Is Pluto a planet after all?

[Trekker4747]

Oh for crying out loud... is it almost spherical and in orbit around the sun, as apposed to another body? That definition can exclude both asteroids and satellites, ditching all this hair-splitting.

There are three basic criteria for planethood, and you've listed two of them. Pluto, Eris, Sedna, Quaoar, and thousands of roundish Kuiper Belt objects and asteroids would be planets by your two terms.

Fortunately, Pluto and its sisters fail to live up to the third category-- they are not the dominant gravitational body in their neighborhood. Adding in that third criteria cuts out all the Kuiper crap and leaves us with a nice manageable quantity of planets.

Is this the "hasn't cleared their orbit" thing. Because, Earth hasn't cleared its orbit either.

I don't see why they didn't make Pluto the "smallest" size for a planet, sure that'd mean other KPOs have to be "planets" as well but who says solar-systems have to have a certain number of planets?

But I think Pluto being used for a new "class" of planets is neat for Trans-neptunian objects. So we have "rocky/terrestrial planets". "gas giant planets" and then we have the "KBOs" or "Plutonian" planets, or whatever the Trans-Neptunian objects are.

 

[Lindley]

Does anyone know where I can find a map of the solar system that has all the planet bodies in their respective orbits. I looked on wiki, but I can't seem to find one with all the dwarf and main planets with their orbits shown.

There's a lot of information here:
http://www48.wolframalpha.com/input/?i=solar+system

In particular, if you go to the Saturn link, there's a to-scale schematic of the solar system at the bottom.

 

[CaptainDonovin]

Oh for crying out loud... is it almost spherical and in orbit around the sun, as apposed to another body? That definition can exclude both asteroids and satellites, ditching all this hair-splitting.

There are three basic criteria for planethood, and you've listed two of them. Pluto, Eris, Sedna, Quaoar, and thousands of roundish Kuiper Belt objects and asteroids would be planets by your two terms.

Fortunately, Pluto and its sisters fail to live up to the third category-- they are not the dominant gravitational body in their neighborhood. Adding in that third criteria cuts out all the Kuiper crap and leaves us with a nice manageable quantity of planets.

Is this the "hasn't cleared their orbit" thing. Because, Earth hasn't cleared its orbit either.

I don't see why they didn't make Pluto the "smallest" size for a planet, sure that'd mean other KPOs have to be "planets" as well but who says solar-systems have to have a certain number of planets?

But I think Pluto being used for a new "class" of planets is neat for Trans-neptunian objects. So we have "rocky/terrestrial planets". "gas giant planets" and then we have the "KBOs" or "Plutonian" planets, or whatever the Trans-Neptunian objects are.

We also have extrasolar planets (or exoplanets). The arguement I've heard that got me was if there was a Mars or Earth size KBO it would be considered a dwarf planet a) because it hadn't cleared the neighborhood & b0 because if the object was closer to the sun it would have a tail or something. Can't remember the person who came up with the latter one (read something close to it on space.com or something) Wouldn't be suprised if during the next IAU convention it's changed.

 

[CaptainDonovin]

Does anyone know where I can find a map of the solar system that has all the planet bodies in their respective orbits. I looked on wiki, but I can't seem to find one with all the dwarf and main planets with their orbits shown.

The closest I could find was this one on wiki actually in the article on the solar system there is a pic that used to be @ the NASA site that has all of them. It does have the dwarf planets in their orbits, but below the 'offical' planets.

 

[iguana_tonante]

http://www.newscientist.com/article...after-all.html?DCMP=OTC-rss&nsref=online-news

I never quit calling it a planet.

Oh jeez...! The governor of Illinois? He must be onto something.

Call Nature and Science, pronto!

 

[Ronald Held]

FWIW, the IAU defines those conventions. They can change them over time.