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High Speed Civil Transport

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The High Speed Civil Transport ( HSCT ) was the focus of the NASA High-Speed Research ( HSR ) program, which intended to develop the technology needed to design and build a supersonic transport that would be environmentally acceptable and economically feasible. The aircraft was to be a future supersonic passenger aircraft, baselined to cruise at Mach 2.4, or more than twice the speed of sound . The project started in 1990 and ended in 1999.

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141-518: It was meant to cross the Atlantic or the Pacific Ocean in half the time of a non-supersonic aircraft. It was also intended to be fuel efficient, carry 300 passengers, and allow customers to buy tickets at a price only slightly higher than those of subsonic aircraft. The goal was to provide sufficient technology for an industry-led product launch decision in 2002, and if a product was launched,

282-655: A mare clausum policy in the Atlantic. The king, who had been inquiring of Genoese experts about a seaway to India, commissioned the Fra Mauro world map , which arrived in Lisbon in 1459. In 1456, Diogo Gomes reached the Cape Verde archipelago. In the next decade captains at the service of Prince Henry, discovered the remaining islands which were occupied during the 15th century. The Gulf of Guinea would be reached in

423-492: A World Heritage Site for their geological value, four of them are considered of "Outstanding Universal Value" based on their cultural and natural criteria: Þingvellir , Iceland; Landscape of the Pico Island Vineyard Culture , Portugal; Gough and Inaccessible Islands , United Kingdom; and Brazilian Atlantic Islands: Fernando de Noronha and Atol das Rocas Reserves, Brazil. Continental shelves in

564-466: A faster-than-exponential population growth world-wide. The concept of discovery has been scrutinized, critically highlighting the history of the core term of this periodization . The term "age of discovery" is in historical literature and still commonly used. J. H. Parry , calling the period the Age of Reconnaissance , argues that not only was the era one of European explorations, but it also produced

705-575: A 'discovery'. Something of which they had no prior knowledge had suddenly presented itself to their gaze." O'Gorman argues that the physical encounter with new territories was less important than the Europeans' effort to integrate this new knowledge into their worldview, what he calls "the invention of America". Pagden examines the origins of the terms "discovery" and "invention". In English, "discovery" and its forms in romance languages derive from " disco-operio , meaning to uncover, to reveal, to expose to

846-675: A Castilian armada of 35 caravels, and a Portuguese fleet for the hegemony of the Guinea trade (gold, slaves, ivory, and malagueta pepper). The war ended with a Portuguese naval victory, followed by the official recognition by the Catholic Monarchs of Portuguese sovereignty over most of the disputed West African territories embodied in the Treaty of Alcáçovas, 1479. This was the first colonial war among European powers. In 1481, João II decided to build São Jorge da Mina factory . In 1482

987-508: A Muslim merchant to India and Southeast Asia. In 1466–1472, Russian merchant Afanasy Nikitin of Tver travelled to India, which he described in his book A Journey Beyond the Three Seas . These overland journeys had little immediate effect. The Mongol Empire collapsed almost as quickly as it formed and soon the route to the east became more difficult and dangerous. The Black Death of the 14th century also blocked travel and trade for

1128-450: A Navy Sonic Depth Finder to draw a continuous map across the bed of the Atlantic. This involved little guesswork because the idea of sonar is straightforward with pulses being sent from the vessel, which bounce off the ocean floor, then return to the vessel. The deep ocean floor is thought to be fairly flat with occasional deeps, abyssal plains , trenches , seamounts , basins , plateaus , canyons , and some guyots . Various shelves along

1269-677: A Venetian merchant, dictated an account of journeys throughout Asia from 1271 to 1295, describing being a guest at the Yuan dynasty court of Kublai Khan in Travels . It was read throughout Europe. The Muslim fleet guarding the Strait of Gibraltar was defeated by Genoa in 1291. In that year, the Genoese attempted their first Atlantic exploration when merchant brothers Vadino and Ugolino Vivaldi sailed from Genoa with two galleys, but disappeared off

1410-522: A book of supposed travels compiled by John Mandeville acquired popularity. Despite the unreliable and often fantastical nature of its accounts, it was used as a reference for the East, Egypt, and the Levant in general, asserting the old belief that Jerusalem was the centre of the world . Following the period of Timurid relations with Europe , in 1439, Niccolò de' Conti published an account of his travels as

1551-721: A branch of the Gulf Stream which flows northward from the Grand Banks ; and the Subpolar Front , an extension of the North Atlantic Current, a wide, vaguely defined region separating the subtropical gyre from the subpolar gyre. This system of currents transports warm water into the North Atlantic, without which temperatures in the North Atlantic and Europe would plunge dramatically. North of

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1692-545: A confederation of merchant guilds and their towns in north Germany, along the North Sea and Baltic Sea, was instrumental in the commercial development of the region. In the 12th century, the regions of Flanders , Hainault , and Brabant produced the finest quality textiles in northwest Europe, which encouraged merchants from Genoa and Venice to sail there from the Mediterranean, through the Strait of Gibraltar, and up

1833-743: A constant deficit in silver and gold , as it only went out, spent on eastern trade now cut off. Several European mines were exhausted, The lack of bullion led to the development of a complex banking system to manage the risks in trade (the first state bank, Banco di San Giorgio , was founded in 1407 at Genoa). Sailing also into the ports of Bruges (Flanders) and England, Genoese communities were then established in Portugal, who profited from their enterprise and financial expertise. European sailing had been primarily close to land cabotage , guided by portolan charts . These charts specified proven ocean routes guided by coastal landmarks: sailors departed from

1974-571: A distinct period of time. Published in 1496 by the Jewish astronomer, astrologer, and mathematician Abraham Zacuto , the Almanac Perpetuum included some of these tables for the movements of stars. These tables revolutionized navigation, allowing the calculation of latitude . Exact longitude remained elusive from mariners for centuries. Using the caravel, systematic exploration continued ever more southerly, advancing on average one degree

2115-511: A government policy in several European states. As such, it is sometimes synonymous with the first wave of European colonization . The colonization reshaped power dynamics causing geopolitical shifts in Europe and creating new centers of power beyond Europe. Having set human history on the global common course, the legacy of the Age still shapes the world today. European oceanic exploration started with

2256-562: A known point, followed a compass heading, and tried to identify their location by its landmarks. For the first oceanic exploration Western Europeans used the compass, as well as progressive new advances in cartography and astronomy. Arab navigational tools like the astrolabe and quadrant were used for celestial navigation . The Muslim lands in Asia were generally more economically developed and had better infrastructure than Europe at this time, despite Europe's economic changes brought about by

