I was recently having a casual conversation with a friend of mine when the subject of great scientists arose. My friend (a professional photographer) mentioned in passing that her son, who is in preschool, has been learning about legendary thinkers such as Newton, Copernicus, and Eratosthenes. While my familiarity with Newton and Copernicus is far from comprehensive, I am not passionately engaged in the fields of physics, mathematics, or astronomy, and am thus satisfied with having only a rudimentary understanding of their admittedly extraordinary scientific insights and discoveries. On the other hand, I had never even heard of Eratosthenes, who turns out to be the reputed “Father of Geography”. As a self-proclaimed Geographer and scientist, it shames me greatly to make this confession. However, I am consoled by the possibility that I may not be the only un-Eratosthened Geographer. As such, and in order to absolve my conscience of this abhorrent act of historical illiteracy pertaining to my chosen discipline, I present you with a brief history of the world’s first and founding Geographer.
One of Eratosthenes’ most remarkable accomplishments was accurately calculating the circumference of Earth. By this time, it had been well established that the Earth was roughly the shape of a sphere (no, it wasn’t Columbus who discovered, more than 1500 years later, that the earth isn’t flat). Having heard that the sun illuminated the bottom of a very deep well on the summer solstice in Syene, Eratosthenes chose this day to measure the shadow of a sundial's gnomon in Alexandria, and determined that the distance between the two cities corresponded to one fiftieth of the circumference of a circle. In performing the calculation, a number of assumptions could not be avoided, including (i) that the Earth is a perfect sphere; (ii) that the sun’s rays are parallel; (iii) that Syene lay exactly on the Tropic of Cancer; (iv) that Syene and Alexandria were on the same meridian; (v) that the distance between the two cities was exactly 5000 stadia. However, it would seem that the errors generated from the most erroneous of these assumptions may have canceled each other out. In the end, Eratosthenes’ estimate was off by either 385 km (0.96%) or 4 932 km (12.3%), depending on his definition of a stade.
According to Randy Alfred, “Eratosthenes was an all-around guy; a Renaissance man centuries before the Renaissance”. Indeed, he studied and wrote on geometry, geodesy, music theory, astronomy, climate, and poetry. His fellow academics even criticized him for his multiple pursuits, accusing him of being spread too thin, and nicknaming him Beta to mock him for being only second best in so many fields. But I find it comforting to learn that the first Geographer was a polymath. Geography, a discipline plagued with a perpetual identity crisis and a touch of existential angst, should aspire to follow in the footsteps of Eratosthenes by embracing generalist and interdisciplinary approaches to scientific inquiry. So to my fellow Geographers I say: Should we not all strive to be a little bit Beta?