Lower River Division is one of the five administrative divisions of the Gambia . Its capital is Mansa Konko . The city and area council elections were held during April 2002, when Wally S.M. Sanneh, an APRC candidate became the Mayor, winning unopposed. The council was led by Alliance for Patriotic Reorientation and Construction (APRC), which won all the 12 seats.
170-398: Per 2013 census, the region had a population of 82,361 with a population density of 051. The total number of households was 8,474 as of 2003. As of 2003, the total area of the region is 1618 km. The infant mortality rate was 96 for every thousand births and the under-five mortality was 137 per every thousand births. The Gambia is the smallest country in mainland Africa , and the width of
340-533: A circumstellar disk , and then the planets grow out of that disk with the Sun. A nebula contains gas, ice grains, and dust (including primordial nuclides ). According to nebular theory , planetesimals formed by accretion , with the primordial Earth being estimated as likely taking anywhere from 70 to 100 million years to form. Estimates of the age of the Moon range from 4.5 Ga to significantly younger. A leading hypothesis
510-736: A confederation of seafaring peoples contributed to the New Kingdom 's collapse in 1069 BC, commencing the Third Intermediate Period . Egypt's collapse liberated the more Egyptianised Kingdom of Kush in Nubia, who manoeuvred into power in Upper Egypt and conquered Lower Egypt in 754 BC to form the Kushite Empire . The Kushites ruled for a century and oversaw a revival in pyramid building , until they were driven out of Egypt by
680-549: A principality into a major power on the trade route between Rome and India through conquering its unfortunately unknown neighbours, gaining a monopoly on Indian Ocean trade in the region. Aksum's rise had them rule over much of the regions from Lake Tana to the valley of the Nile , and they further conquered parts of the ailing Kingdom of Kush , led campaigns against the Noba and Beja peoples, and expanded into South Arabia . This led
850-597: A Berber tribe originally from Yafran (also known as Ifrane ) in northwestern Libya , as well as the city of Ifrane in Morocco . Under Roman rule, Carthage became the capital of the province then named Africa Proconsularis , following its defeat of the Carthaginians in the Third Punic War in 146 BC, which also included the coastal part of modern Libya . The Latin suffix -ica can sometimes be used to denote
1020-492: A common barycenter every 27.32 days relative to the background stars. When combined with the Earth–Moon system's common orbit around the Sun, the period of the synodic month , from new moon to new moon, is 29.53 days. Viewed from the celestial north pole , the motion of Earth, the Moon, and their axial rotations are all counterclockwise . Viewed from a vantage point above the Sun and Earth's north poles, Earth orbits in
1190-542: A counterclockwise direction about the Sun. The orbital and axial planes are not precisely aligned: Earth's axis is tilted some 23.44 degrees from the perpendicular to the Earth–Sun plane (the ecliptic ), and the Earth-Moon plane is tilted up to ±5.1 degrees against the Earth–Sun plane. Without this tilt, there would be an eclipse every two weeks, alternating between lunar eclipses and solar eclipses . The Hill sphere , or
1360-700: A former Italian colony, gained independence. In 1956, Tunisia and Morocco won their independence from France. Ghana followed suit the next year (March 1957), becoming the first of the sub-Saharan colonies to be granted independence. Over the next decade, waves of decolonization took place across the continent, culminating in the 1960 Year of Africa and the establishment of the Organisation of African Unity in 1963. Portugal's overseas presence in sub-Saharan Africa (most notably in Angola , Cape Verde, Mozambique , Guinea-Bissau , and São Tomé and Príncipe) lasted from
1530-420: A full rotation about its axis so that the Sun returns to the meridian . The orbital speed of Earth averages about 29.78 km/s (107,200 km/h; 66,600 mph), which is fast enough to travel a distance equal to Earth's diameter, about 12,742 km (7,918 mi), in seven minutes, and the distance from Earth to the Moon, 384,400 km (238,900 mi), in about 3.5 hours. The Moon and Earth orbit
1700-421: A globe-spanning mid-ocean ridge system. At Earth's polar regions , the ocean surface is covered by seasonally variable amounts of sea ice that often connects with polar land, permafrost and ice sheets , forming polar ice caps . Earth's land covers 29.2%, or 149 million km (58 million sq mi) of Earth's surface. The land surface includes many islands around the globe, but most of
1870-550: A handful of African countries succeeded in obtaining rapid economic growth prior to 1990. Exceptions include Libya and Equatorial Guinea, both of which possess large oil reserves. Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life . This is enabled by Earth being an ocean world , the only one in the Solar System sustaining liquid surface water . Almost all of Earth's water
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#17328487846272040-550: A land (e.g., in Celtica from Celtae , as used by Julius Caesar ). The later Muslim region of Ifriqiya , following its conquest of the Byzantine (Eastern Roman) Empire's Exarchatus Africae , also preserved a form of the name. According to the Romans, Africa lies to the west of Egypt, while "Asia" was used to refer to Anatolia and lands to the east. A definite line was drawn between
2210-425: A liquid outer core that generates a magnetosphere capable of deflecting most of the destructive solar winds and cosmic radiation . Earth has a dynamic atmosphere , which sustains Earth's surface conditions and protects it from most meteoroids and UV-light at entry . It has a composition of primarily nitrogen and oxygen . Water vapor is widely present in the atmosphere, forming clouds that cover most of
2380-677: A millennium. Towards the end of the ancient period, northern Ethiopia and Eritrea bore the Kingdom of D'mt beginning in 980 BC. In modern-day Somalia and Djibouti there was the Macrobian Kingdom , with archaeological discoveries indicating the possibility of other unknown sophisticated civilisations at this time. After D'mt's fall in the 5th century BC the Ethiopian Plateau came to be ruled by numerous smaller unknown kingdoms who experienced strong south Arabian influence , until
2550-625: A monopoly on gold heading north and salt heading south, despite not controlling the gold fields themselves, located in the forest regions . It is probable that Wagadu's dominance on trade allowed for the gradual consolidation of many polities into a confederated state , whose composites stood in varying relations to the core, from fully administered to nominal tribute-paying parity. Based on large tumuli scattered across West Africa dating to this period, it has been stipulated that relative to Wagadu, there were further simultaneous and preceding kingdoms that have unfortunately been lost to time. At
2720-570: A native Libyan tribe, an ancestor of modern Berbers ; see Terence for discussion. The name had usually been connected with the Phoenician word ʿafar meaning "dust", but a 1981 hypothesis has asserted that it stems from the Berber word ifri (plural ifran ) meaning "cave", in reference to cave dwellers. The same word may be found in the name of the Banu Ifran from Algeria and Tripolitania ,
2890-464: A transition from " informal imperialism " – military influence and economic dominance – to direct rule. Imperial rule by Europeans continued until after the conclusion of World War II , when almost all remaining colonial territories gradually obtained formal independence. Independence movements in Africa gained momentum following World War II, which left the major European powers weakened. In 1951, Libya,
3060-537: A youth nominee, a woman nominee and other nominated members of local interest groups. The city and area council elections were held during April 2002, when Wally S.M. Sanneh, an APRC candidate became the Mayor, winning unopposed. The council was led by Alliance for Patriotic Reorientation and Construction (APRC), which won all the 12 seats. 13°24′18″N 15°44′54″W / 13.40500°N 15.74833°W / 13.40500; -15.74833 Africa Africa
3230-508: Is rounded into an ellipsoid with a circumference of about 40,000 km. It is the densest planet in the Solar System . Of the four rocky planets , it is the largest and most massive. Earth is about eight light-minutes away from the Sun and orbits it , taking a year (about 365.25 days) to complete one revolution. Earth rotates around its own axis in slightly less than a day (in about 23 hours and 56 minutes). Earth's axis of rotation
3400-456: Is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. The crust is separated from the mantle by the Mohorovičić discontinuity . The thickness of the crust varies from about 6 kilometres (3.7 mi) under the oceans to 30–50 km (19–31 mi) for the continents. The crust and the cold, rigid, top of the upper mantle are collectively known as
