OK, who can resist a title like How I Killed Pluto...? It promises and then delivers a light, interesting take on the Pluto demotion from one of the nine big ones to a dwarf planet at the edge of our solar system. "My very excellent mother just served us nine pizzas." Do you remember that line from science class in grade school? The words helped us remember the planets and their order in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. Alas, now mother is just serving us nine___?