Pluto

1. With other "bodies" discovered orbiting other stars that aren't in the "plane" that are called Planets, your strike 1 is nullified.

2. Same as above.. Your strike 2 is nullified Plus if they're orbiting at the same relative speed, they'll never be close enough to "suck" one another.. ;-)

3. Since when is the distance from the star the determining factor of the classification of wether it is or not a planet? Your strike 3 is nullified.

Now that we're on level ground ;-).. I say Pluto is a planet since..
1. It's a spherical object. Clearly not just a fragment of rock. +1
2. It has it's own moons! 3 so far.. +2 But we obviously can't say a body *has* to have moons or Venus and Mercury would be left out..
3. It orbits a central star and includes both of the above criteria. +3
4. The orbital plane is irrelevant. See the first #1. And just because there was some gravitational "tug" that moves a body from the established plane doesn't nullify it's planetary classification. You move from LA to outback Adirondak mountains, you're still a city slicker ;-)
5. Since it could be possible that even the Earth *may* itself be a "captured" object, or even a "lost satellite" of a larger "planet", would you say Earth isn't a "planet"? +4
6. The Greek word planes, in which planet is a varient of, means "wanderer".. And if Pluto isn't wandering out there on it's own, no matter what the origin, then we could conclude that our sun has no planets at all since we can't positively proove that any of the planets were born from the sun. Although it is very likely most are sons of the sun

We have what is now called the inner solar system, the asteroid belt, and then the outer solar system. Plus of course the Kuiper belt, the Oort cloud, and maybe even more. So if a larger spherical body, say the size of Mars was discovered, would it not be fair to conclude it would be a planet? Where is the boundary in distance from the star where spherical objects are no longer planets?

Now to get a little crazy.. If Jupiter is redifined and labeled a star, would Io be a planet? Would our Sun then become a binary star system?

To me, Pluto is a Planet.. And so is Xena and any other spherical bodies yet to be discovered.

Terry Friedrichsen said:

Pluto doesn't orbit particularly closely to the plane of the other planets - that alone should make one suspicious that it isn't. Strike 1.

Then there's it's very high orbital eccentricity - it even *crosses* the orbit of Neptune. If it was in an orbit that was rather more in the plane of the other planets, Neptune might have sucked it up long ago, barring their mutual 3:2 orbital-period resonance. Strike 2.

Finally, there's the fact that its origin is clearly as a Kuiper Belt Object that strayed too far inward toward the Sun and begin interacting gravitationally with Neptune - so it's a KBO. Strike 3 and yer out.

Terry (astrotrf)

1. With other "bodies" discovered orbiting other stars that aren't in the "plane" that are called Planets, your strike 1 is nullified.

2. Same as above.. Your strike 2 is nullified Plus if they're orbiting at the same relative speed, they'll never be close enough to "suck" one another.. ;-)

3. Since when is the distance from the star the determining factor of the classification of wether it is or not a planet? Your strike 3 is nullified.

Now that we're on level ground ;-).. I say Pluto is a planet since..
1. It's a spherical object. Clearly not just a fragment of rock. +1
2. It has it's own moons! 3 so far.. +2 But we obviously can't say a body *has* to have moons or Venus and Mercury would be left out..
3. It orbits a central star and includes both of the above criteria. +3
4. The orbital plane is irrelevant. See the first #1. And just because there was some gravitational "tug" that moves a body from the established plane doesn't nullify it's planetary classification. You move from LA to outback Adirondak mountains, you're still a city slicker ;-)
5. Since it could be possible that even the Earth *may* itself be a "captured" object, or even a "lost satellite" of a larger "planet", would you say Earth isn't a "planet"? +4
6. The Greek word planes, in which planet is a varient of, means "wanderer".. And if Pluto isn't wandering out there on it's own, no matter what the origin, then we could conclude that our sun has no planets at all since we can't positively proove that any of the planets were born from the sun. Although it is very likely most are sons of the sun

We have what is now called the inner solar system, the asteroid belt, and then the outer solar system. Plus of course the Kuiper belt, the Oort cloud, and maybe even more. So if a larger spherical body, say the size of Mars was discovered, would it not be fair to conclude it would be a planet? Where is the boundary in distance from the star where spherical objects are no longer planets?

Now to get a little crazy.. If Jupiter is redifined and labeled a star, would Io be a planet? Would our Sun then become a binary star system?

To me, Pluto is a Planet.. And so is Xena and any other spherical bodies yet to be discovered.

Terry Friedrichsen said:

Pluto doesn't orbit particularly closely to the plane of the other planets - that alone should make one suspicious that it isn't. Strike 1.

Then there's it's very high orbital eccentricity - it even *crosses* the orbit of Neptune. If it was in an orbit that was rather more in the plane of the other planets, Neptune might have sucked it up long ago, barring their mutual 3:2 orbital-period resonance. Strike 2.

