"Thomas de Groot" <t.d### [at] internlnet> wrote:
> "Bob Hughes" <bob### [at] charternet> schreef in bericht
> news:42db72ee$1@news.povray.org...
> > Hey Thomas, I've always thought Kepler's model would be the perfect thing
> to
> > do in POV-Ray.
> >
> > Maybe adding a cumpled, scribbled over drawing of the Earth-centered
> > universe on the floor would fit in with this. A drawing of the Copernican
> > heliocentric universe could be put into the bottom of the large
> hemisphere.
> > Would then look like the other were replaced. Well, except I don't think
> > Kepler ever even considered an Earth-centered universe. Not really sure
> what
> > he thought of it. Might throw off the whole scene.
> >
> > Bob

Don't forget about the Tychonic system - Tycho Brahe's odd compromise, with
the Sun & Moon orbiting Earth, and all the other planets orbiting the Sun.

> >
> That's an interesting idea, Bob. I shall see if I follow that up. I think
> that Kepler in his early days may have believed in a Ptolemaic solar system,
> i.e. Earth-centered. But I am really not sure about this. PM 2Ring should
> know!
>
> Thomas

I should know, but memory is a funny thing... Contrary to my post of last
week, Kepler didn't actually help to gather the Mars data, but Tycho hired
him (after leaving Uraniborg) to analyze this data for him, about a year
before Tycho's death.

By his mid-twenties Kepler was a champion of the Copernican system: "In
1596, while a mathematics teacher in Graz, he wrote the first outspoken
defense of the Copernican system, the Mysterium Cosmographicum." (See link
below)

I don't know what Kepler thought of the Ptolemaic system during his student
days (if I did know, I've forgotten :) but most of its various defects were
well-known by then. Not only was it not so accurate with position
prediction, it had no explanation for the variable brightness of Mars, for
example.

For a quick bio and other interesting info, see
http://kepler.nasa.gov/johannes/

Halfway down this page is a very cute little .GIF anim of Kepler's Law of
Areas.

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