Dinky Pluto Loses Its Status As Planet

PRAGUE, Czech Republic -- Pluto, beloved by some as a cosmic underdog but scorned by astronomers who considered it too dinky and distant, was unceremoniously stripped of its status as a planet Thursday.

The International Astronomical Union, dramatically reversing course just a week after floating the idea of reaffirming Pluto's planethood and adding three new planets to Earth's neighborhood, downgraded the ninth rock from the sun in historic new galactic guidelines.

Powerful new telescopes, experts said, are changing the way they size up the mysteries of the solar system and beyond. But the scientists showed a soft side, waving plush toys of the Walt Disney character _ and insisting that Pluto's spirit will live on in the exciting discoveries yet to come.

"The word 'planet' and the idea of planets can be emotional because they're something we learn as children," said Richard Binzel, a professor of planetary science at the Massachusetts Institute of Technology, who helped hammer out the new definition.

"This is really all about science, which is all about getting new facts," he said. "Science has marched on. ... Many more Plutos wait to be discovered."

Pluto, a planet since 1930, got the boot because it didn't meet the new rules, which say a planet not only must orbit the sun and be large enough to assume a nearly round shape, but must "clear the neighborhood around its orbit." That disqualifies Pluto, whose oblong orbit overlaps Neptune's, downsizing the solar system to eight planets from the traditional nine.

Astronomers have labored without a universal definition of a planet since well before the time of Copernicus, who proved that the Earth revolves around the sun, and the experts gathered in Prague burst into applause when the guidelines were passed.

Predictably, Pluto's demotion provoked plenty of wistful nostalgia.

"It's disappointing in a way, and confusing," said Patricia Tombaugh, the 93-year-old widow of Pluto discoverer Clyde Tombaugh.

"I don't know just how you handle it. It kind of sounds like I just lost my job," she said from Las Cruces, N.M. "But I understand science is not something that just sits there. It goes on. Clyde finally said before he died, 'It's there. Whatever it is. It is there.'"

The decision by the IAU, the official arbiter of heavenly objects, restricts membership in the elite cosmic club to the eight classical planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Pluto and objects like it will be known as "dwarf planets," which raised some thorny questions about semantics: If a raincoat is still a coat, and a cell phone is still a phone, why isn't a dwarf planet still a planet?