3570-531: Is approximately 9.8 m/s (32 ft/s ). Local differences in topography, geology, and deeper tectonic structure cause local and broad regional differences in Earth's gravitational field, known as gravity anomalies . The main part of Earth's magnetic field is generated in the core, the site of a dynamo process that converts the kinetic energy of thermally and compositionally driven convection into electrical and magnetic field energy. The field extends outwards from
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#17328487846273740-517: Is contained in 3.45 billion-year-old Australian rocks showing fossils of microorganisms . During the Neoproterozoic , 1000 to 539 Ma , much of Earth might have been covered in ice. This hypothesis has been termed " Snowball Earth ", and it is of particular interest because it preceded the Cambrian explosion , when multicellular life forms significantly increased in complexity. Following
3910-590: Is contained in its global ocean, covering 70.8% of Earth's crust . The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere . Most of Earth's land is at least somewhat humid and covered by vegetation , while large sheets of ice at Earth's polar deserts retain more water than Earth's groundwater , lakes, rivers and atmospheric water combined. Earth's crust consists of slowly moving tectonic plates , which interact to produce mountain ranges, volcanoes , and earthquakes. Earth has
4080-452: Is farthest out from its center of mass at its equatorial bulge, the summit of the volcano Chimborazo in Ecuador (6,384.4 km or 3,967.1 mi) is its farthest point out. Parallel to the rigid land topography the ocean exhibits a more dynamic topography . To measure the local variation of Earth's topography, geodesy employs an idealized Earth producing a geoid shape. Such a shape
4250-516: Is gained if the ocean is idealized, covering Earth completely and without any perturbations such as tides and winds. The result is a smooth but irregular geoid surface, providing a mean sea level (MSL) as a reference level for topographic measurements. Earth's surface is the boundary between the atmosphere, and the solid Earth and oceans. Defined in this way, it has an area of about 510 million km (197 million sq mi). Earth can be divided into two hemispheres : by latitude into
4420-426: Is liquid under normal atmospheric pressure. Differences in the amount of captured energy between geographic regions (as with the equatorial region receiving more sunlight than the polar regions) drive atmospheric and ocean currents , producing a global climate system with different climate regions , and a range of weather phenomena such as precipitation , allowing components such as nitrogen to cycle . Earth
4590-787: Is not always to be taken literally. Africa is considered by most paleoanthropologists to be the oldest inhabited territory on Earth, with the Human species originating from the continent. During the mid-20th century, anthropologists discovered many fossils and evidence of human occupation perhaps as early as seven million years ago ( Before present , BP). Fossil remains of several species of early apelike humans thought to have evolved into modern humans, such as Australopithecus afarensis radiometrically dated to approximately 3.9–3.0 million years BP, Paranthropus boisei (c. 2.3–1.4 million years BP) and Homo ergaster (c. 1.9 million–600,000 years BP) have been discovered. After
4760-501: Is now slightly longer than it was during the 19th century due to tidal deceleration , each day varies between 0 and 2 ms longer than the mean solar day. Earth's rotation period relative to the fixed stars , called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is 86,164.0989 seconds of mean solar time ( UT1 ), or 23 56 4.0989 . Earth's rotation period relative to
4930-612: Is rare, though the alternative spelling Gaia has become common due to the Gaia hypothesis , in which case its pronunciation is / ˈ ɡ aɪ . ə / rather than the more classical English / ˈ ɡ eɪ . ə / . There are a number of adjectives for the planet Earth. The word "earthly" is derived from "Earth". From the Latin Terra comes terran / ˈ t ɛr ə n / , terrestrial / t ə ˈ r ɛ s t r i ə l / , and (via French) terrene / t ə ˈ r iː n / , and from
5100-793: Is surrounded by the Mediterranean Sea to the north, the Arabian Plate and the Gulf of Aqaba to the northeast, the Indian Ocean to the southeast and the Atlantic Ocean to the west. The continent includes Madagascar and various archipelagos . It contains 54 fully recognised sovereign states , eight cities and islands that are part of non-African states , and two de facto independent states with limited or no recognition . This count does not include Malta and Sicily , which are geologically part of
5270-477: Is that it was formed by accretion from material loosed from Earth after a Mars -sized object with about 10% of Earth's mass, named Theia , collided with Earth. It hit Earth with a glancing blow and some of its mass merged with Earth. Between approximately 4.1 and 3.8 Ga , numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of
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5440-453: Is the basis for the astronomical unit (AU) and is equal to roughly 8.3 light minutes or 380 times Earth's distance to the Moon . Earth orbits the Sun every 365.2564 mean solar days , or one sidereal year . With an apparent movement of the Sun in Earth's sky at a rate of about 1°/day eastward, which is one apparent Sun or Moon diameter every 12 hours. Due to this motion, on average it takes 24 hours—a solar day—for Earth to complete
5610-421: Is the chairperson of the council and the council members of each council is elected by people of the area. The legislations indicating the roles were not clearly defined, but the council is responsible for finance, services and planning for each sector under it. Around 25 per cent of the budget is provisioned by the central government. The council also has a Alkalo or Seyfo representative, a Chief representative,
5780-400: Is the world's second-largest and second-most populous continent after Asia . At about 30.3 million km (11.7 million square miles) including adjacent islands, it covers 20% of Earth 's land area and 6% of its total surface area. With nearly 1.4 billion people as of 2021, it accounts for about 18% of the world's human population . Africa's population is the youngest among all
5950-457: Is tied to that of the Sun. Over the next 1.1 billion years , solar luminosity will increase by 10%, and over the next 3.5 billion years by 40%. Earth's increasing surface temperature will accelerate the inorganic carbon cycle , possibly reducing CO 2 concentration to levels lethally low for current plants ( 10 ppm for C4 photosynthesis ) in approximately 100–900 million years . A lack of vegetation would result in
6120-451: Is tilted with respect to the perpendicular to its orbital plane around the Sun, producing seasons . Earth is orbited by one permanent natural satellite , the Moon , which orbits Earth at 384,400 km (1.28 light seconds) and is roughly a quarter as wide as Earth. The Moon's gravity helps stabilize Earth's axis, causes tides and gradually slows Earth's rotation . Tidal locking has made
6290-649: The 11th dynasty , based in Thebes , conquered the others to form the Middle Kingdom of Egypt , with the 12th dynasty expanding into Lower Nubia at the expense of Kerma . In 1700 BC, the Middle Kingdom fractured in two, ushering in the Second Intermediate Period . The Hyksos , a militaristic people from Palestine , invaded and conquered Lower Egypt, while Kerma coordinated invasions deep into Egypt to reach its greatest extent. In 1550 BC,
6460-627: The 18th dynasty expelled the Hyksos , and established the New Kingdom of Egypt . Using the advanced military technology the Hyksos had brought, the New Kingdom conquered the Levant from the Canaanites , Mittani , Amorites , and Hittites , and extinguished Kerma , incorporating Nubia into the empire, and sending the Egyptian empire into its golden age. Internal struggles, drought, famine, and invasions by
6630-659: The Benin Empire . Towards the end of the 3rd century AD, a wet period in the Sahel created areas for human habitation and exploitation that had not been habitable for the best part of a millennium, with the Kingdom of Wagadu , the local name of the Ghana Empire , rising out of the Tichitt culture , growing wealthy following the introduction of the camel to the western Sahel, revolutionising
6800-521: The Cold War , and neocolonialism . Despite this low concentration of wealth, recent economic expansion and a large and young population make Africa an important economic market in the broader global context. Africa has a large quantity of natural resources and food resources, including diamonds , sugar , salt , gold , iron , cobalt , uranium , copper , bauxite , silver , petroleum , natural gas , cocoa beans , and tropical fruit . The continent
6970-854: The Congo Basin , the Empire of Kitara in the African Great Lakes , the Luba Empire in the Upemba Depression , the Kilwa Sultanate in the Swahili coast by crowding out Azania , with Rhapta being its last stronghold by the 1st century AD, and forming various city states constituting the Swahili civilisation . These migrations also prefaced the Kingdom of Mapungubwe in the Zambezi basin . After reaching
