Aug. 16, 2006 The world's astronomers, under the auspices of the
International Astronomical Union (IAU), have concluded two years
of work defining the difference between "planets" and the
smaller "solar system bodies" such as comets and asteroids. If
the definition is approved by the astronomers gathered 14-25
August 2006 at the IAU General Assembly in Prague, our Solar
System will include 12 planets, with more to come: eight
classical planets that dominate the system, three planets in a
new and growing category of "plutons" -- Pluto-like objects --
and Ceres. Pluto remains a planet and is the prototype for the
new category of "plutons." With the advent of powerful new
telescopes on the ground and in space, planetary astronomy has
gone though an exciting development over the past decade. For
thousands of years very little was known about the planets other
than they were objects that moved in the sky with respect to the
background of fixed stars. In fact the word "planet" comes from
the Greek word for "wandere