The Corner

Flat Earth: Columbus Propaganda?

I don’t know if he’s right, but I love this sort of stuff. From a reader:

Ah, Jonah. I wonder how many times you’ll hear this today?

Your dragon blog contained the line

Similarly, for millennia, the logical position, given the evidence at the time, was that the earth was flat.”

Actually this is quite untrue.

Eratosthenes calculated the diameter of the globe over 200 years before Christ (he also invented the first brute force method of finding prime numbers, the Sieve of Eratosthenes). He succeeded within about 3% or so,


And before him, others had proved conclusively that the Earth must be a globe.

Here’s one reason why. People who live on coastlines see evidence of the world as a globe all the time. Were the earth flat, a boat leaving would look smaller and smaller, and a boat arriving would look larger and larger, but you’d always see the whole boat. What you actually see is the tips of the masts when it’s first in sight, and as the boat approaches, you see it not just larger but more of it, eventually all the way down to the waterline.

The men on the boat see something similar in mountainous country — the tops of the mountains are visible long before the coastline, even when the shore is much closer than the mountains. The only way to explain this phenomenon is to understand that the earth is a ball.

Lunar eclipses — there’s one this week, I think — also offer proof of a globe.

The “everyone thought the Earth was flat” business seems to come out of popular American lore about Columbus. It is what was used to explain the resistance to his voyage. The actual resistance came from the fact that education people *knew* the Earth was a ball, and new very closely how big a ball. Columbus has recalculated the size and came up with something less than half the size of the real earth., which is why he thought he could reach India and China buy sailing west. People who understood the math knew it was far too long to go that way.

This is why we’re called the Americas — Columbus came back claiming to have made it to the Indies; Vespucci immediately realized he’d found a new landmass or landmasses, and made the map to show so.

In a remarkable irony, I think I recall that during the voyage Columbus kept two logs, one private where he kept his real navigation and the other available to the mates with phonied up numbers to reassure them about the progress of the voyage. If I recall correctly, it turns out his fudged figures were far more accurate than his private logs when it came to recording his position.

Have a fun day with this one….


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