2397-716: A maiden flight within 20 years. The program was based on the successes and failures of the British/French Concorde and the Russian Tupolev Tu-144 , as well as a previous NASA Supersonic Transport ( SST ) program from the early 1970s (for the latter, see Lockheed L-2000 and Boeing 2707 .) While the Concorde and Tu-144 programs both yielded production aircraft, neither was produced in sufficient numbers to pay for their development costs. In 1989, NASA and industry partners began investigating

2538-571: A personal interest in exports. In 1317, he made an agreement with Genoese merchant sailor Manuel Pessanha , appointing him first admiral of the Portuguese Navy , to defend the country against Muslim pirate raids. Outbreaks of bubonic plague led to severe depopulation in the second half of the 14th century: only the sea offered alternatives, with most population settling in fishing and trading coastal areas. Between 1325 and 1357, Afonso IV of Portugal encouraged maritime commerce and ordered

2679-508: A time. Religion played a critical role in motivating European expansionism . In 1487, Portuguese envoys Pero da Covilhã and Afonso de Paiva were sent on a covert mission to gather intelligence on a potential sea route to India and inquire about Prester John , a Nestorian patriarch and king, believed to rule over parts of the subcontinent. Covilhã was warmly received upon his arrival in Ethiopia, but forbidden from leaving. During

2820-416: A weak Intertropical Convergence Zone , South Atlantic tropical cyclones are rare. The Atlantic Ocean is underlain mostly by dense mafic oceanic crust made up of basalt and gabbro and overlain by fine clay, silt and siliceous ooze on the abyssal plain. The continental margins and continental shelf mark lower density, but greater thickness felsic continental rock that is often much older than that of

2961-744: A year. Senegal and Cape Verde Peninsula were reached in 1445 and in 1446, Álvaro Fernandes pushed on almost as far as present-day Sierra Leone . In 1453, the Fall of Constantinople to the Ottomans was a perceived blow to Christendom and established business links with the East. In 1455, Pope Nicholas V issued the bull Romanus Pontifex reinforcing the previous Dum Diversas (1452), granting all lands and seas discovered beyond Cape Bojador to King Afonso V of Portugal and his successors, as well as mostly cutting off trade to and permitting conquest and increased war against Muslims and pagans, initiating

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3102-621: Is a complex of four water masses, two that form by deep convection in the open ocean – classical and upper Labrador sea water – and two that form from the inflow of dense water across the Greenland-Iceland-Scotland sill – Denmark Strait and Iceland-Scotland overflow water. Along its path across Earth the composition of the NADW is affected by other water masses, especially Antarctic bottom water and Mediterranean overflow water. The NADW

3243-414: Is fed by a flow of warm shallow water into the northern North Atlantic which is responsible for the anomalous warm climate in Europe. Changes in the formation of NADW have been linked to global climate changes in the past. Since human-made substances were introduced into the environment, the path of the NADW can be traced throughout its course by measuring tritium and radiocarbon from nuclear weapon tests in

3384-498: Is found off the eastern coast of Canada. Surface water temperatures, which vary with latitude, current systems, and season and reflect the latitudinal distribution of solar energy, range from below −2 °C (28 °F) to over 30 °C (86 °F). Maximum temperatures occur north of the equator, and minimum values are found in the polar regions. In the middle latitudes, the area of maximum temperature variations, values may vary by 7–8 °C (13–14 °F). From October to June

3525-575: Is interrupted by larger transform faults at two places: the Romanche Trench near the Equator and the Gibbs fracture zone at 53°N . The MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other. The MAR rises 2–3 km (1.2–1.9 mi) above the surrounding ocean floor and its rift valley is the divergent boundary between

3666-854: Is intersected by two perpendicular ridges: the Azores–Gibraltar Transform Fault , the boundary between the Nubian and Eurasian plates , intersects the MAR at the Azores triple junction , on either side of the Azores microplate, near the 40°N . A much vaguer, nameless boundary, between the North American and South American plates, intersects the MAR near or just north of the Fifteen-Twenty fracture zone , approximately at 16°N . In

3807-635: Is likely this last expedition reached as far as Madagascar . The travels were reported by Ma Huan , a Muslim voyager and translator who accompanied Zheng He on three of the expeditions, his account published as the Yingya Shenglan (Overall Survey of the Ocean's Shores) (1433). The voyages had a significant and lasting effect on the organization of a maritime network , using and creating nodes and conduits in its wake, thereby restructuring international and cross-cultural relationships and exchanges. It

3948-729: Is now northern and central Brazil. The formation of the Central American Isthmus closed the Central American Seaway at the end of the Pliocene 2.8 Ma ago. The formation of the isthmus resulted in the migration and extinction of many land-living animals, known as the Great American Interchange , but the closure of the seaway resulted in a "Great American Schism" as it affected ocean currents, salinity, and temperatures in both

4089-794: Is now the Carpathian region, that were similar to the Sargasso Sea. It is possible that the population in the Sargasso Sea migrated to the Atlantic as the Tethys closed at the end of the Miocene around 17 Ma. The origin of the Sargasso fauna and flora remained enigmatic for centuries. The fossils found in the Carpathians in the mid-20th century often called the "quasi-Sargasso assemblage", finally showed that this assemblage originated in

4230-922: The Iliad and the Odyssey , this all-encompassing ocean was instead known as Oceanus , the gigantic river that encircled the world; in contrast to the enclosed seas well known to the Greeks: the Mediterranean and the Black Sea. In contrast, the term "Atlantic" originally referred specifically to the Atlas Mountains in Morocco and the sea off the Strait of Gibraltar and the West African coast. The term " Aethiopian Ocean ", derived from Ancient Ethiopia ,

4371-749: The Age of Discovery , it was known for separating the New World of the Americas ( North America and South America ) from the Old World of Afro-Eurasia ( Africa , Asia , and Europe ). Through its separation of Afro-Eurasia from the Americas, the Atlantic Ocean has played a central role in the development of human society, globalization, and the histories of many nations. While the Norse were

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4512-487: The Black Death allowing for more freedoms for lower- and upper-class people. The gunpowder empires concealed knowledge to European Christian traders about where lucrative locations such as Indonesia were, spurring a further desire for Christian trade with other Muslim nations besides the gunpowder empires despite European Christians generally having antipathy towards Muslims. In 1297, King Denis of Portugal took

4653-564: The Carpathian Basin from where it migrated over Sicily to the central Atlantic where it evolved into modern species of the Sargasso Sea. The location of the spawning ground for European eels remained unknown for decades . In the early 19th century it was discovered that the southern Sargasso Sea is the spawning ground for both the European and American eel and that the former migrate more than 5,000 km (3,100 mi) and

4794-603: The Christian reconquest of Al-Andalus in what is now southern Spain and the siege of Lisbon (1147 AD), in Portugal. The decline of Fatimid Caliphate naval strength, which started before the First Crusade , helped the maritime Italian states, mainly Venice, Genoa and Pisa, dominate trade in the Eastern Mediterranean , with merchants there becoming wealthy and politically influential. Further changing

