[Getter Robo G]

Dammit, if it is a celestial body that orbits our sun and has it's own moon I say it's a planet (just a tiny one)!

Here are some indications that a few people feel the same way

http://www.worth1000.com/cache/gallery/contestcache.asp?contest_id=11570&display=photoshop

My favorite one is the Einstien one...

[karajorma]

Funny.

The product of pure distilled stupidity but funny.


Seriously let it go. Pluto just isn't a planet. Had it been discovered today it never would have been called a planet in the first place. The only reason anyone wants to call it a planet is sentimentality and that's a piss poor reason for a scientific designation.

[Dark Hunter]

Well said.

[Ghostavo]

Isn't by definition Neptune not a planet either?

[Janos]

Isn't by definition Neptune not a planet either?

I beg your pardon?

[Ghostavo]

Isn't by definition Neptune not a planet either?

I beg your pardon?

Well, the current definition involves 3 conditions the last of which supposedly invalidates Pluto from being one.

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
(c) has cleared the neighbourhood around its orbit

Condition (c) is what doesn't make Pluto a planet, but by it's orbit crossing with Neptune (again, condition (c)) Neptune status also becomes unclear. Of course Earth, Mars and Jupiter become also fuzzy, but by having it's orbit crossing with asteroids that don't come under any condition except (a) their status is clearer.

Anyway, personally I think this is not a scientific problem but rather a language one. Planets, dwarf planets and asteroid are too broad terms to designate stellar objects, as they have too many similarities between them.

[Janos]

Isn't by definition Neptune not a planet either?

I beg your pardon?

Well, the current definition involves 3 conditions the last which supposedly invalidates Pluto from being one.

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
(c) has cleared the neighbourhood around its orbit

Condition (c) is what doesn't make Pluto a planet, but by it's orbit crossing with Neptune (again, condition (c)) Neptune status also becomes unclear. Of course Earth, Mars and Jupiter become also fuzzy, but by having it's orbit crossing with asteroids that don't come under any condition except (a) their status is clearer.

Anyway, personally I think this is not a scientific problem but rather a language one. Planets, dwarf planets and asteroid are too broad terms to designate stellar objects, as they have too many similarities between them.

I see.

The vague or nonexistant scientifically accepted definition of planet is exactly what started this mess. Most Kuiper objects fill that classical definition (and actually C does not invalidate either Pluto or Neptune, because their orbits do not really cross so close to each other to have significant impact), and we seriously cannot just have 10 oddball objects rounding the star so far away to be completely insignificant. Trying to define"planet" is what more or less dropped our dear Pluto from the list.

[Ghostavo]

I see.

The vague or nonexistant scientifically accepted definition of planet is exactly what started this mess. Most Kuiper objects fill that classical definition (and actually C does not invalidate either Pluto or Neptune, because their orbits do not really cross so close to each other to have significant impact), and we seriously cannot just have 10 oddball objects rounding the star so far away to be completely insignificant. Trying to define"planet" is what more or less dropped our dear Pluto from the list.

But the problem is that condition (c) is exactly what caused Pluto from being dropped as a planet. Read the IAU reports about the redefinition.

[Janos]

I see.

The vague or nonexistant scientifically accepted definition of planet is exactly what started this mess. Most Kuiper objects fill that classical definition (and actually C does not invalidate either Pluto or Neptune, because their orbits do not really cross so close to each other to have significant impact), and we seriously cannot just have 10 oddball objects rounding the star so far away to be completely insignificant. Trying to define"planet" is what more or less dropped our dear Pluto from the list.

But the problem is that condition (c) is exactly what caused Pluto from being dropped as a planet. Read the IAU reports about the redefinition.

Facing defeat and combatting with is own hazy memories, our hero valiantly googles and...
comes up with rebuttal!

The phrase refers to an orbiting body (a planet or protoplanet) "sweeping out" its orbital region over time, by gravitationally interacting with smaller bodies nearby. Over many orbital cycles, a large body will tend to cause small bodies either to accrete with it, or to be disturbed to another orbit. As a consequence it does not then share its orbital region with other bodies of significant size, except for its own satellites, or those governed by its own gravitational influence. This latter restriction excludes objects whose orbits may cross but which will never collide with each other due to orbital resonance, such as Jupiter and the Trojan asteroids or Neptune and the Plutinos.

[Ghostavo]

I see.

The vague or nonexistant scientifically accepted definition of planet is exactly what started this mess. Most Kuiper objects fill that classical definition (and actually C does not invalidate either Pluto or Neptune, because their orbits do not really cross so close to each other to have significant impact), and we seriously cannot just have 10 oddball objects rounding the star so far away to be completely insignificant. Trying to define"planet" is what more or less dropped our dear Pluto from the list.

But the problem is that condition (c) is exactly what caused Pluto from being dropped as a planet. Read the IAU reports about the redefinition.

Facing defeat and combatting with is own hazy memories, our hero valiantly googles and...
comes up with rebuttal!

