Geography (English)

Reading Material for Geography in English

Great Geographical entities on earth: Where are they located?

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The Himalayas

The Himalayas form a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has many of the Earth’s highest peaks, including the highest, Mount Everest. The Himalayas include over fifty mountains exceeding 7,200 m (23,600 ft) in elevation, including ten of the fourteen 8,000-metrepeaks. By contrast, the highest peak outside Asia (Aconcagua, in the Andes) is 6,961 m (22,838 ft) tall Lifted by the subduction of the Indian tectonic plate under the Eurasian Plate, the Himalayan mountain range runs west-northwest to east-southeast in an arc 2,400 km (1,500 mi) long. Its western anchor, Nanga Parbat, lies just south of the northernmost bend of Indus river. Its eastern anchor, Namcha Barwa, is just west of the great bend of the Yarlung Tsangpo River (upper stream of the Brahmaputra River). The Himalayan range is bordered on the northwest by the Karakoram and the Hindu Kush ranges. To the north, the chain is separated from the Tibetan Plateau by a 50–60 km (31–37 mi) wide tectonic valley called the Indus-Tsangpo Suture. Towards the south the arc of the Himalaya is ringed by the very low Indo-Gangetic Plain. The range varies in width from 350 km (220 mi) in the west (Pakistan) to 150 km (93 mi) in the east (Arunachal Pradesh). The Himalayas are distinct from the other great ranges of central Asia, although sometimes the term ‘Himalaya’ (or ‘Greater Himalaya’) is loosely used to include the Karakoram and some of the other ranges.

The Alps

The Alps are the highest and most extensive mountain range system that lies entirely in Europe,  separating Southern from Central and Western Europe and stretching approximately 1,200 kilometres (750 mi) across eight Alpine countries (from west to east):  France, Switzerland, Italy, Monaco, Liechtenstein, Austria, Germany, and Slovenia. The mountains were formed over tens of millions of years as the African and Eurasian tectonic plates collided. Extreme shortening caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc and the Matterhorn. Mont Blanc spans the French–Italian border, and at 4,810 m (15,781 ft) is the highest mountain in the Alps. The Alpine region area contains about a hundred peaks higher than 4,000 metres (13,000 ft).The altitude and size of the range affects the climate in Europe; in the mountains precipitation levels vary greatly and climatic conditions consist of distinct zones. Wildlife such as ibex live in the higher peaks to elevations of 3,400 m (11,155 ft), and plants such as Edelweiss grow in rocky areas in lower elevations as well as in higher elevations. Evidence of human habitation in the Alps goes back to the Paleolithic era. A mummified man, determined to be 5,000 years old, was discovered on a glacier at the Austrian–Italian border in 1991.

Mariana Trench

Mariana Trench, also called Marianas Trench, deep-sea trench in the floor of the western North Pacific Ocean, the deepest such trench known on Earth, located mostly east as well as south of the Mariana Islands. It is part of the western Pacific system of oceanic trenches coinciding with subduction zones—points where two adjacent tectonic plates collide, one being forced below the other. An arcing depression, the Mariana Trench stretches for more than 1,580 miles (2,540 km) with a mean width of 43 miles (69 km). The greatest depths are reached in Challenger Deep, a smaller steep-walled valley on the floor of the main trench southwest of Guam. The Mariana Trench, which is situated within the territories of the U.S. dependencies of the Northern Mariana Islands and Guam, was designated a U.S. national monument in 2009. The first attempt to measure the depth of the trench was made in 1875 during the Challenger Expedition (1872–76), when a sounding of 26,850 feet (8,184 metres) was obtained near the southern end of the trench. In 1899 Nero Deep (31,693 feet [9,660 metres]) was discovered southeast of Guam. That sounding was not exceeded until a 32,197-foot (9,813-metre) hole was found in the vicinity 30 years later. In 1957, during the International Geophysical Year, the Soviet research ship Vityaz sounded a new world record depth of 36,056 feet (10,990 metres) in Challenger Deep. That value was later increased to 36,201 feet (11,034 metres). Since then several measurements of the Challenger Deep have been made, using increasingly sophisticated electronic equipment.

The Bermuda Triangle

The Bermuda Triangle, also known as the Devil’s Triangle or Hurricane Alley, is a loosely-defined region in the western part of the North Atlantic Ocean, where a number of aircraft and ships are said to have disappeared under mysterious circumstances. Most reputable sources dismiss the idea that there is any mystery. The vicinity of the Bermuda Triangle is amongst the most heavily traveled shipping lanes in the world, with ships frequently crossing through it for ports in the Americas, Europe and the Caribbean islands. Cruise ships and pleasure craft regularly sail through the region, and commercial and private aircraft routinely fly over it. Popular culture has attributed various disappearances to the paranormal or activity by extraterrestrial beings. Documented evidence indicates that a significant percentage of the incidents were spurious, inaccurately reported, or embellished by later authors. The earliest suggestion of unusual disappearances in the Bermuda area appeared in a September 17, 1950, article published in The Miami Herald (Associated Press) by Edward Van Winkle Jones. Two years later, Fate magazine published “Sea Mystery at Our Back Door”, a short article by George X. Sand covering the loss of several planes and ships, including the loss of Flight 19, a group of five US Navy Grumman TBM Avenger torpedo bombers on a training mission.

The Gobi Desert 

The Gobi Desert is a large desert or brushland region in Asia. It covers parts of Northern and Northeastern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Taklamakan Desert to the west, by the Hexi Corridor and Tibetan Plateau to the southwest, and by the North China Plain to the southeast. The Gobi is notable in history as part of the great Mongol Empire, and as the location of several important cities along the Silk Road.The Gobi is a rain shadow desert, formed by the Tibetan Plateau blocking precipitation from the Indian Ocean reaching the Gobi territory.