4935-610: The Columbian exchange while occasionally hosting naval battles. Such naval battles, as well as growing trade from regional American powers like the United States and Brazil , both increased in degree during the early 20th century, and while no major military conflicts have taken place in the Atlantic recently, the ocean remains a core component of trade around the world. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to

5076-588: The Congo River was explored by Diogo Cão , who in 1486 continued to Cape Cross (modern Namibia ). The next crucial breakthrough was in 1488, when Bartolomeu Dias rounded the southern tip of Africa, which he named Cabo das Tormentas, "Cape of Storms", anchoring at Mossel Bay and then sailing east as far as the mouth of the Great Fish River , proving the Indian Ocean was accessible from

5217-530: The Equator . The oldest known mentions of an "Atlantic" sea come from Stesichorus around mid-sixth century BC (Sch. A. R. 1. 211): Atlantikôi pelágei (Ancient Greek: Ἀτλαντικῷ πελάγει , ' the Atlantic sea ' , etym . ' Sea of Atlas ' ) and in The Histories of Herodotus around 450 BC (Hdt. 1.202.4): Atlantis thalassa (Ancient Greek: Ἀτλαντὶς θάλασσα , ' Sea of Atlas ' or '

5358-474: The Icelandic Low produces frequent storms. Icebergs are common from early February to the end of July across the shipping lanes near the Grand Banks of Newfoundland . The ice season is longer in the polar regions, but there is little shipping in those areas. Hurricanes are a hazard in the western parts of the North Atlantic during the summer and autumn. Due to a consistently strong wind shear and

5499-640: The Indies and the European colonization of the Americas by the Spanish and Portuguese , later joined by the English , French and Dutch , spurred in the International global trade . The interconnected global economy of the 21st century has its origins in the expansion of trade networks during this era. The exploration also created colonial empires and marked an increased adoption of colonialism as

5640-523: The Levant raised curiosity and commercial interest in countries which lay further east. There are a few accounts of merchants from North Africa and the Mediterranean, who traded in the Indian Ocean in late medieval times. Christian embassies were sent as far as Karakorum during the Mongol invasions of the Levant , from which they gained a greater understanding of the world. The first of these travellers

5781-484: The New World (the Americas and Australia). This exchange involved the transfer of plants, animals, human populations (including slaves ), communicable diseases , and culture across the Eastern and Western Hemispheres . The Age of Discovery and European exploration involved mapping of the world , shaping a new worldview and facilitating contact with distant civilizations. The continents drawn by European mapmakers of

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5922-625: The New World . By the late 16th and 17th centuries, the latter's presence increased as they sought to reassert their power and revive the Catholic culture of Europe, which had been damaged by the Reformation . The Chinese had wide connections through trade in Asia and been sailing to Arabia , East Africa , and Egypt since the Tang dynasty (AD 618–907). Between 1405-21, the third Ming emperor Yongle sponsored long range tributary missions in

6063-428: The North American and Eurasian plates in the North Atlantic and the South American and African plates in the South Atlantic. The MAR produces basaltic volcanoes in Eyjafjallajökull , Iceland, and pillow lava on the ocean floor. The depth of water at the apex of the ridge is less than 2,700 m (1,500 fathoms ; 8,900  ft ) in most places, while the bottom of the ridge is three times as deep. The MAR

6204-405: The North Atlantic Drift is thought to have at least some influence on climate. For example, the Gulf Stream helps moderate winter temperatures along the coastline of southeastern North America, keeping it warmer in winter along the coast than inland areas. The Gulf Stream also keeps extreme temperatures from occurring on the Florida Peninsula. In the higher latitudes, the North Atlantic Drift, warms

6345-451: The North Atlantic oscillation , occurs. On average, the Atlantic is the saltiest major ocean; surface water salinity in the open ocean ranges from 33 to 37 parts per thousand (3.3–3.7%) by mass and varies with latitude and season. Evaporation, precipitation, river inflow and sea ice melting influence surface salinity values. Although the lowest salinity values are just north of the equator (because of heavy tropical rainfall), in general,

6486-442: The Scotia Sea , and other tributary water bodies. Including these marginal seas the coast line of the Atlantic measures 111,866 km (69,510 mi) compared to 135,663 km (84,297 mi) for the Pacific. Including its marginal seas, the Atlantic covers an area of 106,460,000 km (41,100,000 sq mi) or 23.5% of the global ocean and has a volume of 310,410,900 km (74,471,500 cu mi) or 23.3% of

6627-401: The Treaty of Tordesillas , ratified by Pope Julius II . In 1498, a Portuguese expedition commanded by Vasco da Gama reached India by sailing around Africa, opening up direct trade with Asia. While other exploratory fleets were sent from Portugal to northern North America, Portuguese India Armadas also extended this Eastern oceanic route, touching South America and opening a circuit from

6768-417: The droop nose like that on the Concorde, an "external vision" system would have replaced the cockpit windows entirely with computer-generated graphics made available to the pilots on cockpit displays. Finally, a variety of materials were designed and tested against the very high temperature of Mach 2.4 flight, with titanium and a unique variety of carbon fiber being leading candidates for different areas of

6909-521: The meridional overturning circulation (MOC), the northward heat transport of which is threatened by anthropogenic climate change. Large variations in the subpolar gyre on a decade-century scale, associated with the North Atlantic oscillation , are especially pronounced in Labrador Sea Water , the upper layers of the MOC. The South Atlantic is dominated by the anti-cyclonic southern subtropical gyre. The South Atlantic Central Water originates in this gyre, while Antarctic Intermediate Water originates in

7050-399: The thermocline of the subtropical gyre. The Sargasso Sea in the western North Atlantic can be defined as the area where two species of Sargassum ( S. fluitans and natans ) float, an area 4,000 km (2,500 mi) wide and encircled by the Gulf Stream , North Atlantic Drift , and North Equatorial Current . This population of seaweed probably originated from Tertiary ancestors on

7191-406: The transatlantic voyages of the Italian navigator Christopher Columbus , which from 1492 to 1504 marked the start of colonization in the Americas, and the expedition of the Portuguese explorer Ferdinand Magellan to open a route from the Atlantic Ocean to the Pacific, which later achieved the first circumnavigation of the globe between 1519 and 1522. These Spanish expeditions significantly impacted

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7332-426: The " frontier " (as in Frontier Thesis ) and manifest destiny , up to the contemporary age of space exploration . Alternatively, the term contact , as in first contact , has been used to shed more light on the age of discovery and colonialism, using the alternative names of Age of Contact or Contact Period , discussing it as an "unfinished, diverse project". The Portuguese began systematically exploring

