Topic: THE MEANING OF PLANET

[The Postman]

THE MEANING OF PLANET: What is a planet? For years, astronomers have been debating that question, with the status of tiny Pluto hanging in the balance. Finally, an answer is in the offing. The International Astronomical Union's Planet Definition Committee has proposed a new, official definition:

"A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet." 

In plain language, if it's round and it orbits the Sun, then it's a planet.

On August 24th, astronomers gathered at the IAU General Assembly in Prague will vote on the proposal, yea or nay. If it passes, the Solar System will have twelve planets: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto and Charon (a double planet) and 2003 UB313.

[Tus-XC]

o fun, guess i'll have to learn a new diddy

[J. Carney]

2003 UB313 don't exactly roll off the tounghe, and 'Xena and it's moon Gabrelle' is just a little to corny to work out.

I hope that they give it a REAL name soon.

[Dracho]

Keeping with the theme of the others, I'd suggest

Cania - An area of the frozen lake Cocytus, in Dante's 9th circle of hell. Certainly a frozen hell would be an apt description.

Tartarus - Both a Greek God and a place farther even than Hades, where the cosmos originated.

and Skiron, one of the Winds who chose the air for her earthly body.

[Vipre]

I honestly find this topic very interesting, but I have to ask.

Does anyone else find it ridiculous that a random group of people that I've/we've never heard of are given the authority or take the authority upon themselves to dictate what does or does not constitute a planet? Also that they then decide how many planets our solar system has? "Do I hear 10...12...15 anyone?...16 from the man in the back."

My suggestion for a planet --> Must revolve around a star not another planet (unless some kind of twin planet) and must have an atmosphere. That covers Pluto doesn't it? If not then grandfather it in and dump the rest. The other eight have atmospheres right, even if very thin ones?

Big giant ice covered round rock without atmosphere  <---not a planet

I really don't care who decides what, I can remember nine and MVEMJSUNP and I refuse to learn anymore or drop any of the nine. 
Keep in mind I'm not an astronomer and don't pretend to be.

Oh and be sure to post what they decide

[Dracho]

I'm not sure Mercury has an atmosphere.

[Vipre]

Mercury is much too small for its gravity to retain any significant atmosphere over long periods of time, but it does have a very tenuous atmosphere containing hydrogen, helium, oxygen, sodium, calcium and potassium. The atmosphere is not stable—atoms are continuously lost and replenished, from a variety of sources. The hydrogen and helium atoms probably come from the solar wind, diffusing into Mercury's magnetosphere before later escaping back into space. Radioactive decay of elements within Mercury's crust is another source of helium, as well as sodium and potassium. Water vapor is probably also present, water being brought to Mercury by comets impacting on its surface.

Close enough for me

[AlchemistiD]

What happened to Sedna?  Isn't Sedna a planet also?

[Fedman NCC-3758]

(a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star

Hmmm.....

Some people I know now qualify as a planet.

[Nemesis]

1/ Spherical (approximately - allowing for tidal and rotational forces)

2/ Solid core consisting of rock and or metal.

3/ Remained molten long enough to have denser materials sink to the core.


I suspect that this would disallow Pluto, all asteroids and the objects so far discoverd beyond pluto while allowing the other 8 planets to remain classified that way.  It would also reclassify the Earths moon as a planet.  Other large moons might also so qualify.

[Tus-XC]

i don't care what they do, as long as pluto is grandfathered either way we must have no less then 9 planets

[Fedman NCC-3758]

If they discover a tenth or and an eleventh planet, can I sue my astrologer?

[Nemesis]

A proposal on a method to limit the number of new planets in the solar system

[Ultraprophet]

 Bah!

 Pluto is a planet because we say its a planet . The very concept of  "planet" is an arbitrary human invention , not a law of physics or mathmatics.

[J. Carney]

Bah!

 Pluto is a planet because we say its a planet . The very concept of  "planet" is an arbitrary human invention , not a law of physics or mathmatics.

The very concept of 'numerical worth' was also a human invention.

After all, what 'one' is the value of 'one' based on?

[Ultraprophet]

Bah!

 Pluto is a planet because we say its a planet . The very concept of  "planet" is an arbitrary human invention , not a law of physics or mathmatics.

The very concept of 'numerical worth' was also a human invention.

After all, what 'one' is the value of 'one' based on?

Its precisly half the value of two . 

[Commander Maxillius]

but then if you have .01 of something and not the rest of it, cannot the .01 be redefined as 1?

[Just plain old Punisher]

Bah!

 Pluto is a planet because we say its a planet . The very concept of  "planet" is an arbitrary human invention , not a law of physics or mathmatics.

The very concept of 'numerical worth' was also a human invention.

After all, what 'one' is the value of 'one' based on?

Your IQ?

=) hehe

[J. Carney]

Bah!

 Pluto is a planet because we say its a planet . The very concept of  "planet" is an arbitrary human invention , not a law of physics or mathmatics.

The very concept of 'numerical worth' was also a human invention.

After all, what 'one' is the value of 'one' based on?

Your IQ?

=) hehe

You are setting the value of '1' very high, indeed, grasshopper.

But you perfectly illustrate my point. If the concept of '1' indicates '1' grain of sand, it represnts little, but if it represents '1' SPECIES, it can represnet a lot.

[Just plain old Punisher]

Eh, since the word "Planet" is a human distinction and an admittidley arbitrary definition, I don't have a problem with us declaring one ball of rock a planet and another ball of ice, not.

The people/creatures who live there will experiance the real estate boom or crash depending on the naming of their particular ball of rock/ice a planet or asteroid will just have to deal with it.