Skip to comments.Astronomers say Pluto is not a planet (Eight Planets)
Posted on 08/24/2006 7:18:05 AM PDT by Lunatic Fringe
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.
Wait til the Plutonians hear about this. They're gonna be pissed, blame Bush and start a galactic jihad.
There are still 9 in my book.
"My Very Elegant Machine Just Smashed Up Nine." ???
This is a wise decision.
Pluto was always a nutty anomaly, with its orbit, and later its asymmetric appearance.
It always seemed more like an asteroid.
Mother Very Thoughtfully (Terra) Made a (asteroid belt) Jelly Sandwich Under No Protest!
Personally I would consider an object with an atmosphere that orbits the sun a planet. Moons would still be moons because they orbit planets.
Good riddance. I've always hated this oversized potato.
On ABC radio news the reporter just got finished with the story, and sent it back to the anchor with, "...so now children will be reciting eight planets. Can you name them, Doug?"
"Let's see: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus. This is ..., ABC news"
I'm not sure if he just can't count?...LOL
Doesn't that mean that Neptune too, the orbit of which must overlap Pluto's is also not a planet? Especially since it's orbit overlaps Pluto's, Neptune has failed to have "...cleared the neighborhood around its orbit."
I have'nt been this upset since they declared that Dagobah was not a planet.
That means I can have it?
Mother Visits Every Monday and (asteroid belt) Just Stays Until Noon.
(The "Period" was Pluto. I'd say it's small status in the sentence, foretold it's doom as a planet!)
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