What's the info on Pluto no longer a planet?

Question

I have heard bits and pieces but I cannot find any information on when and how they decided this and what happenes to the (if it can be called) the planet.

help?

Answer 1

I believe Wikipedia had good coverage of the event at the time - probably reading the article there would be the easiest source of details.

Briefly, though, it seems the story is something like this. When Pluto was originally discovered, it was assumed to be a planet comparable in size and structure to Mercury. However, the discovery of Charon allowed astronomers to calculate its mass, and they found Pluto was even smaller than the Moon. This fact first opened the dispute among astronomers.

The proximate cause of the official astronomers' reconsideration of the definition of 'planet', however, was the discovery of Eris, called 'Xena' at the time, a trans-Neptunian object actually larger than Pluto. At this point, it would be absurd to declare that Pluto was a planet and Eris was not, and so the International Astronomical Union (IAU) began deliberating the definition of planet, originally tending towards including Eris as a new planet - the definition would be based on planets both orbiting the sun rather than another planet and being heavy enough to be spherical.

However, they realized their proposal would probably result in dozens if not hundreds of bodies being declared 'planets'. They avoided this inconvenient consequence by instituting a new requirement - that planets have 'cleared the neighborhood' around their orbit. Under this definition, then, there were unambiguously eight planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune - and Pluto demoted to a new category for objects large enough to be planets, but without cleared orbits: "dwarf planet".

Answer 2

Pluto is a planet, it is a dwarf planet.

Pluto is an odd ice ball that orbits somewhere beyond the orbit of Uranus in the middle of the Kipper Belt. The Kuiper Belt is a ring of left over material around our sun similar to the Asteroid Belt between Mars and Jupiter. The Kuiper Belt seems to be the home of the comets and the Near Earth Orbiting (NEO) Asteroids like the one that killed the dinosaurs.

The problem with Pluto is that other objects were found in the Kuiper Belt of the same size and one even larger. So we either got a whole new group of planets or Pluto had to be demoted. Then what about the asteroid Ceres; we have known about it for a long time, it is smaller than Pluto, but not that much smaller and if we defined Pluto as a planet where do we stop would Ceres the Asteroid become a planet?

The definition for a planet was decided on by the International Committee of Astronomers. It was a controversial decision, but as the guy who started the debate said; "Pluto had it coming."

Pluto doesn't clear a path through the Kuiper Belt like a planet would and that is a key part of the definition. Its orbit is the one that is the most off the standard elliptical solar plane and its moon Charon is almost the same size. In fact I have seen animations where the two are orbiting around a common center. In the case of a planet its moon would orbit it.

For more on this you should check out this article: http://en.wikipedia.org/wiki/Pluto

"Pluto and its largest satellite, Charon, are often considered a binary system because the barycentre of their orbits does not lie within either body."

"In the late 20th and early 21st centuries, however, many objects similar to Pluto were discovered in the outer solar system, most notably the scattered disc object Eris, which is 27% more massive than Pluto. On August 24, 2006 the IAU defined the term "planet" for the first time. This definition excluded Pluto from planethood, and reclassified it under the new category of dwarf planet along with Eris and Ceres. After the reclassification, Pluto was added to the list of minor planets and given the number 134340."

"Pluto's orbit is markedly different to those of the planets. The planets all orbit the Sun close to a flat reference plane called the ecliptic, and have nearly circular orbits. In contrast, Pluto's orbit is highly inclined relative to the ecliptic (over 17°) and highly eccentric (elliptical). This high eccentricity leads to a small region of Pluto's orbit lying closer to the Sun than Neptune's."

These are just a few reasons why Pluto isn't considered a major planet any more, just a Dwarf Planet and another object in a field of thousands of objects.

Answer 3

"NPR reports that Pluto has dodged a bullet. An international panel has unanimously recommended that Pluto retain its title as a planet, and it may be joined by other undersized objects that revolve around the sun. Some astronomers had lobbied for reclassifying Pluto as its so tiny. And at least one major museum has excluded Pluto from its planetary display. But sources tell NPR that under the proposal, to be presented at a big meeting of astronomers in Prague next week for a vote, Pluto would become part of a new class of small planets and several more objects could be granted membership."

Answer 4

Last August a group of Astronomer's came and voted on the issue. Most voted to not call it a planet anymore. Nothing happens to the planet, now it's just called a dwarf planet, but it's still out there.

Answer 5

The definition of "what is a planet " was changed. The new definition didn't include bodies with Pluto's characteristics. Simple as that.

Answer 6

they voted that it wasnt a planet during may then they changed back to a planet because their space probe havent reached that far so they are going to wait and see. they say that it is just one of the asteroids in the kuiper belt but they said its strange how it stays on a certain path and orbit so for right now it is a planet

Answer 7

to small. I know it is nuts. Just because some scientists vote on it it is no planet anymore. Since when is science a democratic process?

Answer 8

There is an article on Astronomy.com that talks about this. Also on Discover.com.

Answer 9

So now what is going to happen to the saying.....It was

My very educated mother just served us nine pizza pies......

what is it going to be now?