Christopher Columbus Miscalculates

I have written before of Christopher Columbus’s historic sea voyage, which commenced this week (Aug. 3) in 1492.  Hoping to discover a shorter shipping route from Europe to China, India and Asia’s Spice Islands, he actually — totally inadvertently — discovered “The New World” of the Americas when he landed on what are now the Caribbean islands of the Bahamas, Haiti and the Dominican Republic.

One reason Columbus landed many thousands of miles from his intended destination was his rather unique thinking about the size and shape of planet Earth.  For years, conventional wisdom said that Columbus was prescient in thinking the world was not flat, but round, and not small, but large.  Yet the truth is that most European scholars in 1492 believed the world was both round and large, while Columbus believed it was small — and pear shaped.

Pear shaped or no, his conception of the Earth’s size led him to conclude that the distance between western Europe and eastern China was entirely navigable, even though in the 15th Century most experts agreed with the Greek mathematician Eratosthenes, who had concluded as far back as the Third Century that the Earth’s circumference was approximately 25,000 miles (talk about genius, he was off by about 100 miles!).  That meant the distance between Spain, where Columbus would begin his voyage, and his intended destination in Asia was about 15,000 miles, a journey no ship built in 1493 could possibly make.

Columbus, an experienced sailor who had often sailed the eastern Atlantic, thought Eratosthenes, a landlubber academic, had miscalculated.  Columbus based this belief not only on the intuitive sense of size and distance that he had gained on his many voyages, but also on his belief that a degree of longitude represented a distance of just under 57 miles (in fact it is closer to 69 miles).  By multiplying the 57-mile figure by the number of degrees in a circle, 360, he calculated that the Earth’s circumference was less than 20,500 miles.

Columbus also miscalculated the length of the Eurasian landmass, resulting in his belief that his journey across the Atlantic, and then on to East Asia, was only a little more than 3,000 miles, a distance that Spanish ships could easily traverse.

That was music to the ears of Spain’s Ferdinand and Isabella, who were eager to open trade routes to China, and so — ignoring the advice of their own navigational and astronomy experts, who thought Columbus was crazy — they gave Columbus the go-ahead.

As history records, Columbus was crazy, but his accidental discovery of “The New World,” which he promptly claimed for Spain, would, over the next century, make Spain the wealthiest and most powerful nation on the much-larger-than-he-thought, planet Earth.