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From: Frank Reed (no email)
Date: Tue Mar 14 2006 - 02:12:58 EST
Lu Abel, you wrote:
"While I hesitate to disagree with such giants of this list as George
Huxtable and Frank Reed..."
Ho ho ho. For the record, I am 5 foot 8, quite ungigantic, and an amateur in
these matters, just like everyone else on this list.
And then you asked:
"what about the motion of the planets?"
What about 'em?? It is a popular myth that the Copernican system was
significantly simpler than the Ptolemaic. Most of "de Revolutionibus" is actually
about epicycles. There's some of this that's worth reading in a book I
mentioned recently "The Book Nobody Read" by Owen Gingerich. He has a section on the
popular misconception that the Ptolemaic system was slowly weighed down by
"epicycles upon epicycles".
And:
"If earth and the planets all were in circular
orbits around the Sun, the apparent motion of the planets was easily
explained by their relative motion with respect to the earth."
EARTH and the planets... We say it so easily today. The Earth is a planet,
of course, why didn't we think of that earlier? In fact, it was the first
planet discovered by science. The others had been seen since the dawn of history.
But it's not obvious at all until you invent the telescope.
So here's Copernicus, pre-telescope, and he's got an explanation for the
Solar System. It's one that is certainly not more complicated than the
Ptolemaic, and it produces predicted positions that are just as good (but still
pretty bad in many cases). An equivalent model producing equivalent data starting
from radically different assumptions... That's the sort of thing that
launches a revolution.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
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