is fertile - these areas take moisture from underground rivers and oases.
There are 2 largest deserts in the world - the Sahara and Antarctica. The first thing that comes to mind when you hear the phrase “Sahara Desert” is endless sand and unbearable heat. “Sahara” is simply translated as “sand”. Our desert is truly huge - its area is about 9 million square kilometers and makes up about 30% of the area of the entire continent - Africa. So, interesting facts about the Sugar.
Nature
Sahara Desert - interesting facts about animals and plants. It is amazing how living organisms can survive in such an arid and hot area. Millions of years of evolution have made them resistant to such weather conditions and taught them to take advantage of any situation.
No matter how unsuitable for life this place may seem at first glance, about 4 thousand species of animals live here.
Even such an arid and hot area as Death Valley (not to be confused with the desert in the USA, there is also an arid place with a similar name in the Sahara) is inhabited by various species of animals. Surprisingly, among them there are 13 species of fish.
The lizard Moloch lives here, whose body is dotted with microscopic channels that collect all the moisture from the environment and transport it to Moloch’s mouth. Burying itself in wet sand, the lizard can get drunk.
The desert area is also home to scorpions, monitor lizards, snakes and camels. The latter can feed on thorns and cacti, extracting moisture from them.
Plant roots can extend up to 20 meters deep. In this way they receive moisture from groundwater.
The smallest representative of felines also lives here - the sand cat, whose body is only up to 40 centimeters in length. The tail occupies another 30 cm.
Weather
What can you say about the weather in the Sahara Desert? Interesting facts never cease to amaze us:
- The temperature changes are amazing. For example, during the day we can experience heat of over 50 degrees, but at night it will be very cold and the temperature will drop below zero.
- Snowfall was recorded twice in history on the Egyptian part of the Sahara.
- Monthly precipitation on average does not exceed 20 mm. For example, in St. Petersburg this figure is 662 mm, and in Moscow 708 mm. Rains in the desert (except for the fact that they happen very rarely) do not even have time to be absorbed into the ground - the temperature does its job and the moisture immediately evaporates.
- Once every few decades, heavy rain may fall in a particular place, after which the area is transformed, turning into a flowering steppe - plant seeds can wait a long time for moisture and germinate when it appears.
- About once a century, snow falls in the desert in such quantities that it is possible to play snowballs.
- In Saudi Arabia, which does not belong to the Sahara, but is geographically a continuation of it, there is no river that flows all year round - they all dry up for a certain period and then appear again.
Surely you have heard about such a concept as an “oasis” and wondered: “Where does it actually come from?” The fact is that under such oases you can find a huge underground lake, which in terms of water volume will exceed any land lake. The trees and lakes in such oases are fed by these sources.
Peculiarities
The interesting facts about the desert don’t end there. Undoubtedly, the desert is a real miracle of nature and a unique phenomenon. Have you ever seen geographic objects move right before your eyes?
- Dunes have this property. With the help of the wind they can move from place to place.
- And winds in the desert almost always blow due to the relatively flat surface of the earth. You will be very lucky if at least 25 days a year are windless.
- By the way, the dunes reach up to 200 meters in height.
- The highest point in the Sahara is Emi Kouso at 3415 meters.
- The Sahara was not always a desert. About 5 thousand years ago people lived on its modern territory. Naturally, people would not settle in a scorched wasteland. There were lakes and trees everywhere. After the onset of the desert, people came to the Nile Valley, forming the ancient Egyptian civilization.
The desert can be deceiving. It happens that in the distance a surface of water is seen, which a person can mistake for an oasis. But as soon as he gets close to it, the vision disappears. This is called a mirage. A mirage appears when there is excessive heat, which evaporates moisture. Moisture, in turn, refracts light, as a result of which various objects appear on the horizon that do not actually exist. The Flying Dutchman is a sailor's tale that arose due to mirages that sailors saw.
A truly endless sea of sun-scorched sand, stone and clay, enlivened only by rare green spots of oases and a single river - this is what the Sahara is. The gigantic scale of this largest desert in the world is simply amazing. Its territory occupies almost eight million square kilometers - it is larger than Australia and only slightly smaller than Brazil. Its hot expanses stretch for five thousand kilometers from the Atlantic to the Red Sea.
