Misplaced Pages

#13986

111-727: A prime meridian is an arbitrarily chosen meridian (a line of longitude ) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system ) form a great circle . This great circle divides a spheroid, like Earth, into two hemispheres : the Eastern Hemisphere and the Western Hemisphere (for an east-west notational system). For Earth's prime meridian, various conventions have been used or advocated in different regions throughout history. Earth's current international standard prime meridian

222-516: A Genoese dialect ( Ligurian ) as his first language, though Columbus probably never wrote in it. His name in 15th-century Genoese was Cristoffa Corombo , in Italian, Cristoforo Colombo , and in Spanish Cristóbal Colón . In one of his writings, he says he went to sea at 14. In 1470, the family moved to Savona , where Domenico took over a tavern. Some modern authors have argued that he

333-485: A spherical Earth , the book described the thousands years old customs of the prime meridian , or zero longitude, as passing through Avanti , the ancient name for the historic city of Ujjain , and Rohitaka , the ancient name for Rohtak ( 28°54′N 76°38′E  /  28.900°N 76.633°E  / 28.900; 76.633  ( Rohitaka (Rohtak) ) ), a city near the Kurukshetra . Ptolemy's Geographia

444-410: A compass bearing) of the rising and setting Sun to measure the magnetic variation (difference between magnetic and true north). The true meridian is the chord that goes from one pole to the other, passing through the observer, and is contrasted with the magnetic meridian, which goes through the magnetic poles and the observer. The true meridian can be found by careful astronomical observations, and

555-554: A degree of longitude along the equator) spanned 56.67 Arabic miles (equivalent to 66.2 nautical miles, 122.6 kilometers or 76.2 mi), but he did not realize that this was expressed in the Arabic mile (about 1,830 meters or 1.14 mi) rather than the shorter Roman mile (about 1,480 m) with which he was familiar. Columbus therefore estimated the size of the Earth to be about 75% of Eratosthenes's calculation. Third, most scholars of

666-460: A few degrees. There were some variations. When he noted the sight line for the True Meridian from his family's house to the depot, he could check the declination of his compass before and after surveying throughout the day. He noted this variation down. The meridian passage is the moment when a celestial object passes the meridian of longitude of the observer. At this point, the celestial object

777-532: A five-week voyage across the ocean. On 7 October, the crew spotted "[i]mmense flocks of birds". On 11 October, Columbus changed the fleet's course to due west, and sailed through the night, believing land was soon to be found. At around 02:00 the following morning, a lookout on the Pinta , Rodrigo de Triana , spotted land. The captain of the Pinta , Martín Alonso Pinzón , verified the sight of land and alerted Columbus. Columbus later maintained that he had already seen

888-538: A growing international economy, there was a demand for a set international prime meridian to make it easier for worldwide traveling which would, in turn, enhance international trading across countries. As a result, a Conference was held in 1884, in Washington, D.C. Twenty-six countries were present at the International Meridian Conference to vote on an international prime meridian. Ultimately the outcome

999-841: A light on the land a few hours earlier, thereby claiming for himself the lifetime pension promised by Ferdinand and Isabella to the first person to sight land. Columbus called this island (in what is now the Bahamas) San Salvador (meaning "Holy Savior"); the natives called it Guanahani . Christopher Columbus's journal entry of 12 October 1492 states: I saw some who had marks of wounds on their bodies and I made signs to them asking what they were; and they showed me how people from other islands nearby came there and tried to take them, and how they defended themselves; and I believed and believe that they come here from tierra firme to take them captive. They should be good and intelligent servants, for I see that they say very quickly everything that

1110-550: A line of longitude. In 1541, Mercator produced his famous 41 cm terrestrial globe and drew his prime meridian precisely through Fuerteventura (14°1'W) in the Canaries. His later maps used the Azores, following the magnetic hypothesis. But by the time that Ortelius produced the first modern atlas in 1570, other islands such as Cape Verde were coming into use. In his atlas longitudes were counted from 0° to 360°, not 180°W to 180°E as

1221-566: A mistress in 1487, a 20-year-old orphan named Beatriz Enríquez de Arana . It is likely that Beatriz met Columbus when he was in Córdoba , a gathering place for Genoese merchants and where the court of the Catholic Monarchs was located at intervals. Beatriz, unmarried at the time, gave birth to Columbus's second son, Fernando Columbus , in July 1488, named for the monarch of Aragon. Columbus recognized

SECTION 10

#1732837853014

1332-473: A nearby smaller island, which he named Mariagalante , now a part of Guadeloupe and called Marie-Galante . Other islands named by Columbus on this voyage were Montserrat , Antigua , Saint Martin , the Virgin Islands , as well as many others. On 17 November, Columbus first sighted the eastern coast of the island of Puerto Rico , known to its native Taino people as Borikén . His fleet sailed along

1443-668: A plan to seek a western sea passage to the East Indies , hoping to profit from the lucrative spice trade . After the Granada War , and Columbus's persistent lobbying in multiple kingdoms, the Catholic Monarchs, Queen Isabella I and King Ferdinand II , agreed to sponsor a journey west. Columbus left Castile in August 1492 with three ships and made landfall in the Americas on 12 October, ending

