When is a planet not a planet? Dwarf planets orbit the sun, are solid bodies, and are not moons. But they are not considered regular planets. Learn more about these spherical oddities and why Pluto is still hotly debated today.
"The text is great; the book does an excellent job of explaining the formation of the solar system and the history of the discovery of Ceres and the asteroid belt and later Pluto and the Kuiper belt and how each step in understanding made scientists reexamine what they thought the solar system was."
Planetary Society
"This timely discussion of our solar system's dwarf planets focuses not just on characteristics of these astronomical bodies, but also on the scientific processes of discovery and the deliberations held by astronomers to set guidelines for categorizing space objects. High-quality photographs of the planets and bodies described, plus artistic interpretations of some of their surfaces, illustrate their major features."
