why was pluto rename as a dwarf planet?

Question

what are the qualifications of being a planet?
i think that it is stupid that it is not a planet anymore, i am going to still refer to pluto as the 9th planet from the sun.

Answer 1

the international astronomical union defined three terms "planet", "dwarf planet", and "small solar system body". this does not change anything about the solar system or pluto. this doesn't change pluto's name. it just corrects the mistake of classifying pluto as a planet initially.

i have known since i was about twelve that pluto does not have the physical and orbital characteristics that fit the pattern set by the major bodies in the solar system, and later, after the discovery of hundreds of other similar bodies with similar orbits, i knew this was inevitable. this was the right thing to do, believe me.

because pluto orbits the sun, is round, orbits the sun with a bunch of other similar bodies with similar orbits, and is not a satellite it is a dwarf planet.

(1) A 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, and (c) has cleared the neighborhood 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, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.

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


look here:
http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html

Answer 2

The 2nd answer is close. As of the 8/24 summit, there are now 4 criteria (not 3). Pluto passed 3 of the 4 criteria, but did not qualify due to the 4th - "clear the neighborhood around its orbit"...which means that all the debris in it's orbit has either become part of it or orbits around it like a moon.

Pluto, along w/ 3 are objects are now considered "dwarf planets."

Below is an excerpt from the article in Wikipedia. I'll also attach the link, so you can read more info about it.

The 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.

Answer 3

most of all, it does not have the same orbital plane as the rest of the planets which suggest that it did not form at the same time as the rest of the planets. This alone is the reason why its no longer a planet. Also, that irregular plane also indicate it was probably a trapped object by the sun gravitational force like a meteor or asteroid. The diameter of Pluto is less than the distance across the USA. Just because that it has a moon doesn't mean its a planet either... many asteroids have moons.

Answer 4

Scientest came to the conclusion that "planet" should be defined by three critereas:
1. It is massive enough to render itself quasi-sphereical in shape.
2. It orbit's the sun directly.
3. It's orbital plane is not shared by other objects (i.e the planets gravity has illuminated them by turning them into moon, or having them crash into it).

Pluto answers the first two criterea, but not the third. Ergo, it isn't a planet.

Answer 5

There were like three main reasons and the only one I can remember off the top of my head was that it was in Neptune's orbit. Another reason may be because of its size although I am not sure on that one.

Answer 6

Because we're egotists and are always picking on the little guy. No one will speak up for the Plutonians... you're the first.

Answer 7

There is a good article about this..see my source below. Also some resent pics..

Answer 8

BAD.......BAD Pluto.......because of your non-conformist ways, we the scientific community sentence you to declassification and loss of your planetary status until we say otherwise or public opinion makes us change our minds(?) again!!

Answer 9

Because it's stuck up your Uranus.

Answer 10

because it is