1554-408: A standard time as well. With a standard meridian, stage coach and trains were able to be more efficient. The argument of which meridian is more scientific was set aside in order to find the most convenient for practical reasons. They were also able to agree that the universal day was going to be the mean solar day. They agreed that the days would begin at midnight and the universal day would not impact

1665-507: A variety of ways. Columbus often wrote about seeking gold in the log books of his voyages and writes about acquiring it "in such quantity that the sovereigns... will undertake and prepare to go conquer the Holy Sepulcher " in a fulfillment of Biblical prophecy . Columbus often wrote about converting all races to Christianity. Abbas Hamandi argues that Columbus was motivated by the hope of "[delivering] Jerusalem from Muslim hands" by "using

1776-507: A wool weaver who worked in Genoa and Savona , and owned a cheese stand at which young Christopher worked. His mother was Susanna Fontanarossa . He had three brothers— Bartholomew , Giovanni Pellegrino, and Giacomo (also called Diego) —as well as a sister, Bianchinetta. Bartholomew ran a cartography workshop in Lisbon for at least part of his adulthood. His native language is presumed to have been

1887-541: A young age and traveled widely, as far north as the British Isles and as far south as what is now Ghana . He married Portuguese noblewoman Filipa Moniz Perestrelo , who bore a son, Diego , and was based in Lisbon for several years. He later took a Castilian mistress, Beatriz Enríquez de Arana , who bore a son, Ferdinand . Largely self-educated, Columbus was knowledgeable in geography, astronomy, and history. He developed

1998-460: Is at its highest point. When the Sun passes two times an altitude while rising and setting can be averaged to give the time of meridian passage. Navigators utilized the Sun's declination and the Sun's altitude at local meridian passage, in order to calculate their latitude with the formula. Latitude = (90° – noon altitude + declination) The declination of major stars are their angles north and south from

2109-554: Is known that in the autumn of 1477, he sailed on a Portuguese ship from Galway to Lisbon, where he found his brother Bartholomew, and they continued trading for the Centurione family. Columbus based himself in Lisbon from 1477 to 1485. In 1478, the Centuriones sent Columbus on a sugar-buying trip to Madeira. He married Felipa Perestrello e Moniz , daughter of Bartolomeu Perestrello , a Portuguese nobleman of Lombard origin, who had been

2220-603: Is roughly 43 metres (47 yards) to the west of the Airy Transit Circle, a distance equivalent to roughly 2 seconds of longitude. It was Airy's transit circle that was adopted in principle (with French delegates, who pressed for adoption of the Paris meridian abstaining) as the Prime Meridian of the world at the 1884 International Meridian Conference. All of these Greenwich meridians were located via an astronomic observation from

2331-536: Is said to them; and I believe they would become Christians very easily, for it seemed to me that they had no religion. Our Lord pleasing, at the time of my departure I will take six of them from here to Your Highnesses in order that they may learn to speak. Columbus called the inhabitants of the lands that he visited Los Indios (Spanish for "Indians"). He initially encountered the Lucayan , Taíno , and Arawak peoples. Noting their gold ear ornaments, Columbus took some of

SECTION 20

#1732837853014

2442-570: Is the IERS Reference Meridian . It is derived, but differs slightly, from the Greenwich Meridian , the previous standard. A prime meridian for a planetary body not tidally locked (or at least not in synchronous rotation) is entirely arbitrary, unlike an equator , which is determined by the axis of rotation. However, for celestial objects that are tidally locked (more specifically, synchronous), their prime meridians are determined by

2553-611: Is the same as that of its orbit. East longitudes are used if the rotation is retrograde . The notion of longitude for Greeks was developed by the Greek Eratosthenes (c.   276 – 195   BCE) in Alexandria , and Hipparchus (c.   190 – 120   BCE) in Rhodes , and applied to a large number of cities by the geographer Strabo (64/63   BCE – c.   24   CE). But it

2664-556: Is uncertain; he never clearly renounced his belief he had reached the Far East. As a colonial governor, Columbus was accused by some of his contemporaries of significant brutality and removed from the post. Columbus's strained relationship with the Crown of Castile and its colonial administrators in America led to his arrest and removal from Hispaniola in 1500, and later to protracted litigation over

2775-446: Is usual today. This practice was followed by navigators well into the 18th century. In 1634, Cardinal Richelieu used the westernmost island of the Canaries, El Hierro , 19° 55' west of Paris, as the choice of meridian. The geographer Delisle decided to round this off to 20°, so that it simply became the meridian of Paris disguised. In the early 18th century the battle was on to improve the determination of longitude at sea, leading to

2886-669: The Reconquista , an expensive war against the Moors in the Iberian Peninsula , were eager to obtain a competitive edge over other European countries in the quest for trade with the Indies. Columbus's project, though far-fetched, held the promise of such an advantage. Though Columbus was wrong about the number of degrees of longitude that separated Europe from the Far East and about the distance that each degree represented, he did take advantage of

2997-797: The Americas , each voyage being sponsored by the Crown of Castile . On his first voyage he reached the Americas, initiating the European exploration and colonization of the continent , as well as the Columbian exchange . His role in history is thus important to the Age of Discovery , Western history , and human history writ large. In Columbus's letter on the first voyage , published following his first return to Spain, he claimed that he had reached Asia, as previously described by Marco Polo and other Europeans. Over his subsequent voyages, Columbus refused to acknowledge that

