Pluto: Planet or Not?

[Dragomere]

Quoted from your sourced article "A large body which meets the other criteria for a planet but has not cleared its neighbourhood is classified as a dwarf planet. This includes Pluto"

Yeah, exactly: Pluto is not a planet but a dwarf planet. What's your point?

By the exact definition, Earth is a dwarf planet.

[Spartan Philidelphia]

Why does this matter so much? It's been 8 years.

[Dragomere]

Why does this matter so much? It's been 8 years.

Lets put is this way: by the definition currently used, Pluto may not be a definition, but neither is Earth. Earth IS a planet, thus Pluto is a planet.

[Basking Turtles]

Yeah, exactly: Pluto is not a planet but a dwarf planet. What's your point?

By the exact definition, Earth is a dwarf planet.

Seriously? You skipped the first sentence because the second sentence was more supportive to your claim?

In the end stages of planet formation, a planet will have "cleared the neighbourhood" of its own orbital zone, meaning it has become gravitationally dominant, and there are no other bodies of comparable size other than its own satellites or those otherwise under its gravitational influence. A large body which meets the other criteria for a planet but has not cleared its neighbourhood is classified as a dwarf planet. This includes Pluto, which shares its orbital neighbourhood with Kuiper belt objects such as the plutinos. The IAU's definition does not attach specific numbers or equations to this term, but all the planets have cleared their neighbourhoods to a much greater extent than any dwarf planet, or any candidate for dwarf planet.

I'm not sure how much clearer I can make this.

[Dragomere]

By the exact definition, Earth is a dwarf planet.

Seriously? You skipped the first sentence because the second sentence was more supportive to your claim?

In the end stages of planet formation, a planet will have "cleared the neighbourhood" of its own orbital zone, meaning it has become gravitationally dominant, and there are no other bodies of comparable size other than its own satellites or those otherwise under its gravitational influence. A large body which meets the other criteria for a planet but has not cleared its neighbourhood is classified as a dwarf planet. This includes Pluto, which shares its orbital neighbourhood with Kuiper belt objects such as the plutinos. The IAU's definition does not attach specific numbers or equations to this term, but all the planets have cleared their neighbourhoods to a much greater extent than any dwarf planet, or any candidate for dwarf planet.

I'm not sure how much clearer I can make this.

Wikipedia can be a good source, except it is unreliable. There is a unspoken rule that says do not use Wikipedia except as a last resort. My source quoted the opposite of your claim.

[Spartan Philidelphia]

Why does this matter so much? It's been 8 years.

Lets put is this way: by the definition currently used, Pluto may not be a definition, but neither is Earth. Earth IS a planet, thus Pluto is a planet.

Are you still confused about what "clearing the neighborhood" means?

Please name one celestial body comparable in size to the Earth, other than its own satellites or otherwise under its own gravitational influence.

[East Ormania]

Welcome to the newest debate topic on NS, the SPACE DEBATE.

(Image)

This is part one of the series, on Pluto

The question is: Is Pluto a planet, or just a iceball of the Kuiper Belt?

Well, for me, Pluto is a planet despite it's orbit and distance from the sun. I say this because it gets closer to the sun than Neptune at times. I feel like any object in space that is not a moon, space probe, or asteroid that gets closer to the sun than Neptune, it is a planet.

So, Planet? Not? Please state why with your answer. And stay tuned for next episode, on the Kuiper Belt!!!

You clearly do not know what the definition of "planet" is. If so, then a lot of Kuiper Belt's objects that are not asteroids are full planets. Count our numbers over 10 then. Add Make-Make, Ceres and many more to the equation.

Pluto is not a planet.

[Prusslandia]

Pluto is just a cold, cold celestial dwarf. (High five if you get the reference)

[Xmara]

Pluto was classified as a dwarf planet in 2006.

[Zepplien]

So, do comets count as planets too?

feel like any object in space that is not a moon, space probe, or asteroid that gets closer to the sun than Neptune, it is a planet.

Also, how about the space shuttle, it is not a probe, and is much closer to the sun

[Canuckland]

I don't care what Neil DeGrasse Tyson says, Pluto will always be a planet in my heart.

[Dragomere]

Lets put is this way: by the definition currently used, Pluto may not be a definition, but neither is Earth. Earth IS a planet, thus Pluto is a planet.

Are you still confused about what "clearing the neighborhood" means?

Please name one celestial body comparable in size to the Earth, other than its own satellites or otherwise under its own gravitational influence.

Read the definition again:
Actually, the official definition accepted by astronomists that Earth and Pluto fail is worded "cleared its path of orbital debris" (Source), not "cleared its orbit of significant objects".

[Divair2]

Are you still confused about what "clearing the neighborhood" means?

Please name one celestial body comparable in size to the Earth, other than its own satellites or otherwise under its own gravitational influence.

Read the definition again:
Actually, the official definition accepted by astronomists that Earth and Pluto fail is worded "cleared its path of orbital debris" (Source), not "cleared its orbit of significant objects".

>wikianswers

[Spartan Philidelphia]

Are you still confused about what "clearing the neighborhood" means?

Please name one celestial body comparable in size to the Earth, other than its own satellites or otherwise under its own gravitational influence.

Read the definition again:
Actually, the official definition accepted by astronomists that Earth and Pluto fail is worded "cleared its path of orbital debris" (Source), not "cleared its orbit of significant objects".

