Space and planets are topics of endless fascination to kids and part of every grade-school curriculum. Yet because of the history-making reassignment of Pluto from "planet” to "dwarf planet” on August 24, 2006, all books on the solar system are now out of date. Enter When is a Planet Not a Planet? The Story of Pluto by Elaine Scott, an esteemed writer of non-fiction for children. Scott is the first to put the answer to the title question into terms simple enough for a very young audience to understand, based upon the new definitions determined by the International Astronomical Union. Well-researched and accompanied by large, awe-inspiring photographs and paintings, this exciting new book makes clear what astronomers have argued about for decades.

"A brief description of planets, including what they are, where they are, and how they orbit around the sun"--Provided by publisher.

A Note from the Author: On August 24, 2006, at the 26th General Assembly of the International Astronomical Union (IAU) in Prague, by a majority vote of only the 424 members present, the IAU (an organization of over 10,000 members) passed a resolution defining planet in such a way as to exclude Pluto and established a new class of objects in the solar system to be called "dwarf planets," which was deliberately designed to include Pluto. With the discovery of Eris (2003 UB313)—an outer solar system object thought to be both slightly larger than Pluto and twice as far from the Sun—astronomers have again been thrown into an age-old debate about what is and what is not a planet. One of many sizeable hunks of rock and ice in the Kuiper Belt, Eris has resisted easy classification and inspired much controversy over the definition of planethood. But, Pluto itself has been subject to controversy since its discovery in 1930, and questions over its status linger. Is it a planet? What exactly is a planet? Is Pluto a Planet? tells the story of how the meaning of the word "planet" has changed from antiquity to the present day, as new objects in our solar system have been discovered. In lively, thoroughly accessible prose, David Weintraub provides the historical, philosophical, and astronomical background that allows us to decide for ourselves whether Pluto is indeed a planet. The number of possible planets has ranged widely over the centuries, from five to seventeen. This book makes sense of it all—from the ancient Greeks' observation that some stars wander while others don't; to Copernicus, who made Earth a planet but rejected the Sun and the Moon; to the discoveries of comets, Uranus, Ceres, the asteroid belt, Neptune, Pluto, centaurs, the Kuiper Belt and Eris, and extrasolar planets. Weaving the history of our thinking about planets and cosmology into a single, remarkable story, Is Pluto a Planet? is for all those who seek a fuller understanding of the science surrounding both Pluto and the provocative recent discoveries in our outer solar system.

On August 24, 2006, a group of astronomers made a big announcement: Pluto could no longer be considered a planet. This book explains how advancements in technology have changed our understanding of the universe--and exactly how and why the number of planets in our solar system went from nine to eight.

Discusses the orbit, atmosphere, and exploration of the dwarf planet Pluto.

The solar system most of us grew up with included nine planets, with Mercury closest to the sun and Pluto at the outer edge. Then, in 2005, astronomer Mike Brown made the discovery of a lifetime: a tenth planet, Eris, slightly bigger than Pluto. But instead of adding one more planet to our solar system, Brown’s find ignited a firestorm of controversy that culminated in the demotion of Pluto from real planet to the newly coined category of “dwarf” planet. Suddenly Brown was receiving hate mail from schoolchildren and being bombarded by TV reporters—all because of the discovery he had spent years searching for and a lifetime dreaming about. A heartfelt and personal journey filled with both humor and drama, How I Killed Pluto and Why It Had It Coming is the book for anyone, young or old, who has ever imagined exploring the universe—and who among us hasn’t?

For Pluto, summer has always started with a trip to the planetarium. It’s the launch to her favorite season, which also includes visits to the boardwalk arcade, working in her mom’s pizzeria, and her best friend Meredith’s birthday party. But this summer, none of that feels possible. A month before the end of the school year, Pluto’s frightened mom broke down Pluto’s bedroom door. What came next were doctor’s appointments, a diagnosis of depression, and a big black hole that still sits on Pluto’s chest, making it too hard to do anything. Pluto can’t explain to her mom why she can’t do the things she used to love. And it isn’t until Pluto’s dad threatens to make her move with him to the city—where he believes his money, in particular, could help—that Pluto becomes desperate enough to do whatever it takes to be the old Pluto again. She develops a plan and a checklist: If she takes her medication, if she goes to the planetarium with her mom for her birthday, if she successfully finishes her summer school work with her tutor, if she goes to Meredith’s birthday party . . . if she does all the things that “normal” Pluto would do, she can stay with her mom in Jersey. But it takes a new therapist, a new tutor, and a new (and cute) friend with a checklist and plan of her own for Pluto to learn that there is no old and new Pluto. There’s just her.