The
new definition is all screwed up.
Quote:
|
Originally Posted by IAU
RESOLUTION 5A
The IAU therefore resolves that "planets" and other bodies in our Solar System 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) shape{2} , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects{3} except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".
-----------------------
{1}The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
{2}An IAU process will be established to assign borderline objects into either dwarf planet and other categories.
{3}These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.
|
Number (1)(c) is a really sloppy rule. It's what they used to eliminate Pluto, because it crosses orbits with Neptune but hasn't cleared Neptune. can you look at it from Neptune's perspective too? Doesn't Neptune cross paths with Pluto, and yet didn't assimilate or clear Pluto? That means Neptune isn't a planet. Doesn't Earth have a moon? That mean's we don't live on a planet. Don't the outer planets have rings of debris floating around them? That means they aren't planets. Even if you argue that those things don't count because they are in orbit around the planets, what about asteroids? Ever seen a shooting star? That's an object the Earth hadn't cleared from its path. There are thousands of Near Earth Objects. According to (1)(c), we shouldn't be a planet either.
The astronomers needed to have at least on lawyer there at their meeting to point out all the loopholes in their new rule. I'm a little embarrassed for them. It's sloppy. I bet we could have come up with better definitions here on the Cellar.