What exactly is the difference in definition between a "planet" and a "dwarf planet"?

Question

Is it just a size thing? Does it also have to do with an irregular orbit? What does the new definition exactly entail, not just with Pluto but with any other new bodies discovered out there in the solar system?

Answer 1

the international astronomical union has defined three new terms to categorize the bodies in the solar system. the classical planet is one that is in an isolated orbit. the dwarf planet is one that orbits along with a bunch of other bodies. this makes ceres, pluto, charon, and 2003 UB313 dwarf planets. pluto and charon are considered a binary system. this does not change anything about the solar system, but it does change the language and correct the mistake of classifying pluto initially.

(1) A classical 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".

http://www.iau2006.org/mirror/www.iau.org/iau0602/index.html

Answer 2

A dwarf planet is a category of celestial bodies in the solar system defined in a resolution passed by the International Astronomical Union (IAU) on August 24, 2006. The definition, as far as the IAU is concerned, currently only applies to the Sun's solar system.[1] It applies only to the English language, and the use of the terms may differ in other languages. In the usage approved by the IAU, the category "dwarf planet" is distinct from that of "planet".

The resolution describes a dwarf planet as an object that:

-is in orbit around the Sun,
-has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape,
-has not "cleared the neighbourhood" around its orbit,
-is not a satellite of a planet, or other nonstellar body.

It differs from the definition of the planet in that the dwarf planet has not cleared its orbital neighbourhood. This definition reclassified Pluto from a planet to a dwarf planet because it has not cleared the neighbourhood of its orbit (the Kuiper Belt), meaning part of its orbit falls into that region which lies so far out of the realm of the Solar System that although its still considered a part of the Solar System, nothing beyond it is considered a forminable planet.

Dwarf planets are traditionally known as minor planets along with smaller objects.

Answer 3

Dwarf planets orbit a star that looks remarkably like Snow White.

Answer 4

the new definition is a joke
with the 'clear the neighborhood'
i just read on nytimes.com that Earth and Jupiter hasnt clear its neighborhood either, it has asteroids in its neighborhood!!!
and whether a planet cleared the neighborhood is only a chance thing, if a planet form in a place FILLED with space dust and rocks, how can they clear the neighborhood without becoming a sun themself (size wise)
maybe pluto was unlucky and was formed in a place of mess....

Answer 5

The controversial decision was made yesterday by the INTERNATIONAL ASTRONOMICAL UNION (IUA)and is based on the fact that Plutoâs orbital path overlaps with other objects such as asteroids and the planet Neptune

Answer 6

The dwarf planet has a normal size head with very small arms, legs, and body.

Answer 7

I was going to ask that question!

RULE OF THUMB - Scientists make these rules so they can get schools to pay more money to get new textbook.

That's all.