Eratosthenes Quotes

Where will you go, when the clock strikes twelve? What will you do, when you face yourself? How will you live, knowing what you’ve done? How will you die, if your soul’s already gone? —Excerpt of monologue from Compasia & Eratosthenes, as performed by Willem Denbury

Eratosthenes, the mapmaker who was the first man to accurately measure the size of the Earth, was a librarian.

From the shadow length in Alexandria, the angle A can be measured. But from simple geometry (“if two parallel straight lines are transected by a third line, the alternate interior angles are equal”), angle B equals angle A. So by measuring the shadow length in Alexandria, Eratosthenes concluded that Syene was A = B = 7° away on the circumference of the Earth.

For the observed difference in the shadow lengths, the distance between Alexandria and Syene had to be about seven degrees along the surface of the Earth; that is, if you imagine the sticks extending down to the center of the Earth, they would there intersect at an angle of seven degrees. Seven degrees is something like one-fiftieth of three hundred and sixty degrees, the full circumference of the Earth. Eratosthenes knew that the distance between Alexandria and Syene was approximately 800 kilometers, because he hired a man to pace it out. Eight hundred kilometers times 50 is 40,000 kilometers: so that must be the circumference of the Earth.

Seksen yaşına geldiğinde, korkunç bir gerçekliğin farkına varmıştı: Gözleri, artık görevlerini gereğince yerine getiremiyordu. Gerçi henüz görme gücünü bütünüyle yitirmemişti ama artık hiç okuyamıyordu. Onun yerinde başka biri olsa bütün bütüne kör olmayı beklerdi. Eratosthenes'e gelince, kitaplarından ayrılmak zorunda kalışını, yeterince körlük saydı, kendi istenciyle yemeden içmeden kesildi ve birkaç gün içinde ölüp gitti.

After Eratosthenes’ discovery, many great voyages were attempted by brave and venturesome sailors. Their ships were tiny. They had only rudimentary navigational instruments. They used dead reckoning and followed coastlines as far as they could. In an unknown ocean they could determine their latitude, but not their longitude, by observing, night after night, the position of the constellations with respect to the horizon. The familiar constellations must have been reassuring in the midst of an unexplored ocean. The stars are the friends of explorers, then with seagoing ships on Earth and now with spacefaring ships in the sky.

Using his observations of the different shadows cast by sundials along the same meridian and a little number crunching, Eratosthenes made a calculation of the earth’s diameter that was amazingly accurate: 7,850 miles, only about 60 off the actual mark.

While working at the Great Library, he grew fascinated by a manuscript left by an intrepid mariner named Pytheas from the Greek colony of Massalia (today’s Marseilles). Beginning around 320 BCE, Pytheas had made several voyages at the far end of the western Mediterranean, including beyond the famed Pillars of Hercules, or Strait of Gibraltar. Pytheas also sailed around the coast of Spain and made at least one trip across the English Channel, including circumnavigating the British Isles. In addition, he gathered what information he could about lands lying still farther west. Pytheas had published his extraordinary voyages as the History of the Ocean (now lost). His account fit none of the accepted conceptions about the shape of the world, and Aristotelian scholars in particular branded him a liar. Eratosthenes, however, instantly saw its value.

Eratosthenes took Pytheas’s book and did some quick calculations based on his own estimate of the earth’s diameter. He concluded that if the Indian Ocean was not a landlocked sea, as most Greeks supposed, but opened up onto a still larger ocean extending to the shores of the Pillars of Hercules, as Pytheas’s voyage indicated, then it might be possible for a sailor to sail west from Spain to India, although Eratosthenes calculated it would take at least thirteen thousand miles.§ Furthermore, he speculated, perhaps there was even another “inhabited world” (oikoumenē) to be found between Spain and India, one that covered at least part of the western hemisphere of the globe—a hemisphere that mathematics proved had to exist since the earth was round, but which was still entirely unknown.

His Aristotelian colleagues scoffed. How could one predicate the existence of something no one had ever seen, especially an inhabited landmass; and when everyone knew the Indian Ocean ended at the western shores of India? So Eratosthenes’s stunning thesis of a possible New World located between Europe and Asia never caught on, even after the Romans discovered there was indeed an ocean on the far side of India. His idea of a western continent faded from the science books. It would take Columbus’s accidental discovery in 1492 to finally prove that the Aristotelians at Alexandria had been wrong and Eratosthenes right all along.

The size of the Earth has been known for more than two thousand years, although the number was lost or disputed when the Earth went from being round to being flat again in the Middle Ages (under the prodding of Christian heaven-watchers, the Greek philosophers' [Eratosthenes 276-194 BC] work was erased in Europe and preserved only by Muslim scientists in the Middle East and North Africa).

