2006-10-27 02:30:37 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Because of the size of it,
and also because many of the astronmers voted that it was not
2006-10-27 02:35:00 · answer #1 · answered by Xavier 2 · 1⤊ 0⤋
Because astronomers decided to finally come up with a definition of what is and isn't a planet and Pluto doesn't fit the definition. It's a nomenclature thing, not a science thing. Nothing real about Pluto has changed. It's still a frozen ice ball orbiting the Sun and doesn't care what we call it.
The decision was influenced by the fact that we're finding more Pluto-like objects orbiting the Sun, with one known to be larger than Pluto, and it made sense to either call all these new ones planets or stop calling Pluto one.
But keep calling it a planet if you want to. It's not like the astronomy police are going to come after you.
2006-10-27 03:34:12 · answer #2 · answered by Faeldaz M 4 · 0⤊ 0⤋
There are several rules for planet in the Solar System, and Pluto breaks one of the rules which is :
A planet orbit in the Solar System may not cut the others Planet's orbit but Pluto cuts Neptunus orbit.
Another reason why Pluto is not consider as a planet in the Solar System is that its size and materials that composed Pluto don't belong to any Terrestrial Planet or Earth-Like Planet.
Ppluto is said to be a "Dwarf Planet" like Xena or Charon, some scientist suggest that Pluto can be grouped as the "Asteroid"
2006-10-27 03:13:51 · answer #3 · answered by mesqen d'ice 2 · 0⤊ 0⤋
Pluto is not considered a planet because it doesn't fit the criteria and the characterists of what a planet is supposed to be. It's also smaller than the other planets and their moons. It is now considered a "dwarf planet" which is in a separate classification than real planets.
2006-10-27 02:36:26 · answer #4 · answered by Olha K 2 · 0⤊ 0⤋
The main reason they declassified it from a planet to a large asteroid was not because of its size, but because it shares its orbit with many other objects. Basically, it is in an irregular orbit with tons of other objects, so it is basically orbiting in an astoroid belt with countless other astoroids, and does not have a set orbit around the sun, but an orbit that changes every year.
Rule #1 in qualifying to be a planet is that it must orbit around the sun
Rule #2 in qualifying to be a planet is that you have to have your own unique orbit (i.e., not share that orbit with other objects)
Pluto does not satisfy rule #2
2006-10-27 04:05:18 · answer #5 · answered by TopherM 3 · 0⤊ 0⤋
PLUTO DEMOTED UNDER NEW DEFINITION OF PLANET-
Doesn't qualify because its orbit is inclined relative to the rest of the solar system and crosses over the orbit of Neptune.
2006-10-27 02:54:25 · answer #6 · answered by Anonymous · 0⤊ 0⤋
Because it is too small. We only recently discovered it is smaller than the Moon, not larger than Mars like we used to think. And several other small objects have been discovered, with the possibility of thousands of such discoveries in the future, and nobody wanted thousands of planets.
2006-10-27 02:33:47 · answer #7 · answered by campbelp2002 7 · 0⤊ 0⤋
Its to do with its size and because the "Pluto" is dead, have a read it will give you some insight. www.msnbc.msn.com/id/14489259 or http://www.badastronomy.com/bablog/2006/08/24/breaking-news-pluto-not-a-planet/
2006-10-27 02:37:59 · answer #8 · answered by Angelface 2 · 0⤊ 0⤋
260 members of the IAU said so
2006-10-27 02:31:52 · answer #9 · answered by Anonymous · 0⤊ 0⤋
new to me, how many planets are there now?
2006-10-27 02:32:49 · answer #10 · answered by bluefairymyst 3 · 0⤊ 0⤋