THE PLANETS

A brief tour of the solar system, with liberal dollops of scientific history.

Sobel's previous books (Galileo's Daughter, 1999, etc.) have tended to focus on a key person associated with an important discovery. Here, each planet provides the anchor for a chapter on astronomy and planet history. Sobel opens by discussing her youthful participation in science fairs as a kid (she built a model solar system) and her visits to planetariums before turning focus on the solar family—beginning with an account of the origin of the sun. She then works outward, planet by planet. Airless Mercury is so close to the sun that its motion could be explained only by Einstein's theories. Venus’s thick atmosphere is full of acidic greenhouse gases that raise its temperature to the melting point of lead. The section on Earth includes a history of geography, from Ptolemy through Columbus and Magellan to the seeming certainty of GPS systems, while the section on the Moon covers topics including Moon rocks, which “set a new standard for dryness,” and the effect of lunar gravity on ocean tides. The portion on Mars is narrated from the point of view of a Martian meteorite found in Antarctica (“Of the twenty-eight Martian meteorites definitively identified to date, I am by far the most ancient,” it explains.) Sobel continues with coverage on gigantic Jupiter, ringed Saturn, the team of Uranus and Neptune and finally distant Pluto, perhaps about to be demoted from full planetary status to membership in a group of comet-like objects. Along the way, Sobel offers amusing observations on astrology.

Thoroughly readable: not a dry recitation of facts—though the facts are there—but a lively exploration of the historical and cultural meaning of the planets.