An explanation on what makes a planet a planet - and errr..., Pluto not.
http://http://www.universetoday.com/13573/why-pluto-is-no-longer-a-planet/
If I'm to share my opinion,
I would have to say, no, I don't think Pluto should be given planetary status.
Other reasons aside, memorising the 70,000 other "planets" (icy objects that have shown to be similar to Pluto out in the Kuiper belt) could be a toughy.
Quote:
Is Pluto a planet? Does it qualify? For an object to be a planet, it needs to meet these three requirements defined by the IAU:
- It needs to be in orbit around the Sun – Yes, so maybe Pluto is a planet.
- It needs to have enough gravity to pull itself into a spherical shape – Pluto…check
- It needs to have “cleared the neighborhood” of its orbit – Uh oh. Here’s the rule breaker. According to this, Pluto is not a planet.
What does “cleared its neighborhood” mean? As planets form, they become the dominant gravitational body in their orbit in the Solar System. As they interact with other, smaller objects, they either consume them, or sling them away with their gravity. Pluto is only 0.07 times the mass of the other objects in its orbit. The Earth, in comparison, has 1.7 million times the mass of the other objects in its orbit.
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