why pluto is not consider as a planet?

Answer 1

The International Astronomical Union decided that Pluto was no longer a planet. Instead, they decided to classify it as a "dwarf planet".

See the details below.

RESOLUTION 5A
The IAU therefore resolves that "planets" and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:

(1) A "planet" [footnote 1] 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 neighbourhood 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 [footnote 2] , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects [footnote 3] except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".


Footnote 1: The eight "planets" are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Footnote 2: An IAU process will be established to assign borderline objects into either dwarf planet and other categories.

Footnote 3: These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.

RESOLUTION 6A
The IAU further resolves:

Pluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.

Answer 2

Pluto's orbit is very unusual in comparison to the planets of the solar system. The planets orbit the Sun close to an imaginary flat plane called the plane of the ecliptic, and have nearly circular orbits. In contrast, Pluto's orbit is highly inclined above the ecliptic (up to 17° above it) and very eccentric (non-circular). Owing to the orbit’s inclination, Pluto's perihelion is well above (~8.0 AU) the ecliptic. The high eccentricity means that part of Pluto's orbit is closer to the Sun than Neptune's.

Continuing advances in telescope technology allowed for further discoveries of Trans-Neptunian objects in the 21st century, some of comparable size to that of Pluto. In 2002, 50000 Quaoar was discovered, with a 1,280 kilometers diameter, making it a bit more than half the size of Pluto. In 2004, the discoverers of 90377 Sedna placed an upper limit of 1,800 kilometers on its diameter, near Pluto's diameter of 2,320 kilometers.

On July 29, 2005, a Trans-Neptunian object called Eris was announced, which on the basis of its magnitude and simple albedo considerations is assumed to be slightly larger than Pluto. This was the largest object discovered in the solar system since Neptune in 1846. Discoverers and media initially called it the "tenth planet", although there was no official consensus at the time on whether to call it a planet. Others in the astronomical community considered the discovery to be the strongest argument for reclassifying Pluto as a minor planet.

Answer 3

bec when it has nutcases like u and me its " pluto status as a planet becomes null and void"

Answer 4

Otis F has the right answer. Btw, how were the answers for you the other two times you asked this?

http://answers.yahoo.com/question/index;_ylt=AgGyfj0vT0Kv97L4ftil.qzzy6IX?qid=20061027082004AAXjTkV

http://answers.yahoo.com/question/index;_ylt=At5vlUNrA6ffVk4G3qywe3Dzy6IX?qid=20061027082101AAJk2p8

Answer 5

It is close to Jupitor and is considered one of their moons

Answer 6

I'm tired of answering this question.....

Answer 7

Because it is no longer there.

Answer 8

it doesnt have its own orbit..or something