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7140-726: The Ekoi civilisation rose circa 2nd century AD, and are most notable for constructing the Ikom monoliths and developing the Nsibidi script . Pre-colonial Africa possessed as many as 10,000 different states and polities. These included small family groups of hunter-gatherers such as the San people of southern Africa; larger, more structured groups such as the family clan groupings of the Bantu peoples of central, southern, and eastern Africa; heavily structured clan groups in
7310-595: The Fatimids , Almoravids , Almohads , Ayyubids , Mamluks , Kongo , Mwene Muji , Luba , Lunda , Kitara , Aksum , Ethiopia , Adal , Ajuran , Kilwa , Sakalava , Imerina , Maravi , Mutapa , Rozvi , Mthwakazi , and Zulu . Slave trades created various diasporas , especially in the Americas . From the late 19th century to early 20th century, driven by the Second Industrial Revolution , most of Africa
7480-617: The Horn of Africa ; the large Sahelian kingdoms ; and autonomous city-states and kingdoms, such as those of the Akan ; Edo , Yoruba , and Igbo people in West Africa; and the Swahili coastal trading towns of Southeast Africa. By the 9th century AD, a string of dynastic states, including the earliest Hausa states, stretched across the sub-Saharan savannah from the western regions to central Sudan. The most powerful of these states were Ghana , Gao , and
7650-718: The Isthmus of Suez in Egypt. Other migrations of modern humans within the African continent have been dated to that time, with evidence of early human settlement found in Southern Africa, Southeast Africa, North Africa, and the Sahara . The size of the Sahara has historically been extremely variable, with its area rapidly fluctuating and at times disappearing depending on global climatic conditions. At
7820-667: The Kanem-Bornu Empire . Ghana declined in the eleventh century, but was succeeded by the Mali Empire , which consolidated much of western Sudan in the thirteenth century. Kanem accepted Islam in the eleventh century. In the forested regions of the West African coast, independent kingdoms grew with little influence from the Muslim north. The Kingdom of Nri , which was ruled by the Eze Nri ,
7990-524: The Kingdom of Dahomey , and the Oyo Empire ) adopted different ways of adapting to the shift. Asante and Dahomey concentrated on the development of "legitimate commerce" in the form of palm oil , cocoa , timber and gold, forming the bedrock of West Africa's modern export trade. The Oyo Empire, unable to adapt, collapsed into civil wars. The Scramble for Africa was the conquest and colonisation of most of Africa by seven Western European powers driven by
8160-661: The Mauro-Roman Kingdom and its numerous successor polities in the Maghreb, namely the kingdoms of Ouarsenis , Aurès , and Altava . The Vandals ruled Ifriqiya for a century until Byzantine reconquest in the early 6th century AD. The Byzantines and the Berber kingdoms fought minor inconsequential conflicts, such as in the case of Garmul , however largely coexisted. Further inland to the Byzantine Exarchate of Africa were
8330-566: The Milky Way and orbits about 28,000 light-years from its center. It is about 20 light-years above the galactic plane in the Orion Arm . The axial tilt of Earth is approximately 23.439281° with the axis of its orbit plane, always pointing towards the Celestial Poles . Due to Earth's axial tilt, the amount of sunlight reaching any given point on the surface varies over the course of
8500-607: The Noba caused their disintegration into Makuria , Alodia , and Nobatia in the 5th century AD. The Romans managed to hold on to Egypt for the rest of the ancient period. In the Horn of Africa , there was the Land of Punt , a kingdom on the Red Sea , likely located in modern-day Eritrea or northern Somaliland . The Ancient Egyptians initially traded via middle-men with Punt until in 2350 BC when they established direct relations. They would become close trading partners for over
8670-430: The Nok culture from 1500 BC in modern-day Nigeria , the Daima culture around Lake Chad from 550 BC, Djenné-Djenno from 250 BC in modern-day Mali , and the Serer civilisation in modern-day Senegal , which built the Senegambian stone circles from the 3rd century BC. There is also detailed record of Igodomigodo , a small kingdom founded presumably in 40 BC, which would later go on to form
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#17328487846278840-399: The Ovambo kingdoms , most of which were later conquered. The 1884 Berlin Conference regulated European colonisation and trade in Africa, and is seen as emblematic of the "scramble". In the last quarter of the 19th century, there were considerable political rivalries between the European empires , which provided the impetus for the colonisation. The later years of the 19th century saw
9010-399: The Pacific , North American , Eurasian , African , Antarctic , Indo-Australian , and South American . Other notable plates include the Arabian Plate , the Caribbean Plate , the Nazca Plate off the west coast of South America and the Scotia Plate in the southern Atlantic Ocean. The Australian Plate fused with the Indian Plate between 50 and 55 Ma . The fastest-moving plates are
9180-404: The Punic Wars against the expansionary Roman Republic , however momentum in these wars was not linear, with Carthage initially experiencing considerable success in the Second Punic War following Hannibal 's infamous crossing of the alps into northern Italy . Their defeat and subsequent collapse of their empire would produce two further polities in the Maghreb; Numidia , which had assisted
9350-447: The Romans in 30 BC. The Crisis of the Third Century in the Roman Empire freed the Levantine city state of Palmyra , which conquered Egypt ; their brief rule ended when they were reconquered by the Romans . In the midst of this, Kush regained independence from Egypt, and they would persist as a major regional power until, having been weakened from internal rebellion amid worsening climatic conditions, invasions by Aksum and
9520-494: The Sanhaja in modern-day Algeria , a broad grouping of three groupings of tribal confederations , one of which is the Masmuda grouping in modern-day Morocco , along with the nomadic Zenata ; their composite tribes would later go onto shape much of North African history . In the western Sahel the rise of settled communities occurred largely as a result of the domestication of millet and of sorghum . Archaeology points to sizable urban populations in West Africa beginning in
9690-488: The Sao civilisation flourished for over a millennium beginning in the 6th century BC, in territory that later became part of present-day Cameroon and Chad . Sao artifacts show that they were skilled workers in bronze , copper , and iron , with finds including bronze sculptures, terracotta statues of human and animal figures, coins, funerary urns, household utensils, jewellery, highly decorated pottery, and spears. Nearby, around Lake Ejagham in south-west Cameroon ,
9860-419: The Sassanid Empire and the Himyarite Kingdom in Arabia. The Maghreb and Ifriqiya were mostly cut off from the cradle of civilisation in Egypt by the Libyan desert , exacerbated by Egyptian boats being tailored to the Nile and not coping well in the open Mediterranean Sea . This caused its societies to develop contiguous to those of Southern Europe , until Phoenician settlements came to dominate
10030-417: The Second Industrial Revolution during the era of " New Imperialism " (1833–1914): Belgium , France , Germany , United Kingdom , Italy , Portugal and Spain . In 1870, 10% of the continent was formally under European control. By 1914, this figure had risen to almost 90%; the only states retaining sovereignty were Liberia , Ethiopia , Egba , Aussa , Senusiyya , Mbunda , the Dervish State , and
10200-404: The Zambezi , the Bantu continued southward, with eastern groups continuing to modern-day Mozambique and reaching Maputo in the 2nd century AD. Further to the south, settlements of Bantu peoples who were iron-using agriculturists and herdsmen were well established south of the Limpopo River by the 4th century AD, displacing and absorbing the Khoisan . By the Chari River south of Lake Chad
10370-419: The asthenosphere , the solid but less-viscous part of the upper mantle that can flow and move along with the plates. As the tectonic plates migrate, oceanic crust is subducted under the leading edges of the plates at convergent boundaries. At the same time, the upwelling of mantle material at divergent boundaries creates mid-ocean ridges. The combination of these processes recycles the oceanic crust back into
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#173284878462710540-415: The celestial equator , this is equivalent to an apparent diameter of the Sun or the Moon every two minutes; from Earth's surface, the apparent sizes of the Sun and the Moon are approximately the same. Earth orbits the Sun, making Earth the third-closest planet to the Sun and part of the inner Solar System . Earth's average orbital distance is about 150 million km (93 million mi), which
10710-408: The ocean floor form the top of Earth's crust , which together with parts of the upper mantle form Earth's lithosphere . Earth's crust may be divided into oceanic and continental crust. Beneath the ocean-floor sediments, the oceanic crust is predominantly basaltic , while the continental crust may include lower density materials such as granite , sediments and metamorphic rocks. Nearly 75% of