3108-571: The Cape Route around Africa to Asia. Columbus had to wait until 1492 for King Ferdinand and Queen Isabella of Spain to support his voyage across the Atlantic to find gold, spices, a safer route to the East, and converts to Christianity. Carol Delaney and other commentators have argued that Columbus was a Christian millennialist and apocalypticist and that these beliefs motivated his quest for Asia in

3219-628: The Cape of Good Hope ). Columbus sought an audience with the monarchs Ferdinand II of Aragon and Isabella I of Castile , who had united several kingdoms in the Iberian Peninsula by marrying and now ruled together. On 1 May 1486, permission having been granted, Columbus presented his plans to Queen Isabella, who, in turn, referred it to a committee. The learned men of Spain, like their counterparts in Portugal, replied that Columbus had grossly underestimated

3330-503: The Ciguayos , the only natives who offered violent resistance during this voyage. The Ciguayos refused to trade the amount of bows and arrows that Columbus desired; in the ensuing clash one Ciguayo was stabbed in the buttocks and another wounded with an arrow in his chest. Because of these events, Columbus called the inlet the Golfo de Las Flechas ( Bay of Arrows ). Columbus headed for Spain on

3441-522: The Columbian exchange , named after him. These events and the effects which persist to the present are often cited as the beginning of the modern era . Columbus was widely celebrated in the centuries after his death, but public perception fractured in the 21st century due to greater attention to the harms committed under his governance, particularly the beginning of the depopulation of Hispaniola's indigenous Taíno people, caused by Old World diseases and mistreatment, including slavery . Many places in

Prime meridian - Misplaced Pages Continue

3552-633: The International Meridian Conference in Washington, D.C. , 22 countries voted to adopt the Greenwich meridian as the prime meridian of the world. The French argued for a neutral line, mentioning the Azores and the Bering Strait , but eventually abstained and continued to use the Paris meridian until 1911. The current international standard Prime Meridian is the IERS Reference Meridian . The International Hydrographic Organization adopted an early version of

3663-523: The Niña , but a storm separated him from the Pinta, and forced the Niña to stop at the island of Santa Maria in the Azores. Half of his crew went ashore to say prayers of thanksgiving in a chapel for having survived the storm. But while praying, they were imprisoned by the governor of the island, ostensibly on suspicion of being pirates. After a two-day standoff, the prisoners were released, and Columbus again set sail for Spain. Another storm forced Columbus into

3774-685: The Royal Observatory, Greenwich . "Maskelyne's tables not only made the lunar method practicable, they also made the Greenwich meridian the universal reference point. Even the French translations of the Nautical Almanac retained Maskelyne's calculations from Greenwich – in spite of the fact that every other table in the Connaissance des Temps considered the Paris meridian as the prime." In 1884, at

3885-570: The donatary captain of Porto Santo . In 1479 or 1480, Columbus's son Diego was born. Between 1482 and 1485, Columbus traded along the coasts of West Africa , reaching the Portuguese trading post of Elmina at the Guinea coast in present-day Ghana . Before 1484, Columbus returned to Porto Santo to find that his wife had died. He returned to Portugal to settle her estate and take Diego with him. He left Portugal for Castile in 1485, where he took

3996-623: The fall of Constantinople to the Ottoman Empire in 1453, the Silk Road was closed to Christian traders. In 1474, the Florentine astronomer Paolo dal Pozzo Toscanelli suggested to King Afonso V of Portugal that sailing west across the Atlantic would be a quicker way to reach the Maluku (Spice) Islands, China , Japan and India than the route around Africa, but Afonso rejected his proposal. In

4107-553: The trade winds , which would prove to be the key to his successful navigation of the Atlantic Ocean. He planned to first sail to the Canary Islands before continuing west with the northeast trade wind. Part of the return to Spain would require traveling against the wind using an arduous sailing technique called beating , during which progress is made very slowly. To effectively make the return voyage, Columbus would need to follow

4218-401: The 1480s, Columbus and his brother proposed a plan to reach the East Indies by sailing west. Columbus supposedly wrote to Toscanelli in 1481 and received encouragement, along with a copy of a map the astronomer had sent Afonso implying that a westward route to Asia was possible. Columbus's plans were complicated by Bartolomeu Dias 's rounding of the Cape of Good Hope in 1488, which suggested

4329-816: The 18th century most countries in Europe adapted their own prime meridian, usually through their capital, hence in France the Paris meridian was prime, in Prussia it was the Berlin meridian, in Denmark the Copenhagen meridian, and in United Kingdom the Greenwich meridian . Between 1765 and 1811, Nevil Maskelyne published 49 issues of the Nautical Almanac based on the meridian of

4440-463: The Americas, exploring the Lesser Antilles in 1493, Trinidad and the northern coast of South America in 1498, and the east coast of Central America in 1502. Many names he gave to geographical features, particularly islands, are still in use. He gave the name indios ("Indians") to the indigenous peoples he encountered. The extent to which he was aware the Americas were a wholly separate landmass

4551-420: The Americas. He sailed with nearly 1,500 men, including sailors, soldiers, priests, carpenters, stonemasons, metalworkers, and farmers. Among the expedition members were Alvarez Chanca , a physician who wrote a detailed account of the second voyage; Juan Ponce de León, the first governor of Puerto Rico and Florida; the father of Bartolomé de las Casas; Juan de la Cosa , a cartographer who is credited with making

