Bode's Law

John K Clark (johnkc@well.com)
Wed, 22 Oct 1997 23:01:01 -0700 (PDT)


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On Wed, 22 Oct 1997 Dan@Clemmensen.ShireNet.com (Dan Clemmensen) Wrote:

>Bode's "law" is simply an observation of a relationship between the
>ratios of sizes of the orbits of the six classical planets and a
>certain nesting of platonic solids. This observed nesting "predicts"
>an orbit for a planet between Mars and Jupiter. Bode's law predates
>the telescope. The asteroids were discovered after Bode's law, and
>the Bode's law orbit is consistent with the mean orbit of the
>asteroids.

Bode's law had nothing to do with platonic solids it was a series that seemed
to fit the spacing of the planets. The idea was to give each planet a number
and then add 4 to it, Mercury got a 0, Venus a 3, Earth a 6, Mars a 12 and so
on. Calling the asteroid Ceres a planet was stretching it, but other than
that the fit wasn't too bad and even when Uranus was discovered it was close
to where the law said. Everything was going so well, and then Neptune and
Pluto were found and the "Law" failed badly.

The nesting platonic solids idea for the orbits of the planets was due to the
early work of the great mathematician and astronomer Johann Kepler.
He proposed his idea in 1596 and the agreement with observation was not great
but it wasn't terrible either and Kepler knew that Tycho Brahe had much
better observational data, the best ever made before the telescope. When he
finely got to see Tycho's data he was horrified to discover it did not fit
his theory, the disagreement was not large but it was too large for Kepler
because he knew what a careful observer Tycho was. I think this is where
Kepler proved he was a great scientist, even though he loved his theory and
had spent years of his life on it, when he found it didn't agree with
observation, however slightly, he immediately abandoned it and went on to
other things. The story has a happy ending because the "other things" were
his discovery that planets moved in ellipses and his 3 laws of planetary
motion, and that lead the way for Newton. If he'd screamed that the data must
be wrong, as most would have even today, Kepler would be only a footnote in
the history of science instead of one of the giants.

Incidentally, Kepler was also an astrologer, he had to be, that's how
astronomers made their living back then. I think astrology is pure bull shit
but that's because I'm a Leo and they're notoriously skeptical about that
sort of thing.

John K Clark johnkc@well.com

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