2007-09-28 10:26:30 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Pluto is part of the "Kuiper Belt", an area beyond the immediate solar system with objects made mostly of ice and rock. It was predicted that as many as 50 Pluto-size objects and large may exist in this belt, so when not one, but two objects larger than Pluto were discovered, it was decided to re-define what a planet is, because the alternative would be that we'd need to learn up to 50 new planets.... It's best to demote Pluto - than to try to remember that many planets.
2007-09-28 10:38:24 · answer #1 · answered by quantumclaustrophobe 7 · 0⤊ 0⤋
from a new definition:
Pluto and its moon Charon, which would both have been planets under the initial definition proposed Aug. 16, now get demoted because they are part of a sea of other objects that occupy the same region of space. Earth and the other eight large planets have, on the other hand, cleared broad swaths of space of any other large objects.
"Pluto is a dwarf planet by the ... definition and is recognized as the prototype of a new category of trans-Neptunian objects," states the approved resolution.
Dwarf planets are not planets under the definition, however.
see URL for more detail
2007-09-28 17:35:30 · answer #2 · answered by Indiana Frenchman 7 · 0⤊ 0⤋
yes well
as you were asking
a dwarf planet is a celestial body within the Solar System that satisfies these four conditions:
* 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 neighbourhood around its orbit
http://upload.wikimedia.org/wikipedia/commons/a/a0/TheKuiperBelt_Orbits_Pluto_Polar.svg
* is not a satellite
the picture in the above link shows how the orbits of the two planets sorta intersect.
since pluto doesn't circle only outside or only inside neptunes orbit, its been demoted to dwarf planet
it "was" the smallest planet, but compared to mars its really not much smaller.
pluto is 70% rock and 30% ice
2007-09-28 17:34:38 · answer #3 · answered by Mercury 2010 7 · 0⤊ 0⤋
I guess you haven't heard; it was decided by astrophysicists about 3 years ago that Pluto isn't a planet. It's a mass of ice.
2007-09-28 17:31:15 · answer #4 · answered by ? 6 · 0⤊ 0⤋
It's tiny. It isn't even half the size of our Moon.
.
http://en.wikipedia.org/wiki/Image:Pluto%2C_Earth_size_comparison.jpg
.
2007-09-28 19:59:03 · answer #5 · answered by ericbryce2 7 · 0⤊ 0⤋
its too small. smaller than all the other planets.
2007-09-28 17:36:06 · answer #6 · answered by kimbaaa! 2 · 0⤊ 1⤋