The Sahara Desert

The Sahara or ‘the Great Desert’) is a desert located on the African continent. It is the largest hot desert in the world, and the third largest desert overall after Antarctica and the Arctic.Its area of 9,200,000 square kilometres (3,600,000 sq mi) is comparable to the area of China or the United States.The name ‘Sahara’ is derived from a dialectal Arabic word for “desert”, ṣaḥra. The desert comprises much of North Africa, excluding the fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb, and the Nile Valley in Egypt and Sudan. It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south, it is bounded by the Sahel, a belt of semi-arid tropical savanna around the Niger River valley and the Sudan Region of Sub-Saharan Africa. The Sahara can be divided into several regions including: the western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains, the Ténéré desert, and the Libyan Desert.

The Kalahari Desert

The Kalahari Desert is a large semi-arid sandy savanna in Southern Africa extending for 900,000 square kilometres (350,000 sq mi), covering much of Botswana, parts of Namibia and regions of South Africa. It is not to be confused with the Angolan, Namibian and S. African Namib coastal desert, whose name is of Khoekhoegowa borigin and means “vast place”. Drainage of the desert is by dry valleys, seasonally inundated pans and the large salt pans of the Makgadikgadi Pan in Botswana and Etosha Pan in Namibia. The only permanent river, the Okavango, flows into a delta in the northwest, forming marshes that are rich in wildlife. Ancient dry riverbeds—called omuramba—traverse the central northern reaches of the Kalahari and provide standing pools of water during the rainy season. A semi-desert, with huge tracts of excellent grazing after good rains, the Kalahari supports more animals and plants than a true desert, such as the Namib Desert to the west. There are small amounts of rainfall and the summer temperature is very high. The driest areas usually receive 110–200 millimetres (4.3–7.9 in) of rain per year, and the wettest just a little over 500 millimetres (20 in). The surrounding Kalahari Basin covers over 2,500,000 square kilometres (970,000 sq mi) extending further into Botswana, Namibia and South Africa, and encroaching into parts of Angola, Zambia and Zimbabwe. Numerous pans exist within the Kalahari, including the Groot-vloer Pan and Verneukpan where evidence of a wetter climate exists in the form of former contouring for capturing of water. This and other pans, as well as river bottoms, were written about extensively at Sciforums by an article by Walter Wagner regarding the extensive formerly wet areas of the Kalahari. The Kalahari is extensive and extends further north where abandoned extensive roadways also exist

The Thar Desert

The Thar Desert, also known as the Great Indian Desert, is a large arid region in the northwestern part of the Indian subcontinent that covers an area of 200,000 km2 (77,000 sq mi) and forms a natural boundary between India and Pakistan. It is the world’s 17th largest desert, and the world’s 9th largest subtropical desert. About 85% of the Thar Desert is located within India, with the remaining 15% in Pakistan. In India, it covers about 170,000 km2 (66,000 sq mi), and the remaining 30,000 km2 (12,000 sq mi) of the desert is within Pakistan. The Thar desert forms approximately 5%(~4.56%) of the total geographic area of India. More than 60% of the desert lies in the state of Rajasthan, and extends into Gujarat, Punjab, and Haryana.The desert comprises a very dry part, the Marusthali region in the west, and a semidesert region in the east with fewer sand dunes and slightly more precipitation.

Arabian Desert

The Arabian Desert is a vast desert wilderness in Western Asia. It stretches from Yemen to the Persian Gulf and Oman to Jordan and Iraq. It occupies most of the Arabian Peninsula, with an area of 2,330,000 square kilometers (900,000 sq mi). It is the fifth largest desert in the world, and the largest in Asia. At its center is Ar-Rub’al-Khali (The Empty Quarter), one of the largest continuous bodies of sand in the world.Gazelles, oryx, sand cats, and spiny-tailed lizards are just some of the desert-adapted species that survive in this extreme environment, which features everything from red dunes to deadly quicksand. The climate is mostly dry (the major part receives around 100 mm (3.9 in) of rain per year but some very rare places receives down to 50 mm), and temperatures oscillate between very high heat and seasonal night time freezes. It is part of the deserts and xeric shrublands biome and the Palearctic ecozone.

Atacama Desert

The Atacama Desert  is a desert plateau in South America covering a 1000-km (600-mi) strip of land on the Pacific coast, west of the Andes mountains. The Atacama desert is one of the driest places in the world (the driest being the McMurdo Dry Valleys , as well as the only true desert to receive less precipitation than the polar deserts. According to estimates, the Atacama Desert occupies 105,000 km2 (41,000 sq mi), or 128,000 km2 (49,000 sq mi) if the barren lower slopes of the Andes are included. Most of the desert is composed of stony terrain, salt lakes (salares), sand, and felsic lava that flows towards the Andes. The desert owes its extreme aridity to a constant temperature inversion due to the cool north-flowing Humboldt ocean current, and to the presence of the strong Pacific anticyclone. The most arid region of the Atacama desert is situated between two mountain chains (the Andes and the Chilean Coast Range) of sufficient height to prevent moisture advection from either the Pacific or the Atlantic Oceans, a two-sided rain shadow.

Sonoran Desert

The Sonoran Desert  is a North American desert which covers large parts of the Southwestern United States in Arizona and California and of Northwestern Mexico in Sonora, Baja California, and Baja California Sur. It is the hottest desert in Mexico. It has an area of 260,000 square kilometers (100,000 sq mi). The western portion of the United States–Mexico border passes through the Sonoran Desert. The desert contains a variety of unique and endemic plants and animals, such as the saguaro (Carnegiea gigantea) and organ pipe cactus (Stenocereus thurberi).

