Eratosthenes Paragraph

Eratosthenes, Alexandria Egypt, 276 – 194 BCE. Dorian Hoppie Math 124 Section 13 11.20.09 The time that Eratosthenes grew up in was one of chaos. Over half a century earlier, the man who had single handedly conquered most of Europe, Asia Minor, and Egypt, and made it look like a piece of cake, had died of heavy drinking and a fever in Babylon before appointing himself a successor. Alexander’s commanders made the best of the situation. Ptolemy, and later his long descending family of Ptolemy’s, received Egypt, and all were under the command of Perdikkas. Eratosthenes was born two years before the first Syrian war, the first of six wars that wouldn’t end until the middle of the next century. It is thought that he was born to a humble family, his mother’s name is unknown, his father has two possible names that are documented, Aglaos or Ambrosios. Humble, though they may have been, they had to be able to afford an education for their son, not to mention that according to the Cyrene Constitution, a man had to own land worth at least twenty minas, and he had to be born to free parents. Scholars blame Eratosthenes’ childhood for the lack of information, but also the conflict surrounding his life. Wars and battles burned libraries and official documents, texts that recounted history in a much more detailed fashion (Nicastro. 61). Young Eratosthenes moved from Cyrene to Athens for a time, studying under men such as the scholar Lysanias, the philosopher Ariston, and the poet Callimachus. The great School of Athens, founded by Aristotle had attracted many scholars and free thinkers from everywhere. Eratosthenes was considered a Polymath, meaning he was an expert in literary criticism, poetry, geography, and mathematics. He was criticized for rarely ever accomplishing much, however, and gained himself the nickname Beta which was the second letter in the Greek Alphabet. After a

time as the writer and mathematician, Eratosthenes moved to Alexandria at the request of Egypt’s Satrap, Ptolemy II. While traveling back and forth between Syene and Alexandria, Eratosthenes noticed on the summer solstice in Syene, that the sun was at the zenith and reach perpendicularly down into a well, reflecting brilliantly off of the water at the bottom. He reasoned that the sun is so far away that its rays could be thought of as parallel, and that they should cast the same angle of light across the Earth’s surface all over. Eratosthenes traveled back to Alexandria and noted that the shadow cast across the ground at the same time had a 7º difference. Using that, and the distance between Syene and Alexandria in stades. He measured the circumference of the Earth, which was only off by 10% from the modern day circumference. Longitudes and latitudes were also a thing of his time. His discoveries were welcomed by the age of chaos. Rulers, Generals and warlords sent their men out to remap territories. The newer more current geography helped warring cities to gain knew knowledge of bordering lands, giving them advantages against each other. Eratosthenes is also accredited with coming up with an algorithm for finding the prime numbers, which are still being found today. The sieve method was efficient for smaller primes, although quite tedious The method crossed off primes of smaller obvious numbers, which made the hunt easier. He was said to be a conceited individual, arrogant and short sighted in the works of others and ended his life by starving himself, after having gone blind. Eratosthenes may have been a joke in his early years, but his studies were the beginnings of many other great things.