7473-564: The 11th century. It was adopted by Arab traders in the Indian Ocean. The compass spread to Europe by the late 12th or early 13th century. Use of the compass for navigation in the Indian Ocean was first mentioned in 1232. The first mention of use of the compass in Europe was in 1180. The Europeans used a "dry" compass, with a needle on a pivot. The compass card was also a European invention. Ships grew in size, required smaller crews and were able to sail longer distances without stopping. This led to significant lower long-distance shipping costs by

7614-506: The 1460s. In 1460, Pedro de Sintra reached Sierra Leone. Prince Henry died in November of that year after which, given the meagre revenues, exploration was granted to Lisbon merchant Fernão Gomes in 1469, who in exchange for the monopoly of trade in the Gulf of Guinea had to explore 100 miles (161 kilometres) each year for five years. With his sponsorship, explorers João de Santarém , Pedro Escobar , Lopo Gonçalves, Fernão do Pó , and Pedro de Sintra made it beyond those goals. They reached

7755-426: The 14th century. Cogs remained popular for trade because of their low cost. Galleys were also used in trade. The Periplus of the Erythraean Sea , a document from 40-60 AD, describes a newly discovered route through the Red Sea to India, with descriptions of the markets in towns around Red Sea, Persian Gulf and the Indian Ocean, including along the east coast of Africa, which states "for beyond these places

7896-421: The 17th century, during which seafarers from a number of European countries explored, colonized, and conquered regions across the globe. The Age of Discovery was a transformative period in world history when previously isolated parts of the world became connected to form the world-system and laid the groundwork for globalization . The extensive overseas exploration, particularly the opening of maritime routes to

8037-400: The 1870s, the Challenger expedition discovered parts of what is now known as the Mid-Atlantic Ridge, or: An elevated ridge rising to an average height of about 1,900 fathoms [3,500 m; 11,400 ft] below the surface traverses the basins of the North and South Atlantic in a meridianal direction from Cape Farewell, probably its far south at least as Gough Island, following roughly

8178-434: The 1953 definition it extends south to Antarctica, while in later maps it is bounded at the 60° parallel by the Southern Ocean. The Atlantic has irregular coasts indented by numerous bays, gulfs and seas. These include the Baltic Sea , Black Sea , Caribbean Sea , Davis Strait , Denmark Strait , part of the Drake Passage , Gulf of Mexico , Labrador Sea , Mediterranean Sea , North Sea , Norwegian Sea , almost all of

8319-411: The 1960s and CFCs . The clockwise warm-water North Atlantic Gyre occupies the northern Atlantic, and the counter-clockwise warm-water South Atlantic Gyre appears in the southern Atlantic. In the North Atlantic, surface circulation is dominated by three inter-connected currents: the Gulf Stream which flows north-east from the North American coast at Cape Hatteras ; the North Atlantic Current ,

8460-408: The Aegean, Bosporus, and Black Sea. The Venetians and other maritime republics maintained more limited access to Asian goods, via south-eastern Mediterranean trade, in such ports as Antioch, Acre, and Alexandria. Forced to reduce their activities in the Black Sea, and at war with Venice, the Genoese had turned to North African trade of wheat, olive oil and a search for silver and gold. Europeans had

8601-435: The Age developed from abstract "blobs" into the outlines more recognizable to us today. Simultaneously, the spread of new diseases, especially affecting American Indians , led to rapid population declines . The era saw widespread enslavement , exploitation and military conquest of native populations , concurrent with the growing economic influence and spread of western and European culture , science and technology leading to

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8742-463: The Arab seamen, and its southern extent was unknown. There were reports of great African Sahara , but the knowledge was limited for the Europeans, to the Mediterranean coast and little else, since the Arab blockade of North Africa precluded exploration inland. Knowledge about the Atlantic African coast was fragmented and derived mainly from old Greek and Roman maps based on Carthaginian knowledge, including Roman exploration of Mauritania . The Red Sea

8883-408: The Atlantic and Pacific. Marine organisms on both sides of the isthmus became isolated and either diverged or went extinct. Age of Discovery The Age of Discovery ( c.  1418  – c.  1620 ), also known as the Age of Exploration , was part of the early modern period and largely overlapped with the Age of Sail . It was a period from approximately the late 15th century to

9024-407: The Atlantic are wide off Newfoundland, southernmost South America, and northeastern Europe. In the western Atlantic carbonate platforms dominate large areas, for example, the Blake Plateau and Bermuda Rise . The Atlantic is surrounded by passive margins except at a few locations where active margins form deep trenches : the Puerto Rico Trench (8,376 m or 27,480 ft maximum depth) in

9165-472: The Atlantic coast of Africa in 1418, under the sponsorship of Prince Henry the Navigator . In 1488, Bartolomeu Dias reached the Indian Ocean by this route. In 1492, the Catholic Monarchs of Spain funded Genoese mariner Christopher Columbus 's ( Italian : Cristoforo Colombo ) plan to sail west to reach the Indies , by crossing the Atlantic. Columbus encountered a continent uncharted by Europeans (though it had been explored and temporarily colonized by

9306-460: The Atlantic coast. Nicolòzzo Spinola made the first recorded direct voyage from Genoa to Flanders in 1277. Technological advancements that were important to the Age of Exploration were the adoption of the magnetic compass and advances in ship design. The compass was an addition to the ancient method of navigation based on sightings of the sun and stars. It was invented during the Chinese Han dynasty and had been used for navigation in China by

9447-468: The Atlantic include the Challenger expedition and the German Meteor expedition ; as of 2001 , Columbia University 's Lamont–Doherty Earth Observatory and the United States Navy Hydrographic Office conduct research on the ocean. The MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR reaches above 2,000 m (6,600 ft) along most of its length, but

9588-403: The Atlantic north of the equator. The coldest zones are in high latitudes, with the coldest regions corresponding to the areas covered by sea ice. Ocean currents influence the climate by transporting warm and cold waters to other regions. The winds that are cooled or warmed when blowing over these currents influence adjacent land areas. The Gulf Stream and its northern extension towards Europe,

9729-455: The Atlantic sea ' ) where the name refers to "the sea beyond the pillars of Heracles " which is said to be part of the sea that surrounds all land. In these uses, the name refers to Atlas , the Titan in Greek mythology , who supported the heavens and who later appeared as a frontispiece in medieval maps and also lent his name to modern atlases . On the other hand, to early Greek sailors and in ancient Greek mythological literature such as

9870-431: The Atlantic. Simultaneously Pero da Covilhã , sent out travelling secretly overland, had reached Ethiopia having collected important information about the Red Sea and Quenia coast, suggesting a sea route to the Indies would soon be forthcoming. Soon the cape was renamed by King John II of Portugal the " Cape of Good Hope ", because of the great optimism engendered by the possibility of a sea route to India, proving false

