Eratosthenes: This African was the first To Measure The Circumference of Earth
More than 2000 years ago, A man in Africa proved his ingenuity to the world!
A time when not even a calculator existed, let alone other technical devices that facilitate the research process, Eratosthenes calculated the spherical size of the Earth.
Eratosthenes calculated it with considerable accuracy, obviously without the use of modern equipment but only by comparing the position of the Sun’s rays in two locations.
Born in 276 BC in Cyrene, the present-day city of Shahhat, Libya in North Africa, Eratosthenes grew to become a keen learner and a man of many talents.
He pursued his studies in Athens then returned back to Cyrene where he excelled among his peers and stood out in scholarly endeavors.
When he became well-known among his peers, the ruler of Egypt, Pharaoh Ptolemy III Euergetes asked him to come to tutor his son in the city of Alexandria, Egypt.
In 236 BC, when the chief librarian of the eminent Library of Alexandria passed away, Eratosthenes (around 40 years old now) was appointed as Director of the Library of Alexandria, the most prominent intellectual institution in the ancient world.
At the time, the library contained over half a million books in the form of scrolls. Eratosthenes expanded the library’s assets by creating accurate duplicates of all books to the extent that it was hard to tell the original from the copy.
He wanted to maintain the reputation of the Library of Alexandria against competition from the other important ancient library of the time, the Library of Pergamum in Turkey.
The library was a hub where scientists, philosophers and poets gathered to discuss their intellectual quests.
His many talents started to shine not only as a librarian but in other fields as well, for Eratosthenes made considerable contributions in mathematics, astronomy, history and poetry.
This made his colleagues and friends at the library give him the nickname “Pentathlos”, which is an athlete who competes in five different events.
The name was extremely fitting to a scholar who excelled in many different fields of knowledge. He however, used to call himself “philologos” which means the lover of learning.
Eratosthenes made extensive writings and findings, most of which were lost but other scientists did report his work.
Read also: Top 5 Leading Banks in Africa
Eratosthenes other accomplishments
Eratosthenes created a mathematical method that is still used today which is known as the “Sieve of Eratosthenes”.
The method involves an algorithmic system that he designed for finding prime numbers, which are whole numbers that are only divisible either by themselves or by the number one.
The term “geography” was used for the first time by Eratosthenes, which originated from geo (Greek for Earth) + graphy (field of study).
He created a map of the known world and invented a system of latitude and longitude. Ptolemy reported that Eratosthenes was the first to calculate the tilt of the Earth’s axis with remarkable accuracy.
He also calculated the distance between the Earth and the Moon, and the distance between the Earth and the Sun, but with less accuracy.
He constructed an astral catalogue containing 675 stars. Moreover, he organized the dates of literary and political events starting from the siege of Troy (around 1194-1184 BC) to his own time.
This allowed him to make a calendar with leap years by which he laid the foundation of chronology used in the world.
Eratosthenes knew that the Egyptian city of Swenet (the present day Aswan) on the Nile River is located close to the Tropic of Cancer (about 23.5 degrees north), the northernmost latitude at which the sun at noon is directly overhead.
He also heard about a famous well in Swenet, where one day each year, on the summer solstice, the sun’s rays would shine straight down into the well’s deep pit.
The rays illuminated only the water at the bottom and not the sides of the well as it was the case on other days. This proved that the sun was directly overhead.
Eratosthenes worked in Alexandria, where he erected a pole and observed it on the summer solstice. He saw that it cast a shadow, indicating that the sun was slightly south.
By recognizing the curvature of the Earth and the distance between Swenet and Alexandria, Eratosthenes was able through solving the equation to find that the Earth’s circumference is 250,000 stadia or 40,000 Km.
Donwload our apps now!
Download our apps now for easier access to recent news and articles!
If you are interested in positive African stories projecting the continent, then please click here to join our WhatsApp group now.