Amazon River

The Amazon River  in South America is the largest river by discharge volume of water in the world, and by some definitions it is the longest. The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon’s most distant source, until a 2014 study found it to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru.The Mantaro and Apurímac join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro to form what Brazilians call the Amazon at the Meeting of Waters  at Manaus, the river’s largest city. At an average discharge of about 209,000 cubic metres per second (7,400,000 cu ft/s; 209,000,000 L/s; 55,000,000 USgal/s)—approximately 6,591 cubic kilometres per annum (1,581 cu mi/a), greater than the next seven largest independent rivers combined—the Amazon represents 20% of the global riverine discharge to the ocean. The Amazon basin is the largest drainage basin in the world, with an area of approximately 7,050,000 square kilometres (2,720,000 sq mi). The Amazon River is disputed longest river in the world (Brazilian government claims it to be longer than the Nile, while every other nation claims that the Nile is the longest River in the world). The portion of the river’s drainage basin in Brazil alone is larger than any other river’s basin. The Amazon enters Brazil with only one-fifth of the flow it finally discharges into the Atlantic Ocean, yet already has a greater flow at this point than the discharge of any other river.

Brahamaputra River

The Brahmaputra is one of the major rivers of Asia, a trans-boundary river which flows through China, India and Bangladesh. As such, it is known by various names in the region such as   Brohmoputro noi in Assam, masculine form of the tatsama ‘nodi “river”) Brohmoputro; Brahmaputra in Sanskrit ;  and yar klung gtsang po Yarlung Tsangpo in Tibetan language. It is also called Tsangpo-Brahmaputra (when referring to the whole river including the stretch within Tibet). The Manas River, which runs through Bhutan, joins it at Jogighopa, in India. It is the ninth largest river in the world by discharge, and the 15th longest. With its origin in the Manasarovar Lake region, located on the northern side of the Himalayas in Burang County of Tibet as the Yarlung Tsangpo River, it flows across southern Tibet to break through the Himalayas in great gorges (including the Yarlung Tsangpo Grand Canyon) and into Arunachal Pradesh (India). It flows southwest through the Assam Valley as Brahmaputra and south through Bangladesh as the Jamuna (not to be mistaken with Yamuna of India). In the vast Ganges Delta, it merges with the Padma, the popular name of the river Ganges in Bangladesh, and finally the Meghna and from here it is known as Meghna before emptying into the Bay of Bengal. About 2,899.9 km (1,801.9 mi) long, the Brahmaputra is an important river for irrigation and transportation. The basin, especially south of Tibet, is characterized by high levels of rainfall. Kanchenjunga (8,586 m) is the only peak above 8,000 m, hence is the highest point within the Brahmaputra basin.

Ganges River

The Ganges  flows through the nations of India and Bangladesh. The 2,525 km (1,569 mi) river rises in the western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of North India. After entering West Bengal, it divides into two rivers: the Hooghly and the Padma River. The Hooghly, or Adi Ganga, flows through several districts of West Bengal and into the Bay of Bengal near Sagar Island. The other, the Padma, also flows into and through Bangladesh, and joins the Meghna river which ultimately empties into the Bay of Bengal.

The Ganges is highly polluted. Pollution threatens not only humans, but also more than 140 fish species, 90 amphibian species and the endangered Ganges river dolphin. The Ganges is a major source of global ocean plastic pollution. The levels of fecal coliform bacteria from human waste in the waters of the river near Varanasi are more than 100 times the Indian government’s official limit. The Ganga Action Plan, an environmental initiative to clean up the river, has been a major failure thus far, due to rampant corruption, lack of will on behalf of the government and its bureaucracy, lack of technical expertise, poor environmental planning, and lack of support from religious authorities.

The Indus River

The Indus River (locally called Sindhu) is one of the longest rivers in Asia. Originating in the Tibetan Plateau in the vicinity of Lake Manasarovar, the river runs a course through the Ladakh region of Jammu and Kashmir, India, towards the Gilgit-Baltistan region of Pakistan and the Hindukush ranges, and then flows in a southerly direction along the entire length of Pakistan to merge into the Arabian Sea near the port city of Karachi in Sindh. It is the longest river and national river of Pakistan. The river has a total drainage area exceeding 1,165,000 km2 (450,000 sq mi). Its estimated annual flow stands at around 243 km3(58 cu mi), twice that of the Nile River and three times that of the Tigris and Euphrates rivers combined, making it one of the largest rivers in the world in terms of annual flow. The Zanskar is its left bank tributary in Ladakh. In the plains, its left bank tributary is the Panjnad which itself has five major tributaries, namely, the Chenab, Jhelum, the Ravi, the Beas, and the Sutlej. Its principal right bank tributaries are the Shyok, the Gilgit, the Kabul, the Gomal, and the Kurram. Beginning in a mountain spring and fed with glaciers and rivers in the Himalayas, the river supports ecosystems of temperate forests, plains and arid countryside.

The Yellow River

Yellow River or Huang He  is the second longest river in China, after the Yangtze River, and the sixth longest river system in the world at the estimated length of 5,464 km (3,395 mi). Originating in the Bayan Har Mountains in Qinghai province of Western China, it flows through nine provinces, and it empties into the Bohai Sea near the city of Dongying in Shandong province. The Yellow River basin has an east–west extent of about 1,900 kilometers (1,180 mi) and a north–south extent of about 1,100 km (680 mi). Its total drainage area is about 752,546 square kilometers (290,560 sq mi). Its basin was the birthplace of ancient Chinese civilization, and it was the most prosperous region in early Chinese history. There are frequent devastating floods and course changes produced by the continual elevation of the river bed, sometimes above the level of its surrounding farm fields.

Volga

The Volga  is the longest river in Europe with a catchment area of 1,350,000 square kilometres. It is also Europe’s largest river in terms of discharge and drainage basin. The river flows through central Russia and into the Caspian Sea, and is widely regarded as the national river of Russia.

