According to American mythology, Christopher Columbus discovered the Earth was round when he set sail for Asia in 1492 by travelling west instead of the long, easterly route that was already known. When Columbus hit land, he thought he was in India and called the native peoples Indians. Although the myth of Columbus discovering the spherical nature of the Earth is taught to school children in the U.S. as fact, it is not true.
In the beginning of the history of humankind, it is true that the prevailing theory of the universe included a flat Earth around which the sun, moon, and stars all revolved. In China, this theory persisted until the late 17th century when Europeans brought knowledge of the spherical model to them. However, the ancient Greeks began to assert that the Earth is spherical as far back as 570 BC when Pythagoras made the hypothesis. Pythagoras was never able to prove the spherical model of the Earth, but he was so influential that after his death, no record of any Greeks believing in a flat Earth exists. In the centuries that followed, other influential Greek teachers and scholars taught that the Earth is a sphere. After studying Pythagorean mathematics, Plato taught all of his students the spherical model. Aristotle, a student of Plato, reasoned that the Earth must be curved because in Egypt, stars can be seen that are not present in Greece. He also argued that the shadow of the Earth on the moon during a lunar eclipse is round and the stars rise higher in the sky as travelers move south.
In 240 BC, Eratosthenes, a Greek mathematician accurately estimated the circumference of the Earth, using trigonometry, with only a 5 - 10 percent margin of error . In 150 BC, Ptolemy published his eight-volume compendium, Geographia. This early encyclopedia and atlas showed the earth as spherical, and Ptolemy also gave the Earth latitudinal and longitudinal coordinates.
Through the dark ages, most people with access to schooling had held on to the belief in the spherical Earth. Columbus had been taught this at an early age and he used Ptolemy’s Geographia for the calculations for his trip in 1492. In 1522, explorer Ferdinand Magellan finally provided first-hand proof by being the first person to sail completely around the Earth.
Posted 2775 day ago