If celestial bodies were sentient and had high-speed Internet access, I think they would be struck by the irony exhibited last month on the blogosphere.
First, on Aug. 24, the International Astronomical Union declared that Pluto, long-considered by both scientists and 8-year-olds to be our solar system's ninth planet, is actually only a "dwarf planet." It lacked the ability to "clear its neighborhood," a phrase that, while connoting flatulence problems, really just means that Pluto is a gravitational weakling. This proved to be the ruling which put the IAU on popular culture's map, spawning protests by people dressed in Disney costumes, and (as all good protests must) a series of Facebook groups, the largest having over 400,000 members.
Herald opinions columnist Kevin Roose '09 spoke ably in these pages about the need to "root for the underdog," and grant Pluto status as a full planet ("Show some Plutonic love", Sept. 12). This sentiment, and others like it, is sometimes humorous, sometimes angry and sometimes just ironic. It represents a defense of our elementary school conceptions of the world. But that worldview is wrong and the facts that we were taught in fourth grade no longer reflect reality.
This became apparent only three weeks after the IAU's decision, when the planets were back in the public eye. A team of astrophysicists reported finding a planet six times closer to its star than Mercury is to ours, with a radius 30 percent larger than Jupiter, the largest planet in our solar system, and a density so low that, as opposed to planets like Earth and even Saturn, it appears to be nothing more than a ball of gas. These statistics speak to an object that does not conform to any previous expectations of what a "planet" should be. When asked how the planet, given the very sexy title of HAT-P-1, originally formed billions of years ago, Digital Sasselov, a co-discoverer, responded, "I have no idea."
In a single month, the very conception of a planet, which would seem to be as unchangeable as a hunk of rock 13,000 miles in diameter, has been under attack on two fronts.
And that's how it should be.
Definitions, especially about scientific concepts, are messy and often fluid attempts to use words to describe physical concepts, objects and mechanisms, the nature of which often isn't truly understood to begin with.
Thirty years ago, students in high school biology classes were taught that there were only two major divisions of life: prokaryotes, which are organisms without a cell nucleus, and eukaryotes, life forms having that special type of organelle. But then, with the advent of better DNA technology, scientists realized that a new type of life existed, one which exhibited some traits of prokaryotes, some of eukaryotes and some very odd characteristics held by neither "classic" categories, such as the ability to survive in boiling water. In time, a new term was coined - Archea - and the scientific world is better for it.
Planets are no different. Fifty years ago, we had no idea about the extent of the Kuiper belt, the collection of millions of Pluto-like objects orbiting out beyond Neptune. Even 10 years ago, the concept of a very large object, composed only of gas, orbiting a skip away from a star would have belonged in the realm of science-fiction, and not particularly realistic sci-fi at that. Now, it's reality, albeit a confusing and poorly understood reality. As with biology, planetary science has become a much broader and more complex field - and old terms just don't seem to work anymore.
This is why the IAU's decision attempt to re-define the word "planet" was the right one. New knowledge demands new responses, and when old concepts are no longer adequate, or no longer have the precision required for their meaning to be clear, it is time to start anew. For the first time, the scientific community has, at the least, a working definition of the word "planet" - a definition that is responsive to new discoveries, and that attempts to explain the content of the world around us. That's how science works.
Clinging to elementary school facts is comforting, but science isn't supposed to be comforting. Science is complex, frustrating and sometimes painful in its rejection of our deeply-held beliefs. And if we reject change, if we insist on clinging to old, confusing and inadequate schemas, than we're really just rejecting science. And that's not a step I'm willing to take, not even for Pluto.
Joey Borson '07 wonders what Jupiter's e-mail address would be.
