2007-03-24 03:41:55 · 12 answers · asked by Seth B 1 in Science & Mathematics ➔ Astronomy & Space
AU Decision
Main article: 2006 redefinition of planet
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.
Pluto fails to meet the third condition.[40] The IAU further resolved that Pluto be classified in the simultaneously created dwarf planet category, and that it act as prototype for a yet-to-be-named category of trans-Neptunian objects, in which it would be separately, but concurrently, classified.
2007-03-24 03:51:47 · answer #1 · answered by Koko 4 · 1⤊ 0⤋
Mostly because of it's characteristics. With the more modern telescopes, Pluto like objects seem to be everywhere at the deep parts of the solar system. In fact at least one object found is smaller than Pluto. Since it's orbit is so tilted, it's clear it didn't form with the rest of the planets. Considering all the Pluto like objects that have been and will be discovered, the scientific community did not want to deal wit 50 planets so they just demoted Pluto.
2007-03-24 10:52:02 · answer #2 · answered by Gene 7 · 2⤊ 0⤋
There used to be nine planets in our solar system. But now there are only eight because Pluto was marked as a dwarf planets. And dwarf planets are not really planets at all. It was too far from the sun and too small and too close to the orbit of Neptune.
2007-03-24 10:52:44 · answer #3 · answered by MelMel 2 · 0⤊ 0⤋
pluto is merely a big ball of ice.it does not fit in the pattern of planet .A planet<1> should revolve around the sun and <2> it should have a gravitational force
pluto revolved around the sun but later it was discovered that the 2 moons of pluto were not actully its moon,it was not attracted by the gravitational pull of pluto and also it is merely just a minor plane "asteroid"
so pluto is not considered a planet anymore
2007-03-24 10:53:18 · answer #4 · answered by kitkat 3 · 0⤊ 0⤋
They decided that Pluto was just a ball of gas and mud that it really wasn't a planet at all. So they said it moved across the Galaxy and over centuries of time it grew in size.
2007-03-24 10:57:06 · answer #5 · answered by Anitha P 1 · 0⤊ 0⤋
as i have read in some articles, pluto was not already considered a planet because the scientist and astronomers have found out that it is just one of the satellites of neptune.. so like in our planet, the moon is our satellite.. it is the same with the case of neptune and pluto..
2007-03-24 10:55:34 · answer #6 · answered by bonjette 2 · 0⤊ 0⤋
Because it is too small. It is now classified as a dwarf planet. So, to me it is still a planet.
2007-03-24 10:50:29 · answer #7 · answered by Aliz 6 · 0⤊ 0⤋
cuz they are saying if it was closer to the sun it would melt, so not a planet
2007-03-24 10:45:16 · answer #8 · answered by Anonymous · 0⤊ 0⤋
!Because it's NOT a planet,They were mistaken years ago when they found it!
2007-03-24 10:53:20 · answer #9 · answered by jack y 4 · 0⤊ 0⤋
because of its size and part of its orbit is inside neptunes orbit.
2007-03-24 10:45:53 · answer #10 · answered by Anonymous · 0⤊ 0⤋