10011-409: The Bahamas, while coarse river outwash sands and silt are common in shallow shelf areas like the Georges Bank . Coarse sand, boulders, and rocks were transported into some areas, such as off the coast of Nova Scotia or the Gulf of Maine during the Pleistocene ice ages. The break-up of Pangaea began in the central Atlantic, between North America and Northwest Africa, where rift basins opened during

10152-471: The Canary Islands in 1402 but became distracted by internal Iberian politics and the repelling of Islamic invasion attempts and raids through most of the 15th century. Late in the century, following the unification of the crowns of Castile and Aragon, an emerging modern Spain became fully committed to the search for new trade routes overseas. The Crown of Aragon had been an important maritime power in

10293-499: The European perceptions of the world. These discoveries led to numerous naval expeditions across the Atlantic , Indian, and Pacific Oceans , and land expeditions in the Americas, Asia , Africa , and Australia that continued into the late 19th century, followed by the exploration of the polar regions in the 20th century. European exploration initiated the Columbian exchange between the Old World (Europe, Asia, and Africa) and

10434-460: The European shores of the former Tethys Ocean and has, if so, maintained itself by vegetative growth , floating in the ocean for millions of years. Other species endemic to the Sargasso Sea include the sargassum fish , a predator with algae-like appendages which hovers motionless among the Sargassum . Fossils of similar fishes have been found in fossil bays of the former Tethys Ocean, in what

10575-494: The Indian Ocean under the command of admiral Zheng He . A large fleet of new junk ships was prepared for the international diplomatic expeditions. The largest of these junks—that the Chinese termed bao chuan (treasure ships) —may have measured 121 metres, and thousands of sailors were involved. The first expedition departed in 1405. At least seven well-documented expeditions were launched, each bigger and more expensive than

10716-777: The Indian Ocean, tapping source regions in the Far East and shipping for trading emporiums in India, mainly Kozhikode , westward to Ormus in the Persian Gulf and Jeddah in the Red Sea . From there, overland routes led to the Mediterranean coasts. Venetian merchants distributed the goods through Europe until the rise of the Ottoman Empire , which eventually led to the Fall of Constantinople in 1453, barring Europeans from some important combined-land-sea routes in areas around

10857-623: The Late Triassic and Early Jurassic. This period also saw the first stages of the uplift of the Atlas Mountains. The exact timing is controversial with estimates ranging from 200 to 170 Ma. The opening of the Atlantic Ocean coincided with the initial break-up of the supercontinent Pangaea , both of which were initiated by the eruption of the Central Atlantic Magmatic Province (CAMP), one of

10998-514: The Mediterranean, controlling territories in eastern Spain, southwestern France, major islands like Sicily , Malta , and the Kingdom of Naples and Sardinia , with mainland possessions as far as Greece. In 1492 the joint rulers conquered the Moorish kingdom of Granada , which had been providing Castile with African goods through tribute, and decided to fund Christopher Columbus 's expedition in

11139-577: The Middle Ages, the spread of Christianity throughout Europe fueled the desire to sermonise in lands beyond. This evangelical effort became a significant part of the military conquests of European powers, like Portugal , Spain , and France , often leading to the conversion of indigenous peoples, voluntarily or forced. Religious orders such as the Franciscans , Dominicans , Augustinians , and Jesuits partook in most missionary endeavours in

11280-542: The Ming treasure fleet generated and intensified competition among contending polities and rivals, each seeking an alliance with the Ming. The expeditions developed into a maritime trade enterprise, with imperial control over local markets and court-monitored transactions, generating revenue for China and its partners. They boosted regional trade and production, caused a supply shock in Eurasia and led to price spikes in Europe in

11421-733: The Moroccan coast, feeding fears of oceanic travel. From 1325 to 1354, a Moroccan scholar from Tangier , Ibn Battuta , journeyed through North Africa, the Sahara desert, West Africa, Southern Europe, Eastern Europe, the Horn of Africa, the Middle East and Asia, having reached China. After returning, he dictated an account to a scholar he met in Granada, The Rihla ("The Journey"), the unheralded source on his adventures. Between 1357 and 1371

11562-691: The New World to Asia (starting in 1500 by Pedro Álvares Cabral ), and explored islands in the South Atlantic and Southern Indian Oceans. The Portuguese sailed further eastward, to the valuable Spice Islands in 1512, landing in China one year later. Japan was reached by the Portuguese in 1543. In 1513, Spanish Vasco Núñez de Balboa crossed the Isthmus of Panama and reached the "other sea" from

11703-403: The New World. Thus, Europe first received news of the eastern and western Pacific within a one-year span around 1512. East and west exploration overlapped in 1522, when a Spanish expedition sailing westward, led by Portuguese navigator Ferdinand Magellan and, after his death by navigator Juan Sebastián Elcano , completed the first circumnavigation of the world. Spanish conquistadors explored

11844-598: The Norse 500 years earlier). Later, it was called America after Amerigo Vespucci , a trader working for Portugal . Portugal quickly claimed those lands under the terms of the Treaty of Alcáçovas , but Castile was able to persuade the Pope, who was Castilian, to issue four papal bulls to divide the world into two regions of exploration, where each kingdom had exclusive rights to claim newly discovered lands. These were modified by

11985-613: The North Atlantic Gyre, the cyclonic North Atlantic Subpolar Gyre plays a key role in climate variability. It is governed by ocean currents from marginal seas and regional topography, rather than being steered by wind, both in the deep ocean and at sea level. The subpolar gyre forms an important part of the global thermohaline circulation . Its eastern portion includes eddying branches of the North Atlantic Current which transport warm, saline waters from

12126-578: The Pacific Ocean around South America, and eventually by following the Portuguese around Africa, into the Indian Ocean; discovering Australia in 1606, New Zealand in 1642, and Hawaii in 1778. From the 1580s to the 1640s, Russians explored and conquered almost the whole of Siberia and Alaska in the 1730s. After the fall of the Western Roman Empire largely severed the connection between Europe, and lands further east, Christian Europe

12267-492: The South Atlantic, and the "Atmospheric Bridge", which evaporates subtropical Atlantic waters and exports it to the Pacific. The Atlantic Ocean consists of four major, upper water masses with distinct temperature and salinity. The Atlantic subarctic upper water in the northernmost North Atlantic is the source for subarctic intermediate water and North Atlantic intermediate water. North Atlantic central water can be divided into

12408-716: The Southern Hemisphere and islands of the Gulf of Guinea, including São Tomé and Príncipe and Elmina on the Gold Coast in 1471. There, in what came to be called the "Gold Coast" in what is today Ghana , a thriving alluvial gold trade was found among the natives, Arab and Berber traders. In 1478, during the War of the Castilian Succession , near the coast at Elmina a large battle was fought between

