Our Expanding Universe

According to the New York Times, last summer's discovery of a 10th planet (named Xena, after TV's warrior princess--sorry, I've never actually seen the show, but don't call me Xenaphobic) and last week's discovery that Xena had a moon (named Gabrielle, after Xena's sidekick, apparently), the question "what the heck is a planet?" rages again. Some may recall the debate back in 1998 or so when the powers that rule the heavens (or so it would seem) wanted to demote Pluto from "planet" to "Kuiper Belt object" or the more poetic (at least to me...) "trans-Neptunian object." Although, if you ever take the tour of the Lowell Observatory in Flagstaff, AZ (where Pluto was discovered), they're having none of it. To their mind, Pluto may as well be Jupiter.