Nowhere else on Earth is there such a vast waterless space. There are places in the interior of the Sahara where there is no rain for years. Thus, in the In-Salah oasis, in the heart of the desert, in eleven years, from 1903 to 1913, it rained only once - in 1910, and only eight millimeters of precipitation fell.
These days the Sahara is not that difficult to reach. From the city of Algiers, along a good highway, you can reach the desert in one day. Through the picturesque El Kantara gorge - the “Gateway to the Sahara” - the traveler finds himself in places whose landscape does not at all resemble the expected “sand sea” with golden waves of dunes. To the left and right of the road, which runs along a rocky and clayey plain, rise small rocks, to which the wind and sand have given the intricate outlines of fairy-tale castles and towers.
Sandy deserts - ergs - occupy less than a quarter of the entire territory of the Sahara, the rest is made up of rocky plains, as well as clayey areas cracked by the scorching heat and salt-white depressions, salt marshes, giving rise to deceptive mirages in the unsteady haze of heated air.
In general, the Sahara is a vast tableau, the flat character of which is broken only by the depressions of the Nile and Niger valleys and Lake Chad. On this plain, only in three places do truly high, albeit small in area, mountain ranges rise. These are the Ahaggar and Tibesti highlands and the Darfur plateau, rising more than three kilometers above sea level.
The mountainous, completely dry landscapes of Ahaggar are often compared to lunar landscapes. But under natural rock overhangs, archaeologists discovered an entire Stone Age art gallery here. Cave paintings of ancient people depicted elephants and hippopotamuses, crocodiles and giraffes, rivers with floating boats and people harvesting... All this suggests that the climate of the Sahara was previously more humid, and most of the current desert was once savannah.
Now they are found only on the slopes of the Tibesti highlands and the flat, elevated plains of Darfur, where for a month or two a year, while there is rain, real rivers even flow through the gorges, and abundant springs feed the oases with water all year round.
In the rest of the Sahara, precipitation falls less than two hundred and fifty millimeters per year. Geographers call such areas arid. They are unsuitable for agriculture, and they can only be used to drive herds of sheep and camels in search of scarce food.
Here are the hottest places on our planet. For example, in Libya there are areas where the heat reaches fifty-eight degrees! And in some areas of Ethiopia, even the average annual temperature does not drop below plus thirty-five.
The sun regulates the entire life of the Sahara. Its radiation, taking into account rare cloudiness, low air humidity and lack of vegetation, reaches very high values. Daily temperatures here are characterized by large jumps. The difference between day and night temperatures reaches thirty degrees! Sometimes frosts occur at night in February, and on Ahaggar or Tibesti the temperature can drop to minus eighteen degrees.
Of all the atmospheric phenomena, the most difficult for a traveler to endure in the Sahara are prolonged storms. The desert wind, hot and dry, causes hardship even when it is transparent, but it is even more difficult for travelers when it carries dust or small grains of sand. Dust storms occur more often than sand storms. The Sahara is perhaps the dustiest place on Earth. From a distance, these storms look like fires that quickly engulf everything around, clouds of smoke from which rise high into the sky. With furious force they rush across the plains and mountains, blowing dust from the destroyed rocks on their way.
Storms in the Sahara are extremely powerful. The wind speed sometimes reaches fifty meters per second (remember that thirty meters per second is already a hurricane!). Caravan workers say that sometimes heavy camel saddles are carried away by the wind two hundred meters away, and stones the size of chicken eggs roll on the ground like peas.
Quite often, tornadoes occur when highly heated air from the sun-hot earth rapidly rises, capturing fine dust and carrying it high into the sky. Therefore, such whirlwinds are visible from afar, which, as a rule, allows the rider to save his life by avoiding a meeting with the “genie of the desert” in time, as the Bedouins call a tornado. A gray pillar rises into the air all the way to the clouds. The pilots encountered dust devils sometimes at an altitude of one and a half kilometers. It happens that the wind carries Saharan dust across the Mediterranean Sea to Southern Europe.
On the endless Saharan plains the wind almost always blows. It is estimated that in the desert there are only six windless days per hundred days. The hot winds of the Northern Sahara are especially notorious, capable of destroying the entire harvest in the oasis in a few hours. These winds - sirocco - blow more often at the beginning of summer. In Egypt, this wind is called khamsin (literally “fifty”), since it usually blows for fifty days after the spring equinox. During its almost two-month rampage, window glass that is not covered with shutters becomes frosted - this is how grains of sand carried by the wind scratch it.