12549-541: The Western Ocean's regional integration and increase in international circulation of people, ideas, and goods. It provided a platform for cosmopolitan discourses, which took place in locations such as the ships of the Ming treasure fleet, the Ming capitals of Nanjing as well as Beijing, and the banquet receptions organized by the Ming court for foreign representatives. Diverse groups of people from maritime countries congregated, interacted, and traveled together as

12690-475: The atmosphere over the oceans, keeping the British Isles and northwestern Europe mild and cloudy, and not severely cold in winter, like other locations at the same high latitude. The cold water currents contribute to heavy fog off the coast of eastern Canada (the Grand Banks of Newfoundland area) and Africa's northwestern coast. In general, winds transport moisture and air over land areas. Every winter,

12831-410: The concept of colonial claiming of "discovery" over their lands and people, as forced and negating indigenous presence. The period alternatively called the Age of Exploration , has been scrutinized through reflections on the exploration . Its understanding and use, has been discussed as being framed and used for colonial ventures, discrimination and exploitation , by combining it with concepts such as

12972-462: The craft. Though the project was largely successful, it was canceled in 1999 due to budget constraints, as well as Boeing withdrawing interest (i.e. funding) from the project. Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceanic divisions , with an area of about 85,133,000 km (32,870,000 sq mi). It covers approximately 17% of Earth's surface and about 24% of its water surface area. During

13113-408: The early 15th century. The tributary relations promoted during the voyages manifested a trend toward cross-regional interconnections and early globalization in Asia and Africa. Diplomatic relations were built on mutually beneficial maritime trade and China's strong naval presence in foreign waters, with Chinese naval superiority being a key factor in these interactions. The voyages brought about

13254-608: The east, and the Americas to the west. As one component of the interconnected World Ocean , it is connected in the north to the Arctic Ocean , to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south. Other definitions describe the Atlantic as extending southward to Antarctica . The Atlantic Ocean is divided in two parts, the northern and southern Atlantic, by

13395-554: The east, the boundaries of the ocean proper are Europe: the Strait of Gibraltar (where it connects with the Mediterranean Sea  – one of its marginal seas  – and, in turn, the Black Sea , both of which also touch upon Asia) and Africa. In the southeast, the Atlantic merges into the Indian Ocean. The 20° East meridian , running south from Cape Agulhas to Antarctica defines its border. In

13536-544: The eastern and western North Atlantic central water since the western part is strongly affected by the Gulf Stream and therefore the upper layer is closer to underlying fresher subpolar intermediate water. The eastern water is saltier because of its proximity to Mediterranean water. North Atlantic central water flows into South Atlantic central water at 15°N . There are five intermediate waters: four low-salinity waters formed at subpolar latitudes and one high-salinity formed through evaporation. Arctic intermediate water flows from

13677-468: The emperor's death, as the Chinese lost interest in what they termed barbarian lands, turning inward, and successor emperors felt the expeditions were harmful to the Chinese state; Hongxi Emperor ended further expeditions and Xuande Emperor suppressed much of the information about Zheng He's voyages. From the 8th until the 15th century, the Republic of Venice and neighboring maritime republics held

13818-479: The environmental technologies and other high-risk technologies for economic viability. Phase 1 focused on several environmental concerns: NOx emissions which can deplete the ozone layer, community noise , sonic boom noise, and high-altitude radiation. Tests relevant to each concern were carried out. A U-2 spy plane, renamed to the ER-2 , was used to measure high-altitude emissions from a Concorde jet and to measure

13959-430: The expansion of geographical knowledge and empirical science . "It saw also the first major victories of empirical inquiry over authority, the beginnings of that close association of science, technology, and everyday work which is an essential characteristic of the modern western world." Anthony Pagden draws on the work of Edmundo O'Gorman for the statement that "For all Europeans, the events of October 1492 constituted

14100-405: The exploration of the coast of Africa. This was an existing Iberian ship type, used for fishing, commerce and military purposes. Unlike other vessels of the time, the caravel had a sternpost-mounted rudder (as opposed to a side-mounted steering oar). It had a shallow draft, which was helpful in exploring unknown coastlines. It had good sailing performance, with a windward ability that was notable by

14241-485: The feasibility of radically higher-speed passenger aircraft. By 1990 the design converged to a Mach 2.4, 300-passenger capable aircraft, and the High-Speed Research program was started. The project was split into two phases which examined a variety of areas for development. The first phase "focused on the development of technology concepts for environmental compatibility". The second phase aimed to demonstrate

14382-552: The first explorations. The Canary Islands , already known to the Genoese, were claimed as officially discovered under the patronage of the Portuguese, but in 1344 Castile disputed them, expanding their rivalry into the sea. To ensure their monopoly on trade, Europeans (beginning with the Portuguese) attempted to install a Mediterranean system of trade which used military might and intimidation, to divert trade through ports they controlled; there it could be taxed. In 1415, Ceuta

14523-493: The first known humans to cross the Atlantic, it was the expedition of Christopher Columbus in 1492 that proved to be the most consequential. Columbus' expedition ushered in an age of exploration and colonization of the Americas by European powers , most notably Portugal , Spain , France , and the United Kingdom . From the 16th to 19th centuries, the Atlantic Ocean was the center of both an eponymous slave trade and

14664-751: The gaze", what was revealed existed previously. Few Europeans during the period used the term "invention" for the European encounters, with the exception of Martin Waldseemüller , whose map first used the term " America ". A central legal concept of the discovery doctrine , expounded by the US Supreme Court in 1823, draws on assertions of European powers' right to claim land during their explorations. The concept of "discovery" has been used to enforce colonial claiming and discovery, but has been challenged by indigenous peoples and researchers. Many indigenous peoples have fundamentally challenged

14805-470: The idea that the Indian Ocean was landlocked. A prelude to the Age of Discovery was a series of European expeditions crossing Eurasia by land in the late Middle Ages. The Mongols had threatened Europe, but Mongol states also unified much of Eurasia and, from 1206 on, the Pax Mongolica allowed safe trade routes and communication lines from the Middle East to China. The close Italian links to

14946-537: The interconnecting of river and sea trade routes. Before the 12th century, an obstacle to trade east of the Strait of Gibraltar , which divided the Mediterranean from the Atlantic Ocean, was Muslim control of territory, including the Iberian Peninsula and the trade monopolies of Christian city-states on the Italian Peninsula, especially Venice and Genoa . Economic growth of Iberia followed