Prime meridian - Misplaced Pages Continue

4662-528: The April 1492 " Capitulations of Santa Fe ", King Ferdinand and Queen Isabella promised Columbus that if he succeeded he would be given the rank of Admiral of the Ocean Sea and appointed Viceroy and Governor of all the new lands he might claim for Spain. He had the right to nominate three persons, from whom the sovereigns would choose one, for any office in the new lands. He would be entitled to 10% ( diezmo ) of all

4773-523: The Arawaks prisoner and insisted that they guide him to the source of the gold. Columbus did not believe he needed to create a fortified outpost, writing, "the people here are simple in war-like matters ... I could conquer the whole of them with fifty men, and govern them as I pleased." The Taínos told Columbus that another indigenous tribe, the Caribs , were fierce warriors and cannibals , who made frequent raids on

4884-533: The Atlantic Ocean sponsored by the Catholic Monarchs , opening the way for the widespread European exploration and colonization of the Americas . His expeditions were the first known European contact with the Caribbean and Central and South America. The name Christopher Columbus is the anglicization of the Latin Christophorus Columbus . Growing up on the coast of Liguria , he went to sea at

4995-457: The Canary Islands west to Japan; the actual distance is 10,600 nmi (19,600 km; 12,200 mi). No ship in the 15th century could have carried enough food and fresh water for such a long voyage, and the dangers involved in navigating through the uncharted ocean would have been formidable. Most European navigators reasonably concluded that a westward voyage from Europe to Asia was unfeasible. The Catholic Monarchs, however, having completed

5106-618: The Castilian crown, known as the pleitos colombinos , alleging that the Crown had illegally reneged on its contractual obligations to Columbus and his heirs. The Columbus family had some success in their first litigation, as a judgment of 1511 confirmed Diego's position as viceroy but reduced his powers. Diego resumed litigation in 1512, which lasted until 1536, and further disputes initiated by heirs continued until 1790. Between 1492 and 1504, Columbus completed four round-trip voyages between Spain and

5217-644: The Catholic Monarchs of Spain. They were replaced by the Treaty of Tordesillas of 1494. The two earliest published copies of Columbus's letter on the first voyage aboard the Niña were donated in 2017 by the Jay I. Kislak Foundation to the University of Miami library in Coral Gables, Florida , where they are housed. On 24 September 1493, Columbus sailed from Cádiz with 17 ships, and supplies to establish permanent colonies in

5328-402: The Earth, prime meridians must be arbitrarily defined. Often a landmark such as a crater is used; other times a prime meridian is defined by reference to another celestial object, or by magnetic fields . The prime meridians of the following planetographic systems have been defined: Meridian (geography) The first prime meridian was set by Eratosthenes in 200 BC. This prime meridian

5439-439: The Earth. Therefore, a compass needle will be parallel to the magnetic meridian. However, a compass needle will not be steady in the magnetic meridian, because of the longitude from east to west being complete geodesic . The angle between the magnetic and the true meridian is the magnetic declination , which is relevant for navigating with a compass. Navigators were able to use the azimuth (the horizontal angle or direction of

5550-401: The Earth; and the number of miles or leagues in a degree of longitude , which was possible to deduce from the theory of the relationship between the size of the surfaces of water and the land as held by the followers of Aristotle in medieval times. From Pierre d'Ailly 's Imago Mundi (1410), Columbus learned of Alfraganus 's estimate that a degree of latitude (equal to approximately

5661-539: The IERS Reference Meridian, the plane of which passes through the centre of mass of the Earth. This differs from the plane established by the Airy transit, which is affected by vertical deflection (the local vertical is affected by influences such as nearby mountains). The change from relying on the local vertical to using a meridian based on the centre of the Earth caused the modern prime meridian to be 5.3″ east of

SECTION 50

#1732837853014

5772-644: The IRM in 1983 for all nautical charts. It was adopted for air navigation by the International Civil Aviation Organization on 3 March 1989. Since 1984, the international standard for the Earth's prime meridian is the IERS Reference Meridian. Between 1884 and 1984, the meridian of Greenwich was the world standard. These meridians are very close to each other. In October 1884 the Greenwich Meridian

5883-441: The Indies implausible. Columbus had left for France when Ferdinand intervened, first sending Talavera and Bishop Diego Deza to appeal to the queen. Isabella was finally convinced by the king's clerk Luis de Santángel , who argued that Columbus would take his ideas elsewhere, and offered to help arrange the funding. Isabella then sent a royal guard to fetch Columbus, who had traveled 2 leagues (over 10 km) toward Córdoba. In

5994-425: The Latin meridies , meaning "midday"; the subsolar point passes through a given meridian at solar noon , midway between the times of sunrise and sunset on that meridian. Likewise, the Sun crosses the celestial meridian at the same time. The same Latin stem gives rise to the terms a.m. (ante meridiem) and p.m. (post meridiem) used to disambiguate hours of the day when utilizing the 12-hour clock . Because of

6105-403: The Spanish crown sent him 20,000 maravedis to buy new clothes and instructions to return to the Spanish court for renewed discussions. Columbus waited at King Ferdinand's camp until Ferdinand and Isabella conquered Granada , the last Muslim stronghold on the Iberian Peninsula, in January 1492. A council led by Isabella's confessor, Hernando de Talavera , found Columbus's proposal to reach