And when there is calm in the Sahara and the air is filled with dust, the “dry fog” known to all travelers occurs. In this case, visibility completely disappears, and the sun appears as a dim spot and does not provide a shadow. Even wild animals lose their orientation at such moments. They say that there was a case when gazelles, usually very shy, calmly walked in a caravan during the “dry fog”, walking between people and camels.
Sahara loves to remind herself unexpectedly. It happens that a caravan sets off when there is no sign of bad weather. The air is still clean and calm, but some strange heaviness is already spreading in it. Gradually, the sky on the horizon begins to turn pink, then takes on a purple hue. It is somewhere far away that the wind has picked up and is driving the red sands of the desert towards the caravan. Soon the dim sun barely breaks through the quickly rushing sand clouds. It becomes difficult to breathe, it seems that the sand has replaced the air and filled everything around. Hurricane winds rush at speeds of up to hundreds of kilometers per hour. The sand burns, suffocates, knocks you down. Such a storm sometimes lasts a week, and woe to those whom it finds on the way.
But if the weather in the Sahara is calm and the sky is not covered with dust raised by the wind, it is difficult to find a more beautiful sight than the sunset in the desert. Perhaps only the aurora makes a greater impression on the traveler. Each time the sky in the rays of the setting sun amazes with a new combination of shades - blood red and pink-pearl, imperceptibly merging with soft blue. All this is piled on the horizon in several floors, burns and sparkles, growing into some bizarre, fabulous forms, and then gradually fades away. Then almost instantly an absolutely black night sets in, the darkness of which even the bright southern stars are unable to dispel.
Of course, the most desirable and most picturesque places in the Sahara are oases.
The Algerian oasis of El Ouedde lies in the golden-yellow sands of the Grand Erg Orient. It is connected to the outside world by an asphalt highway, but this is how it appears only on the map. In many places the wide road surface is thoroughly covered with sand. Telegraph poles are buried in a good two-thirds of it, and teams of workers with shovels and brooms are constantly clearing out drifts in one area or another. After all, the wind blows here all year round. And even a weak breeze, tearing off the tops of sandy dune hills, steadily moves sand waves from place to place. When the wind is strong, traffic on desert roads sometimes stops completely, and not for just one day.
Like all oases of the Sahara, El Ouedde is surrounded by palm groves. Date palms are the basis of life for local residents. In other oases, irrigation systems are installed in order to provide them with water, but in El Ouedde they do things simpler. In the dry bed of the river flowing through the oasis, deep funnel holes are dug and palm trees are planted in them. Water always flows under the rus house at a depth of five to six meters, so the roots of palm trees planted in this way easily reach the level of the underground stream and do not require irrigation.
Each crater contains between fifty and one hundred palm trees. The sinkholes are located in rows along the riverbed, and they are all threatened by a common enemy - sand. To prevent the slopes from sliding, the edges of the craters are reinforced with fences made of palm branches, but sand still seeps down. You have to take it out on donkeys or carry it in baskets all year round. In the heat of summer, this hard work can only be done at night, by torchlight or in the glow of the full moon. Water wells are also dug in these same craters. It is enough for drinking and for watering gardens. Camel droppings serve as fertilizer.
Dates and camel milk are the main food of fellah farmers. And the valuable muscat variety of dates is sold and even exported to Europe.
The capital of the Algerian Sahara - the oasis of Ouargla - differs from other oases in that it has... a real lake. This tiny town in the center of the desert has a huge reservoir, by local standards, with an area of four hundred hectares. It was formed from water released from palm plantations after irrigation. Water is always supplied to fields and date groves in excess, otherwise evaporation will lead to the accumulation of salts in the soil. Excess water along with salts is dumped into a depression next to the oasis. This is how artificial lakes arise in the Sahara.
True, most of them are not as large as in Ouargla, and do not withstand the mortal struggle with sand and sun. Most often, these are simply swampy depressions, the surface of which is covered with a dense, transparent, glass-like layer of salt.
But oases in the Sahara are rare, and from one “island of life” to another you have to travel along endless desert roads, overcoming the heat of the sun, hot wind, dust and... the temptation to turn off the road. Such a temptation often arises among travelers both on ancient caravan trails and on modern asphalt highways in these inhospitable lands. When the desired outlines of an oasis appear on the horizon before the traveler, exhausted by a long journey, the Arab guide only shakes his head negatively. He knows that there are still tens of kilometers to the oasis under the scorching sun, and what the traveler sees “with his own eyes” is just a mirage.
