You mistake what the brightest of the time knew for what the authors of the Bible knew. You wouldn't necessarily expect someone today writing a religious book today to necessarily be written by people that are up on current science today would you?
There is lots of placing in the Bible where it depicts the Earth as flat. For example, Jesus is taken up the mountain by Satan and can see all the kingdoms of the world. This implies a flat world.
The writing style of Isaiah, the prophet in who's book the round earth is declared was analyzed by linguistic pedants. They said his Hebrew literary skill was superior to Shakespeare's English writing style. These men were by no means uneducated. In fact, the known Old Testament writers were all men of high status. (Kings such as David and Solomon, "Priest-princes" such as the royal Egyptian upbringing of Moses, priests, such as the prophet Samuel, (secular Historians will tell you that the priest class and the political authority/ruling class were intermingled in the early civilizations from Samaria and Egypt down to the reformation) and other temple scribes who were among the foremost educated people in their society.
In the New testament, you would seem to at least be able to make a case for Peter and James and John (despite no real evidence that they were undereducated in formal secular education), however they were capable of complex exegesis and ideals as expressed in their writing. Oh, and their writings do not cover the claims relevant to this topic.
Christ was a "carpenter" so, geometry would have been a part of his trade, though he left no known firsthand writing. Matthew was a tax collector, which would also appear that he had some handle on organization and mathematics. Luke was a physician. Mark, a historian. Paul was a privileged pharisee brought up at the feet of Gameliel. Paul would have had a very very good education. He was a pharisee and trained from his youth in the academic arts. Your claim is unfounded.
As for the encounter with satan in the desert.... I refer you to the encounter with Moses and Elijah at the transfiguration. What makes you think this isn't a supernatural vision such as the transfiguration? The author knows about horizons and diminished sight. You are looking at this in a very literal way.
Take a saucer, and put a semicircle cap on it. Like a serving plate with one of those half-sphere covers on it
The earth has depth and height. Mountains and valleys. I see how you are interpreting this. I have the image in my head. I just don't agree with how you are looking at it. At the present time I don't know a way to convincingly argue your vision of this with mine. No evidence to discredit either one of our interpretations.
12And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood;
13And the stars of heaven fell unto the earth, even as a fig tree casteth her untimely figs, when she is shaken of a mighty wind.
14And the heaven departed as a scroll when it is rolled together; and every mountain and island were moved out of their places.
I do not see anything to suggest a flat earth here, so I am assuming you are talking about the stars falling?
The Greek word used there is asteres. The word can refer to stars, but it actually means any heavenly body. (notice how it screams the etymology of asteroid?) This is further complicated by the mention of a great star/meteor called "wormwood" in the book which falls and destroys a great part of the earth. When when large meteors impact the earth, they tend to break up in the atmosphere and potentially can "rain" asteroids down from the heavens.
Have you ever read the book of Revelation in its entirety? There is an awful lot of symbolism in it. Nobody, and I mean nobody reads this book with an ultra literal perspective. --Nobody. Read it yourself if you have time and have not and youll see why. The book even begins with John explaining he was "in the spirit" when he saw this vision. Several times in the book, John talks about things he is seeing and how an Angel there with him, and at times Christ himself explains the meaning of the symbols of his vision. For instance, the very first chapter has Jesus explaining that the seven candlesticks (menorah) are the seven Churches of Asia (minor/Anatolia). Another example:
Revelation 17
1And there came one of the seven angels which had the seven vials, and talked with me, saying unto me, Come hither; I will shew unto thee the judgment of the great whore that sitteth upon many waters:
2With whom the kings of the earth have committed fornication, and the inhabitants of the earth have been made drunk with the wine of her fornication.
3So he carried me away in the spirit into the wilderness: and I saw a woman sit upon a scarlet coloured beast, full of names of blasphemy, having seven heads and ten horns.
4And the woman was arrayed in purple and scarlet colour, and decked with gold and precious stones and pearls, having a golden cup in her hand full of abominations and filthiness of her fornication:
5And upon her forehead was a name written, MYSTERY, BABYLON THE GREAT, THE MOTHER OF HARLOTS AND ABOMINATIONS OF THE EARTH.
6And I saw the woman drunken with the blood of the saints, and with the blood of the martyrs of Jesus: and when I saw her, I wondered with great admiration.
7And the angel said unto me, Wherefore didst thou marvel? I will tell thee the mystery of the woman, and of the beast that carrieth her, which hath the seven heads and ten horns.
8The beast that thou sawest was, and is not; and shall ascend out of the bottomless pit, and go into perdition: and they that dwell on the earth shall wonder, whose names were not written in the book of life from the foundation of the world, when they behold the beast that was, and is not, and yet is.
9And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth.
10And there are seven kings: five are fallen, and one is, and the other is not yet come; and when he cometh, he must continue a short space.
11And the beast that was, and is not, even he is the eighth, and is of the seven, and goeth into perdition.
12And the ten horns which thou sawest are ten kings, which have received no kingdom as yet; but receive power as kings one hour with the beast.
13These have one mind, and shall give their power and strength unto the beast.
14These shall make war with the Lamb, and the Lamb shall overcome them: for he is Lord of lords, and King of kings: and they that are with him are called, and chosen, and faithful.
15And he saith unto me, The waters which thou sawest, where the whore sitteth, are peoples, and multitudes, and nations, and tongues.
16And the ten horns which thou sawest upon the beast, these shall hate the whore, and shall make her desolate and naked, and shall eat her flesh, and burn her with fire.
Virtually EVERY chapter of this book is riddled top to bottom in extreme symbolism. Using Revelation to make any argument of the natural order of the world and universe just doesnt work.
Okay, I know what I said earlier and now Im screwed. Off to homework. :P