10880-430: The precessing or moving mean March equinox (when the Sun is at 90° on the equator), is 86,164.0905 seconds of mean solar time (UT1) (23 56 4.0905 ) . Thus the sidereal day is shorter than the stellar day by about 8.4 ms. Apart from meteors within the atmosphere and low-orbiting satellites, the main apparent motion of celestial bodies in Earth's sky is to the west at a rate of 15°/h = 15'/min. For bodies near
11050-419: The presidential system of rule. However, few of them have been able to sustain democratic governments on a permanent basis—per the criteria laid out by Lührmann et al. (2018), only Botswana and Mauritius have been consistently democratic for the entirety of their post-colonial history. Most African countries have experienced several coups or periods of military dictatorship . Between 1990 and 2018, though,
11220-413: The sphere of gravitational influence , of Earth is about 1.5 million km (930,000 mi) in radius. This is the maximum distance at which Earth's gravitational influence is stronger than that of the more distant Sun and planets. Objects must orbit Earth within this radius, or they can become unbound by the gravitational perturbation of the Sun. Earth, along with the Solar System, is situated in
11390-780: The trans-Saharan trade that linked their capital and Aoudaghost with Tahert and Sijilmasa in North Africa. Soninke traditions likely contain content from prehistory, mentioning four previous foundings of Wagadu , and holds that the final founding of Wagadu occurred after their first king did a deal with Bida , a serpent deity who was guarding a well, to sacrifice one maiden a year in exchange for assurance regarding plenty of rainfall and gold supply. Wagadu's core traversed modern-day southern Mauritania and western Mali , and Soninke tradition portrays early Ghana as warlike, with horse-mounted warriors key to increasing its territory and population, although details of their expansion are extremely scarce. Wagadu made its profits from maintaining
11560-410: The tropic of Cancer , in the northern temperate zone . In the other extreme of the continent, southern Namibia , southern Botswana , great parts of South Africa , the entire territories of Lesotho and Eswatini and the southern tips of Mozambique and Madagascar are located below the tropic of Capricorn , in the southern temperate zone . Africa is highly biodiverse ; it is the continent with
11730-424: The written word . During the colonial period , oral sources were deprecated by European historians, which gave them the impression Africa had no recorded history. African historiography became organized at the academic level in the mid-20th century, and saw a movement towards utilising oral sources in a multidisciplinary approach, culminating in the General History of Africa , edited by specialists from across
11900-464: The "last ice age", covered large parts of the continents, to the middle latitudes, in ice and ended about 11,700 years ago. Chemical reactions led to the first self-replicating molecules about four billion years ago. A half billion years later, the last common ancestor of all current life arose. The evolution of photosynthesis allowed the Sun's energy to be harvested directly by life forms. The resultant molecular oxygen ( O 2 ) accumulated in
12070-459: The 16th and 19th centuries. In West Africa, the decline of the Atlantic slave trade in the 1820s caused dramatic economic shifts in local polities. The gradual decline of slave-trading, prompted by a lack of demand for slaves in the New World , increasing anti-slavery legislation in Europe and America, and the British Royal Navy's increasing presence off the West African coast, obliged African states to adopt new economies. Between 1808 and 1860,
12240-579: The 16th century to 1975, after the Estado Novo regime was overthrown in a military coup in Lisbon . Rhodesia unilaterally declared independence from the United Kingdom in 1965, under the white minority government of Ian Smith , but was not internationally recognized as an independent state (as Zimbabwe ) until 1980, when black nationalists gained power after a bitter guerrilla war . Although South Africa
12410-590: The 1st and 4th cataracts of the Nile . The 4th dynasty oversaw the height of the Old Kingdom , and constructed many great pyramids . Under the 6th dynasty power gradually decentralised to the nomarchs, culminating in the disintegration of the kingdom, exacerbated by drought and famine, thus commencing the First Intermediate Period in 2200 BC. This shattered state would last until 2055 BC when
12580-567: The 2nd century BC Mauretania fought alongside Numidia's Jugurtha in the Jugurthine War against the Romans after he had usurped the Numidian throne from a Roman ally. Together they inflicted heavy casualties that quaked the Roman Senate , with the war only ending inconclusively when Mauretania's Bocchus I sold out Jugurtha to the Romans. At the turn of the millennium, they both would face
12750-716: The 4th millennium BC the Congo Basin was inhabited by the Bambenga , Bayaka , Bakoya , and Babongo in the west, the Bambuti in the east , and the Batwa who were widely scattered and also present in the Great Lakes region ; together they are grouped as Pygmies . On the later-named Swahili coast there were Cushitic -speaking peoples, and the Khoisan (a neologism for the Khoekhoe and San ) in
12920-416: The 4th millennium BC, which had crucially developed iron metallurgy by 1200 BC, in both smelting and forging for tools and weapons. Extensive east-west belts of deserts , grasslands , and forests from north to south were crucial for the moulding of their respective societies and meant that prior to the accession of trans-Saharan trade routes , symbiotic trade relations developed in response to
13090-513: The African continent. Algeria is Africa's largest country by area, and Nigeria is its largest by population. African nations cooperate through the establishment of the African Union , which is headquartered in Addis Ababa . Africa straddles the equator and the prime meridian . It is the only continent to stretch from the northern temperate to the southern temperate zones. The majority of
13260-678: The Assyrians in 663 BC in reprisal for their expansion towards the Assyrian Empire . The Assyrians installed a puppet dynasty that later gained independence and once more unified Egypt , until they were conquered by the Achaemenid Empire in 525 BC. Egypt regained independence under the 28th dynasty in 404 BC but they were reconquered by the Achaemenids in 343 BC. The conquest of Achaemenid Egypt by Alexander
13430-553: The British West Africa Squadron seized approximately 1,600 slave ships and freed 150,000 Africans who were aboard. Action was also taken against African leaders who refused to agree to British treaties to outlaw the trade, for example against "the usurping King of Lagos ", deposed in 1851. Anti-slavery treaties were signed with over 50 African rulers. The largest powers of West Africa (the Asante Confederacy ,
13600-479: The Cambrian explosion, 535 Ma , there have been at least five major mass extinctions and many minor ones. Apart from the proposed current Holocene extinction event, the most recent was 66 Ma , when an asteroid impact triggered the extinction of non-avian dinosaurs and other large reptiles, but largely spared small animals such as insects, mammals , lizards and birds. Mammalian life has diversified over
13770-637: The Earth. Terra is also the name of the planet in some Romance languages , languages that evolved from Latin , like Italian and Portuguese , while in other Romance languages the word gave rise to names with slightly altered spellings, like the Spanish Tierra and the French Terre . The Latinate form Gæa or Gaea ( English: / ˈ dʒ iː . ə / ) of the Greek poetic name Gaia ( Γαῖα ; Ancient Greek : [ɡâi̯.a] or [ɡâj.ja] )
13940-635: The Great in 332 BC marked the beginning of Hellenistic rule and the installation of the Macedonian Ptolemaic dynasty in Egypt. The Ptolemaics lost their holdings outside of Africa to the Seleucids in the Syrian Wars , expanded into Cyrenaica and subjugated Kush in the 3rd century BC. In the 1st century BC, Ptolemaic Egypt became entangled in a Roman civil war , leading to its conquest by
14110-564: The Iberian peninsula during the eleventh century. The Banu Hilal and Banu Ma'qil were a collection of Arab Bedouin tribes from the Arabian Peninsula who migrated westwards via Egypt between the eleventh and thirteenth centuries. Their migration resulted in the fusion of the Arabs and Berbers, where the locals were Arabized , and Arab culture absorbed elements of the local culture, under
14280-527: The Latin Tellus comes tellurian / t ɛ ˈ l ʊər i ə n / and telluric . The oldest material found in the Solar System is dated to 4.5682 +0.0002 −0.0004 Ga (billion years) ago. By 4.54 ± 0.04 Ga the primordial Earth had formed. The bodies in the Solar System formed and evolved with the Sun. In theory, a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into