Eleven of the twenty largest cities of Russia, including the capital, Moscow, are located in the Volga’s drainage basin. Rising in the Valdai Hills 225 meters (738 ft) above sea level northwest of Moscow and about 320 kilometers (200 mi) southeast of Saint Petersburg, the Volga heads east past Lake Sterzh, Tver, Dubna, Rybinsk, Yaroslavl, Nizhny Novgorod, and Kazan. From there it turns south, flows past Ulyanovsk, Tolyatti, Samara, Saratov and Volgograd, and discharges into the Caspian Sea below Astrakhan at 28 meters (92 ft) below sea level. At its most strategic point, it bends toward the Don (“the big bend”). Volgograd, formerly Stalingrad, is located there. The fertile river valley provides large quantities of wheat, and also has many mineral riches. A substantial petroleum industry centers on the Volga valley. Other resources include natural gas, salt, and potash. The Volga Delta and the nearby Caspian Sea offer superb fishing grounds. Astrakhan, at the delta, is the center of the caviar industry.

The Danube River

The Danube is Europe’s second longest river, after the Volga. It is located in Central and Eastern Europe. The Danube was once a long-standing frontier of the Roman Empire, and today flows through 10 countries, more than any other river in the world. Originating in Germany, the Danube flows southeast for 2,850 km (1,770 mi), passing through or bordering Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before draining into the Black Sea. Its drainage basin extends into nine more countries. The Danube river basin is home to fish species such as pike, zander, huchen, Wels catfish, burbot and tench. It is also home to a large diversity of carp and sturgeon, as well as salmon and trout. A few species of euryhaline fish, such as European seabass, mullet, and eel, inhabit the Danube Delta and the lower portion of the river. Since ancient times, the Danube has become a traditional trade route in Europe, nowadays 2,415 km (1,501 mi) of its total length being navigable. The river is also an important source of energy and drinking water.

Rhine River

The Rhine  is one of the major European rivers, which has its sources in Switzerland and flows in a mostly northerly direction through Germany and The Netherlands, emptying into the North Sea. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps, forms part of the Swiss-Liechtenstein, Swiss-Austrian, Swiss-German and then the Franco-German border, then flows through the German Rhineland and the Netherlands and eventually empties into the North Sea. The largest city on the Rhine is Cologne, Germany, with a population of more than 1,050,000 people. It is the second-longest river in Central and Western Europe (after the Danube), at about 1,230 km (760 mi),with an average discharge of about 2,900 m3/s (100,000 cu ft/s). The Rhine and the Danube formed most of the northern inland frontier of the Roman Empire and, since those days, the Rhine has been a vital and navigable waterway carrying trade and goods deep inland. Its importance as a waterway in the Holy Roman Empire is supported by the many castles and fortifications built along it. In the modern era, it has become a symbol of German nationalism.Other important cities on the Rhine are Düsseldorf (Germany), Rotterdam (Netherlands), Strasbourg (France) and Basel (Switzerland).

The Kama

The Kama is a river 1,805 kilometres (1,122 mi) long in Russia. It is the longest left tributary of the Volga and the largest one in discharge. At their confluence, in fact, the Kama is even larger than the Volga. It starts in the Udmurt Republic, near Kuliga, flowing northwest for 200 kilometres (120 mi), turning northeast near Loyno for another 200 kilometres (120 mi), then turning south and west in Perm Krai, flowing again through the Udmurt Republic and then through the Republic of Tatarstan, where it meets the Volga.

The Moskva River

The Moskva River  is a river of western Russia. It rises about 140 km (90 mi) west of Moscow, and flows roughly east through the Smolensk and Moscow Oblasts, passing through central Moscow. About 110 km (70 mi) south east of Moscow, at the city of Kolomna, it flows into the Oka River, itself a tributary of the Volga, which ultimately flows into the Caspian Sea. The river is 503 km (313 mi) long, with a vertical drop of 155 m (509 ft) (long-term average In Moscow, the river freezes occasionally; during an unusually warm winter in 2006–2007, ice began melting on January 25.

The Seine

The Seine  is a 777-kilometre-long (483 mi) river and an important commercial waterway within the Paris Basin in the north of France. It rises at Source-Seine, 30 kilometres (19 mi) northwest of Dijon in northeastern France in the Langres plateau, flowing through Paris and into the English Channel at Le Havre (and Honfleur on the left bank). It is navigable by ocean-going vessels as far as Rouen, 120 kilometres (75 mi) from the sea. Over 60 percent of its length, as far as Burgundy, is negotiable by commercial riverboats, and nearly its whole length is available for recreational boating; excursion boats offer sightseeing tours of the river banks in Paris, lined with top monuments including Notre-Dame, the Eiffel Tower, the Louvre Museum and Musée d’Orsay.

Tigris River

The Tigris is the eastern of the two great rivers that define Mesopotamia, the other being the Euphrates. The river flows south from the mountains of southeastern Turkey through Iraq and empties into the Persian Gulf. The Tigris is 1,750 km long, rising in the Taurus Mountains of eastern Turkey about 25 km southeast of the city of Elazig and about 30 km from the headwaters of the Euphrates. The river then flows for 400 km through Turkish territory before becoming the border between Syria and Turkey. This stretch of 44 km is the only part of the river that is located in Syria. Baghdad, the capital of Iraq, stands on the banks of the Tigris. The port city of Basra straddles the Shatt al-Arab. In ancient times, many of the great cities of Mesopotamia stood on or near the Tigris, drawing water from it to irrigate the civilization of the Sumerians. Notable Tigris-side cities included Nineveh, Ctesiphon, and Seleucia, while the city of Lagash was irrigated by the Tigris via a canal dug around 2900 B.C.

