Since the time of the ancient Greeks (and perhaps longer), every educated person believed the Earth to be spherical. Cite #1, Cite #2, Cite #3.
In the absence of a theory of gravitation, how did these people account for the fact that one didn’t tend to start slipping (down) the farther south one traveled, nor did one feel more firmly supported the farther north one traveled? And, of course, no one fell off the Earth once they had traveled south of the Equator. How did all this used to be rationalized?
I may have missed it, but your link doesn’t really answer my question, ie. what did the educated “man in the street” believe accounted for the fact that one doesn’t fall off the earth as one crosses the Equator, etc.?
It appears that the educated man in the street realized that objects near the Earth were pulled towards its center, but, until Newton, failed to realize that this gravitational force extended as well to objects very far from the Earth, that this was the force responsible for the orbit of the moon, and that similar attraction occurred between every pair of massive bodies, this being capable of explaining all orbits; those realizations, along with the particular discovery that Kepler’s laws were derivable from an inverse-square law of gravity, were Newton’s great accomplishments.
But “things near the Earth fall towards the center of the Earth”? That predates him.
The old concept of gravity was called “kindly inclyning.” (or some variant of that spelling) The idea was that things that were alike–of a kind–were attracted to each other, as they were all made of the same 4 elements. Rocks and other material things fall down because they are attracted to the earth, being made mainly of earth. Similar for water–both are heavy. Fire, OTOH, goes up because it is inclined towards the sphere of pure fire that is above the atmosphere. And gases, of course, go up too, towards the sphere of air.
Does that help? The best explanation I’ve read of it is in C. S. Lewis’ book The discarded image, all about the old vision of the universe. It’s a fascinating read–remember he was a literary professor and not a theologian, and he knew all about it.
I guess I should add that you didn’t fall south because everyone knew that “down” was towards the center of the earth, and you were inclined to go towards the earth itself, not towards the south. Incidentally, it was believed that the equator was uninhabitable and uncrossable due to the fervent heat (as the northernmost and southernmost places were equally uninhabitable due to cold), and therefore it was impossible to ever meet the Antipodean people or creatures, whoever they might be. Dante took advantage of this and put Purgatory there, but he was making that up.
Until the renaissance, Aristotelian theory was widely acclaimed, which seems to be what mr. Lewis is describing.
Aristotle thought the universe to be made up of fire, water, earth, air and aether. Each thing has a telos, a goal it strives for. The elements want to get nearer their natural place, which for earth and water was the center of the earth. (The Greeks all knew about the earth being round. They even made some pretty good estimates. Much better then Columbus’ anyway.) The larger the object, the more telos, and thus they would fall faster.
Not to mention, of course, that, given the Mediterranean centered viewpoints of the ancients, it’s not clear that they would have thought of the area south of the equator as pointing down. It’s only our later modeling that puts us on a ball that is routinely oriented that way for viewing.
No, I mean that wasn’t part of the picture of Creation!