If you reject Wikipedia, why the hell would you accept Wikianswers?

[Dragomere]

Read the definition again:
Actually, the official definition accepted by astronomists that Earth and Pluto fail is worded "cleared its path of orbital debris" (Source), not "cleared its orbit of significant objects".

If you reject Wikipedia, why the hell would you accept Wikianswers?

more accurate. Plus it is one of the easiest to quote, even though I could have used many other sources that said the same exact thing.

[Divair2]

If you reject Wikipedia, why the hell would you accept Wikianswers?

more accurate. Plus it is one of the easiest to quote, even though I could have used many other sources that said the same exact thing.

>wikianswers
>accurate
Pick one.

[Basking Turtles]

Wikipedia can be a good source, except it is unreliable. There is a unspoken rule that says do not use Wikipedia except as a last resort. My source quoted the opposite of your claim.

This conversation is getting silly.
Me: Check this wiki article
You: Aha! The article proves my point!
Me: Actually it doesn't
You: Well, wiki is not a good source anyway.

But anyway, if I understand correctly, you are arguing that "clearing the neighbourhood" is an unclear phrase, which can be interpreted such as to consider all planets dwarfs. This is obviously not how it was intended. Michael Brown (who discovered Eris and thereby triggered the whole issue) sheds some light on the matter:

Because of the relatively chaotic process that occured before reaching this very rational decision the actual wording of the definition is not as precise as it might have been, giving people room to quibble and to say that the definition is unclear. The important point to remember, however, is that the difference between the eight planets and everything else known in the solar system is so huge that even a definition with a lot of wiggle room will not make any difference. If you are trying to define the difference between North America and Europe, for example, the exact position of the line that you draw in the middle of the Atlantic Ocean does not matter much. The precise definition in the IAU resolution may be a tad unclear, but the concept is absolutely rock solid with absolutely no room for doubt about which objects do and do not belong.

[Dread Lady Nathicana]

You'll always be a planet to meeeeeeee ...

Seriously, I was disappointed at the declassifying. I grew up with it as a planet, it was interesting given its differences and smaller size after the gas giants, and how here we are finding more and more things out there that could or couldn't be possibly classified as in like or bigger size.

I mean, it has moons - its own orbiting satellites. It orbits the sun as well, along with the rest. I guess part of it is we do keep learning new things, and rethinking how we classify everything out there, but still. It seemed kinda petty to me at the time. *shrugs*

[Basking Turtles]

Read the definition again:
Actually, the official definition accepted by astronomists that Earth and Pluto fail is worded "cleared its path of orbital debris" (Source), not "cleared its orbit of significant objects".

Okay, just so we are at least on the same page about what definition we are talking about, this is the official definition from the IAU website:

A "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, and (c) has cleared the neighbourhood around its orbit.

[AiliailiA]

Actually, there are comets, meteors, and other such objects that have intersecting paths with Earth's orbit.

Comets (and associated objects such as meteors) are on highly eccentric, almost parabolic or even hyperbolic trajectories. They may intersect Earth's orbit once in a blue moon, but they don't "share" the orbit in any meaningful way.


edit: Apparently there's a whole wiki article about clearing the neighbourhood. It's interesting. Check the table of (dwarf) planets: see the gap between planets and dwarfs? That's significant enough to justify a distinction, if you ask me.

And though Jupiter is famous as the 'vacuum cleaner' Earth has the least dirty neighbourhood.

As someone who doesn't approve of big rocks falling out of the sky, I like that

[Dragomere]

Read the definition again:
Actually, the official definition accepted by astronomists that Earth and Pluto fail is worded "cleared its path of orbital debris" (Source), not "cleared its orbit of significant objects".

Okay, just so we are at least on the same page about what definition we are talking about, this is the official definition from the IAU website:

A "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, and (c) has cleared the neighbourhood around its orbit.

Yep (c) proves my point!

[Basking Turtles]

Okay, just so we are at least on the same page about what definition we are talking about, this is the official definition from the IAU website:

Yep (c) proves my point!

As you are in the habit of conveniently ignoring things you don't like, I am forced to point you to this post that you skipped.

[The Scientific States]

Dwarf Planet. /Thread

[AiliailiA]

Okay, just so we are at least on the same page about what definition we are talking about, this is the official definition from the IAU website:

Yep (c) proves my point!

There are five orders of magnitude difference between the least-cleared planetary orbit (Neptune's) and the next most cleared orbit ... and that's not even Pluto. It's Ceres in the Asteroid belt! Pluto's orbit is another 4 times more cluttered than that, and probably more since only a tiny fraction of Kuiper Belt objects are known.

That's by Soter's criterion of observed material in orbits; the Wikipedia page explains how that is calculated and footnote 3 is Steven Soters actual article. It's 22 pages long so you may not actually want to read it, but it's freely available if you do.

[Dragomere]

Yep (c) proves my point!

There are five orders of magnitude difference between the least-cleared planetary orbit (Neptune's) and the next most cleared orbit ... and that's not even Pluto. It's Ceres in the Asteroid belt! Pluto's orbit is another 4 times more cluttered than that, and probably more since only a tiny fraction of Kuiper Belt objects are known.

That's by Soter's criterion of observed material in orbits; the Wikipedia page explains how that is calculated and footnote 3 is Steven Soters actual article. It's 22 pages long so you may not actually want to read it, but it's freely available if you do.

However, because it is vague, it may be interpreted multiple ways.