Potomac River

The Potomac River is located within the Mid-Atlantic region of the United States and flows from the Potomac Highlands into the Chesapeake Bay. The river (main stem and North Branch) is approximately 405 miles (652 km) long, with a drainage area of about 14,700 square miles (38,000 km2). In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the United States and the 21st largest in the United States. Over 5 million people live within the Potomac watershed. The river forms part of the borders between Maryland and Washington, D.C., on the left descending bank and West Virginia and Virginia on the river’s right descending bank. The majority of the lower Potomac River is part of Maryland. Exceptions include a small tidal portion within the District of Columbia, and the border with Virginia being delineated from “point to point” (thus various bays and shoreline indentations lie in Virginia). Except for a small portion of its headwaters in West Virginia, the North Branch Potomac River is considered part of Maryland to the low water mark on the opposite bank. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, which lie in Virginia.

Hudson River

The Hudson River is a 315-mile (507 km) river that flows from north to south primarily through eastern New York in the United States. The river originates in the Adirondack Mountains of Upstate New York, flows southward through the Hudson Valley to the Upper New York Bay between New York City and Jersey City. It eventually drains into the Atlantic Ocean at New York Harbor. The river serves as a political boundary between the states of New Jersey and New York at its southern end. Further north, it marks local boundaries between several New York counties. The lower half of the river is a tidal estuary, deeper than the body of water into which it flows, occupying the Hudson Fjord, an inlet which formed during the most recent period of North American glaciation, estimated at 26,000 to 13,300 years ago. Tidal waters influence the Hudson’s flow from as far north as the city of Troy. The river is named after Henry Hudson, an Englishman sailing for the Dutch East India Company, who explored it in 1609, and after whom Hudson Bay in Canada is also named.

Nile River

The Nile is a major north-flowing river in northeastern Africa, and is the longest river in Africa and the disputed longest river in the world (Brazilian government claims that the Amazon River is longer than the Nile). The Nile, which is about 6,650 km (4,130 mi) long, is an “international” river as its drainage basin covers eleven countries, namely, Tanzania, Uganda, Rwanda, Burundi, the Democratic Republic of the Congo, Kenya, Ethiopia, Eritrea, South Sudan, Republic of the Sudan and Egypt. In particular, the Nile is the primary water source of Egypt and Sudan.The river Nile has two major tributaries, the White Nile and Blue Nile. The White Nile is considered to be the headwaters and primary stream of the Nile itself. The Blue Nile, however, is the source of most of the water and silt. The White Nile is longer and rises in the Great Lakes region of central Africa, with the most distant source still undetermined but located in either Rwanda or Burundi. It flows north through Tanzania, Lake Victoria, Uganda and South Sudan. The Blue Nile begins at Lake Tana in Ethiopia and flows into Sudan from the southeast. The two rivers meet just north of the Sudanese capital of Khartoum. The northern section of the river flows north almost entirely through the Sudanese desert to Egypt, then ends in a large delta and flows into the Mediterranean Sea. Egyptian civilization and Sudanese kingdoms have depended on the river since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of Aswan, and nearly all the cultural and historical sites of Ancient Egypt are found along river banks.

Congo River

The great Congo River , formerly known as the Zaire River under the Mobutu regime, is the second longest river in Africa, shorter only than the Nile, as well as the second largest river in the world by discharge volume, following only the Amazon. It is also the world’s deepest recorded river, with measured depths in excess of 220 m (720 ft). The Congo-Lualaba-Chambeshi River system has an overall length of 4,700 km (2,920 mi), which makes it the world’s ninth-longest river. The Chambeshi is a tributary of the Lualaba River, and Lualaba is the name of the Congo River upstream of Boyoma Falls, extending for 1,800 km (1,120 mi). Measured along with the Lualaba, the main tributary, the Congo River has a total length of 4,370 km (2,715 mi). It is the only river to cross the equator twice.The Congo Basin has a total area of about 4,000,000 km2 (1,500,000 sq mi), or 13% of the entire African landmass.

The Niger River

The Niger River  is the principal river of West Africa, extending about 4,180 km (2,600 mi). Its drainage basin is 2,117,700 km2 (817,600 sq mi) in area. Its source is in the Guinea Highlands in southeastern Guinea. It runs in a crescent through Mali, Niger, on the border with Benin and then through Nigeria, discharging through a massive delta, known as the Niger Delta or the Oil Rivers, into the Gulf of Guinea in the Atlantic Ocean. The Niger is the third-longest river in Africa, exceeded only by the Nile and the Congo River (also known as the Zaïre River). Its main tributary is the Benue River. The Niger River is a relatively “clear” river, carrying only a tenth as much sediment as the Nile because the Niger’s headwaters lie in ancient rocks that provide little silt. Like the Nile, the Niger floods yearly; this begins in September, peaks in November, and finishes by May. The Niger takes one of the most unusual routes of any major river, a boomerang shape that baffled geographers for two centuries. Its source is just 240 km (150 mi) inland from the Atlantic Ocean, but the river runs directly away from the sea into the Sahara Desert, then takes a sharp right turn near the ancient city of Timbuktu (Tombouctou) and heads southeast to the Gulf of Guinea. An unusual feature of the river is the Inner Niger Delta, which forms where its gradient suddenly decreases. The result is a region of braided streams, marshes, and lakes the size of Belgium; the seasonal floods make the Delta extremely productive for both fishing and agriculture.