Finally, there's the fact that its origin is clearly as a Kuiper Belt Object that strayed too far inward toward the Sun and begin interacting gravitationally with Neptune - so it's a KBO. Strike 3 and yer out.

Terry (astrotrf)

Aw Darrell, don't take it so personal. There's no room for sentimentality here. Science marches on! 8)

Well, I just looked up planets in Cartes du Ciel and Planetarium for the Palm and Pluto is included so I guess that's good enough for me.

Jon

The results of this poll so far are very surprising to me.
I was wondering how far ahead the "isn'ts" were when I voted. I was shocked to see that the "is's" are ahead!

I never knew so many of my brethren amateurs are so sentimental, rather that scientific minded.

Only Walt Disney Knows for sure what pluto is and He's not Talking.. 8)

I can understand that point of view as well.

The biggest problem I have with this whole discussion is that changing how we classify something is not advancing our knowledge or understanding of anything. It is merely changing the name of something that 99.997% of us will never even be able to see directly. In short, my question is: who cares what we call it? There are many thing in (and out of) this world where the cultural definition and the scientific definition are very different. Also there are things which may fall into two categories; where do large planet-like objects end and brown drarfs begin? And are brown dwarfs really stars? I think we should stop making a mountain out of mole a hill. A planet by any other name is still an orbiting rock (in this case).

Clyde said so. And I value his opinion and contribution.

I know how passionate people are about this whole Pluto thing, but I would like to through in my 2 centavos worth. As one who has had a near lifelong interest in astronomy I feel compelled to attempt to clarify the actions of the IAU in re-categorizing Pluto from a planet to a minor planet. I think most of the controversy can be eliminated by a small change in perspective of the situation. I present my own perspective.

Pluto as we can all agree has never been and never will be a typical "planet" as compared with the other eight. This can be attested to by its very small size, its composition, its highly eccentric orbit and its vastly exaggerated orbital inclination. It has always been and always will be rouge. Having said this, I want to make it clear that any of these aforementioned attributes in no way trivialize Pluto as a member of our solar system.

Most of the controversy has been in the semantics. Pluto has not physically changed through all of this. It is still the same size, still shines, albeit dimly, in the night sky, still has 3 moons. The change in classification has in no way changed the object itself. It has merely clarified some confusion and made us think of exactly how we want to classify the objects that inhabit our solar system.

As we all know, orbiting closest to the sun we have the 4 inner terrestrial planets (Mercury, Venus, Earth, and Mars). Following this is a boundary of objects we choose to call asteroids, made up of fragments of rocky and metallic debris which never coalesced into a single object, a failed planet, if you will. Next we have the 2 majestic gas giants (Jupiter and Saturn). Finally we have the ice giants (Uranus and Neptune). Now comes the little guy that has been causing all the trouble. He doesn't fit into any of the classic categories and doesn't even seem to belong where he is. NOW! Along come several discoveries of objects far beyond Pluto. One is even said to be larger than Pluto. The main feature, however, is that these new objects are identical, so far, in many ways to our little oddity we call Pluto. Now what?

As happens throughout history, when new discoveries are made it forces us to look at things in a new light. Remember when we thought the earth was flat? Remember when we thought the earth was the center of the solar system? Following these discoveries, our entire view of the solar system was turned upside-down. There were groups who maintained these nonsensical views long after they were proven erroneous. Even today I hear the argument that traditionally Pluto has been considered a planet and thus should continue to be considered a planet. If we use that argument, then by tradition we live on a flat planet in the center of the solar system and that is the way it should be. Period!

I know many have thought that Pluto, and its good name, was trashed in this process, but I think nothing could be further from the truth. Pluto now holds the GREAT distinction of being the prototypical object of all the distant objects yet discovered called Kuiper Belt Objects. Yes, Pluto was #1, numero uno. And instead of looking at it that Clyde Taumbaugh was a looser that discovered a looser planet...I see it that through his hard work and dedication he was the discoverer of the VERY FIRST Kuiper Belt Object. He did this by using primitive equipment and acute, refined powers of observation. The next one discovered took the use of unbelievably complex technology and 70 more years of time. This discovery was no trivial object and no trivial feat by Clyde Taumbaugh!!!!!

I applaud the IAU in their thankless job of classifying the countless objects out there trying to make some sense and order of our vast universe. The new classification of Pluto does not make me think any less of the object OR its discoverer. Remember this was the first object of its type discovered by back-breaking, grueling dedication to a cause...this marks a new beginning in our understanding of our solar system. THIS IS THE REBIRTH OF PLUTO AS A UNIQUE TYPE OF NEW OBJECT, NOT ITS DEMISE!