Our Growing Family of Planets

The solar system has 12 planets.

That is the conclusion, to be announced today, of an international panel formed
to devise a scientific definition of a planet and settle an increasingly intense
dispute over whether Pluto qualifies. The panel suggests retaining Pluto and
immediately adding three new planets to the nine that are familiar to any schoolchild:
Ceres, currently considered a large asteroid; Charon, now considered a moon of
Pluto; and Xena, a recently discovered object that is larger than Pluto.

from the
Boston Globe

It’s about time! For the past thirty years we have
been regularly reading reports of a repeatedly rediscovered tenth
planet,
to the point that our unofficial count was up to about 16 planets in
all. A nice round dozen sounds fair to us.