This optical illusion sometimes misleads even experienced people. Experienced travelers, who have walked through the sands on more than one expedition route and have studied the desert for many years, also happened to become victims of mirages. When you see palm groves and a lake, white clay houses and a mosque with a high minaret at a short distance, it is difficult to bring yourself to believe that in reality they are several hundred kilometers away. Experienced caravan guides sometimes fell under the power of the mirage. One day, sixty people and ninety camels died in the desert, following a mirage that carried them sixty kilometers away from the well.
In ancient times, travelers, to make sure whether it was a mirage or reality, lit a fire. If even a slight breeze blew in the desert, the smoke spreading along the ground quickly dispersed the mirage. For many caravan routes, maps have been drawn up, which indicate places where mirages are often found. These maps even mark what exactly is seen in a particular place: wells, oases, palm groves, mountain ranges, and so on.
And yet, in our time, when two modern highways run from north to south through the great desert, when multi-colored car caravans of the Paris-Dakar rally rush along it every year, and artesian wells drilled along the roads make it possible, if necessary, to walk to the nearest source of water, the Sahara gradually turns out to be that disastrous place that European travelers feared more than the Arctic snows and Amazonian jungles.
Increasingly, inquisitive tourists, fed up with beach idleness and contemplation of the ruins of Carthage and other picturesque ruins, go by car or on a camel deep into this unique region of the planet to breathe a breath of the night wind on the slopes of Ahaggar, hear the rustle of palm crowns in the green coolness of the oasis, see the graceful running gazelles and admire the colors of Saharan sunsets. And next to their caravan, running along the side of the road with a quiet rustle are the mysterious guardians of the peace of this hot but beautiful region - dusty-gray, wind-swept “genies of the desert.”
The air temperature in summer rises to 58°, and in winter it remains within 15-28° C.
Strong winds, during frequent sandstorms, can carry sand dust from the Sahara even to Europe.
An interesting fact is that there are maps on which areas where mirages are observed are marked. And more than 150 thousand of them are observed in the Sahara!
The mysterious and almost mystical eye of the Sahara.
Map of the ancient Sahara.
Vegetation
The vegetation cover of the Sahara includes 1,200 plant species. Most of them are xerophytes or ephemerals. Rocky areas seem lifeless, but even on such soil, seemingly unreal for life, you can find plants that amaze with their ability to adapt to the harsh conditions of the desert.
Rose of Jericho is a plant whose short branches seem to be pinching its seeds with fingers. When it rains, these “fingers” unclench and the seeds fall into moist soil, where they germinate very quickly.
Seeds of other plants also use every drop of moisture, but if there are no favorable conditions, they can sit in dry soil even for several years.
Lichens, small plants with spines and small leaves, spread on the sands and rocks. Gray, grey-green and yellow tones of the vegetation give a lifeless, sad look to the entire desert.
Shrubs and some tough grasses appear near the southern border of the Sahara, and wild pistachios, jujubes and oleanders can be found in the north.
Animal world
The fauna of the Sahara is poor in species, but quite rich in individuals. It includes animals that can move quickly in search of food and water, and can also endure all the harsh conditions of the desert.
The most typical of the Sahara are the oryx and addax antelopes, the dama gazelle, the Dorcas gazelle, and mountain goats. Due to their valuable skins and tasty meat, some species are at risk of extinction.
The most famous predators are jackals, foxes, hyenas, and cheetahs.
There are also birds - migratory and permanent. Among the permanent residents, the desert raven is especially popular.
Of the reptiles, lizards predominate, and there are also many snakes and turtles. And in some reservoirs, real crocodiles have been preserved.
Of course, living in the conditions of the Sahara is very difficult, but for many it is their native land, so they get to feel not only the severity, but also the caress of the desert.
Watch the video: Fearless Planet - Sahara Desert (Discovery: Fearless Planet. Episode 1 Sahara Desert).
Sahara. Tuareg salt caravan. Jim Brasher lives the life of a Tuareg in a salt caravan in the middle of the Sahara Desert.
