[Sigia-l] The planetary classification conundrum... mental models outside of the Web

[Fred Beecher]

This may not seem to have any bearing on IA at first, but please, bear
with me...

The International Astronomical Union (IAU) recently made a very big
decision. They defined what a planet is.

http://www.nytimes.com/2006/08/16/us/16pluto.html?ex=1313380800&en=9f6789344376a6c9&ei=5088&partner=rssnyt&emc=rss

According to the IAU, a planet is something that is a) large enough
that gravity forces it to become round, and b) orbits a star rather
than another planet. This seems like a fairly reasonable definition.
They have also defined another type of astronomical body, the
"pluton," a small, distant body with a highly elliptical orbit.

However, I have noticed that, while it makes perfect *logical* sense,
the way they have applied these definitions makes no *human* sense. By
this definition, Pluto's largest moon, Charon, is counter-intuitively
classified as a pluton. Apparently, Pluto and Charon orbit around the
same gravitational point in space. Charon does not actually orbit
Pluto.

Logically, this makes Charon a pluton, but the problem is that the
entire world currently has the mental model of the planet and moon.
Very, very few people have the mental model of a binary planet
orbiting around a gravitational point. : )

The question this brings up for me is where is the point in
classification when we need to abandon logic for understanding? In a
scientific context, e.g. classifying life or astronomical
structures, there is a strong argument for logic. But how do we teach
a potentially non-intuitive logical organization system to
non-scientists? Can it be taught? As IAs, we deal with perceptual
(human, emotional) organization every day... we go out and find out
how people think of things and organize our sites based on that
understanding. Do we have any input on this discussion? Should we even
bother having the discussion at all? : )

Just some thoughts...

- Fred