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Pluto has been demoted to dwarf planet status

DailyTech reported last week that Pluto was coming close to being dismissed as an official planet of our solar system. Pluto, which was first discovered in 1930, has been the subject of debate for astronomers for over 70 years. The International Astronomical Union's 2,500 astronomers (representing 75 countries) gathered to decide the fate of Pluto and the results are in.

The International Astronomical Union (IAU) voted to demote Pluto from the ranks of the solar system's now 8 planets.  The decision comes as Pluto no longer fits the newly ratified definition of a planet decided upon by the IAU this week. The new definition states that a planet is “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 does not clear the neighborhood around its orbit because its orbit overlaps with its much larger neighbor Neptune. This therefore disqualifies it from planet status according to the IAU. Instead, Pluto will be classified as a dwarf planet and join the ranks of other dwarf planets such as Ceres, which lies between Mars and Jupiter and 2003 UB313 or ‘Xena’ as discoverer Michael Brown of the California Institute of Technology has nicknamed it. ‘Xena’ is an icy object that lies after Pluto and is slightly larger than the now dwarf planet.

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RE: Definition of a Planet
By SilthDraeth on 8/24/2006 3:16:11 PM , Rating: 2
Not really.

The part that Pluto does not meet is:
c) has cleared the neighbourhood around its orbit.

Neptune does meet that. Pretty much Neptune fits all other definitions of a planet, and has a normal orbit of the Sun. Pluto does not, and does not match any other planet's orbital patterns. Neptune never crosses the path of Uranus, and since it has a regular path, then Pluto is crossing it's path, and not the other way around.
"Pluto's orbit is inclined, or tilted, 17.1 degrees from the ecliptic -- the plane that Earth orbits in. Except for Mercury's inclination of 7 degrees, all the other planets orbit more closely to the ecliptic."

RE: Definition of a Planet
By Chernobyl68 on 8/24/2006 3:40:30 PM , Rating: 2
The asteroid Ceres would have been classified a planet had they not included the bit about cleared its neighborhood.

Personally, I think they should have "grandfathered" Pluto's status in, to make everyone happy.

RE: Definition of a Planet
By SilthDraeth on 8/25/2006 10:38:24 AM , Rating: 2
I believe that would have been a good idea.

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