14450-696: The Moon always face Earth with the same side. Earth, like most other bodies in the Solar System, formed 4.5 billion years ago from gas and dust in the early Solar System . During the first billion years of Earth's history , the ocean formed and then life developed within it. Life spread globally and has been altering Earth's atmosphere and surface, leading to the Great Oxidation Event two billion years ago. Humans emerged 300,000 years ago in Africa and have spread across every continent on Earth. Humans depend on Earth's biosphere and natural resources for their survival, but have increasingly impacted
14620-426: The Moon and, by inference, to that of Earth. Earth's atmosphere and oceans were formed by volcanic activity and outgassing . Water vapor from these sources condensed into the oceans, augmented by water and ice from asteroids, protoplanets , and comets . Sufficient water to fill the oceans may have been on Earth since it formed. In this model, atmospheric greenhouse gases kept the oceans from freezing when
14790-550: The Persian prophet Mani to consider Aksum as one of the four great powers of the 3rd century AD alongside Persia , Rome , and China . In the 4th century AD Aksum's king converted to Christianity and Aksum's population, who had followed syncretic mixes of local beliefs , slowly followed. The end of the 5th century saw Aksum allied with the Byzantine Empire , who viewed themselves as defenders of Christendom , balanced against
14960-558: The Romans in the Second Punic War, Mauretania , a Mauri tribal kingdom and home of the legendary King Atlas , and various tribes such as Garamantes , Musulamii , and Bavares . The Third Punic War would result in Carthage's total defeat in 146 BC and the Romans established the province of Africa , with Numidia assuming control of many of Carthage's African ports. Towards the end of
15130-756: The Sahara region was becoming increasingly dry and hostile. Around 3500 BC, due to a tilt in the Earth's orbit , the Sahara experienced a period of rapid desertification. The population trekked out of the Sahara region towards the Nile Valley below the Second Cataract where they made permanent or semi-permanent settlements. A major climatic recession occurred, lessening the heavy and persistent rains in Central and Eastern Africa . Since this time, dry conditions have prevailed in Eastern Africa and, increasingly during
15300-517: The Saharan climate started to become drier at an exceedingly fast pace. This climate change caused lakes and rivers to shrink significantly and caused increasing desertification . This, in turn, decreased the amount of land conducive to settlements and encouraged migrations of farming communities to the more tropical climate of West Africa. During the first millennium BC, a reduction in wild grain populations related to changing climate conditions facilitated
15470-458: The Solar System's planetary-sized objects, Earth is the object with the highest density . Earth's mass is approximately 5.97 × 10 kg ( 5.970 Yg ). It is composed mostly of iron (32.1% by mass ), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to gravitational separation ,
15640-403: The Sun when the star reaches its maximum radius, otherwise, with tidal effects, it may enter the Sun's atmosphere and be vaporized. Earth has a rounded shape , through hydrostatic equilibrium , with an average diameter of 12,742 kilometres (7,918 mi), making it the fifth largest planetary sized and largest terrestrial object of the Solar System . Due to Earth's rotation it has
15810-520: The West African countries, the Gambia has a relative stable governance. The Local Govemment Act passed in 2002 superseded the previous local government acts like Local Government Act (Amended 1984), LocalGovernment (City of Banjul) Act (Amended 1988), The Kanifing Municipal Council Act 1991 and the Provinces Act. There were seven local governments defined each subdivided into districts and wards. The Mayor who
15980-425: The atmosphere and due to interaction with ultraviolet solar radiation, formed a protective ozone layer ( O 3 ) in the upper atmosphere. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes . True multicellular organisms formed as cells within colonies became increasingly specialized. Aided by the absorption of harmful ultraviolet radiation by
16150-450: The center, the temperature may be up to 6,000 °C (10,830 °F), and the pressure could reach 360 GPa (52 million psi ). Because much of the heat is provided by radioactive decay, scientists postulate that early in Earth's history, before isotopes with short half-lives were depleted, Earth's heat production was much higher. At approximately 3 Gyr , twice the present-day heat would have been produced, increasing
16320-409: The century period between 1886 and 1992, there has been a reduction in rainfall of around 15-20 per cent and the wet season has been shortened. Per 2013 census, the region had a population of 82,361 with a population density of 051. The total number of households was 8,474 as of 2003. As of 2003, the total area of the region is 1618 km. The infant mortality rate was 96 for every thousand births and
16490-425: The coastline. Over the river segment of 487 km (303 mi), there are numerous creeks, which are locally called boloons . The months from June to September experience a wet season, while the remaining seven months are dry. The average annual rainfall is around 1,400 mm (55 in) in the south east, while it is 720 mm (28 in) in the northwest. Experts have assessed that the overall rainfall during
16660-532: The continent and its countries are in the Northern Hemisphere , with a substantial portion and a number of countries in the Southern Hemisphere . Most of the continent lies in the tropics, except for a large part of Western Sahara , Algeria , Libya and Egypt , the northern tip of Mauritania , and the entire territories of Morocco , Ceuta , Melilla , and Tunisia , which in turn are located above
16830-463: The continent as a whole has trended towards more democratic governance. Upon independence an overwhelming majority of Africans lived in extreme poverty . The continent suffered from the lack of infrastructural or industrial development under colonial rule, along with political instability. With limited financial resources or access to global markets, relatively stable countries such as Kenya still experienced only very slow economic development. Only
17000-424: The continent most vulnerable to climate change . The history of Africa is long, complex, and varied, and has often been under-appreciated by the global historical community . In African societies the oral word is revered, and they have generally recorded their history via oral tradition , which has led anthropologists to term them oral civilisations, contrasted with literate civilisations which pride
17170-457: The continent's south. The Bantu expansion constituted a major series of migrations of Bantu peoples from central Africa to eastern and southern Africa and was substantial in the settling of the continent. Commencing in the 2nd millennium BC, the Bantu began to migrate from Cameroon to central, eastern, and southern Africa, laying the foundations for future states such as the Kingdom of Kongo in
17340-473: The continent. Africa, particularly Eastern Africa , is widely accepted to be the place of origin of humans and the Hominidae clade , also known as the great apes . The earliest hominids and their ancestors have been dated to around 7 million years ago, and Homo sapiens (modern human) are believed to have originated in Africa 350,000 to 260,000 years ago. Africa is also considered by anthropologists to be
17510-454: The continental crust , particularly during the early stages of Earth's history. New continental crust forms as a result of plate tectonics , a process ultimately driven by the continuous loss of heat from Earth's interior. Over the period of hundreds of millions of years, tectonic forces have caused areas of continental crust to group together to form supercontinents that have subsequently broken apart. At approximately 750 Ma , one of
17680-616: The continental surfaces are covered by sedimentary rocks, although they form about 5% of the mass of the crust. Earth's surface topography comprises both the topography of the ocean surface , and the shape of Earth's land surface. The submarine terrain of the ocean floor has an average bathymetric depth of 4 km, and is as varied as the terrain above sea level. Earth's surface is continually being shaped by internal plate tectonic processes including earthquakes and volcanism ; by weathering and erosion driven by ice, water, wind and temperature; and by biological processes including
17850-419: The continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Based on 2024 projections, Africa's population will reach 3.8 billion people by 2099. Africa is the least wealthy inhabited continent per capita and second-least wealthy by total wealth, ahead of Oceania . Scholars have attributed this to different factors including geography , climate , corruption , colonialism ,
18020-419: The core are chaotic; the magnetic poles drift and periodically change alignment. This causes secular variation of the main field and field reversals at irregular intervals averaging a few times every million years. The most recent reversal occurred approximately 700,000 years ago. The extent of Earth's magnetic field in space defines the magnetosphere . Ions and electrons of the solar wind are deflected by
