Why isn't Pluto a planet anymore?

Question

Why isn't Pluto being noticed for not being a planet anymore.

Answer 1

Science Sux

Answer 2

This question has been asked many times before.. read. But if you must know, they changed the rules for planets since there are 3 new ones that fall under the same chriteria as pluto. Since pluto does not have an independent orbit, and it crosses neptunes for a point of time where neptune is further away from the sun than pluto is, that now makes it so it is not a planet anymore.

Answer 3

It no longer qualifies as a fully fledged planet after the update to the specification.

International Astronomical Union (IAU), the official scientific body for astronomical nomenclature, defines "planet" as a celestial body that:[1][2]

(a) is in orbit around a star or stellar remnants;
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape;
(c) is not massive enough to initiate thermonuclear fusion of deuterium in its core; and,
(d) has cleared the neighbourhood around its orbit.

Under this definition, the solar system is considered to have eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Three bodies which fulfil the first three conditions but not the fourth are now classified as dwarf planets: Ceres, Pluto and 2003 UB313.

Answer 4

After a tumultuous week of clashing over the essence of the cosmos, the International Astronomical Union stripped Pluto of the planetary status it has held since its discovery in 1930. The new definition of what is -- and isn't -- a planet fills a centuries-old black hole for scientists who have labored since Copernicus without one.

Although astronomers applauded after the vote, Jocelyn Bell Burnell -- a specialist in neutron stars from Northern Ireland who oversaw the proceedings -- urged those who might be "quite disappointed" to look on the bright side.

"It could be argued that we are creating an umbrella called 'planet' under which the dwarf planets exist," she said, drawing laughter by waving a stuffed Pluto of Walt Disney fame beneath a real umbrella.

The decision by the prestigious international group spells out the basic tests that celestial objects will have to meet before they can be considered for admission to the elite cosmic club.

For now, membership will be restricted to the eight "classical" planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Much-maligned Pluto doesn't make the grade under the new rules for a planet: "a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit."

Instead, it will be reclassified in a new category of "dwarf planets," similar to what long have been termed "minor planets." The definition also lays out a third class of lesser objects that orbit the sun -- "small solar system bodies," a term that will apply to numerous asteroids, comets and other natural satellites.

It was unclear how Pluto's demotion might affect the mission of NASA's New Horizons spacecraft, which earlier this year began a 9 1/2-year journey to the oddball object to unearth more of its secrets.

The decision at a conference of 2,500 astronomers from 75 countries was a dramatic shift from just a week ago, when the group's leaders floated a proposal that would have reaffirmed Pluto's planetary status and made planets of its largest moon and two other objects. (Watch why some think planet size doesn't matter -- 3:39)

That plan proved highly unpopular, splitting astronomers into factions and triggering days of sometimes combative debate that led to Pluto's undoing.

Now, two of the objects that at one point were cruising toward possible full-fledged planethood will join Pluto as dwarfs: the asteroid Ceres, which was a planet in the 1800s before it got demoted, and 2003 UB313, an icy object slightly larger than Pluto whose discoverer, Michael Brown of the California Institute of Technology, has nicknamed "Xena."

Charon, the largest of Pluto's three moons, is no longer under consideration for any special designation.

Brown was pleased by the decision. He had argued that Pluto and similar bodies didn't deserve planet status, saying that would "take the magic out of the solar system."

"UB313 is the largest dwarf planet. That's kind of cool," he said

Answer 5

The new definition of planet requires a planet to be "a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a nearly round shape, and has cleared the neighbourhood around its orbit." That eliminates about 23,000 possible candidates that orbit out near Pluto, as well as Pluto itself.

Pluto was part of something large that was broken up by passing too near to a large planet. We have seen how comets are shattered by passing close to Jupiter. It does not make sense to call all the little pieces 'planets.'

;-D I like the name 'Plutinos' for all the little pieces!

Answer 6

I think their saying because it doesn't have a gravitational pull but if it doesn't then why does it have a moon called charon.
You should probably mention that if someone says your stupid for saying pluto is a planet and take this to thought...if it isn't a planet then why has been around so long in a rotational orbit.

Answer 7

Because of Democarcy.

They let Scientists take a vote and they elected BUSH President!

It has to do with orbit (it's cockeeye, off axis and sometimes goes inside Neptune), size (it's small) and density (it's light as a feather).

Basically, OUR MOON is larger and denser and we don't call it a planet.

The BIG question remains

Why are PHOBOS and DEMOS still considered moons!

One is 5 miles and the other is 10 miles.

They aren't round.

We KNOW they look more like asteroids.

So what. They ORBIT MARS, big deal.

Does that MAKE them a MOON.

In light of Pluto, that needs to be addressed next!

Answer 8

The real reason is because it's mainly a large mass of ice surrounding a small rocky core. It's still a planet, sort of, in that it is now designated as a dwarf planet. It's really just a piece of space junk with enough gravity to form itself into a ball, or round shape. It's interesting but not all that significant.

Answer 9

What do you mean "anymore"? Pluto never was a planet. End of discussion.

Answer 10

I think it comes down to Pluto's rotation is oblong into Neptunes pull and therefore it doesn't rotate around the sun like was previously thought.