“Once upon a time in our solar system, couldn’t make do without 9. But Pluto’s not a planet now, so 8’ll do fine.”
I’ll admit that I was with America in its indignant reaction to Pluto’s demotion to dwarf planet back in 2006. The decision, made official by a vote of the International Astronomical Union’s members, was preceded by a quietly bubbling controversy surrounding the redesign of the Hayden Planetarium in New York City’s American Museum of Natural History in 2000.
The museum’s then-new Scales of the Universe exhibit grouped Mercury, Venus, Earth, and Mars as terrestrial planets, and Jupiter, Saturn, Neptune, and Uranus as gas giant or Jovian planets. But, over the course of a year, astute visitors, many of them children, would count up the planets and come up with only 8, leading them to make the observation, “Did they forget about Pluto?”
In his surprisingly light and lively book, The Pluto Files: The Rise and Fall of America’s Favorite Planet, Neil DeGrasse Tyson, an astrophysicist and director of the Hayden Planetarium, recounts the science that left dwarf planet Pluto in a class, it would seem, by itself. By reviewing Pluto’s ups and downs, from its discovery back in 1930 to its entrenchment in pop culture, and, ultimately, to its central role in the first major cosmic recategorization dustup of the 21st century, Tyson explores the powerful forces exerted on space science by tradition, sentiment, enculturation, and even universally memorized solar system mnemonics.
What I love about this book is that it’s full of factoids (like these—By mass, Pluto is mostly rock, but by volume, it’s mostly ice; and, after the discovery of the planet qua asteroid Ceres back in 1801, the planetary count skyrocketed to 23, only to be knocked back down to 8 when all the asteroids in the belt between Mars and Jupiter were deleted from the planetary roster). It also weaves in fun tidbits (Like in 2006, the seven dwarves invited Pluto to join them, making the count of both dwarves and the planets an even 8; and, in the midst of the controversy, Stephen Colbert gave this shout-out to Pluto’s fellow Kuiper belt object 2003 UB313, which is now known as the dwarf planet Eris: “Hey 2003 UB313, if that is your real name, you’re not a planet you’re just a lazy comet. Your mama’s so ugly, she named you 2003 UB313!”).
For me, the thought-provoking part of the book came when it shed light on revolutions in science. When Copernicus proposed that the Earth revolved around the Sun, for example, he was changing a long-held paradigm. Art, literature, commercial branding, and even the religion of the time might have held on to the “Earth is the center” model, but that wasn’t going to change the fact that the paradigm was wrong. The same is true of Pluto. We can think what we will about its planethood (and grieve that “My Very Elegant Mother Just Sent Us Nothing” doesn’t have the ring of its former 9 word incarnation), but none of that changes the fact that Pluto is more like the other icy objects in the Kuiper belt that lies beyond Neptune than it is like its former planetary colleagues.
Tyson doesn’t come out and say this, but the way I look at it we’re Americans (those of us who live in America, at least), and if we can recast used cars as “pre-owned,” garbage men as “sanitation engineers,” and the artist currently known as “Prince” as the successor to the artist formerly known as “Prince,” then I’m sure that we can get the hang of this dwarf planet thing.
Just don’t ask me to call the Lehigh Engineers the “Brown and White.” That was just wrong.