18190-527: The core is primarily composed of the denser elements: iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. The most common rock constituents of the crust are oxides . Over 99% of the crust is composed of various oxides of eleven elements, principally oxides containing silicon (the silicate minerals ), aluminium, iron, calcium, magnesium, potassium, or sodium. The major heat-producing isotopes within Earth are potassium-40 , uranium-238 , and thorium-232 . At
18360-463: The core, through the mantle, and up to Earth's surface, where it is, approximately, a dipole . The poles of the dipole are located close to Earth's geographic poles. At the equator of the magnetic field, the magnetic-field strength at the surface is 3.05 × 10 T , with a magnetic dipole moment of 7.79 × 10 Am at epoch 2000, decreasing nearly 6% per century (although it still remains stronger than its long time average). The convection movements in
18530-524: The days shorter. Above the Arctic Circle and below the Antarctic Circle there is no daylight at all for part of the year, causing a polar night , and this night extends for several months at the poles themselves. These same latitudes also experience a midnight sun , where the sun remains visible all day. By astronomical convention, the four seasons can be determined by the solstices—the points in
18700-428: The earliest instances of agriculture in human history. Its cultivation would gradually spread across Africa, before spreading to India around 2000 BC. People around modern-day Mauritania started making pottery and built stone settlements (e.g., Tichitt , Oualata ). Fishing, using bone-tipped harpoons , became a major activity in the numerous streams and lakes formed from the increased rains. In West Africa,
18870-605: The earliest known supercontinents, Rodinia , began to break apart. The continents later recombined to form Pannotia at 600–540 Ma , then finally Pangaea , which also began to break apart at 180 Ma . The most recent pattern of ice ages began about 40 Ma , and then intensified during the Pleistocene about 3 Ma . High- and middle-latitude regions have since undergone repeated cycles of glaciation and thaw, repeating about every 21,000, 41,000 and 100,000 years. The Last Glacial Period , colloquially called
19040-535: The end of the Ice ages , estimated to have been around 10,500 BC, the Sahara had again become a green fertile valley, and its African populations returned from the interior and coastal highlands in sub-Saharan Africa , with rock art paintings depicting a fertile Sahara and large populations discovered in Tassili n'Ajjer dating back perhaps 10 millennia. However, the warming and drying climate meant that by 5,000 BC,
19210-544: The equally large area of land under permafrost ) or deserts (33%). The pedosphere is the outermost layer of Earth's land surface and is composed of soil and subject to soil formation processes. Soil is crucial for land to be arable. Earth's total arable land is 10.7% of the land surface, with 1.3% being permanent cropland. Earth has an estimated 16.7 million km (6.4 million sq mi) of cropland and 33.5 million km (12.9 million sq mi) of pastureland. The land surface and
19380-576: The evolution of Homo sapiens approximately 350,000 to 260,000 years BP in Africa, the continent was mainly populated by groups of hunter-gatherers . These first modern humans left Africa and populated the rest of the globe during the Out of Africa II migration dated to approximately 50,000 years BP, exiting the continent either across Bab-el-Mandeb over the Red Sea , the Strait of Gibraltar in Morocco, or
19550-647: The expansion of farming communities and the rapid adoption of rice cultivation around the Niger River. By the first millennium BC, ironworking had been introduced in Northern Africa. Around that time it also became established in parts of sub-Saharan Africa, either through independent invention there or diffusion from the north and vanished under unknown circumstances around 500 AD, having lasted approximately 2,000 years, and by 500 BC, metalworking began to become commonplace in West Africa. Ironworking
19720-638: The growth and decomposition of biomass into soil . Earth's mechanically rigid outer layer of Earth's crust and upper mantle , the lithosphere , is divided into tectonic plates . These plates are rigid segments that move relative to each other at one of three boundaries types: at convergent boundaries , two plates come together; at divergent boundaries , two plates are pulled apart; and at transform boundaries , two plates slide past one another laterally. Along these plate boundaries, earthquakes, volcanic activity , mountain-building , and oceanic trench formation can occur. The tectonic plates ride on top of
19890-502: The growth and expansion of Aksum in the 1st century BC. Along the Horn's coast there were many ancient Somali city-states that thrived off of the wider Red Sea trade and transported their cargo via beden , exporting myrrh , frankincense , spices , gum , incense , and ivory , with freedom from Roman interference causing Indians to give the cities a lucrative monopoly on cinnamon from ancient India . The Kingdom of Aksum grew from
20060-404: The heat in Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges . The final major mode of heat loss is through conduction through the lithosphere, the majority of which occurs under the oceans. The gravity of Earth is the acceleration that is imparted to objects due to the distribution of mass within Earth. Near Earth's surface, gravitational acceleration
20230-443: The historical process is largely a communal one, with eyewitness accounts, hearsay , reminiscences, and occasionally visions , dreams, and hallucinations, crafted into oral traditions . Time is sometimes mythical and social, and truth generally viewed as relativist . Oral tradition can be exoteric or esoteric . It speaks to people according to their understanding, unveiling itself in accordance with their aptitudes, and
20400-509: The kingdoms of Lower Egypt and Upper Egypt in northeast Africa . Around 3100 BC Upper Egypt conquered Lower Egypt to unify Egypt under the 1st dynasty , with the process of consolidation and assimilation completed by the time of the 3rd dynasty who formed the Old Kingdom of Egypt in 2686 BC. The Kingdom of Kerma emerged around this time to become the dominant force in Nubia , controlling territory as large as Egypt between
20570-406: The land surface is taken by the four continental landmasses , which are (in descending order): Africa-Eurasia , America (landmass) , Antarctica , and Australia (landmass) . These landmasses are further broken down and grouped into the continents . The terrain of the land surface varies greatly and consists of mountains, deserts , plains , plateaus , and other landforms . The elevation of
20740-508: The land surface varies from a low point of −418 m (−1,371 ft) at the Dead Sea , to a maximum altitude of 8,848 m (29,029 ft) at the top of Mount Everest . The mean height of land above sea level is about 797 m (2,615 ft). Land can be covered by surface water , snow, ice, artificial structures or vegetation. Most of Earth's land hosts vegetation, but considerable amounts of land are ice sheets (10%, not including
20910-507: The largest number of megafauna species, as it was least affected by the extinction of the Pleistocene megafauna . However, Africa also is heavily affected by a wide range of environmental issues , including desertification, deforestation, water scarcity , and pollution . These entrenched environmental concerns are expected to worsen as climate change impacts Africa . The UN Intergovernmental Panel on Climate Change has identified Africa as
21080-599: The last 200 years, in Ethiopia . The domestication of cattle in Africa preceded agriculture and seems to have existed alongside hunter-gatherer cultures. It is speculated that by 6,000 BC, cattle were domesticated in North Africa. In the Sahara-Nile complex, people domesticated many animals, including the donkey and a small screw-horned goat that was common from Algeria to Nubia . Between 10,000 and 9,000 BC, pottery
21250-399: The lithosphere, which is divided into independently moving tectonic plates. Beneath the lithosphere is the asthenosphere , a relatively low-viscosity layer on which the lithosphere rides. Important changes in crystal structure within the mantle occur at 410 and 660 km (250 and 410 mi) below the surface, spanning a transition zone that separates the upper and lower mantle. Beneath
21420-410: The loss of oxygen in the atmosphere, making current animal life impossible. Due to the increased luminosity, Earth's mean temperature may reach 100 °C (212 °F) in 1.5 billion years, and all ocean water will evaporate and be lost to space, which may trigger a runaway greenhouse effect , within an estimated 1.6 to 3 billion years. Even if the Sun were stable, a fraction of the water in
21590-456: The lowercase when it is preceded by "the", such as "the atmosphere of the earth". It almost always appears in lowercase in colloquial expressions such as "what on earth are you doing?" The name Terra / ˈ t ɛr ə / occasionally is used in scientific writing and especially in science fiction to distinguish humanity's inhabited planet from others, while in poetry Tellus / ˈ t ɛ l ə s / has been used to denote personification of
