I came of age in the 1980s. During elementary school, the mnemonic device "My Very Excellent Mother Just Served Us Nine Pizzas" helped me and my fellow students remember the name and order of the nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. That's right, Pluto. Pluto was always the smallest, the coldest, and, it seemed to me, the most forgotten. The humiliation only increased a few years back when the International Astronomical Union (IAU) decided to define just exactly what a "planet" was. After much hemming and hawing at the general assembly in Prague, a vote was taken (one that constituted only 4% of the IAU's 10,000 members) and Pluto was