6216-403: The Taínos, often capturing their women, although this may have been a belief perpetuated by the Spaniards to justify enslaving them. Columbus also explored the northeast coast of Cuba, where he landed on 28 October. On the night of 26 November, Martín Alonso Pinzón took the Pinta on an unauthorized expedition in search of an island called "Babeque" or "Baneque", which the natives had told him

6327-402: The Western Hemisphere bear his name , including the South American country of Colombia , the Canadian province of British Columbia , the American city Columbus, Ohio , and the United States capital, the District of Columbia . Columbus's early life is obscure, but scholars believe he was born in the Republic of Genoa between 25 August and 31 October 1451. His father was Domenico Colombo ,

6438-450: The angle at the center of the Earth between where it and the prime meridian cross the equator. As there are 360 degrees in a circle, the meridian on the opposite side of the Earth from Greenwich, the antimeridian, forms the other half of a circle with the one through Greenwich, and is at 180° longitude near the International Date Line (with land mass and island deviations for boundary reasons). The meridians from Greenwich (0°) west to

6549-464: The antimeridian (180°) define the Western Hemisphere and the meridians from Greenwich (0°) east to the antimeridian (180°) define the Eastern Hemisphere . Most maps show the lines of longitude. The position of the prime meridian has changed a few times throughout history, mainly due to the transit observatory being built next door to the previous one (to maintain the service to shipping). Such changes had no significant practical effect. Historically,

6660-440: The astronomic Greenwich prime meridian through the Airy Transit Circle. At the latitude of Greenwich, this amounts to 102 metres (112 yards). This was officially accepted by the Bureau International de l'Heure (BIH) in 1984 via its BTS84 (BIH Terrestrial System) that later became WGS84 (World Geodetic System 1984) and the various International Terrestrial Reference Frames (ITRFs). Due to the movement of Earth's tectonic plates ,

6771-420: The average error in the determination of longitude was much larger than the change in position. The adoption of World Geodetic System 84 " (WGS84) as the positioning system has moved the geodetic prime meridian 102.478 metres east of its last astronomic position (measured at Greenwich). The position of the current geodetic prime meridian is not identified at all by any kind of sign or marking at Greenwich (as

SECTION 60

#1732837853014

6882-424: The basis for its own national time zone system. The second was that in the late 19th century, 72% of the world's commerce depended on sea-charts which used Greenwich as the Prime Meridian. The recommendation was based on the argument that naming Greenwich as Longitude 0º would be of advantage to the largest number of people. Toward the ending of the 12th century there were two main locations that were acknowledged as

6993-572: The boy as his offspring. Columbus entrusted his older, legitimate son Diego to take care of Beatriz and pay the pension set aside for her following his death, but Diego was negligent in his duties. Columbus learned Latin , Portuguese, and Castilian. He read widely about astronomy, geography, and history, including the works of Ptolemy , Pierre d'Ailly 's Imago Mundi , the travels of Marco Polo and Sir John Mandeville , Pliny 's Natural History , and Pope Pius II 's Historia rerum ubique gestarum . According to historian Edmund Morgan , Columbus

7104-415: The celestial equator. The meridian passage will not occur exactly at 12 hours because of the Earth orbit excentricity (see Equation of time ). A standard meridian is a meridian used for determining standard time . For instance, the 30th meridian east ( UTC+02:00 ) is the standard meridian for Eastern European Time . Since the adoption of time zones – as opposed to local mean time or solar time – in

7215-446: The curving trade winds northeastward to the middle latitudes of the North Atlantic, where he would be able to catch the " westerlies " that blow eastward to the coast of Western Europe. The navigational technique for travel in the Atlantic appears to have been exploited first by the Portuguese, who referred to it as the volta do mar ('turn of the sea'). Through his marriage to his first wife, Felipa Perestrello, Columbus had access to

7326-422: The development of the marine chronometer by John Harrison . But it was the development of accurate star charts, principally by the first British Astronomer Royal , John Flamsteed between 1680 and 1719 and disseminated by his successor Edmund Halley , that enabled navigators to use the lunar method of determining longitude more accurately using the octant developed by Thomas Godfrey and John Hadley . In

7437-408: The distance to Asia. They pronounced the idea impractical and advised the Catholic Monarchs to pass on the proposed venture. To keep Columbus from taking his ideas elsewhere, and perhaps to keep their options open, the sovereigns gave him an allowance, totaling about 14,000 maravedis for the year, or about the annual salary of a sailor. In May 1489, the queen sent him another 10,000 maravedis , and

7548-401: The east than Japan, including the mythical Antillia , which he thought might lie not much farther to the west than the Azores , and the distance westward from the Canary Islands to the Indies as only 68 degrees, equivalent to 3,080 nmi (5,700 km; 3,540 mi) (a 58% error). Based on his sources, Columbus estimated a distance of 2,400 nmi (4,400 km; 2,800 mi) from

7659-475: The face always inward of the orbit (a planet facing its star, or a moon facing its planet), just as equators are determined by rotation. Longitudes for the Earth and Moon are measured from their prime meridian (at 0°) to 180° east and west. For all other Solar System bodies, longitude is measured from 0° (their prime meridian) to 360°. West longitudes are used if the rotation of the body is prograde (or 'direct', like Earth), meaning that its direction of rotation

