Writers of astronomy textbooks just keep recycling the myth, sort of like the flat-Earth myth, which was the idea that Columbus was told the Earth was flat and he thought it was round. That's just wrong."
"Scholars at the time knew it was a sphere" . "Even the ancient Greeks knew it was a sphere."
"They'd known it for a thousand years or more," said Richards.
I knew they were right about that. David Lindberg, former professor of the history of science and currently director of the Institute for Research in the Humanities at the University of Wisconsin, said in a recent interview:
One obvious [myth] is that before Columbus, Europeans believed nearly unanimously in a flat Earth-a belief allegedly drawn from certain biblical statements and enforced by the medieval church. This myth seems to have had an eighteenth century origin, elaborated and popularized by Washington Irving, who flagrantly fabricated evidence for it in his four-volume history of Columbus.... The truth is that it's almost impossible to find an educated person after Aristotle who doubts that the Earth is a sphere. In the Middle Ages, you couldn't emerge from any kind of education, cathedral school or university, without being perfectly clear about the Earth's sphericity and even its approximate circumference.
Now in addition to the flat-Earth myth being exploded, here were Richards and Gonzalez asserting that the Copernican Principle was based on faulty history as well.
There have always been less educated people who affirm a flat earth. Educated and knowledgeable people know it was a sphere since the time of the Greeks. Eratosthenes of Cyrene even calculated the size of the earth in stadia.