total off the theme of the week, and the word occiput, but the idea that Columbus was unaware the earth was round was a joke made up by Washington Irving... and taken to be true. there is a good deal of evidence the ancients new the world to be round.. and as sphere, not a round plate..
first there was the moon, and it phases, and eclipses added further evidence.. and wasn't Archimedes who first measured the earth? by noting, that a certain well in Egypt, on the day of the summer solstice, had the sun directly overhead.. and the sun would shine down the well shaft, at high noon, and reflect a perfect circle.. He used this information, and then had walkers, who were trained to always move forward the same distance, (and used by map makers, and tax accountants to measure far distances) pace to a town so many *miles distance to an other point in Egypt, and in that town, the next year, at noon, on the day of solstice, he measured the shadow of stick.. (*i don't remember the unit of measure, but it for this purpose miles works..)
(and now, if you know any geometry, you know you have 2 sides, and right angle, and with a bit of math, can figure out the remaining 2 angles..) and so he did, he figured out the angle of the sun rays in the distant town... (about a 7 degree angle as i recalled..) and since he knew how long a interval was a 7 degree angle, he could multiply till he had 360 degree, and figure out the circumference of the globe.. as i recall, he ended up close to 24,000 miles which ain't bad considering his tools! (my atlas puts it at 24,902-- so he had a error of about 4%-- not bad..) and since much of the knowledge of the ancient greeks would have been known to educated people of columbus's time, we can expect he knew the world to be round..
as to whether or not the ancients considered the heavens to be a sphere as well.. who knows.. but the most certainly realized the moon was a sphere, and the earth.. and suspected the same of the sun (a ball of fire... not plate.. and since they made flat plate into oil lanterns.. the would have known both) and yes, all the Atlas (s) i have seen carry the weight of the world on their shoulders..
since i don't know the greek-- was he condemmed to carry the world? the heavens? the cosmos?
what ever, it was percieved as an ordered whole.. something that could be carried..
(what ever unit of measurement it was, it noted the two town, and what he percieved to be the distance between them,-- the towns still existed in more modern times, and the distance was remeasured, and from this actual measurement, and Archimedes numbers, scholars have worked it all out again.. )
occiput
