How did scientist of Hellenistic times differ from scientists of Columbus's time in their thinking about the earth?

Answer 1

They did not. It is often thought that until Columbus' travels, people thought that the world was flat. But they didn't. Every medieval scientist and sailor knew that it was round. And it was the ancient Greek scientists that had not only already figured this out 2,500 years earlier, but they had - with astonishing precision - calculated the Earth's exact circumference and size. And both groups of scientists had more or less equal knowledge of the empires (and products) of the Far East. There had been extensive overland contact with them for thousands of years.

The only (small) difference was that to the ancient Greeks, the geography outside the Mediterranean world was little known, and to the scientist in Columbus' time, just a little more: the coasts of Africa had been explored and partially mapped by then. And the Portuguese knew how they had to navigate from there to get to India and China.

It was for that reason that the Portuguese refused to fund Columbus when he first approached them. They looked at his maps and calculations and decided that these estimated the size of the globe at less than 2/3rds of its real size - and that he therefore would never find India where he thought it would be.

Columbus by the way refused to ever acknowledge that he had discovered a 'new' continent. Until his dying day he maintained that he had discovered islands close to the coast of mainland India.