2007-10-09 17:41:13 · 15 answers · asked by scouser_huyton 2 in Science & Mathematics ➔ Astronomy & Space
And who has the say what is what with those type of classifications?
2007-10-09 17:42:10 · update #1
http://en.wikipedia.org/wiki/Image:TheKuiperBelt_Orbits_Pluto_Polar.svg
see where the orbits intersect? (sorta)
thats why..... It "hasn't cleared the neighborhood"
a dwarf planet
* is in orbit around the Sun
* has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (near-spherical) shape
* has not cleared the neighborhood around its orbit
* is not a satellite
distance is fine no matter how far and pluto's size is large enough to be classified as a planet. Its the orbit that makes it a "dwarf planet"
many were upset about the redenifing of pluto.
in 2006 only 424 out of 2700 astronomers at a convention casted a vote on the change. the group actually has 9000+ members, but many could not make it to the convention.
http://en.wikipedia.org/wiki/2006_definition_of_planet
I'm sure it will change again over time
ps pluto has 3 moons
nix and hryda where discovered in 2005
charon was discovered in 1978
http://answers.yahoo.com/question/index;_ylt=Aj_kPCeUVhEsFhGLMvaR_R4Bxgt.;_ylv=3?qid=20071009224707AAvRZ6H
2007-10-09 18:33:51 · answer #1 · answered by Mercury 2010 7 · 3⤊ 0⤋
As people have said, it's because the definition of "planet" was changed. What no-one has explained is WHY the defintion was changed.
Pluto was once called a planet because it was a solid body, thought to be bigger than Mercury, orbiting the sun. Recent decades brought the discovery that it was smaller than Mercury, but it kept its designation as a planet.
In the last few years, a number of bodies, some slightly smaller and some larger than Pluto, have been found not much further from the sun, in similar orbits (inclined, and possible coming inside Neptune's orbit). There is reason to believe that there may be hundreds of them.
If Pluto was to be considered a planet, then the new discoveries would have to be also. This would mean that there could be several hundred "planets".
Men with beards decided that this was too untidy, so they changed the definition of the word "planet" to exclude Pluto and others like it. Thus, we have 8 planets.
It's an arbitrary definition. Pluto is the same as it always was, it's where it's always been, and its feelings aren't hurt by what we call it.
2007-10-10 22:28:24 · answer #2 · answered by Choose a bloody best answer. It's not hard. 7 · 0⤊ 0⤋
Because it's so small and so far away.
Here's some info:
The debate came to a head in 2006 with an IAU resolution that created an official definition for the term "planet". According to this resolution, there are three main conditions for an object to be considered a 'planet':
1. The object must be in orbit around the Sun.
2. The object must be massive enough to be a sphere by its own gravitational force. More specifically, its own gravity should pull it into a shape of hydrostatic equilibrium.
3.It must have cleared the neighbourhood around its orbit.[89]
2007-10-10 00:46:11 · answer #3 · answered by Kendra 3 · 2⤊ 1⤋
Too far out, too small, there are other "dwarf planets" in its proximity that would have to be included too, etc. It's all just semantical posturing - it's still a "planet," since it orbits the sun, but not important enough to be considered among the "top dogs" of the solar system.
The biggest tragedy is now no one knows what my very excellent mother just served us nine of.
2007-10-10 00:51:35 · answer #4 · answered by damlovash 6 · 0⤊ 1⤋
It's to small, before people didnt mind of its size. But then we discovered allot of dwarf planets orbiting our sun that where just like pluto. So the scientist decided to call it a dwarf planet and leave it at that.
2007-10-10 00:45:01 · answer #5 · answered by zachmebay 2 · 0⤊ 1⤋
They believe it could be a giant ball of ice and part of the Kuiper Belt thus it is now classified as a dwarf planet.
2007-10-10 00:45:34 · answer #6 · answered by Anonymous · 0⤊ 1⤋
It has a funny orbit which penetrates the neptuneian orbit and it is far too small for a planet so it is a PLANETIOD what a wierd name LOL!!!!
2007-10-10 01:29:43 · answer #7 · answered by Anonymous · 1⤊ 0⤋
Too small and outside of planetary plane. Plus many other objects in the Oort Cloud are as big or even bigger that they would have to be included.
2007-10-10 00:44:42 · answer #8 · answered by mike w 2 · 0⤊ 1⤋
Because it is too small and it does not have a satelitte (moons) like all the other planets..
Who clasifies them would be the astronomical society which is the largest oldest worldwide astro body
2007-10-10 01:37:30 · answer #9 · answered by stormydays 5 · 0⤊ 3⤋
becoz we no so little about it bcoz its too far located in the space its too cold out there we cant gather 2 much information obout it bcoz of its weather conditions
2007-10-10 12:53:05 · answer #10 · answered by tiya b. 2 · 0⤊ 0⤋