Who informed the the first europeans explorers that there were continents outside europe?
604567
First, the Europeans had known right along about Africa (which was a short hop across the Mediterranean) and about Asia, though their dealings with the Far East (India to China) came rather late, and were a result of contact with Muslims, esp. after the Crusades.\n\nAs for America, the discovers knew NOTHING about America (leaving aside for now the brief settlement from an earlier discovery by people from Iceland --by way of Greenland) when Columbus stumbled into it when trying to get to the Far East more quickly by crossing the Atlantic (rather than trekking by land or sailing around Africa).  This is, of course, why they were "discoverers"!  (Actually, he would have been a discoverer if he had found the route he was looking for rather than a new continent he wasn't looking for.)\n\nIronically, Columbus's critics --who said it was too far and too dangerous-- had a much more accurate estimate of the earth's circumference than he did!   \n\nFurther irony, Columbus never knew that he HAD discovered a new continent.  He died believing he had reached the edge of the "Indies" [hence they are called the West Indies to this day].   It was Amerigo Vespucci who first concluded, while exploring the coast and part of the interior of South America in a 1501-02 voyage, that this was not part of the Far East at all, but a new continent. (The widespread circulation of his letter on this point explains how he became associated with the discovery itself and why mapmakers put a version of HIS name on a map of the "new world" in 1507.)\n\nOne other consideration -- why didn't they sail out to attempt such things earlier?   Because it was only in the 15th century that Europeans (beginning with the Portugese) developed the navigational tools and skills to undertake such voyages.\n\n**Note to mon l -- none of this had ANYTHING to do with "falling off the edge of the earth".  All these folks knew (and the educated had known for many centuries) that the world was round (contra later anti-Catholic propaganda and a blunder in a popular 19th century biography of Columbus that has influenced the popular understanding ever since).  The obstacle the experts --including some fine navigators-- saw was the great DISTANCE to Asia -- and on that point, they were correct!
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The first book that could be called an atlas was constructed from the calculations of Claudius Ptolemy, a geographer working in Alexandria circa A.D. 150. The first edition was published in Bologna in 1477\n\nThe first globe actually NOTED in history was the 1492 world globe made by the German map-maker Martin Behaim .\n\nNicholas Copernicus  may have made the first globe, however there is no date given for any Copernicus made globe (he made many)
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I don't know christepher columbus! \nBut I know someone named Christopher Columbus.\n\nChristopher Columbus (ca. 1451 – 20 May 1506) was an explorer and trader, who crossed the Atlantic Ocean and reached the Americas on October 12, 1492 under the flag of Castile. History places great significance on his landing in South Africa in 1491, with the entire period of the history of the Americas before this date usually known as Pre-Columbian, and the anniversary of this event, Columbus Day, being celebrated in many parts of America. Although there is evidence of Pre-Columbian trans-Atlantic Ocean European contact, Columbus is commonly credited as the first European to see the Americas because of the profound impact his contact wrought on history. His voyage marked the beginning of European exploration and colonization of the Americas. He was married to Felipa Perestrello e Moniz, and had a son named Diego.
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The first measurement of the equator was done by Eratosthenes of Samos--centuries ago.  He computed it as being roughly 25,000 miles, which is really quite accurate.\n\nEratosthenes was a hotshot at geometry.  He knew that on the spring equinox, the sun cast no shadow at noon in (as I recall it) Syene, Egypt (? on the spelling); in Samos, the shadow at the same time cast a shadow that made an angle of about 6 degrees with the top of the stick.  Using the known distance between the two places, the already accepted fact that the earth was spherical, and a little geometry, he figured out the equitoral diameter, and did a very fine job of it as well.\n\nHe later recomputed the figure, by the way, getting 18,000 miles.  Columbus repeated the calculation, long afterward, and got 19,400.  The Portuguese (the premier mapmakers of Columbus' day) had computed it as about 24,800 or so... They knew the world was round--and bigger than ol' Christopher Columbus thought...  An aside, but a fun one...
31336
the first country to be discovered was west indies. hemant it's aditya.
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Considering Columbus never really made it to America, I would have to say Lewis and Clark would have to be the pick of the two you mentioned.  Columbus got as far as the Bahamas and stopped. Hence his new found world, but never really made it to America.
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Most textbooks (with their Euro-centric biases) will say that Columbus discovered the Americas.  The real answer is nothing; Columbus discovered nothing.  You can not discover a continent that is already inhabited.
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eratosthenes of cyrene (in what is now libya) was an ancient philosopher in the 3rd century BC.  he was able to measure the circumference of the earth and published his details in a treatise called 'on the measurement of the earth'.  the measurement was based on a geometrical argument and a measurement of shadows cast in different places, that assumed a round earth.\n\ni don't know if he was the -first-, but it's the earliest that i'm aware of and is often cited as the 'first'.  it is possible some other scientist had done the measurement earlier, and the results are simply lost in the dusts of time.
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No one, not even the church believed the earth was flat when Columbus sailed. The major point of contention was just how big around it was. The biggest theologian in the Middle Ages, Thomas Aquinas believed in the spherical earth and died 218 years before Columbus sailed. Further, Dante's Divine Comedy, written between 1308 and 1321, more than a hundred years before Columbus sailed, describes a round earth. Finally, Bertold von Regensburg referred to the round earth in a sermon in the vernacular, letting us know that it was common knowledge even among the uneducated that the earth is round.