In the wilds of Africa-2. Episode 3. Sahara. Life on the edge / Sahara. Life On The Edge
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Let's take a little break from serious topics and take a walk... through the Sahara Desert. Although in real life many of us are unlikely to be able to do this. The hot sand will not allow you to walk, as on some summer days the sand heats up to 80 degrees. And not everyone will be able to travel to Africa to take a tour through the desert by bus.
But we can take a virtual walk through the desert, and it’s also possible to learn interesting facts about this amazing desert. So, let's go!
The Sahara Desert is the largest desert in the world. It is located in the north and occupies a third of the African continent, which is slightly larger than the territory of a state such as Brazil. It stretches over an area of about 8.6 million km². From west to east the length of the desert is 4800 km, from north to south – 800-1200 km. On the western side, the desert is bordered by the Atlas Mountains and washed by the Mediterranean Sea, and on the east by the Red Sea, and on the south is the Sahel, a transitional region to the Sudanese savannah.
There are 10 countries in the desert: Algeria, Egypt, Western Sahara, Libya, Mauritania, Mali, Morocco, Sudan, Tunisia and Chad.
Life in the desert without water is impossible, but despite this, almost 2.5 million people live in the desert. They lead a sedentary lifestyle in oases in the valleys of the Nile and Niger rivers, where there is water and vegetation. The most numerous peoples of the desert are the Tuaregs and Berbers.
Features of the Sahara Desert
In our minds, the desert is sands and dunes that move with the help of the wind. But the sands in the Sahara Desert occupy only a fifth. The thickness of the sands is approximately 150 meters. The sands are swept into dunes, some of which sometimes reach the height of the Eiffel Tower in Paris. There is so much sand in the desert that if every person living on our planet had to scoop up sand using 10-liter buckets, they would have to carry out 3 million buckets.
70% of the desert territory is occupied by sandstone mountains, and the remaining 10% is sand and pebble wasteland, on which you cannot even see a trace of vegetation - it is barren rocky land and salt marshes.
Sahara Desert. Safari
In the Sahara there is a city called Tegazi, where the walls of the houses are made of rock salt. But the residents of this city are not afraid that their houses may dissolve from the rains. This is the driest place on Earth.
Climate
Until recently, it was believed that the Sahara Desert appeared about 5 million years ago. But scientists currently believe that the lands of modern Sahara became deserted only 2.7 thousand years ago.
It's still so hot in the desert! It’s simply impossible to be in the sun, or rather in the open. In summer, the air temperature rises to 58°, and in winter – to 15-28° C, which is typical for annual temperature changes. We have this temperature in the summer, and in the desert - in the winter! Such changes in annual temperatures are observed more often in the northern regions of the desert. But differences between day and night are observed within 20-25°.
The climate of the Sahara is determined by the northeast trade wind, and sandstorms often occur that even reach Europe. The climate in the north of the desert is dry subtropical, in the south it is dry tropical.
Water
Life in the desert is concentrated only near water. The largest river flowing through the Sahara Desert is the Nile. Its main tributaries - the Blue and White Nile - merge in the south-east of the Sahara, passing along the eastern side of the desert, flowing into the Mediterranean Sea. In the sixties of the 20th century, a large Nasser reservoir was created, which, when overflowed, formed Lake Toshka. The Niger River flows along the southwestern edge of the Sahara, near the inner delta of which there are lakes Fagibin, Garou, Niangai, and others.
Nile River near Luxor
Precipitation is rare in the desert. And what sometimes falls in the rains does not reach the ground, evaporating from the hot sand along the way. The Sahara is one of the places where evaporation is several times higher than the amount of precipitation.
But the most interesting thing is that under the sands of the Sahara there are huge “deposits” of groundwater, which are larger in area than our Baikal.
Saharan groundwater is used for irrigation. The first mention of irrigation systems dates back to the culture of Ancient Egypt. It is safe to say that the Egyptians developed a method of irrigating land. The Egyptians dug many parallel small canals perpendicular to the movement of the Nile. Some of them converge into basins, from which water was distributed over irrigated lands, providing them with moisture.
Mirages
Mirages are another interesting fact about the Sahara Desert. How many people, traveling through the desert, have suddenly seen oases with water and palm trees, thinking that it is located about 2-3 km from them? In fact, sometimes you have to walk 500 kilometers or more to get to the nearest water.
A mirage is an optical phenomenon in the atmosphere; a stream of light is refracted at the boundary between layers of air of different density and temperature.