Quote:
Originally Posted by mswhin63
I agree it for the de-classifacation. I think it was only considered a planet because first observation saw it as almost the size of the earth.
I also heard that ever so possible it could be considered a Comet. Mainly because it has a tail.
I think we will have to wait till the probe gets there to confirm a lot of things
|
Pluto has enough mass to form a globe and the definition of a planet is below and comets dont form a globe so how can it be classed as a comet.
Quote:
|
A celestial body moving in an elliptical orbit around a star.Wikipedia dictonary
|
Even this definition still calls it a Dwarf planet so still refered to as a planet even if it is a small one
Quote:
IAU definition of planet
From Wikipedia, the free encyclopedia
This article is about the formal definition established in 2006. For prior usage, see Definition of planet.
The definition of planet set in 2006 by the International Astronomical Union (IAU) states that in the Solar System a planet is a celestial body that:
- is in orbit around the Sun,
- has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and
- has "cleared the neighbourhood" around its orbit.
A non-satellite body fulfilling only the first two of these criteria is classified as a "dwarf planet". According to the IAU, "planets and dwarf planets are two distinct classes of objects". A non-satellite body fulfilling only the first criterion is termed a "small solar system body" (SSSB). Initial drafts planned to include dwarf planets as a subcategory of planets, but because this could potentially have led to the addition of several dozens of planets into the Solar System, this draft was eventually dropped. In 2006, it would only have led to the addition of three (Ceres, Eris and Makemake) and the reclassification of one (Pluto). The definition was a controversial one and has drawn both support and criticism from different astronomers, but has remained in use.
According to the definition, there are currently eight planets and five dwarf planets known in the Solar System. The definition distinguishes planets from smaller bodies and is not useful outside the Solar System, where smaller bodies cannot be found yet. Extrasolar planets, or exoplanets, are covered separately under a complementary 2003 draft guideline for the definition of planets, which distinguishes them from dwarf stars, which are larger.
|
Going by the above definition there are actually 13 planets because it defines 5 dwarf planets