7770-436: The first world map depicting the New World ; and Columbus's youngest brother Diego. The fleet stopped at the Canary Islands to take on more supplies, and set sail again on 7 October, deliberately taking a more southerly course than on the first voyage. On 3 November, they arrived in the Windward Islands ; the first island they encountered was named Dominica by Columbus, but not finding a good harbor there, they anchored off

7881-478: The first voyage , probably dispatched to the Spanish court upon arrival in Lisbon, was instrumental in spreading the news throughout Europe about his voyage. Almost immediately after his arrival in Spain, printed versions began to appear, and word of his voyage spread rapidly. Most people initially believed that he had reached Asia. The Bulls of Donation , three papal bulls of Pope Alexander VI delivered in 1493, purported to grant overseas territories to Portugal and

7992-475: The geographic location of the meridian, France and Britain. These two locations often conflicted and a settlement was reached only after there was an International Meridian Conference held, in which Greenwich was recognized as the 0° location. The meridian through Greenwich (inside Greenwich Park) , England, called the Prime Meridian , was set at zero degrees of longitude, while other meridians were defined by

8103-405: The grounds that Columbus's estimate for a voyage of 2,400 nmi was only a quarter of what it should have been. In 1488, Columbus again appealed to the court of Portugal, and John II again granted him an audience. That meeting also proved unsuccessful, in part because not long afterwards Bartolomeu Dias returned to Portugal with news of his successful rounding of the southern tip of Africa (near

8214-739: The ideal International Terrestrial Reference System (ITRS) and its realization, the International Terrestrial Reference Frame (ITRF). A current convention on the Earth uses the line of longitude 180° opposite the IRM as the basis for the International Date Line . Download coordinates as: On Earth, starting at the North Pole and heading south to the South Pole , the IERS Reference Meridian (as of 2016) passes through 8 countries, 4 seas, 3 oceans and 1 channel: As on

8325-503: The interpreter Luis de Torres , and founded the settlement of La Navidad , in present-day Haiti . Columbus took more natives prisoner and continued his exploration. He kept sailing along the northern coast of Hispaniola with a single ship until he encountered Pinzón and the Pinta on 6 January. On 13 January 1493, Columbus made his last stop of this voyage in the Americas, in the Bay of Rincón in northeast Hispaniola. There he encountered

8436-580: The island's southern coast for a whole day, before making landfall on its northwestern coast at the Bay of Añasco , early on 19 November. Upon landing, Columbus christened the island San Juan Bautista after John the Baptist , and remained anchored there for two days from 20 to 21 November, filling the water casks of the ships in his fleet. On 22 November, Columbus returned to Hispaniola to visit La Navidad in modern-day Haiti , where 39 Spaniards had been left during

8547-531: The lands he visited and claimed for Spain were not part of Asia, in the face of mounting evidence to the contrary. This might explain, in part, why the American continent was named after the Florentine explorer Amerigo Vespucci —who received credit for recognizing it as a " New World "—and not after Columbus. On the evening of 3 August 1492, Columbus departed from Palos de la Frontera with three ships. The largest

8658-553: The late 19th century and early 20th century, most countries have adopted the standard time of one of the 24 meridians closest to their geographical position, as decided by the International Meridian Conference in 1884. Although, a few time zones are offset by an additional 30 or 45 minutes, such as in the Chatham Islands , South Australia and Nepal . Many of these instruments rely on the ability to measure

8769-456: The line of 0° longitude along the surface of the Earth has slowly moved toward the west from this shifted position by a few centimetres (inches); that is, towards the Airy Transit Circle (or the Airy Transit Circle has moved toward the east, depending on your point of view) since 1984 (or the 1960s). With the introduction of satellite technology, it became possible to create a more accurate and detailed global map. With these advances there also arose

8880-599: The link between longitude and time. Based on observations to satellites and celestial compact radio sources (quasars) from various coordinated stations around the globe, Airy's transit circle drifts northeast about 2.5 centimetres (1 inch) per year relative to this Earth-centred 0° longitude. It is also the reference meridian of the Global Positioning System operated by the United States Department of Defense , and of WGS84 and its two formal versions,

8991-604: The location of the Airy Transit Circle ever since the first observation he took with it. Prior to that, it was defined by a succession of earlier transit instruments, the first of which was acquired by the second Astronomer Royal , Edmond Halley in 1721. It was set up in the extreme north-west corner of the Observatory between Flamsteed House and the Western Summer House. This spot, now subsumed into Flamsteed House,

9102-503: The longitude and latitude of the Earth. These instruments also were typically affected by local gravity, which paired well with existing technologies such as the magnetic meridian. Christopher Columbus Christopher Columbus ( / k ə ˈ l ʌ m b ə s / ; between 25 August and 31 October 1451 – 20 May 1506) was an Italian explorer and navigator from the Republic of Genoa who completed four Spanish-based voyages across

9213-425: The magnetic meridian is simply parallel to the compass needle. The arithmetic difference between the true and magnetic meridian is called the magnetic declination , which is important for the calibration of compasses. Henry D. Thoreau classified this true meridian versus the magnetic meridian in order to have a more qualitative, intuitive, and abstract function. He used the true meridian since his compass varied by

