Pluto is an important planet.

[Keatah]

http://www.thespacereview.com/article/450/1

Reading this article makes you feel just a little bit better about Pluto. It says something about Pluto being the first harbinger of a whole new classification. If that's the case, THEN, Pluto is in a class of "normal" planets with the other 8 being stupid planets or misfit planets.

I'm old school, so, to me, there are still NINE planets. I could also get used to the idea of 9 planets and thousands of minor planets though.

 

[Jarvitä]

I'm old school, so, to me, there are still NINE planets. I could also get used to the idea of 9 planets and thousands of minor planets though.

The new classification is more accurate, clearly defined and logical. "Because we used to think of it as a planet back when we had no clear definition of what a planet is" just doesn't make sense.

 

[N_Molson]

Yes, and anyway now that the international scientific community validated this, it's how things are.

 

[Mantis]

I really don't get it why they had to reclassify Pluto as something less than an ordinary planet when any miniscule odd-shaped rock orbiting a planet is classified as a moon. Personally, I think if they want to crack down on planets, they should do the same with moons and apply a similar definition - The requirement that "it is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion" would "demote" the vast majority of moons in the solar system.

 

[bujin]

I'm old school, so, to me, there are still NINE planets. I could also get used to the idea of 9 planets and thousands of minor planets though.

But there can't be nine planets, can there?

There are either eight planets, with Pluto classed as a dwarf planet, or there are more than nine planets, with Pluto, Ceres and Eris (probably among others) also classed as planets.

It certainly makes no sense to call Pluto a planet but then call Eris a dwarf planet, when Eris is physically larger and more massive than Pluto!

 

[Izack]

"it is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion"

Wait, what? :blink:

No planet (let alone moon!!) in this system is anywhere close to starting fusion and becoming a star. There is only enough mass here for one - the Sun.

 

[Jarvitä]

I really don't get it why they had to reclassify Pluto as something less than an ordinary planet when any miniscule odd-shaped rock orbiting a planet is classified as a moon. Personally, I think if they want to crack down on planets, they should do the same with moons and apply a similar definition - The requirement that "it is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion" would "demote" the vast majority of moons in the solar system.

A moon is a natural object in orbit around a planet or dwarf planet. I don't see what the problem is with this definition? Also, the "rounded by its own gravity" is only a requirement for planets and dwarf planets, it doesn't make any sense for moons.

For moons, a simple size requirement of a few hundred meters, combined with the current requirement to orbit a planet/dwarf planet would suffice. Otherwise, each speck of ice in Saturn's rings can be classified as a moon.

 

[T.Neo]

I still feel that this classification of 'planet' is defined to exclude numerous, smaller bodies, just to keep the classification of 'planet' exclusive.

You can remove the "neighborhood clearing" classification, and still have an objective and logical classification system. And it also solves other problems, that you get with scenarios that could be possible, but aren't currently seen in our solar system.

But saying that Pluto should be considered a planet because it was considered a planet at one point makes no sense at all; that is the definition that isn't logical. Pluto-like objects are either planets, or they aren't planets. Pluto may be a unique object with its own scientific secrets, but it isn't exceptionally special just because we discovered it first.

 

[Pyromaniac605]

For moons, a simple size requirement of a few hundred meters, combined with the current requirement to orbit a planet/dwarf planet would suffice. Otherwise, each speck of ice in Saturn's rings can be classified as a moon.

I wasn't aware that there was a size requirement for moons, I thought it was just any naturally occurring satellite orbiting a planet.

 

[boogabooga]

I remember the NOVA episode they did on this where Neil deGrasse Tyson lamented getting "hate mail" from schoolchildren. :rofl:

I don't get the neighborhood clearing either. Don't many asteroids still cross Mars' orbit? What about Trojans?

