Why isn't Pluto a Planet anymore?

Answer 1

http://en.wikipedia.org/wiki/pluto

on 24 august 2006, the international astronomical union reclassified pluto.

http://www.iau.org/fileadmin/content/pdfs/Resolution_GA26-5-6.pdf

pluto does orbit the sun, is ball-shaped and is not a satellite, but it does not have an isolated orbit (a bunch of other similar bodies have similar orbits.) so it is not a planet.

this was the right thing to do, believe me. this does not change anything about pluto or the solar system. this just corrects the mistake of classifying pluto as a planet initially.

i have been waiting for this since i was about ten when i learned that pluto didn't fit the pattern set by the major bodies in the solar system so it was an anomaly. it just felt "out of place". now that astronomers have found hundreds of other bodies with similar orbits, classifying "134340 pluto" as a planet is even more irrational. i feel somewhat satisfied, but i don't know how long this will drag on tho. many planetary astronomers are satisfied that the definition is rigorous enuf. i can accept that the definition is flawed, but i can not accept that "134340 pluto" is a planet.

this same thing happened has happened before. in 1800, an astronomer found a body orbiting the sun between the orbits of mars and jupiter and thought it was a planet. astronomers finally stopped classifying them as planets after they found several other bodies with similar orbits, and no one thinks ceres, pallas, juno, and vesta are planets today.

many astronomers consider pluto and charon to be a binary system, but two small bodies orbit that system. they are called nix and hydra.

incidentally, "134340 pluto" was never a moon of neptune. neptune did capture triton. this is why triton has a retrograde orbit

Answer 2

Despite its well-known peculiarities, Pluto's official status as a planet was never in jeopardy until 1992 when David Jewitt and J. Luu discovered a curious object called 1992 QB1. QB1 is a small icy body, similar in size to an asteroid, orbiting 1.5 times further from the sun than Neptune. QB1 was the first hint that there might be more than just Pluto in the distant reaches of the solar system.

Since then nearly 100 objects like QB1 have been found. They are thought to be similar to Pluto in composition and, like Pluto, many orbit the sun in a 3:2 resonance with Neptune. This swarm of Pluto-like objects beyond Neptune is known as the Kuiper Belt, after Gerard Kuiper, who first proposed that such a belt existed and served as a source of short period comets. Astronomers estimate that there are at least 35,000 Kuiper Belt objects greater than 100 km in diameter, which is several hundred times the number (and mass) of similar sized objects in the main asteroid belt.

So, is Pluto really a planet or is it more like a dormant comet, simply the largest known member of the Kuiper Belt? That's the question that astronomers have recently been debating.

Answer 3

I believe that it was a close vote by scientist in Fall 2006 to decide if Pluto was a plant. The scientists from around the world gathered and debated characteristics of planets. I think the irregular shape and the fact that Pluto is influenced by the orbit of Neptune were the big factors is most voting that Pluto is not a planet.

Answer 4

Its size. Pluto has been demoted to a "planetoid". There are several planetoids in the asteroid belt past mars as well. They just decided that it was too small to be considered a real planet.

Answer 5

I think because it doesn't follow the normal pattern of other planets in our solar system and that it's too small.

Answer 6

its considered a dwarf planet, and it doesn't qualify as a planet because of the new definition of a planet

Answer 7

I think they believe that it is too far away from the sun to be considered in our galaxy or what not. It's too small. Then they say that its rotation is laying flat on its side.( i learned that last yr)...
Now that have to change everything on the dictionaries and stuff.

Answer 8

This is one of those questions you can type into google. I'm not jumping on you, I'm just letting you know that you can research things yourself before coming here.