The Legacy of Eratosthenes


There’s always a tendency to discredit knowledge and geniuses from the past.  We have access to an abundance of scientific information and data today, and it’s very easy to pass judgment.  We may think they were ignorant, or just didn’t know any better.  However, it’s always important to fully appreciate the context of the time and realize the intelligence of those who paved the way for modern science can still be impressive.

Take, for example, Eratosthenes, chief librarian of the Library of Alexandria, and most famous for calculating the circumference of the earth.  No ancient civilizations had much knowledge of the earth, as proven by ancient maps.  Little was known, and to have an idea of the size was incomprehensible.  In the third century BA, Eratosthenes actually devised a way to calculate the size of the earth.

While in Syene, Egypt, Eratosthenes measured the sunlight striking the bottom of a well on the longest day of the year.  He figured that the angle of the shadow at the same exact time would be different in Alexandria, further to the north.  He determined that if he could measure this angle, and with the knowledge of the exact distance between the two cities, he could then make a determination of how big the earth is.  Hiring someone to walk that distance, he determined the distance between the two cities by means of counting the precision steps.  With the calculations in hand, Eratosthenes arrived at a value of 24,700 miles.

How did he do?  By today’s instruments, the earth’s circumference around the equator is 24,902 miles.  Not bad for someone about 2,000 years ago.  Armed with only rudimentary calculating skills, and essentially no technology, his accuracy is quite impressive.

Eratosthenes was a predecessor of a genius mind, similar to that of Leonardo da Vinci, or a Benjamin Franklin.  He was one of the first people to seriously attempt to put historical events into chronological order.  He was a mathematician, geographer, musical scholar, poet, astronomer, and inventor.  We owe him a debt for modern concepts of longitude, latitude, musical scales, and knowledge of prime numbers.  He was a man of many talents, and his legacy will be forever ensured with his ability to accurately calculate just how big the world is.

Simply because someone predates out time, does not take away from their genius.  Take inspiration from the people you admire today, but reflecting through history can draw much inspiration as well.  True, their ideas may not all have turned out accurately, but these people throughout history all build up a foundation for modern science and knowledge.  Some of the concepts and building blocks have been around for a long time.  Some may have been tortured for going against religious doctrines of their time.  Others were mocked and thought of as second class, as was Eratosthenes.  Step out into the world, and look around, and in most cases, you are literally looking at the legacy of intelligence and genius from millennia past.

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