Ancient historians like Josephus the Jew, Berosus the Chaldean, Hieronymus the Egyptian, Mnaseas, and Nicolaus of Damascus (Josephus even mentions these last four) discussed a powerful flood that occurred in their past. Ancient Greek historians like Xenophanes, Herodotus, Eratosthenes, and Strabo all commented on fossils being from a significant water event in the past (not always to the extent of biblical proportions but they understood the point).

When I saw Melite, I blanched: her husband was watching her. I said, trembling: 'May I push back the bolt on your double door to loosen the bolt-pin so that I can insert the tip of my key in the parting middle and penetrate your door's wet foundation?' With a side glance at her husband, she said, laughing, 'Keep clear of my door or the dog may get you.

replying to Dennster Trent Meyer @meyer_the_fire If you knew anything about history, you’d know the world’s leading thinkers have all believed the earth is round since Pythagoras in the 6th century BC. Plato said the earth was a globe. So did Euclid. So did Archimedes and Aristotle 1/... RT 8 L 90 Trent Meyer @meyer_the_fire The Greek mathematician Eratosthenes used geometry to calculate the earth’s circumference in about 250BC and got it nearly right. The Romans believed the earth was round. So did St Augustine, the Venerable Bede and Thomas Aquinas 2/... RT 7 L 84 Trent Meyer @meyer_the_fire You can disagree with all those learned historical figures if you want, but don’t tell me everyone was a flat-earther before Columbus. That’s a downright lie 3/3 RT 5 L 79 Dennster @true_earth_matters Sorry, Terg, but you don’t know what you’re talking about RT 8 L 118 Trent Meyer @meyer_the_fire Actually I have a doctorate in the history of science. What’s your qualification? RT 6 L 89 Dennster blocked Trent Meyer Sally Jenkinson @saljenk07342 STFU Terg RT 0 L 57

Eratosthenes of Cyrene, a polymath and one of the first directors of the library,

Eratosthenes was the first to use a scientific method to calculate the circumference of the earth

In the 8th Century, the Greek philosopher Homer thought that the Earth was flat. Many of the less educated people in the 15th Century still held on to that concept when Columbus set sail, following the setting sun west. The less informed warned Columbus and his crew of the danger of sailing right off the edge of the Earth. However, navigators and mathematicians knew better, since Greek philosophers in the 5th Century such as Parmenides, Empedocles and Pythagoras had already proved, by using various scientific methods, that the Earth was round. In about 200 BC Eratosthenes, who lived along the Nile near Alexandria, Egypt, calculated the circumference of the Earth to within a very close tolerance. Later in Prussia, Copernicus presented his concept that the Sun was the center of the Solar system and theorized that the planets revolved around it. It was not coincidental that Copernicus did this shortly after Columbus discovered the new continent. Although the ancients did not have radio and television, they could communicate by various means, and definitely knew what was going on. However there were those who remained superstitious, believing that there were monstrous sea creatures near the edge of the Earth. But Columbus and other relatively educated people knew better!

The first person to measure the circumference of the Earth was the astronomer Eratosthenes of Cyrene, in the third century BCE. His result was fairly close to the actual value, which is about 40,000 kilometres. For most of history this was considered an enormous distance, but with the Enlightenment that conception gradually changed, and nowadays we think of the Earth as small.

The second one was the Libyan (Euripides), the third the Delphian (Chrysippus), the fourth the Cimmerian (Naevius and Piso), the fifth the Erythraean (Apollodorus of Erythrae), the sixth the Samian (Eratosthenes), the seventh the Cumaean (Varro), the eighth the Hellespontine (Heraclides), and the ninth the Phrygian.

People believed the world was flat before Columbus discovered America. An Ancient Greek mathematician, Eratosthenes deduced that the Earth was round in 500 B.C. He perfectly calculated the circumference of the Earth over a millennium before it was confirmed because why the hell not. He had some spare time one weekend and invented geography. Columbus didn’t even think the Earth was round. He thought it was pear-shaped. And he didn’t discover it. Bjarni Herjolfsson of Iceland was the first to find America 500 years before Columbus. In fact, Columbus didn’t even land in America (DID COLUMBUS DO ANYTHING???) He landed in the Bahamas and ventured from Dominica all the way southward. He never went to the area that became the United States in his entire life.

By the 5th century B.C., however, most of the constellations had come to be associated with myths, and the Catasterismi of Eratosthenes completed the mythologization of the stars.

The Greek geographers of Alexandria, when they prepared their world map using the circumference of Eratosthenes, had in front of them source maps that had been drawn without the Eratosthenian error, that is, apparently without any discernible error at all. We shall see further evidence of this, evidence suggesting that the people who originated the maps possessed a more advanced science than that of the Greeks.