21760-497: The magnetosphere. During magnetic storms and substorms , charged particles can be deflected from the outer magnetosphere and especially the magnetotail, directed along field lines into Earth's ionosphere , where atmospheric atoms can be excited and ionized, causing an aurora . Earth's rotation period relative to the Sun—its mean solar day—is 86,400 seconds of mean solar time ( 86,400.0025 SI seconds ). Because Earth's solar day
21930-409: The magnetosphere; solar wind pressure compresses the day-side of the magnetosphere, to about 10 Earth radii, and extends the night-side magnetosphere into a long tail. Because the velocity of the solar wind is greater than the speed at which waves propagate through the solar wind, a supersonic bow shock precedes the day-side magnetosphere within the solar wind. Charged particles are contained within
22100-478: The magnetosphere; the plasmasphere is defined by low-energy particles that essentially follow magnetic field lines as Earth rotates. The ring current is defined by medium-energy particles that drift relative to the geomagnetic field, but with paths that are still dominated by the magnetic field, and the Van Allen radiation belts are formed by high-energy particles whose motion is essentially random, but contained in
22270-452: The major cashcrop. The weather is usually warm and dry. The elevation of the country reaches to a maximum of 50 m (160 ft) above the mean sea level. There are vast segments of sedimentary sandstone and claystone in the valleys of the rivers and the regions surrounding it. The river flows from Guinea and has an east–west axis. The shallow water in the coastline are important sources of fishing. There are mangrove and banto forests along
22440-417: The mantle, an extremely low viscosity liquid outer core lies above a solid inner core . Earth's inner core may be rotating at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year, although both somewhat higher and much lower rates have also been proposed. The radius of the inner core is about one-fifth of that of Earth. The density increases with depth. Among
22610-600: The mantle. Due to this recycling, most of the ocean floor is less than 100 Ma old. The oldest oceanic crust is located in the Western Pacific and is estimated to be 200 Ma old. By comparison, the oldest dated continental crust is 4,030 Ma , although zircons have been found preserved as clasts within Eoarchean sedimentary rocks that give ages up to 4,400 Ma , indicating that at least some continental crust existed at that time. The seven major plates are
22780-548: The modern oceans will descend to the mantle , due to reduced steam venting from mid-ocean ridges. The Sun will evolve to become a red giant in about 5 billion years . Models predict that the Sun will expand to roughly 1 AU (150 million km; 93 million mi), about 250 times its present radius. Earth's fate is less clear. As a red giant, the Sun will lose roughly 30% of its mass, so, without tidal effects, Earth will move to an orbit 1.7 AU (250 million km; 160 million mi) from
22950-643: The most genetically diverse continent as a result of being the longest inhabited. In the 4th and 3rd millennia BC Ancient Egypt , Kerma , Punt , and the Tichitt Tradition emerged in North , East and West Africa , while from 4000 BC until 1000 AD the Bantu expansion was substantial in laying the foundations for societies and states in Central , East , and Southern Africa . Some African empires include Wagadu , Mali , Songhai , Sokoto , Ife , Benin , Asante ,
23120-399: The most lucrative trading locations in the Gulf of Tunis . Phoenician settlements subsequently grew into Ancient Carthage after gaining independence from Phoenicia in the 6th century BC, and they would build an extensive empire and a strict mercantile network, all secured by one of the largest and most powerful navies in the ancient Mediterranean . Carthage would meet its demise in
23290-399: The mother of Thor . Historically, "Earth" has been written in lowercase. Beginning with the use of Early Middle English , its definite sense as "the globe" was expressed as "the earth". By the era of Early Modern English , capitalization of nouns began to prevail , and the earth was also written the Earth , particularly when referenced along with other heavenly bodies. More recently,
23460-424: The name is sometimes simply given as Earth , by analogy with the names of the other planets , though "earth" and forms with "the earth" remain common. House styles now vary: Oxford spelling recognizes the lowercase form as the more common, with the capitalized form an acceptable variant. Another convention capitalizes "Earth" when appearing as a name, such as a description of the "Earth's atmosphere", but employs
23630-425: The newly forming Sun had only 70% of its current luminosity . By 3.5 Ga , Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind . As the molten outer layer of Earth cooled it formed the first solid crust , which is thought to have been mafic in composition. The first continental crust , which was more felsic in composition, formed by
23800-586: The ocean may have covered Earth completely. The world ocean is commonly divided into the Pacific Ocean, Atlantic Ocean, Indian Ocean, Antarctic or Southern Ocean , and Arctic Ocean, from largest to smallest. The ocean covers Earth's oceanic crust , with the shelf seas covering the shelves of the continental crust to a lesser extent. The oceanic crust forms large oceanic basins with features like abyssal plains , seamounts , submarine volcanoes , oceanic trenches , submarine canyons , oceanic plateaus , and
23970-648: The oceanic plates, with the Cocos Plate advancing at a rate of 75 mm/a (3.0 in/year) and the Pacific Plate moving 52–69 mm/a (2.0–2.7 in/year). At the other extreme, the slowest-moving plate is the South American Plate, progressing at a typical rate of 10.6 mm/a (0.42 in/year). Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical ( rheological ) properties. The outer layer
24140-439: The official religion, built mosques, and brought to Gao Muslim scholars, including al-Maghili (d.1504), the founder of an important tradition of Sudanic African Muslim scholarship. By the eleventh century, some Hausa states – such as Kano , Jigawa , Katsina , and Gobir – had developed into walled towns engaging in trade, servicing caravans , and the manufacture of goods. Until the fifteenth century, these small states were on
24310-460: The opportunities afforded by north–south diversity in ecosystems. Various civilisations prospered in this period. From 4000 BC, the Tichitt culture in modern-day Mauritania and Mali was the oldest known complexly organised society in West Africa, with a four tiered hierarchical social structure. Other civilisations include the Kintampo culture from 2500 BC in modern-day Ghana ,
24480-581: The orbit of maximum axial tilt toward or away from the Sun—and the equinoxes , when Earth's rotational axis is aligned with its orbital axis. In the Northern Hemisphere, winter solstice currently occurs around 21 December; summer solstice is near 21 June, spring equinox is around 20 March and autumnal equinox is about 22 or 23 September. In the Southern Hemisphere, the situation is reversed, with
24650-625: The ozone layer, life colonized Earth's surface. Among the earliest fossil evidence for life is microbial mat fossils found in 3.48 billion-year-old sandstone in Western Australia , biogenic graphite found in 3.7 billion-year-old metasedimentary rocks in Western Greenland , and remains of biotic material found in 4.1 billion-year-old rocks in Western Australia. The earliest direct evidence of life on Earth
24820-469: The partial melting of this mafic crust. The presence of grains of the mineral zircon of Hadean age in Eoarchean sedimentary rocks suggests that at least some felsic crust existed as early as 4.4 Ga , only 140 Ma after Earth's formation. There are two main models of how this initial small volume of continental crust evolved to reach its current abundance: (1) a relatively steady growth up to
24990-501: The past 66 Mys , and several million years ago, an African ape species gained the ability to stand upright. This facilitated tool use and encouraged communication that provided the nutrition and stimulation needed for a larger brain, which led to the evolution of humans . The development of agriculture , and then civilization , led to humans having an influence on Earth and the nature and quantity of other life forms that continues to this day. Earth's expected long-term future
25160-524: The periphery of the major Sudanic empires of the era, paying tribute to Songhai to the west and Kanem-Borno to the east. Slavery had long been practiced in Africa. Between the 15th and the 19th centuries, the Atlantic slave trade took an estimated 7–12 million slaves to the New World. In addition, more than 1 million Europeans were captured by Barbary pirates and sold as slaves in North Africa between
25330-478: The planet's environment . Humanity's current impact on Earth's climate and biosphere is unsustainable , threatening the livelihood of humans and many other forms of life, and causing widespread extinctions . The Modern English word Earth developed, via Middle English , from an Old English noun most often spelled eorðe . It has cognates in every Germanic language , and their ancestral root has been reconstructed as * erþō . In its earliest attestation,