The  Andean Mountains

The  Andean Mountains are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. This range is about 7,000 km (4,300 mi) long, about 200 to 700 km (120 to 430 mi) wide (widest between 18° south and 20° south latitude), and of an average height of about 4,000 m (13,000 ft). The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile and Argentina. Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high plateaus – some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Sucre, Mérida and La Paz. The Altiplano plateau is the world’s second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the Tropical Andes, the Dry Andes, and the Wet Andes.The Andes Mountains are the world’s highest mountain range outside Asia. The highest mountain outside Asia, Argentina’s Mount Aconcagua, rises to an elevation of about 6,961 m (22,838 ft) above sea level. The peak of Chimborazo in the Ecuadorian Andes is farther from the Earth’s center than any other location on the Earth’s surface, due to the equatorial bulge resulting from the Earth’s rotation. The world’s highest volcanoes are in the Andes, including Ojos del Salado on the Chile-Argentina border, which rises to 6,893 m (22,615 ft). The Andes are also part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that form the western “backbone” of North America, Central America, South America and Antarctica.

The Tibetan Plateau

The Tibetan Plateau is a vast elevated plateau in Central Asia and East Asia, covering most of the Tibet Autonomous Region and Qinghai in western China, as well as Ladakh (Jammu and Kashmir) and Lahaul & Spiti (Himachal Pradesh) in India. It stretches approximately 1,000 kilometres (620 mi) north to south and 2,500 kilometres (1,600 mi) east to west. With an average elevation exceeding 4,500 metres (14,800 ft), the Tibetan Plateau is sometimes called “the Roof of the World” because it stands over 3 miles (4.8 km) above sea level and is surrounded by imposing mountain ranges that harbor the world’s two highest summits, Mount Everest and K2, and is the world’s highest and largest plateau, with an area of 2,500,000 square kilometres (970,000 sq mi) (about five times the size of Metropolitan France). Sometimes termed the Third Pole, the Tibetan Plateau contains the headwaters of the drainage basinsof most of the streams in surrounding regions. Its tens of thousands of glaciers and other geographical and ecological features serve as a “water tower” storing water and maintaining flow. The impact of global warming on the Tibetan Plateau is of intense scientific interest.

BPSC Exam: Quick Geographical Facts about Bihar

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  • Bihar is the thirteenth-largest Indian state, with an area of 94,163 km2 (36,357 sq mi).
  • Bihar is the third-largest state of India.by population (10.4 crore)
  • Bihar state is located between 24°-20′-10″ N ~ 27°-31′-15″ N latitude and between 83°-19′-50″ E ~ 88°-17′-40″ E longitude. Its average elevation above sea level is 173 feet (53 m).
  • Bihar is contiguous with Uttar Pradesh to its west, Nepal to the north, the northern part of West Bengal to the east, with Jharkhand to the south.
  • Bihar is an amalgamation of three distinct regions: Magadh, Mithila, and Bhojpur.
  • Most of Bihar’s population belongs to Indo-Aryan-speaking ethnic groups along with few Dravidian-speaking and Austroasiatic-speaking people mostly in Chhotanagpur Plateau (now part of Jharkhand).
  • On 15 November 2000, southern Bihar was ceded to form the new state of Jharkhand.
  • After the 2011 Census, Bihar was the third most populous state of India with total population of 104,099,452 (54,278,157 male and 49,821,295 female).
  • Nearly 89% of Bihar’s population lived in rural areas.
  • Only 11.3% of the population of Bihar lives in urban areas, which is the lowest in India after Himachal Pradesh.
  • According to 2011 census, the population density of Bihar was 1,106. The sex ratio was 918 females per 1000 males.
  • As of the 2011 census, population density surpassed 1,000 per square kilometre, making Bihar India’s most densely-populated state, but still lower than West Java or Banten of Indonesia.
  • According to 2011 census, Bihar has a total literacy rate of 63.82% (73.39% for males and 53.33% for females), recording a growth of 20% in female literacy over the period of a decade.
  • According to the 2011 census, 82.7% of Bihar’s population practised Hinduism, while 16.9% followed Islam.
  • Almost 58% of Biharis are below the age of 25, giving Bihar the highest proportion of young people of any Indian state.
  • Bihar is a vast stretch of fertile plain. It is drained by the Ganges River, including its northern tributaries Gandak and Koshi, originating in the Nepal Himalayas and the Bagmati originating in the Kathmandu Valley that regularly flood parts of the Bihar plains.
  • Central parts of Bihar have some small hills, for example the Rajgir hills. To the south is the Chota Nagpur plateau, which was part of Bihar until 2000 but now is part of a separate state called Jharkhand.
  • Bihar has notified forest area of 6,764.14 km2 (2,612 sq mi), which is 7.2% of its geographical area.

11 Most Important Geographical Phenomena

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1. Solstice

The word solstice is derived from the Latin sol (sun) and sistere (to stand still), because at the solstices, the Sun stands still in declination; that is, the seasonal movement of the Sun’s path (as seen from Earth) comes to a stop before reversing direction. A solstice is an astronomical event that occurs twice each year (in June and December) as the Sun reaches its highest or lowest excursion relative to the celestial equator on the celestial sphere. The seasons of the year are directly connected to both the solstices and the equinoxes. The term solstice can also be used in a broader sense, as the day when this occurs. The day of the solstice is either the longest day of the year (summer solstice) or the shortest day of the year (winter solstice) for any place outside of the tropics. Alternative terms, with no ambiguity as to which hemisphere is the context, are June solstice and December solstice, referring to the months of year in which they take place. At latitudes in the temperate zone, the summer solstice marks the day when the sun appears highest in the sky. However, in the tropics, the sun appears directly overhead (called the sub solar point) some days (or even months) before the solstice and again after the solstice, which means the sub solar point occurs twice each year.

2. Equinox

An equinox is an astronomical event in which the plane of Earth’s equator passes through the center of the Sun, which occurs twice each year, around 20 March and 23 September. On an equinox, day and night are of approximately equal duration all over the planet. They are not exactly equal, however, due to the angular size of the sun and atmospheric refraction. To avoid this ambiguity, the word equilux is sometimes used to mean a day in which the durations of light and darkness are equal.

