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Pluto. Planet, not a planet

not a planet?

Posted by jellopeacemaker14 on 2006-10-20 00:50:53

how can they decide if its a planet it's been a planet for years. I think they just want to confuse people.

Posted by Colin MacD on 2006-10-27 06:16:32

Semantics. It is what it is. And there are many others just like it.

Posted by gerty on 2007-05-06 05:48:40

thought to be an asteroid?

it is a celestial body within our solar system, albeit it's pretty far. sometimes within the orbit of neptune. it does orbit about our sun, and does have sufficient mass that is round in shape. it has a moon called charon which is nearly identical in size. i say planet.

Posted by RWM on 2007-11-11 03:21:38

The decision was based on a number of things:

1) There is an asteroid belt (known as the Kuiper Belt) outside the orbit of Neptune. This was not known when Pluto was originally classified as a planet.

2) Pluto is similar in size to the larger asteroids in the Kuiper Belt, and its eccentric orbit, which is somewhat inclined relative to the plane of the planets, resembles that of an asteroid like Eros rather than that of a planet.

3) Pluto is nowhere near as far from the Sun as would be expected if it were a tenth planet.

Posted by Philogynist on 2011-03-25 05:29:36

There were originally 12 planets, which fissioned off from the Sun in pairs. 6 blew themselves to bits, with Mars, a moon of 1 of them surviving, and Mercury, a moon of Venus, leaving Venus' orbit, making the current 8 planets. The asteroids and KBOs are just debris, with some possibly former moons. And it doesn't make sense that Pluto could be a planet while the other KBOs aren't. See astro-taxonomy.info (or .net) for more information.