25500-400: The planet. The water vapor acts as a greenhouse gas and, together with other greenhouse gases in the atmosphere, particularly carbon dioxide (CO 2 ), creates the conditions for both liquid surface water and water vapor to persist via the capturing of energy from the Sun's light . This process maintains the current average surface temperature of 14.76 °C (58.57 °F), at which water
25670-421: The polar Northern and Southern hemispheres; or by longitude into the continental Eastern and Western hemispheres. Most of Earth's surface is ocean water: 70.8% or 361 million km (139 million sq mi). This vast pool of salty water is often called the world ocean , and makes Earth with its dynamic hydrosphere a water world or ocean world . Indeed, in Earth's early history
25840-585: The predecessor to the African Union. The nascent countries decided to keep their colonial borders, with traditional power structures used in governance to varying degrees. Afri was a Latin name used to refer to the inhabitants of what was then known as northern Africa , located west of the Nile river, and in its widest sense referring to all lands south of the Mediterranean , also known as Ancient Libya . This name seems to have originally referred to
26010-490: The present day, which is supported by the radiometric dating of continental crust globally and (2) an initial rapid growth in the volume of continental crust during the Archean , forming the bulk of the continental crust that now exists, which is supported by isotopic evidence from hafnium in zircons and neodymium in sedimentary rocks. The two models and the data that support them can be reconciled by large-scale recycling of
26180-493: The rates of mantle convection and plate tectonics, and allowing the production of uncommon igneous rocks such as komatiites that are rarely formed today. The mean heat loss from Earth is 87 mW m , for a global heat loss of 4.42 × 10 W . A portion of the core's thermal energy is transported toward the crust by mantle plumes , a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce hotspots and flood basalts . More of
26350-475: The same fate as Carthage and be conquered by the Romans who established Mauretania and Numidia as provinces of their empire, while Musulamii , led by Tacfarinas , and Garamantes were eventually defeated in war in the 1st century AD however weren't conquered. In the 5th century AD the Vandals conquered north Africa precipitating the fall of Rome . Swathes of indigenous peoples would regain self-governance in
26520-515: The shape of an ellipsoid , bulging at its Equator ; its diameter is 43 kilometres (27 mi) longer there than at its poles . Earth's shape also has local topographic variations; the largest local variations, like the Mariana Trench (10,925 metres or 35,843 feet below local sea level), shortens Earth's average radius by 0.17% and Mount Everest (8,848 metres or 29,029 feet above local sea level) lengthens it by 0.14%. Since Earth's surface
26690-465: The strip-like structure never exceeds 48 km (30 mi). It is bordered by the Atlantic Ocean on the west, and is otherwise surrounded by Senegal . The Gambia River flows throughout the country and is the principal source of water and transport medium. The banks of the river have swampy beaches, while it has alluvial soil in all other parts, which is conducive for the growth of rice. Peanuts are
26860-481: The two continents by the geographer Ptolemy (85–165 CE), indicating Alexandria along the Prime Meridian and making the isthmus of Suez and the Red Sea the boundary between Asia and Africa. As Europeans came to understand the real extent of the continent, the idea of "Africa" expanded with their knowledge. Other etymological hypotheses have been postulated for the ancient name "Africa": In African societies,
27030-453: The under-five mortality was 137 per every thousand births. The poverty gap ratio was 19.8 per cent as of 2003. The literacy rate of the province was 69.3 compared to a national average of 62.9 per cent. The net enrollment ratio in primary education was 65 per cent, children entering first grade of primary school reaching last grade of primary education was 96 per cent and the ratios of boys against girls in primary, secondary and tertiary education
27200-489: The unifying framework of Islam. Following the breakup of Mali, a local leader named Sonni Ali (1464–1492) founded the Songhai Empire in the region of middle Niger and the western Sudan and took control of the trans-Saharan trade. Sonni Ali seized Timbuktu in 1468 and Jenne in 1473, building his regime on trade revenues and the cooperation of Muslim merchants. His successor Askia Mohammad I (1493–1528) made Islam
27370-516: The wet phase ushered in an expanding rainforest and wooded savanna from Senegal to Cameroon . Between 9,000 and 5,000 BC, Niger–Congo speakers domesticated the oil palm and raffia palm . Black-eyed peas and voandzeia (African groundnuts), were domesticated, followed by okra and kola nuts . Since most of the plants grew in the forest, the Niger–Congo speakers invented polished stone axes for clearing forest. Around 4,000 BC,
27540-456: The word eorðe was used to translate the many senses of Latin terra and Greek γῆ gē : the ground, its soil , dry land, the human world, the surface of the world (including the sea), and the globe itself. As with Roman Terra /Tellūs and Greek Gaia , Earth may have been a personified goddess in Germanic paganism : late Norse mythology included Jörð ("Earth"), a giantess often given as
27710-428: The year. This causes the seasonal change in climate, with summer in the Northern Hemisphere occurring when the Tropic of Cancer is facing the Sun, and in the Southern Hemisphere when the Tropic of Capricorn faces the Sun. In each instance, winter occurs simultaneously in the opposite hemisphere. During the summer, the day lasts longer, and the Sun climbs higher in the sky. In winter, the climate becomes cooler and
27880-418: Was rapidly conquered and colonised by European nations , save for Ethiopia and Liberia . European rule had significant impacts on Africa's societies , and colonies were maintained for the purpose of economic exploitation and extraction of natural resources. Most present states emerged from a process of decolonisation following World War II , and established the Organisation of African Unity in 1963,
28050-462: Was 1.13 as of 2007. The Gambia along with modern-day Senegal were colonies of French and British until 1894 when it became a British colony. Both the countries got independence in 1965 and operated in a federation called Senegambia from 1982. During 1989, the confederation collapsed. In a bloodless coup, Lieutenant Yahya Jamme in 1994 and went on to win multi party elections in three subsequent elections. He has also defeated coups successfully and unlike
28220-401: Was established around the ninth century, making it one of the oldest kingdoms in present-day Nigeri. The Nri kingdom is famous for its elaborate bronzes , found at the town of Igbo-Ukwu . The Kingdom of Ife , historically the first of these Yoruba city-states or kingdoms, established government under a priestly oba ('king' or 'ruler' in the Yoruba language ), called the Ooni of Ife . Ife
28390-450: Was fully established by roughly 500 BC in many areas of East and West Africa, although other regions did not begin ironworking until the early centuries AD. Copper objects from Egypt , North Africa, Nubia, and Ethiopia dating from around 500 BC have been excavated in West Africa, suggesting that Trans-Saharan trade networks had been established by this date. From 3500 BC, nomes (ruled by nomarchs ) coalesced to form
28560-474: Was independently invented in the region of Mali in the savannah of West Africa. In the steppes and savannahs of the Sahara and Sahel in Northern West Africa, people possibly ancestral to modern Nilo-Saharan and Mandé cultures started to collect wild millet , around 8,000 to 6,000 BC. Later, gourds , watermelons , castor beans , and cotton were also collected. Sorghum was first domesticated in Eastern Sudan around 4,000 BC, in one of
28730-444: Was noted as a major religious and cultural centre in West Africa and for its unique naturalistic tradition of bronze sculpture. The Ife model of government was adapted by the Oyo Empire , whose obas, called the Alaafins of Oyo , controlled many other Yoruba and non-Yoruba city-states and kingdoms including the Fon Kingdom of Dahomey . The Almoravids were a Berber dynasty from the Sahara that spread over northwestern Africa and
28900-514: Was one of the first African countries to gain independence, the state remained under the control of the country's white minority, initially through qualified voting rights and from 1956 by a system of racial segregation known as apartheid , until 1994. Today, Africa contains 54 sovereign countries. Since independence, African states have frequently been hampered by instability, corruption, violence, and authoritarianism. The vast majority of African states are republics that operate under some form of
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