Day is usually defined as the period when sunlight reaches the ground in the absence of local obstacles. On the day of the equinox, the center of the Sun spends a roughly equal amount of time above and below the horizon at every location on the Earth, so night and day are about the same length. In reality, the day is longer than the night at an equinox. There are two reasons for this:

First, from the Earth, the Sun appears as a disc rather than a point of light, so when the centre of the Sun is below the horizon, its upper edge is visible. Sunrise, which begins daytime, occurs when the top of the Sun’s disk rises above the eastern horizon. At that instant, the disk’s centre is still below the horizon.

Second, Earth’s atmosphere refracts sunlight. As a result, an observer sees daylight before the top of the Sun’s disk rises above the horizon. Even when the upper limb of the Sun is 0.4 degrees below the horizon, its rays curve over the horizon to the ground.

In sunrise/sunset tables, the assumed semi diameter (apparent radius) of the Sun is 16 minutes of arc and the atmospheric refraction is assumed to be 34 minutes of arc. Their combination means that when the upper limb of the Sun is on the visible horizon, its centre is 50 minutes of arc below the geometric horizon, which is the intersection with the celestial sphere of a horizontal plane through the eye of the observer. These effects make the day about 14 minutes longer than the night at the equator and longer still towards the poles. The real equality of day and night only happens in places far enough from the equator to have a seasonal difference in day length of at least 7 minutes, actually occurring a few days towards the winter side of each equinox. The times of sunset and sunrise vary with the observer’s location (longitude and latitude), so the dates when day and night are equal also depend upon the observer’s location. At the equinoxes, the rate of change for the length of daylight and night-time is the greatest. At the poles, the equinox marks the transition from 24 hours of nighttime to 24 hours of daylight (or vice versa).

3. International Date Line

The International Date Line (IDL) is an imaginary line of navigation on the surface of the Earth that runs from the north pole to the south pole and demarcates the change of one calendar day to the next. It passes through the middle of the Pacific Ocean, roughly following the 180° line of longitude but deviating to pass around some territories and island groups. The IDL is roughly based on the meridian of 180° longitude, roughly down the middle of the Pacific Ocean, and halfway around the world from the Greenwich meridian. In many places, the IDL follows the 180° meridian exactly. However, in other places, the IDL deviates east or west away from that meridian. These various deviations generally accommodate the political and/or economic affiliations of the affected areas.

Proceeding from north to south, the first deviation of the IDL from 180° is to pass to the east of Wrangel Island and the Chukchi Peninsula, the easternmost part of Russian Siberia. It then passes through the Bering Strait between the Diomede Islands at a distance of 1.5 kilo meters (0.93 mi) from each island. It then bends considerably west of 180°, passing west of St. Lawrence Island and St. Matthew Island. It crosses between the Aleutian Islands, belonging to the US—Attu Island being the westernmost—and the Commander Islands belonging to Russia. It then bends southeast again to return to 180°. Thus all of Russia is to the west of the IDL and all of the United States is to the east.

The IDL remains on the 180° meridian until passing the equator. Two US-owned uninhabited atolls, Howland Island and Baker Island, just north of the equator in the central Pacific Ocean (and ships at sea between 172.5°W and 180°) have the latest time on Earth of UTC-12 hours. The IDL circumscribes Kiribati by swinging far to the east, almost reaching the 150°W meridian. Kiribati’s easternmost islands, the southern Line Islands south of Hawaii, have the most advanced time on Earth, UTC+14 hours. South of Kiribati, the IDL returns westwards but remains east of 180°, passing between Samoa and American Samoa. In much of this area, the IDL follows the 165°W meridian. Accordingly, Samoa, Tokelau,Wallis and Futuna, Fiji, Tonga, Tuvalu and New Zealand’s Kermadec Islands and Chatham Islands are all west of the IDL and have the same date. American Samoa, the Cook Islands, Niue, and French Polynesia are east of the IDL and one day behind.The IDL then bends southwest to return to 180°. It follows that meridian until reaching Antarctica. Conventionally, the IDL is not drawn into Antarctica on most maps.

4. The Doldrums

The doldrums is a colloquial expression derived from historical maritime usage, which refers to those parts of the Atlantic Ocean and the Pacific Ocean affected by the Inter tropical Convergence Zone, a low-pressure area around the equator where the prevailing winds are calm. The doldrums are also noted for calm periods when the winds disappear altogether, trapping sail-powered boats for periods of days or weeks. The term appears to have arisen in the eighteenth century, when cross-equator sailing voyages became more common. Since this zone is the meeting place of two trade winds, it is also called inter tropical convergence zone. n maritime usage, the low pressure characteristics of the doldrums is caused by the expanding atmosphere due to heating at the equator, which makes the air rise and travel north and south high in the atmosphere, until it subsides again in the horse latitudes. Some of that air returns to the doldrums through the trade winds. This process can lead to light or variable winds and more severe weather, in the form of squalls, thunderstorms, and hurricanes. The doldrums are also noted for calm periods when the winds disappear altogether, trapping sail-powered boats for periods of days or weeks.

5. Horse latitudes 

Horse latitudes or subtropical highs are subtropical latitudes between 30 and 38 degrees both north and south where Earth’s atmosphere is dominated by the subtropical high, an area of high pressure, which suppresses precipitation and cloud formation, and has variable winds mixed with calm winds. The horse latitudes are associated with the subtropical anticyclone and the large-scale descent of air from high-altitude currents moving toward the poles. After reaching the earth’s surface, this air spreads toward the equator as part of the prevailing trade winds or toward the poles as part of the westerlies. The belt in the Northern Hemisphere is sometimes called the “calms of Cancer” and that in the Southern Hemisphere the “calms of Capricorn”. The consistently warm, dry, and sunny conditions of the horse latitudes are the main cause for the existence of the world’s major non-polar deserts, such as the Sahara Desert in Africa, the Arabian and Syrian deserts in the Middle East, the Mojave and Sonoran deserts in the southwestern United States and northern Mexico, all in the Northern Hemisphere; and the Atacama Desert, the Kalahari Desert, and the Australian Desert in the Southern Hemisphere.