15087-688: The interior of the Americas, and some of the South Pacific islands. Their main objective was to disrupt Portuguese trade in the East. From 1495, the French, English, and Dutch entered the race of exploration, after learning of Columbus' exploits, defying the Iberian monopoly on maritime trade by searching for new routes. The first expedition was John Cabot in 1497 to the north, in the service of England, followed by French expeditions to South America and later to North America. Later expeditions went to

15228-438: The last. The fleets visited Arabia , East Africa , India , Malay Archipelago and Thailand (then called Siam ), exchanging goods along the way. They presented gifts of gold, silver, porcelain and silk ; in return, received such novelties as ostriches , zebras , camels , ivory and giraffes . After the emperor's death, Zheng He led a final expedition departing from Nanking in 1431 and returning to Beijing in 1433. It

15369-517: The latter 2,000 km (1,200 mi). Ocean currents such as the Gulf Stream transport eel larvae from the Sargasso Sea to foraging areas in North America, Europe, and northern Africa. Recent but disputed research suggests that eels possibly use Earth's magnetic field to navigate through the ocean both as larvae and as adults. The climate is influenced by the temperatures of the surface waters and water currents as well as winds. Because of

15510-666: The limits of the oceans and seas in 1953, but some of these definitions have been revised since then and some are not recognized by various authorities, institutions, and countries, for example the CIA World Factbook . Correspondingly, the extent and number of oceans and seas vary. The Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait , Greenland Sea , Norwegian Sea and Barents Sea . To

15651-501: The lowest values are in the high latitudes and along coasts where large rivers enter. Maximum salinity values occur at about 25° north and south , in subtropical regions with low rainfall and high evaporation. The high surface salinity in the Atlantic, on which the Atlantic thermohaline circulation is dependent, is maintained by two processes: the Agulhas Leakage/Rings , which brings salty Indian Ocean waters into

15792-514: The margins of the continents constitute about 11% of the bottom topography with few deep channels cut across the continental rise. The mean depth between 60°N and 60°S is 3,730 m (12,240 ft), or close to the average for the global ocean, with a modal depth between 4,000 and 5,000 m (13,000 and 16,000 ft). In the South Atlantic the Walvis Ridge and Rio Grande Rise form barriers to ocean currents. The Laurentian Abyss

15933-617: The maritime expeditions of Portugal to the Canary Islands in 1336, and later with the Portuguese discoveries of the Atlantic archipelagos of Madeira and Azores , the coast of West Africa in 1434, and the establishment of the sea route to India in 1498 by Vasco da Gama , which initiated the Portuguese maritime and trade presence in Kerala and the Indian Ocean . During the Age of Discovery, Spain sponsored and financed

16074-664: The maximum depth, the Milwaukee Deep in the Puerto Rico Trench , is 8,376 m (27,480 ft). Top large seas: The bathymetry of the Atlantic is dominated by a submarine mountain range called the Mid-Atlantic Ridge (MAR). It runs from 87°N or 300 km (190 mi) south of the North Pole to the subantarctic Bouvet Island at 54°S . Expeditions to explore the bathymertry of

16215-477: The mercantile situation in the east Mediterranean, was the waning of Christian Byzantine naval power following the death of Emperor Manuel I Komnenos in 1180, whose dynasty had made notable treaties and concessions with Italian traders, permitting the use of Byzantine Christian ports. The Norman Conquest of England, in the late 11th century, allowed for peaceful trade on the North Sea . The Hanseatic League ,

16356-501: The monopoly of European trade with the Middle East. The silk and spice trade , involving spices, incense , herbs, drugs and opium , made these Mediterranean city-states phenomenally rich. Spices were among the most expensive and demanded products of the Middle Ages, as they were used in medieval medicine , religious rituals, cosmetics, perfumery, as well as food additives and preservatives. They were all imported from Asia and Africa. Muslim traders dominated maritime routes throughout

16497-732: The most extensive and voluminous large igneous provinces in Earth's history associated with the Triassic–Jurassic extinction event , one of Earth's major extinction events . Theoliitic dikes , sills , and lava flows from the CAMP eruption at 200 Ma have been found in West Africa, eastern North America, and northern South America. The extent of the volcanism has been estimated to 4.5 × 10  km (1.7 × 10  sq mi) of which 2.5 × 10  km (9.7 × 10  sq mi) covered what

16638-571: The north to become the source for North Atlantic deep water, south of the Greenland-Scotland sill. These two intermediate waters have different salinity in the western and eastern basins. The wide range of salinities in the North Atlantic is caused by the asymmetry of the northern subtropical gyre and a large number of contributions from a wide range of sources: Labrador Sea, Norwegian-Greenland Sea, Mediterranean, and South Atlantic Intermediate Water. The North Atlantic deep water (NADW)

16779-425: The ocean's great capacity to store and release heat, maritime climates are more moderate and have less extreme seasonal variations than inland climates. Precipitation can be approximated from coastal weather data and air temperature from water temperatures. The oceans are the major source of atmospheric moisture that is obtained through evaporation. Climatic zones vary with latitude; the warmest zones stretch across

16920-627: The outlines of the coasts of the Old and the New Worlds. The remainder of the ridge was discovered in the 1920s by the German Meteor expedition using echo-sounding equipment. The exploration of the MAR in the 1950s led to the general acceptance of seafloor spreading and plate tectonics . Most of the MAR runs under water but where it reaches the surfaces it has produced volcanic islands. While nine of these have collectively been nominated

17061-651: The pond" or "on the other side of the pond" or "across the pond", rather than to discuss the ocean itself. The term dates to 1640, first appearing in print in a pamphlet released during the reign of Charles I , and reproduced in 1869 in Nehemiah Wallington 's Historical Notices of Events Occurring Chiefly in The Reign of Charles I , where "great Pond" is used in reference to the Atlantic Ocean by Francis Windebank , Charles I's Secretary of State . The International Hydrographic Organization (IHO) defined

17202-508: The radiation environment at high altitudes. New engine nozzle technologies were tested to reduce takeoff and landing noise. Sonic boom mitigation technologies were tested using an SR-71 Blackbird , but were considered to be economically unviable; instead, HSCT would be limited to subsonic speeds over land. Phase 2 demonstrated several key technologies' economic viability. Two F-16XLs were used to test supersonic laminar flow control and to validate advanced CFD design methods. Instead of using

17343-438: The seafloor. The oldest oceanic crust in the Atlantic is up to 145 million years and is situated off the west coast of Africa and the east coast of North America, or on either side of the South Atlantic. In many places, the continental shelf and continental slope are covered in thick sedimentary layers. For instance, on the North American side of the ocean, large carbonate deposits formed in warm shallow waters such as Florida and

