It's very interesting to consider Ptolemy's contributions to astronomy and how Copernicus completely knocked them down centuries upon centuries later.
Something that is amazing about Ptolemy is how he charted the movement of the visible planets, accounted for their brief periods of retrograde movement by theorizing that each planet moved in small circles while taking the big orbit around Earth--not just turning on each axis, but an actual small repeated circular movement like a Cheerio loop repeated around the orbit. Ptolemy's belief was supported by his remarkable--incredible, really--ability to map out accurately the positions of the visible planets as they (to him) rotated around the Earth and his ability to account for retrograde movement of the planets. It was his mathematical accuracy in showing and predicting those positions that caused his theories to be respected.
Of course, he was finally incorrect. Today it's too easy to give him little consideration since we are privy to developments in astronomy.
But he's worth taking a look at just to realize how far his mind did see, if only into a universe that was not quite what it actually is--at least as far as we know today what it is.
On another note, it was interesting to read that the Pope declared that Copernicus--after his death and upon the publication of his observations and findings -- a heretic because his writings were not in accordance with the Bible, and it wasn't until 1992--after the launching of the Hubble telescope!-- that that pope stated that Copernicus was not a heretic. Copernicus gets a lot of credit for putting the sun in the center of the solar system, but Aristarchus, 2000 years (I believe) before Copernicus had done the same. His theories were not respected. There is some ancient Chinese scholar who had theorized the same, but his name escapes me.
I enjoy trying to grasp the minds of these past thinkers better no matter how inaccurate or accurate they may have been. It's the process of thinking that fascinates.
