Even More Things in Heaven and Earth

ASTRONOMERS announced last month that, contrary to previous assumptions, the orbiting body Eris might be smaller than Pluto after all. Since it was the discovery in 2005 of Eris, an object seemingly larger than what had been considered our smallest planet, that precipitated the downgrading of Pluto from full planet to “dwarf,” some think it may be time to revisit Pluto’s status.

Most of us can’t help rooting for Pluto. We liked the idea of a ninth planet, hanging out there like a period at the end of the gorgeous sentence of the solar system. It gave us a sense of completeness. And besides, we were used to it. Pluto’s demotion caused such an outcry because it altered something we thought we knew to be true about our world.

Of course, science doesn’t, and shouldn’t, care what we learned in first grade. If Pluto’s odyssey teaches us anything, it’s that whenever we think we’ve discovered a measure of certainty about the universe, it’s often fleeting, and more often pure dumb luck. The 1930 discovery of Pluto — by Clyde Tombaugh, who coincidentally was born 105 years ago today — is a prime example, a testament not only to Tombaugh’s remarkable perseverance, but also to how a stupendously unlikely run of circumstances can lead to scientific glory.

The search for a ninth planet was led by the Harvard-trained Percival Lowell, a Boston Brahmin who was widely known for announcing the existence of a Martian civilization. Lowell’s hypotheses about a “Planet X” were based on optimistic interpretations of inconclusive data. Many had observed that the orbit of Uranus seemed to be perturbed by a gravitational influence beyond the orbit of Neptune. If the source of that pull could be determined, he speculated, a fellow could point a telescope at that source and find an undiscovered world.

http://www.nytimes.com/2011/02/04/opinion/04byers.html?nl=todaysheadlines&emc=tha212