9324-463: The nautical charts and logs that had belonged to her deceased father, Bartolomeu Perestrello , who had served as a captain in the Portuguese navy under Prince Henry the Navigator . In the mapmaking shop where he worked with his brother Bartholomew, Columbus also had ample opportunity to hear the stories of old seamen about their voyages to the western seas, but his knowledge of the Atlantic wind patterns

9435-516: The necessity to define a reference meridian that, whilst being derived from the Airy Transit Circle, would also take into account the effects of plate movement and variations in the way that the Earth was spinning. As a result, the IERS Reference Meridian was established and is commonly used to denote the Earth's prime meridian (0° longitude) by the International Earth Rotation and Reference Systems Service , which defines and maintains

9546-540: The older astronomic position was), but can be located using a GPS receiver. It was in the best interests of the nations to agree to one standard meridian to benefit their fast growing economy and production. The disorganized system they had before was not sufficient for their increasing mobility. The coach services in England had erratic timing before the GWT. United States and Canada were also improving their railroad system and needed

9657-510: The period of human habitation in the Americas now referred to as the pre-Columbian era . His landing place was an island in the Bahamas , known by its native inhabitants as Guanahani . He then visited the islands now known as Cuba and Hispaniola , establishing a colony in what is now Haiti . Columbus returned to Castile in early 1493, with captured natives. Word of his voyage soon spread throughout Europe. Columbus made three further voyages to

9768-583: The port at Lisbon. From there he went to Vale do Paraíso north of Lisbon to meet King John II of Portugal, who told Columbus that he believed the voyage to be in violation of the 1479 Treaty of Alcáçovas . After spending more than a week in Portugal, Columbus set sail for Spain. Returning to Palos on 15 March 1493, he was given a hero's welcome and soon afterward received by Isabella and Ferdinand in Barcelona. To them he presented kidnapped Taínos and various plants and items he had collected. Columbus's letter on

9879-498: The privileges he and his heirs claimed were owed to them by the crown. Columbus's expeditions inaugurated a period of exploration, conquest, and colonization that lasted for centuries, thus bringing the Americas into the European sphere of influence. The transfer of plants, animals, precious metals, culture, human populations, technology, diseases, and ideas between the Old World and New World that followed his first voyage are known as

9990-481: The resources of newly discovered lands". Despite a popular misconception to the contrary, nearly all educated Westerners of Columbus's time knew that the Earth is spherical , a concept that had been understood since antiquity . The techniques of celestial navigation , which uses the position of the Sun and the stars in the sky, had long been in use by astronomers and were beginning to be implemented by mariners. However Columbus made several errors in calculating

10101-399: The revenues from the new lands in perpetuity. He also would have the option of buying one-eighth interest in any commercial venture in the new lands, and receive one-eighth ( ochavo ) of the profits. In 1500, during his third voyage to the Americas, Columbus was arrested and dismissed from his posts. He and his sons, Diego and Fernando, then conducted a lengthy series of court cases against

10212-499: The same year the monarchs furnished him with a letter ordering all cities and towns under their dominion to provide him food and lodging at no cost. Columbus also dispatched his brother Bartholomew to the court of Henry VII of England to inquire whether the English crown might sponsor his expedition, but he was captured by pirates en route, and only arrived in early 1491. By that time, Columbus had retreated to La Rábida Friary , where

10323-539: The size of the Earth, the distance the continent extended to the east, and therefore the distance to the west to reach his goal. First, as far back as the 3rd century BC, Eratosthenes had correctly computed the circumference of the Earth by using simple geometry and studying the shadows cast by objects at two remote locations. In the 1st century BC, Posidonius confirmed Eratosthenes's results by comparing stellar observations at two separate locations. These measurements were widely known among scholars, but Ptolemy's use of

10434-457: The smaller, old-fashioned units of distance led Columbus to underestimate the size of the Earth by about a third. Second, three cosmographical parameters determined the bounds of Columbus's enterprise: the distance across the ocean between Europe and Asia, which depended on the extent of the oikumene , i.e., the Eurasian land-mass stretching east–west between Spain and China; the circumference of

10545-423: The statement in the apocryphal book 2 Esdras ( 6:42 ) that "six parts [of the globe] are habitable and the seventh is covered with water." He was also aware of Marco Polo's claim that Japan (which he called "Cipangu") was some 2,414 km (1,500 mi) to the east of China ("Cathay"), and closer to the equator than it is. He was influenced by Toscanelli's idea that there were inhabited islands even farther to

10656-432: The surface of the Earth, oriented via a plumb line along the direction of gravity at the surface. This astronomic Greenwich meridian was disseminated around the world, first via the lunar distance method , then by chronometers carried on ships, then via telegraph lines carried by submarine communications cables , then via radio time signals. One remote longitude ultimately based on the Greenwich meridian using these methods

10767-539: The time accepted Ptolemy's estimate that Eurasia spanned 180° longitude, rather than the actual 130° (to the Chinese mainland) or 150° (to Japan at the latitude of Spain). Columbus believed an even higher estimate, leaving a smaller percentage for water. In d'Ailly's Imago Mundi , Columbus read Marinus of Tyre 's estimate that the longitudinal span of Eurasia was 225° at the latitude of Rhodes . Some historians, such as Samuel Eliot Morison , have suggested that he followed

