Everyone knows that there are 9 planets:Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Plutowhich you remember by saying My Very Eager Mother Just Served Us Nine Pickels (or some variation on the theme.Except that now, there are only 8 planets.Pluto just got demoted.So, a once critical fact, an immutable truth about the nature of the solar system has now changed.Plus, I really feel bad for all those Pluto scholars out there who once studied the most mysterious planet and now just study a dwarf object or whatever. Its kind of like being a specialist on the Soviet General...