Re: New shuttle

> > Sailors always knew it. They could plainly see a ship sink below the 
> > curve as it sailed away. Partial eclipses were also a pretty 
> > good clue. Haaaaay, lookit that big round shadow on the moon!
> 
> You're thinking that sailors knew that this shadow was the earth blocking
> the light getting from the sun to the moon and back before Newton figured
> out celestial motion and the effects of gravity?  Seems unlikely to me.

Those are two different examples.

A) The partial eclipses are a great clue as to the circular (and, by extension, spherical) nature of the Earth.  This is how the ancient Greeks proved that the Earth was round.

B) Sailors can plainly see that a ship sinks below the curve of the Earth as it sails away, which is *also* a proof that the Earth is round.

The two are utterly and completely distinct proofs of the Earth's rotundity, and shall not be combined to form the non-contained statement that "sailors see the round shadow..."  The sailors do not factor into the eclipse example, nor does the eclipse factor into the sailing ships example.   Neither example relies upon a knowledge of gravity at any level.  Gravity, or the belief in an attractive force between massive objects, simply doesn't enter into it, and was a concept which came *long* after numerous and varied proofs of the Earth's rotundity.

As noted before, Columbus was turned down by the English Crown because the Royal Society knew that the Earth's diameter was *much* larger than Columbus was claiming, and thus there was no practical way for Columbus to find a western naval route to the Indies.  Their analysis was 100% correct.

-Sloth