Astronomers say Pluto is not a planet

(Note: This story came from the AP over at Yahoo. Unfortunately the link no longer works so I took it out 1/4/07)

PRAGUE, Czech Republic - Leading astronomers declared Thursday that Pluto is no longer a planet under historic new guidelines that downsize the solar system from nine planets to eight.

After a tumultuous week of clashing over the essence of the cosmos, the International Astronomical Union stripped Pluto of the planetary status it has held since its discovery in 1930. The new definition of what is — and isn't — a planet fills a centuries-old black hole for scientists who have labored since Copernicus without one.

Although astronomers applauded after the vote, Jocelyn Bell Burnell — a specialist in neutron stars from Northern Ireland who oversaw the proceedings — urged those who might be "quite disappointed" to look on the bright side.

"It could be argued that we are creating an umbrella called 'planet' under which the dwarf planets exist," she said, drawing laughter by waving a stuffed Pluto of Walt Disney fame beneath a real umbrella.

The decision by the prestigious international group spells out the basic tests that celestial objects will have to meet before they can be considered for admission to the elite cosmic club.

For now, membership will be restricted to the eight "classical" planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Much-maligned Pluto doesn't make the grade under the new rules for a planet: "a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit."

Pluto is automatically disqualified because its oblong orbit overlaps with Neptune's.

Instead, it will be reclassified in a new category of "dwarf planets," similar to what long have been termed "minor planets." The definition also lays out a third class of lesser objects that orbit the sun — "small solar system bodies," a term that will apply to numerous asteroids, comets and other natural satellites.

It was unclear how Pluto's demotion might affect the mission of NASA's New Horizons spacecraft, which earlier this year began a 9 1/2-year journey to the oddball object to unearth more of its secrets.

The decision at a conference of 2,500 astronomers from 75 countries was a dramatic shift from just a week ago, when the group's leaders floated a proposal that would have reaffirmed Pluto's planetary status and made planets of its largest moon and two other objects.

That plan proved highly unpopular, splitting astronomers into factions and triggering days of sometimes combative debate that led to Pluto's undoing.

Now, two of the objects that at one point were cruising toward possible full-fledged planethood will join Pluto as dwarfs: the asteroid Ceres, which was a planet in the 1800s before it got demoted, and 2003 UB313, an icy object slightly larger than Pluto whose discoverer, Michael Brown of the California Institute of Technology in Pasadena has nicknamed Xena.

Charon, the largest of Pluto's three moons, is no longer under consideration for any special designation.

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My question is, how will this affect the education of our children? Every piece of information I have in my home library states that Pluto is a planet. Should I just throw out all my books that make reference to that statement? I don't know that I'm willing to give up my belief about Pluto. Pluto being a planet has been ingrained in me for too many years to speak of here. I'm sure the publishers of educational materials are rushing to their presses to start printing out new books with the new information in them. Will the schools stop using their current books? The information is now incorrect in them so they shouldn't be using them, right? Let's spend more of my hard earned money and buy all new books with the new information in them. I think I will just tell my child that some crazy scientists are now convinced that Pluto is not a planet. Instead of calling them planets, why not just call them "heavenly bodies" and leave it at that. Next thing you know, they'll start calling our moon a planet. I refuse to throw away my model of the planets. Am I being ignorant? No, just stubborn. I happen to like having Pluto as a planet. It means that something is still the same as it was when I was a kid. After all so many things have changed since I was a child and some of those things aren't so good. I say let's start a petition to keep Pluto a planet. What say you?