10878-515: The use of local time. A report was submitted to the "Transactions of the Royal Society of Canada", dated 10 May 1894; on the "Unification of the Astronomical, Civil and Nautical Days"; which stated that: The magnetic meridian is an equivalent imaginary line connecting the magnetic south and north poles and can be taken as the horizontal component of magnetic force lines along the surface of

10989-495: The western tip of Africa (17.5° W) as negative numbers were not yet in use. His prime meridian corresponds to 18° 40' west of Winchester (about 20°W) today. At that time the chief method of determining longitude was by using the reported times of lunar eclipses in different countries. One of the earliest known descriptions of standard time in India appeared in the 4th century CE astronomical treatise Surya Siddhanta . Postulating

11100-584: Was Ptolemy (c.   90 – 168   CE) who first used a consistent meridian for a world map in his Geographia . Ptolemy used as his basis the " Fortunate Isles ", a group of islands in the Atlantic , which are usually associated with the Canary Islands (13° to 18°W), although his maps correspond more closely to the Cape Verde islands (22° to 25° W). The main point is to be comfortably west of

11211-598: Was a carrack , the Santa María , owned and captained by Juan de la Cosa , and under Columbus's direct command. The other two were smaller caravels , the Pinta and the Niña , piloted by the Pinzón brothers . Columbus first sailed to the Canary Islands. There he restocked provisions and made repairs then departed from San Sebastián de La Gomera on 6 September, for what turned out to be

11322-461: Was as follows: there would be only one prime meridian, the prime meridian was to cross and pass at Greenwich (which was the 0°), there would be two longitude direction up to 180° (east being plus and west being minus), there will be a universal day, and the day begins at the mean midnight of the initial meridian. There were two main reasons for this. The first was that the USA had already chosen Greenwich as

11433-482: Was eventually settled at 370 leagues (2,193 kilometers, 1,362 statute miles, or 1,184 nautical miles) west of Cape Verde . This is shown in the copies of Spain's Padron Real made by Diogo Ribeiro in 1527 and 1529. São Miguel Island (25.5°W) in the Azores was still used for the same reason as late as 1594 by Christopher Saxton , although by then it had been shown that the zero magnetic declination line did not follow

11544-483: Was first printed with maps at Bologna in 1477, and many early globes in the 16th century followed his lead. But there was still a hope that a "natural" basis for a prime meridian existed. Christopher Columbus reported (1493) that the compass pointed due north somewhere in mid-Atlantic, and this fact was used in the important Treaty of Tordesillas of 1494, which settled the territorial dispute between Spain and Portugal over newly discovered lands. The Tordesillas line

11655-642: Was not a scholarly man. Yet he studied these books, made hundreds of marginal notations in them and came out with ideas about the world that were characteristically simple and strong and sometimes wrong ... Under the Mongol Empire 's hegemony over Asia and the Pax Mongolica , Europeans had long enjoyed a safe land passage on the Silk Road to India , parts of East Asia , including China and Maritime Southeast Asia , which were sources of valuable goods. With

11766-844: Was not from Genoa, but from the Aragon region of Spain or from Portugal. These competing hypotheses have been discounted by most scholars. In 1473, Columbus began his apprenticeship as business agent for the wealthy Spinola , Centurione, and Di Negro families of Genoa. Later, he made a trip to the Greek island Chios in the Aegean Sea , then ruled by Genoa. In May 1476, he took part in an armed convoy sent by Genoa to carry valuable cargo to northern Europe. He probably visited Bristol , England, and Galway , Ireland, where he may have visited St. Nicholas' Collegiate Church . It has been speculated he went to Iceland in 1477, though many scholars doubt this. It

11877-489: Was rich in gold. Columbus, for his part, continued to the northern coast of Hispaniola , where he landed on 6 December. There, the Santa María ran aground on 25 December 1492 and had to be abandoned. The wreck was used as a target for cannon fire to impress the native peoples. Columbus was received by the native cacique Guacanagari , who gave him permission to leave some of his men behind. Columbus left 39 men, including

11988-411: Was selected by delegates (forty-one delegates representing twenty-five nations) to the International Meridian Conference held in Washington, D.C. , United States to be the common zero of longitude and standard of time reckoning throughout the world. The position of the historic prime meridian, based at the Royal Observatory, Greenwich , was established by Sir George Airy in 1851. It was defined by

12099-459: Was still imperfect at the time of his first voyage. By sailing due west from the Canary Islands during hurricane season , skirting the so-called horse latitudes of the mid-Atlantic, he risked being becalmed and running into a tropical cyclone , both of which he avoided by chance. By about 1484, Columbus proposed his planned voyage to King John II of Portugal . The king submitted Columbus's proposal to his advisors, who rejected it, correctly, on

12210-666: Was that of the North American Datum 1927 or NAD27, an ellipsoid whose surface best matches mean sea level under the United States . Beginning in 1973 the International Time Bureau and later the International Earth Rotation and Reference Systems Service changed from reliance on optical instruments like the Airy Transit Circle to techniques such as lunar laser ranging , satellite laser ranging , and very-long-baseline interferometry . The new techniques resulted in

12321-409: Was used to provide measurement of the earth, but had many problems because of the lack of latitude measurement. Many years later around the 19th century there were still concerns of the prime meridian. Multiple locations for the geographical meridian meant that there was inconsistency, because each country had their own guidelines for where the prime meridian was located. The term meridian comes from

#13986