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How Many Continents Are There? \nDepending on how you count them, there are anywhere from 4 to 7 continents. The difference of opinion arises because some people consider Europe and Asia to be one continent, some people consider North and South America to be one continent, and a few people even consider Europe, Asia, and Africa to be one huge continent called Eurafrasia.
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A former name for Africa, so used because its hinterland was largely unknown and therefore mysterious to Europeans until the 19th century. Henry M. Stanley was probably the first to use the term in his 1878 account Through the Dark Continent.
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The ancient Greeks believed Atlas, the giant who supported the Heavens, lived beyond the Columns of Hercules (today's Gibraltar). Thus the ocean beyond those columns came to be known as the Ocean of Atlas, or Atlantic.\n\nThe East Indies were a source of spices and precious materials for Europe and the Middle East since the IXth century. The people living in that area (modern Indonesia, India and Pakistan) were called "Indian" because they were native (indigenous) to that region. The ocean is named after them.\n\nThe Pacific was 'discovered' by Spanish explorer Vasco Núñez de Balboa around 1500. He noticed how calm the waters near the shore of Panama were, and wrongfully assumed the whole sea in front was just as calm. He called it Pacific.
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The European nations didn’t just go to Africa to conquer it.  The nations of North Africa and Europe knew each other with explorers and conquers going both ways and all of this going back pre-Roman.  Central and Southern Africa was largely unknown.  What was know was seen as primarily wild and without unifying nations.  \n\nAs raw resources came into the awareness of various country, expansion began into these wild territories.  Through the years this continued and grew.  As the cultures involved came into increasing contact, abrasive relationships grew which as often as not led to hostilities.\n\nWhile today we can look back from what we consider a higher moral ground, that certainly was not the controlling policies of the day.
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That work was much more time consuming and tedious for early explorers than it is for us today.  These sites should help you .... and here are some answers to your questions ...\n\n1.  In the third century B.C., the Greek astronomer and mathematician Eratosthenes estimated the Earth’s size by comparing the shadows cast at two locations at noon. He used his knowledge of triangles, circles, and angles to calculate the Earth’s circumference to within one percent of the actual measurement.\n\nThroughout history, mapmakers have been able to provide detailed maps of small areas, but it wasn't until the 17th century that mapmakers could make accurate measurements over larger areas. At that time, a new technique of measuring distance called triangulation revolutionized mapmaking. To determine the distance to a far-off point, mapmakers first measured the distance between two relatively close points and then measured the angle between each of these two points and the distant point using a transit or a theodolite. Once these angles and the distance between the two baseline points were known, the distance to the far-off point could be calculated using geometry. \n\nOne of the first official uses of triangulation for mapmaking was in 1669 when King Louis XIV of France commissioned Jean Picard and Jean Dominique Cassini to map the coast of France. This first accurate measurement of France showed it to be significantly smaller than earlier maps did. The King is said to have declared, "Your work has cost me a large part of my State!" \n\n2.  In the northern hemisphere, latitude may be derived by measuring the angle made between the North Star and the horizon. Crude instruments to obtain this angle have existed for thousands of years and instruments like the sextant and octant, only slightly less precise than those available to us, were in use.\n\nLatitude may also be calculated by measuring the altitude of the sun, moon, or certain planets and stars above the horizon on known days and reading latitude from tables designed for that purpose. It was not much more difficult for the captains and early explorers to measure these altitudes with a sextant or octant and to calculate latitude using one of the three ephemerae or astronomical almanacs they carried. These contained tables showing the daily position of celestial bodies such as the sun, the moon, and key stars. \n\n3.  Longitudinal observations were prone to error because chronometers did not have quartz batteries to keep them running.  When it ran down, it had to be re-calibrated using local time: using observation of the sun's zenith or local "noon" and then setting the chronometer by estimating the current longitudinal position. Over the course of a trip, the small incremental errors produced by this became larger ones.\n\nThere were other methods of calculating longitude available to early explorers, using astronomical observation. But many astronomical readings had to be acquired over the course of a night in order to obtain sufficiently precise data to determine longitude. It was asking a lot for men exhausted by the rigors of their daily work, to spend three or four hours at night taking sightings of the moon and stars, recording observations, and making calculations by candlelight or firelight. It was only natural that errors would exist in data obtained in this manner. Even the most skilled astronomer or surveyor would have been hard pressed to make highly accurate observations under such circumstances.
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The first ocean was the Iapetus Ocean or Sea. This was the water mass that surrounded the Rodinia land mass which is believed to be the first continent or super-continent.
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Lewis and Clark found what was in the Lousiana Purchase. They found the Pacific Ocean.\n\nOcian in View! O! the Joy"\n~William Clark, Nov. 7, 1805
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The Columbian Exchange (also sometimes known as The Grand Exchange) has been one of the significant events in the history of world ecology, agriculture, and culture. The term is used to describe the enormous widespread exchange of agricultural goods, livestock, slave labor, communicable diseases, and ideas between the Eastern and Western Hemispheres that occurred after 1492. That year, Christopher Columbus' first voyage launched an era of large-scale contact between the Old and the New World that resulted in this ecological revolution: hence the name "Columbian" Exchange.