 

[iamwearingpants]

I remember the NOVA episode they did on this where Neil deGrasse Tyson lamented getting "hate mail" from schoolchildren. :rofl:

I don't get the neighborhood clearing either. Don't many asteroids still cross Mars' orbit? What about Trojans?

The thing with clearing orbits is that pluto didn't eat or sling all the major bodies out of it's way. There are still KBO's that are a similar size to itself.

Ceres isn't a planet not because of the little asteroids, but because of big ones like Vesta and Pallas. Ceres didn't clear them.

Mercury however, is a planet, because there isn't anything big, or really anything at all there. Same with Venus, Earth, and Mars

 

[iamwearingpants]

Are you convincing us that Pluto is a planet?

Nope.

 

[iamwearingpants]

I'm asking Keatah <.<

Oops

I think you should have been more clear about to whom you were speaking too

 

[N_Molson]

Problem is, if you don't set an arbitrary limit for what is a planet and what isn't, it would be quickly a real mess :

Legend

Red = The Sun
Aquamarine = Giant Planet
Green = Kuiper belt object
Orange = Scattered disc object or Centaur
Pink = Trojan of Jupiter
Yellow = Trojan of Neptune

Axes list distances in AU, projected onto the ecliptic, with ecliptic longitude zero being to the right, along the "x" axis).

Edit : in Orbiter 2034 P3, all the objects depicted above will be in the simulation :crystalball2:

Edit2 : And there isn't even the Oort cloud on this map, where there is even more rocks (much farther away).

 

[iamwearingpants]

I didn't know that there were that many KBO's :blink:

 

[bujin]

Edit : in Orbiter 2034 P3, all the objects depicted above will be in the simulation :crystalball2:

Along with the planet Nibiru, once they've found that... :thumbup:

 

[orb]

I didn't consider Pluto a planet since 2002, when I found Orbiter, and not since the definition of a planet changed. :lol:

 

[RisingFury]

Pluto not a planet? Still only in New York!

 

[Mantis]

I still feel that this classification of 'planet' is defined to exclude numerous, smaller bodies, just to keep the classification of 'planet' exclusive.

That's precisely what I meant by my comment about moons. Why be exclusive about planets but include every tiny irregular chunk of rock orbiting a planet as a moon?

---------- Post added at 11:18 AM ---------- Previous post was at 11:17 AM ----------

Wait, what? :blink:

No planet (let alone moon!!) in this system is anywhere close to starting fusion and becoming a star. There is only enough mass here for one - the Sun.

I know that - but that IS one of the criteria that defines a planet.

---------- Post added at 11:19 AM ---------- Previous post was at 11:18 AM ----------

I wasn't aware that there was a size requirement for moons, I thought it was just any naturally occurring satellite orbiting a planet.

That is correct and it doesn't make a lot of sense.

 

[RisingFury]

Wait, what? :blink:

No planet (let alone moon!!) in this system is anywhere close to starting fusion and becoming a star. There is only enough mass here for one - the Sun.

I know that - but that IS one of the criteria that defines a planet.

Certain people are wrong, but you're magnitudes of order more wrong.


A planet is a body that:
1.) Is the primary body in orbit around it's star
2.) Is round due to its own gravity
3.) Has cleared its orbital region of orbital debris, so that its orbit is at least a few magnitudes more cleared than the surroundings.


I'd very much like to see where you got the idea that a planet needs to sustain fusion to be a planet.

---------- Post added at 15:44 ---------- Previous post was at 15:42 ----------

That's precisely what I meant by my comment about moons. Why be exclusive about planets but include every tiny irregular chunk of rock orbiting a planet as a moon?

There's no formal definition of what a moon is. The word 'moon' is astrophysics slang for 'natural satellite' of an object that is not the primary body in the system.

---------- Post added at 15:46 ---------- Previous post was at 15:44 ----------

And because someone will eventually bring this up:

There are no binary planets in our solar system. The definition of a binary planet would only make sense if the barycenter was roughly half way between the bodies, +-20%