My very eager mother just served us nine pizzas nachos.
The crazy sentence used by generations of children as a mnemonic for learning the order of the planets was quickly revised once Pluto lost its spot in the majors in 2006.
Elaine Scott's “When Is a Planet Not a Planet? The Story of Pluto” is a remarkable work that adults as well as youngsters will find fascinating and accessible (Clarion Books, $17, ages 8 and older).
Not only the saga of Pluto, it's also a terrific introduction to astronomy and a fascinating look at the way scientists work.
Scott packs ages of astronomical history into a few easy-to-digest pages. She describes the work of early astronomers, such as Ptolemy, Copernicus and Galileo, and how their discoveries led to the identification and naming of each planet.
With the groundwork laid in earlier chapters – and clear, compelling explanation of the eventual new three-part planet definition – many youngsters and adults will understand for the first time what the heck happened to Pluto.
Basically, it came down to the fact that the ex-planet didn't have enough size and gravity to be able to “clear its neighborhood” – or push other celestial objects out of its orbit.