The phrase refers to an orbiting body (a planet or protoplanet) "sweeping out" its orbital region over time, by gravitationally interacting with smaller bodies nearby. Over many orbital cycles, a large body will tend to cause small bodies either to accrete with it, or to be disturbed to another orbit. As a consequence it does not then share its orbital region with other bodies of significant size, except for its own satellites, or those governed by its own gravitational influence. This latter restriction excludes objects whose orbits may cross but which will never collide with each other due to orbital resonance, such as Jupiter and the Trojan asteroids or Neptune and the Plutinos.

Odd, then why isn't Pluto a planet? 

[karajorma]

Pluto's orbit is often described as 'crossing' that of Neptune. In fact, Pluto's nodes (the points at which the orbit crosses the ecliptic) are both situated outside Neptune’s orbit and are separated by a distance of 6.4 AU (that is, over six times the distance of the Earth from the Sun). Furthermore, due to the orbital resonance between them, Pluto executes 2 full cycles while Neptune makes 3; this means that when Neptune reaches the 'closest' point on the orbit, Pluto remains far behind and when Pluto in turn reaches that point, Neptune is far (over 50°) ahead. During the following orbit of Pluto, Neptune is half an orbit away. Consequently, Pluto never gets closer than 30 AU to Neptune at this point in its orbit.

Neptune can not be excluded as a planet because it never has the chance to clear out Pluto. Pluto and Neptunes orbits never actually intercept in the first place.

[Nuke]

i personally think a better definition for planet as a round object in orbit around the sun that has an orbital plane which is close to paralell with the ecliptic plane. that definition would exclude pluto but the scientists probibly had a reason not to use that one and have all reached their consensous.

[BS403]

I see.

The vague or nonexistant scientifically accepted definition of planet is exactly what started this mess. Most Kuiper objects fill that classical definition (and actually C does not invalidate either Pluto or Neptune, because their orbits do not really cross so close to each other to have significant impact), and we seriously cannot just have 10 oddball objects rounding the star so far away to be completely insignificant. Trying to define"planet" is what more or less dropped our dear Pluto from the list.

But the problem is that condition (c) is exactly what caused Pluto from being dropped as a planet. Read the IAU reports about the redefinition.

Facing defeat and combatting with is own hazy memories, our hero valiantly googles and...
comes up with rebuttal!

The phrase refers to an orbiting body (a planet or protoplanet) "sweeping out" its orbital region over time, by gravitationally interacting with smaller bodies nearby. Over many orbital cycles, a large body will tend to cause small bodies either to accrete with it, or to be disturbed to another orbit. As a consequence it does not then share its orbital region with other bodies of significant size, except for its own satellites, or those governed by its own gravitational influence. This latter restriction excludes objects whose orbits may cross but which will never collide with each other due to orbital resonance, such as Jupiter and the Trojan asteroids or Neptune and the Plutinos.

Odd, then why isn't Pluto a planet? 

Yeah pluto meets all 3 conditions for being a planet so why isn't it?

[Janos]

I see.

The vague or nonexistant scientifically accepted definition of planet is exactly what started this mess. Most Kuiper objects fill that classical definition (and actually C does not invalidate either Pluto or Neptune, because their orbits do not really cross so close to each other to have significant impact), and we seriously cannot just have 10 oddball objects rounding the star so far away to be completely insignificant. Trying to define"planet" is what more or less dropped our dear Pluto from the list.

But the problem is that condition (c) is exactly what caused Pluto from being dropped as a planet. Read the IAU reports about the redefinition.

Facing defeat and combatting with is own hazy memories, our hero valiantly googles and...
comes up with rebuttal!

The phrase refers to an orbiting body (a planet or protoplanet) "sweeping out" its orbital region over time, by gravitationally interacting with smaller bodies nearby. Over many orbital cycles, a large body will tend to cause small bodies either to accrete with it, or to be disturbed to another orbit. As a consequence it does not then share its orbital region with other bodies of significant size, except for its own satellites, or those governed by its own gravitational influence. This latter restriction excludes objects whose orbits may cross but which will never collide with each other due to orbital resonance, such as Jupiter and the Trojan asteroids or Neptune and the Plutinos.

Odd, then why isn't Pluto a planet? 

Yeah pluto meets all 3 conditions for being a planet so why isn't it?

hey dudes i'm not there, don't ask me

maybe because pluto is situated in kuiper belt with ****load of stuff so it really does not fill "cleared the neighbourhood criteria"

but i can google

he IAU...resolves that planets and other bodies in our Solar System be defined into three distinct categories in the following way:

(1) A planet [1] 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.

(2) A "dwarf 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 [2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects [3] orbiting the Sun shall be referred to collectively as “Small Solar System Bodies”.

[1] The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

[2] An IAU process will be established to assign borderline objects into either "dwarf planet" and other categories.

[3] These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.

[Dark Hunter]

(2) A "dwarf 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 [2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

Isn't that rather redundant? I mean, if it's a satellite it's orbiting a planet(or other Solar Body), not the Sun.

[Janos]

(2) A "dwarf 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 [2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

Isn't that rather redundant? I mean, if it's a satellite it's orbiting a planet(or other Solar Body), not the Sun.

one day the sun will explode and black hole red dwarf giant neutron nova superbrown stuff, and then it's important to know!

[watsisname]

[Col. Fishguts]

QFT