When, in the year 1492, Columbus sailed out to the west on his memorable voyage, his expectation of reaching India had full scientific warrant, however much it may have been scouted by certain ecclesiastics and by the average man of the period.

Nevertheless, we may well suppose that the successful voyage of Columbus, and the still more demonstrative one made about thirty years later by Magellan, gave the theory of the earth's rotundity a certainty it could never previously have had.

Alexandrian geographers had measured the size of the earth, and had not hesitated to assert that by sailing westward one might reach India.

But there is a wide gap between theory and practice, and it required the voyages of Columbus and his successors to bridge that gap.
After the companions of Magellan completed the circumnavigation of the globe, the general shape of our earth would, obviously, never again be called in question.

But demonstration of the sphericity of the earth had, of course, no direct bearing upon the question of the earth's position in the universe.