6. The Roaring Forties

The Roaring Forties are strong westerly winds found in the Southern Hemisphere, generally between the latitudes of 40 and 50 degrees. The strong west-to-east air currents are caused by the combination of air being displaced from the Equator towards the South Pole and the Earth’s rotation, and there are few landmasses to serve as windbreaks.

The Roaring Forties were a major aid to ships sailing the Brouwer Route from Europe to the East Indies or Australasia during the Age of Sail, and in modern usage are favoured by yachtsmen on round-the-world voyages and competitions. The boundaries of the Roaring Forties are not consistent, and shift north or south depending on the season. Similar but stronger conditions occur in more southerly latitudes and are referred to as the Furious Fifties and Shrieking or Screaming Sixties. Hot air rises at the Equator and is pushed towards the poles by cooler air travelling towards the Equator (an atmospheric circulation feature known as the Hadley Cell). At about 30 degrees from the equator, the outward-travelling air sinks to lower altitudes, and continues toward the poles closer to the ground (the Ferrel Cell), then rises up again from about 60 degrees as the air joins the Polar vortex. This travel in the 30 to 60 degree zone combines with the rotation of the earth to move the air currents from west to east, creating westerly winds.

Unlike the northern hemisphere, the large tracts of open ocean below 40th parallel south (interrupted only by Tasmania, New Zealand, and the southern part of South America) mean that higher wind speeds — the Roaring Forties — can develop. Similar but stronger wind conditions are prevalent closer to the South Pole; these are referred to as the “Furious Fifties” (50 to 60 degrees south), and the “Shrieking” or “Screaming Sixties” (below 60 degrees south). The latitude ranges for the Roaring Forties and similar winds are not consistent, shifting towards the South Pole in the southern summer, and towards the Equator in the southern winter.

During the Age of Sail, ships travelling from Europe to the East Indies or Australasia would sail down the west coast of Africa and round the Cape of Good Hope to use the Roaring Forties to speed their passage across the Indian Ocean, then on the return leg, continue eastwards across the Pacific Ocean and under Cape Horn before sailing up the east coast of the Americas to home. It was first used by Dutch explorer Hendrik Brouwer in his Brouwer Route, discovered in 1611, which effectively halved the duration of the trip from Europe to Java. “To run the easting down” was the phrase used to describe the fast passages achieved in the Roaring Forties.  Round-the-world sailors also take advantage of the Roaring Forties to speed travel times, in particular those involved in record attempts or races.

7. Solar Eclipse

As seen from the Earth, a solar eclipse is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and the Moon fully or partially blocks (“occults”) the Sun. This can happen only at new moon, when the Sun and the Moon are in conjunction as seen from Earth in an alignment referred to as syzygy.

8. Lunar Eclipse

A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the sun, Earth and moon are aligned (in “syzygy”) exactly, or very closely so, with the Earth in the middle. Hence, a lunar eclipse can occur only the night of a full moon.

9. Aurora Borealis (Northern Lights)

The Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights) are the result of electrons colliding with the upper reaches of Earth’s atmosphere. (Protons cause faint and diffuse aurora, usually not easily visible to the human eye.) The bright dancing lights of the aurora are actually collisions between electrically charged particles from the sun that enter the earth’s atmosphere. The lights are seen above the magnetic poles of the northern and southern hemispheres.

10. Jet Streams

Jet streams are fast flowing, narrow, meandering air currents found in the upper atmosphere or in troposphere of some planets, including Earth. The main jet streams are located near the altitude of the tropopause. The major jet streams on Earth are westerly winds (flowing west to east). Their paths typically have a meandering shape. Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to the direction of the remainder of the jet. The strongest jet streams are the polar jets, at 9–12 km (30,000–39,000 ft) above sea level, and the higher altitude and somewhat weaker subtropical jets at 10–16 km (33,000–52,000 ft). The Northern Hemisphere and the Southern Hemisphere each have a polar jet and a subtropical jet. The northern hemisphere polar jet flows over the middle to northern latitudes of North America, Europe, and Asia and their intervening oceans, while the southern hemisphere polar jet mostly circles Antarctica all year round. Jet streams are the product of two factors: the atmospheric heating by solar radiation that produces the large scale Polar, Ferrel, and Hadley circulation cells, and the action of the Coriolis force acting on those moving masses. The Coriolis force is caused by the planet’s rotation on its axis. On other planets, internal heat drives their jet streams. The Polar jet stream forms near the interface of the Polar and Ferrel circulation cells; while the subtropical jet forms near the boundary of the Ferrel and Hadley circulation cells.

11. El Niño

El Niño is the warm phase of the El Niño Southern Oscillation (commonly called ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (between approximately the International Date Line and 120°W), including off the Pacific coast of South America. El Niño Southern Oscillation refers to the cycle of warm and cold temperatures, as measured by sea surface temperature, SST, of the tropical central and eastern Pacific Ocean. El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific. The cool phase of ENSO is called “La Niña” with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific. The ENSO cycle, both El Niño and La Niña, causes global changes of both temperatures and rainfall. Mechanisms that cause the oscillation remain under study. Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected. In American Spanish, the capitalized term “El Niño” refers to “the boy”, so named because the pool of warm water in the Pacific near South America is often at its warmest around Christmas. “La Niña”, chosen as the ‘opposite’ of El Niño, literally translates to “the girl”.