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2006-08-29 12:19:13 · 17 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
the international astronomical union defined three terms "planet", "dwarf planet", and "small solar system body". this does not change anything about the solar system or pluto. it just corrects the mistake of classifying pluto as a planet initially.
(1) A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.
(2) A dwarf planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.
(3) All other objects orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
because pluto orbits the sun, is round, orbits the sun with a bunch of other similar bodies with similar orbits, and is not a satellite it is a dwarf planet.
look here:
http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html
2006-08-29 15:33:49 · answer #1 · answered by warm soapy water 5 · 2⤊ 0⤋
Is Pluto a Planet?
Scientists disagree on whether Pluto is a planet or a big ball of ice. Here's Ben's summary of the arguments for and against, based on information from an article by David Holtzman in Smithsonian Magazine.
Reasons to agree that Pluto is a planet
1. Pluto is very large compared to comets.
2. It seems to have a core and a mantle.
3. It has a moon (named Charon) orbiting it.
4. It sometimes has an atmosphere.
Reasons to agree that Pluto is not a planet
1. It is very close to the Kuiper Belt.
2. It has a strange orbit compared to the other 8 planets.
3. It is too small to be a planet.
2006-08-29 15:34:12 · answer #2 · answered by hamdi_batriyshah 3 · 0⤊ 1⤋
According to the new rules a planet meet three criteria: it must orbit the Sun, it must be big enough for gravity to squash it into a round ball, and it must have cleared other things out of the way in its orbital neighborhood. The latter measure knocks out Pluto and Xena, which orbit among the icy wrecks of the Kuiper Belt, and Ceres, which is in the asteroid belt.
Dwarf planets only have to be round.
2006-08-29 12:32:11 · answer #3 · answered by mom_with_twins_in_milpitas 4 · 2⤊ 0⤋
Some guys who get paid more than me wanted to make a fuss over something. That is as good a reason as any for what they did. I am not an astronomer, but the reasoning seemed stupid to others in the field. Why did someone name a car a car? That would likely make more sense than saying that Pluto is not a planet because of some rules VERY recently invented.
2006-08-29 12:44:18 · answer #4 · answered by Jack 7 · 1⤊ 2⤋
Why IS Pluto not a planet anymore?
Well go to the NASA website and it will explain it all !!!
2006-08-29 12:23:06 · answer #5 · answered by teacher4u25f 2 · 0⤊ 1⤋
Because it crosses w/ Neptune's orbit(Pluto was the alternating 8th and 9th planet). Also if it was considered a planet, there would b more "official" planets and i guess the ppl who declassified Pluto didn't like that.
2006-08-29 12:30:37 · answer #6 · answered by Anonymous · 1⤊ 2⤋
plutos not a planet anymore?
2006-08-29 12:26:23 · answer #7 · answered by michelle 2 · 1⤊ 2⤋
Pluto is not a planet? I thought Pluto was a dog!!!
2006-08-29 12:42:55 · answer #8 · answered by ♫ sf_ca ღ 4 · 0⤊ 3⤋
Because of its shape, atomshpere (i dont think it has one) and rotation around the sun. it is now considered a Dwarf-Planet...
2006-08-29 12:27:56 · answer #9 · answered by LLH 2 · 0⤊ 1⤋
There were others found bigger than Pluto even farther away. So they took it out from its planetary status.
2006-08-29 12:39:10 · answer #10 · answered by *Ginelle* 3 · 0⤊ 2⤋