WHAT IF physicians had ignored death rates that suggested bloodletting wasn't such a great cure? What if mapmakers kissed off sailors' stories that disproved the Earth is flat? What if astronomers had evidence that Pluto isn't really a planet but decided to keep calling it one anyway? Hold it, that's where we are.
The International Astronomical Union says it will continue to list Pluto as our solar system's ninth planet even if it doesn't measure up. The IAU has gone medieval by placing tradition over science.
Yet the more astronomers learn about Pluto, the less it resembles other planets.
It's smaller than the Earth's moon. Its mass is only one five-hundredth of Earth's. It's neither rocky nor gaseous like the other eight planets. And it has an oval orbit -- not round like the others -- that puts it closer to the sun than Neptune for 20 of every 248 years.
Knowledge now available to scientists suggests Pluto is merely another trans-Neptunian object, one of about 100 other small, icy asteroids, spent comets, etc., found in that part of space.
A suggestion was made to redesignate Pluto as "Minor Planet 10,000," rather than "Planet Nine." But the IAU this month succumbed to U.S. sentiment for the only "planet" discovered by an American, Clyde Tombaugh in 1930. Pluto's status won't change.
It's true that a planet is pretty much whatever the IAU says it is. But there is precedent for making astronomical corrections as knowledge increases. The asteroid Ceres, even smaller than Pluto, used to be considered a planet.
With Pluto, science is taking a back seat to sentiment. As the millennium ends, that is disconcerting. History smolders yet from the bonfires set by past ignorance. Truth known must be revealed and accepted. The IAU should set specific criteria for a planet. If Pluto doesn't meet the rules, it's time to rewrite the science books.
Pub Date: 2/27/99