The Pluto Files

In case you have not heard the news, the planet Pluto has been demoted to dwarf planet status. I attended the International Astronomical Union's General Assembly in Prague in August 2006, when that august body did the dastardly deed but, perhaps fortunately for me, I was not able to stay for the final day and did not participate in the infamous vote.

I say fortunately because I fear that, if I had stayed, I would have voted along with most of the attendees to demote Pluto, and so would now be a pariah among many of my friends here in the US. You see, although I am a professional astronomer, I am also a member of an amateur astronomy club in New Jersey. I confess that I was unprepared for the extent of the public outcry over the change in Pluto's status, and the impassioned disdain that many of my amateur astronomer friends and the general public held for what I thought was a decision based on cold, irrefutable science.

In The Pluto Files, a short, lavishly illustrated and highly entertaining book, author Neil deGrasse Tyson brings to life the entire controversy, which had been brewing since long before 2006, and in which he played a particularly public, if inadvertent, central role.

As director of the Rose Centre's Hayden Planetarium in New York City, Tyson found himself at the centre of the controversy in January 2001, when a New York Times article noted that Pluto was missing from the newly opened Rose Centre exhibit. That is when the angry letters from schoolchildren started, several of which appear in the book in their original handwriting. The book follows the history of Pluto's discovery, the dawning realisation of how unplanet-like Pluto is, and the subsequent discovery of myriad other bodies just like Pluto (one, Eris, is even larger). It also follows the author's role in the controversy, which has been considerable at least in the public arena (although occasionally I got the feeling his role might have been overstated, as when he suggested that he might have been responsible for "Pizza" in the planetary names mnemonic My Very Educated Mother Just Served Us Nine Pizzas). Tyson is not a humble man. But he is a gifted speaker, writer and populariser of astronomical science.

The main purpose of the book is not to explain the scientific rationale for the IAU decision, although it is thoroughly explored as background for understanding the controversy, but rather to take a lighthearted look at the surprising public response and the cultural phenomenon it represents.

As the author points out, the response is strongest in America, where Pluto's discoverer Clyde Tombaugh hailed from, and where Mickey Mouse's dog Pluto has long been conflated with the planet as part of the cultural lexicon. Although Pluto was named by an 11-year-old English schoolgirl, it is only in the US that the controversy has inspired protest marches, songs, poems, petitions and public debates.

The controversy over Pluto's place in the solar system continues. In March 2009, the State of Illinois joined New Mexico and California in declaring Pluto to be a planet. The next IAU General Assembly is in August 2009, and some astronomers plan to raise the issue again in an effort to overturn the 2006 decision. And in 2015, Nasa's New Horizons spacecraft will fly past Pluto and its three known moons, to beam back our first close-up look at the dwarf planet.

The Pluto Files is a timely and enjoyable way for readers to understand the scientific and cultural underpinnings of these news-making events.