17484-483: The south like the supposed long-lost Christian kingdom of Prester John and probe whether it was possible to reach the Indies by sea, the source of the lucrative spice trade . He invested in sponsoring voyages down the coast of Mauritania , gathering a group of merchants, shipowners and stakeholders interested in new sea lanes. Soon the Atlantic islands of Madeira (1419) and the Azores (1427) were reached. The expedition leader who established settlements on Madeira,

17625-450: The standards of the time. The lateen rig was less useful when sailing downwind – which explains Christopher Columbus ( Italian : Cristoforo Colombo ) re-rigging the Niña with square rig . For celestial navigation the Portuguese used the ephemerides , which experienced a remarkable diffusion in the 15th century. These were astronomical charts plotting the location of the stars over

17766-551: The subtropics to the northeastern Atlantic. There this water is cooled during winter and forms return currents that merge along the eastern continental slope of Greenland where they form an intense (40–50  Sv ) current which flows around the continental margins of the Labrador Sea . A third of this water becomes part of the deep portion of the North Atlantic Deep Water (NADW). The NADW, in turn, feeds

17907-421: The surface is usually covered with sea ice in the Labrador Sea , Denmark Strait , and Baltic Sea. The Coriolis effect circulates North Atlantic water in a clockwise direction, whereas South Atlantic water circulates counter-clockwise. The south tides in the Atlantic Ocean are semi-diurnal; that is, two high tides occur every 24 lunar hours. In latitudes above 40° North some east–west oscillation, known as

18048-428: The total volume of the Earth's oceans. Excluding its marginal seas, the Atlantic covers 81,760,000 km (31,570,000 sq mi) and has a volume of 305,811,900 km (73,368,200 cu mi). The North Atlantic covers 41,490,000 km (16,020,000 sq mi) (11.5%) and the South Atlantic 40,270,000 km (15,550,000 sq mi) (11.1%). The average depth is 3,646 m (11,962 ft) and

18189-408: The treasure fleet sailed from and to China. For the first time, the maritime region from China to Africa was under the dominance of a single imperial power and allowed for the creation of a cosmopolitan space. These long-distance journeys were not followed up, as the Ming dynasty retreated in the haijin , a policy of isolationism , having limited maritime trade. Travels were halted abruptly after

18330-620: The unexplored ocean curves around toward the west, and running along by the regions to the south of Aethiopia and Libya and Africa, it mingles with the western sea (possible reference to the Atlantic Ocean)". European medieval knowledge about Asia beyond the reach of the Byzantine Empire was sourced in partial reports, often obscured by legends, dating back from the conquests of Alexander the Great and successors. Another source

18471-637: The upper layers of the circumpolar region, near the Drake Passage and the Falkland Islands. Both these currents receive some contribution from the Indian Ocean. On the African east coast, the small cyclonic Angola Gyre lies embedded in the large subtropical gyre. The southern subtropical gyre is partly masked by a wind-induced Ekman layer . The residence time of the gyre is 4.4–8.5 years. North Atlantic Deep Water flows southward below

18612-413: The view that had existed since Ptolemy that the Indian Ocean was land-locked . Based on many later stories of the phantom island known as Bacalao and the carvings on Dighton Rock some have speculated that Portuguese explorer João Vaz Corte-Real discovered Newfoundland in 1473, but the sources are considered unreliable. Portugal's Iberian rival, Castile , had begun to establish its rule over

18753-424: The western Atlantic and South Sandwich Trench (8,264 m or 27,113 ft) in the South Atlantic. There are numerous submarine canyons off northeastern North America, western Europe, and northwestern Africa. Some of these canyons extend along the continental rises and farther into the abyssal plains as deep-sea channels. In 1922, a historic moment in cartography and oceanography occurred. The USS Stewart used

18894-634: Was Giovanni da Pian del Carpine , dispatched by Pope Innocent IV to the Great Khan , who journeyed to Mongolia and back from 1241 to 1247. Russian prince Yaroslav of Vladimir , and his sons Alexander Nevsky and Andrey II of Vladimir , travelled to the Mongolian capital. Though having strong political implications, their journeys left no detailed accounts. Other travellers followed, like French André de Longjumeau and Flemish William of Rubruck , who reached China through Central Asia. Marco Polo ,

19035-793: Was conquered by the Portuguese aiming to control navigation of the African coast. The young prince Henry the Navigator was there and became aware of profit possibilities in the trans-Saharan trade routes. For centuries slave and gold trade routes linking West Africa with the Mediterranean passed over the Western Sahara Desert, controlled by the Moors of North Africa. Henry wished to know how far Muslim territories in Africa extended, hoping to bypass them and trade directly with West Africa by sea, find allies in legendary Christian lands to

19176-525: Was Portuguese explorer João Gonçalves Zarco . Europeans did not know what lay beyond Cape Non ( Cape Chaunar ) on the African coast, and whether it was possible to return once it was crossed. Nautical myths warned of oceanic monsters or an edge of the world, but Henry's navigation challenged such beliefs: starting in 1421, systematic sailing overcame it, reaching the difficult Cape Bojador that in 1434 one of Henry's captains, Gil Eanes , finally passed. From 1440 onwards, caravels were extensively used for

19317-424: Was applied to the southern Atlantic as late as the mid-19th century. During the Age of Discovery , the Atlantic was also known to English cartographers as the Great Western Ocean . The pond is a term often used by British and American speakers in reference to the northern Atlantic Ocean, as a form of meiosis , or ironic understatement. It is used mostly when referring to events or circumstances "on this side of

19458-420: Was barely known and only trade links with the Maritime republics , Venice especially, fostered the collection of accurate maritime knowledge. Indian Ocean trade routes were sailed by Arab traders. By 1400, a Latin translation of Ptolemy 's Geographia reached Italy from Constantinople. The rediscovery of Roman geographical knowledge was a revelation, both for map-making and worldview, although reinforcing

19599-445: Was especially impactful as no other polity had exerted naval dominance over all sectors of the Indian Ocean, prior to these voyages. The Ming promoted alternative nodes as a strategy to establish control over the network. For instance, due to Chinese involvement, ports such as Malacca (in Southeast Asia), Cochin (Malabar Coast), and Malindi (Swahili Coast) had grown as key alternatives to other established ports. The appearance of

19740-409: Was largely a backwater compared to the Arab world, which conquered and incorporated large territories in the Middle East and North Africa. The Christian Crusades to retake the Holy Land , from the Muslims, were not a military success, but did bring Europe into contact with the Middle East and the valuable goods manufactured or traded there. From the 12th century, the European economy was transformed by

19881-426: Was the Radhanite Jewish trade networks of merchants established as go-betweens between Europe and the Muslim world during the time of the Crusader states . In 1154, the Arab geographer Muhammad al-Idrisi created a description of the world and a world map , the Tabula Rogeriana , at the court of King Roger II of Sicily , but still Africa was only partially known to either Christians, Genoese and Venetians, or

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