The earth is round and the water cycle of the world. How about the inner core has as much water as the ocean? The bible says that is how the flood took place. and tons more proof.
For all the ancients knew, the oceans went all the way down. There is NOTHING remarkable here. Not only well within the ability of men to know, but expected of them.
Bob, you're abusing the word proof. Why do you ignore me when I tell you this? Aren't you capable of learning new information?
Scientific proof
It is often said that proof is for alcohol and mathematics, as these are really the only areas where proof has any real meaning. "Proof" is something that the opponents of science are always clamouring for, yet is not actually something that science suggests it will give - specifically in the common sense definition of "proof" that suggests that a claim has been proven 100%.
Surprisingly to some, science does not deal in proof, in spite of the word being associated with science a whole lot more than perhaps it should be. Scientists will throw around phrases like "we've just proved our theory" when they should know better, but this can be excusable human nature. With some theories its very difficult not to think of them as proven (Newton's laws of motion, for instance, which always have and always will describe the behavior of objects within the limits of those theories.) Science as a method, however, deals not in proof but in evidence, and perhaps disproof when the evidence contradicts a hypothesis.
For example, finding a fingerprint at the scene of a crime may be construed by most people as "proof" that the owner of the fingerprint was, at some stage, at that location. Science would say that the fingerprint is "evidence" that somehow a means of leaving that fingerprint was at that location. More evidence can be collected that shows a person was there at the right time, or perhaps some evidence is shown that they weren't there. It is up to someone working in the world of science to put together a hypothesis which is consistent with this evidence when taken together.
A scientist hasn't strictly proved anything by putting together this hypothesis, but they have constructed a realistic scenario based on overwhelming evidence.