why is pluto did not now considered as a planet?

Answer 1

Pluto

Solar system body, regarded as the ninth planet from the Sun until struck from the list of planets and reclassified as a dwarf planet in August 2006. It was discovered in 1930 by Clyde W. Tombaugh (1906–97) and named after the Greek god of the underworld. Its average distance from the Sun is about 3.7 billion mi (5.9 billion km) — it is located within the Kuiper belt — but its eccentric orbit brings it closer to the Sun than Neptune for 22 years during its 248-year orbit. Its axis is tipped 120°, so it rotates nearly on its side and “backward” (see retrograde motion) once every 6.39 days, locked synchronously with the orbit of its largest moon, Charon, discovered in 1978. Two additional, small moons were discovered in 2005. Pluto has a diameter of about 1,455 mi (2,340 km), less than 1% of Earth's mass, and only about 6% of Earth's surface gravity. Its estimated average surface temperature is near −390 °F (−235 °C). Its thin atmosphere contains nitrogen, methane, and perhaps other heavier gases. Pluto is thought to be made of frozen gases with a significant fraction of rocky material. Its size, composition, and orbital location in the Kuiper belt sparked a long debate over its classification as a major planet, which culminated in a decision by the International Astronomical Union to drop it from the planetary ranks.-

Answer 2

Actually, pluto is still a planet but not a normally planet it is called the dwarf planet. Pluto is the most distant among all known planets. It is a small plabet w/ a size similar to the mercury.

Pluto's orbit is most unusual. Pluto's orbit is very much elliptical. Due to irregular orbit of pluto, every 248 years it moves inside neptune's orbit for about a 20-year period. At that time, Pluto is now closer to the sun than neptune. pluto crossed neputne's orbit in january 1979 and remained within until mid-march 1999.

Plutos orbit is unusually inclined 16 degrees to the eliptic. its degreee of inclination is not completely predictable. In some addition, Pluto resembles a jovian satellites. Pluto has one satellite, charon, which is almost as big as itself.

Some astronomers think that pluto and its satellite may have been captured from a Jovian planet by a still another bigger planet that lies beyond the orbit of pluto.........

Answer 3

Pluto now is not considered a planet because it is too small to be a planet it is even smaller than our moon, and also all other planets are made of rocks and Pluto is made of ice. Pluto is now known as "Dwarf planet".

Answer 4

Pluto isn't a planet, that is a dwarf planet Pluto has that's own little type of dwarf planets noted as Plutoids. different Plutoids are Sedna, Makemake, Haumea, Eris. those are all dwarf planet previous The orbit of Neptune.

Answer 5

As a recent astronomers agreement (Praga meeting, august 2006) to precisely define the terms of solar system bodies, now that a lot of are known and will be known thank to probes, telescopes, etc. Here down are the specs:

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"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) shape2,
(c) has not cleared the neighbourhood around its orbit, and
(d) is not a satellite.

(3) All other objects3, except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

1The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
2An IAU process will be established to assign borderline objects into either dwarf planet and other categories.
3These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.

RESOLUTION 5B
Insert the word "classical" before the word "planet" in Resolution 5A, Section (1), and footnote 1. Thus reading:

(1) A classical "planet"1 is a celestial body . . .

and
1The eight classical planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Source(s):

http://www.iau.org/iau0602.423.0.html...

Answer 6

To be considered a planet, a body must have cleared its orbit of debris. Take a look at the link below, which can explain it in more detail.

Answer 7

coz now pluto doesn't follow the correct defination of planets.

Answer 8

cuz of its small size