Sunday, August 20, 2006
Eight Planets, Nine, Eleven, Twelve. Can't We All Just Get Along?
There is one theme about the debate over defining "planet" that is a bit bothersome. More than one scientist has made comments similar to this one.
"'Scientifically, whether Pluto is also a planet is a non-issue,' [astronomer David] Jewitt writes on his web site. 'No scientific definition of planet-hood exists or is needed. Is that a boat or a ship? It doesn't matter if you are using it to float across the ocean. Scientists are interested in learning about the origin of the solar system, and setting up arbitrary definitions of planet-hood is of no help here.'" (Here.)(First of all, Jewitt can cross the ocean in a dinky boat slammed around by the waves if he wants. Leaves that much more room on the ships for the rest of us. The big roomy safe ships. But we digress.)
Let's stipulate that whether Pluto remains a planet should not be the primary consideration. But it is useful to have a definition of planet. Scientists may only be interested in learning about the origin of the solar system but there are a lot of us who are interested in understanding the solar system as it exists now.
Science is not just for scientists.
It helps to make astronomy more accessible to laypeople to develop categories for objects in our solar system. The competing proposals both do that. But the pluton proposal is superior to the planet/dwarf planet option in one respect. Scientists agree there are lots of objects that may qualify as either a pluton or a dwarf planet waiting to be discovered way out there in the Kuiper Belt. Under the pluton proposal the number of planets will increase with each new discovery whereas under the opposing proposal we will never have more than eight planets.
Under the pluton proposal newly discovered plutons will be considered planets. With each discovery the number of planets will increase and public knowledge about the solar system is likely to grow as new planets are discovered and added. Under the planet/dwarf planet proposal the number of planets remains fixed. With each discovery of a new dwarf planet the number of planets remains the same. It'll be much easier to ignore discoveries of new dwarf planets because they aren't in a category that matters. They aren't real planets. The same happens now with asteroids. Newly tracked or discovered asteroids don't matter unless they have the potential to destroy civilization as we know it. Public knowledge of the solar system is unlikely to grow much under the planet/dwarf planet proposal.
But maybe astronomers don't care about public knowledge of their field. It would be a shame if that were the case and if the scientists voting on the competing proposals only had their own narrow interests in mind.
YUSUFALI: Behold! Joseph said to his father: "O my father! I did see eleven stars and the sun and the moon: I saw them prostrate themselves to me!"
PICKTHAL: When Joseph said unto his father: O my father! Lo! I saw in a dream eleven planets and the sun and the moon, I saw them prostrating themselves unto me.