Lost a planet we have?

[Crazy Gringo]

Pluto gets the boot click link for story.

Today is indeed a sad day for astrologers everywhere. Everything they ever told us is now officially a lie.

3000 eggheads, who make a living looking at the heavens above, made it quite clear that Pluto is no longer a planet.

Why should 3000 eggheads decide why a planet is no longer a planet?

This is science gone bad to the bone I say. What do you think?

[Pete]

So... are they saying it's too small? Not enough atmosphere? Made up of the wrong stuff?

 

Ah, I rmember a bit about Puto and it's biggest moon facing each other with the same points - here's a link: https://en.wikipedia.org/wiki/Charon_%28moon%29

 

So... is it a double-planet? Is this what the argument is? I 'unno Shaggy.

 

I personally say "stop picking on Pluto you mean astrologers".

[FullAuto]

Isn't it now a 'dwarf planet' or something?

 

Cue more screams of "Everything you were taught in school is a lie"

[Skonar]

Pluto is smaller than the moon, you know.

 

Do we really want that damn moon of ours to claim it's a planet too?

[Kernel]

Do we really want that damn moon of ours to claim it's a planet too?

 

No because our moon orbits the Earth, Pluto on the other hand orbits the Sun.

Now it seems to that Pluto is what's known as "A Pluton".

[Kret]

CG, out of the 3000 "eggheads" that were present only 300 actually voted, the rest didn't.

 

A planet within our solar system is defined by the International Astronomical Union as a celestial body that is in orbit around the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and has cleared the neighbourhood around its orbit. Those bodies which fulfil the first two conditions but not the third are dwarf planets if they are not satellites.

 

That is the main issue of Pluto, it's orbit overlaps with Neptune's thus not "clearing the neighbourhood around it's orbit". Size had nothing to do with it.

[Pete]

Soooooo are they suggesting it's a moon of Neptune then?

[Matri]

That's no moon, it's a space station.

 

*nonchalantly strolls out, whistling*

[Accounting Troll]

Gentlemen, astrologers are actually quite pleased at the change in status of Pluto. They've never worked out how to incorporate Pluto into their system of beliefs that the position of the planets affects your personality and life. Trying to assign personality traits to new planets forces them to actually do some work for once.

 

After the discovery of Neptune, observations of its orbit indicated tht it was being affected by the gravitational pull of a large planet beyond its orbit. When Pluto was discovered, it was initially believed to be this planet before we learned what a tiddler it really is. This mysterious planet affecting the orbit of Neptune has yet to be discovered.

 

Current theories and observational evidence of the creatiopn of a solar system indicate that a star is born in a nebula, and the rest of the matter in the nebula (dust, gases and small rocks) ends up orbiting the star. Eventually through a process of gravitational attraction and collisions, some of the rocks hoover up all the crud in their path, forming the planets, including Earth; this is what astronomers mean when they talk about a planet dominating its orbit.

 

All planets have an elliptical orbit around the Sun (technically, a planet and the Sun revolve aroundf their common centre of gravity, but why complicate things?). The orbit of Pluto is so elliptical that it crosses the orbit of Neptune at two seperate points. Coincidentally, two Pluto years equal three Neptune years, so there is no possibility of the two objects colliding.

 

The orbit of the planets around the central star forms a relatively flat plane (give or take a couple of degrees) called the Invariable Plane (or ecliptic plane from the point of view of someone on Earth), so it is possible for the planets to arrange themselves in a straight line like you sometimes see in astronomy textbooks. And no this does not have any noticeable effects on Earth. Pluto is the exception; it has an angle of 17.2 degrees to the ecliptic plane. This and the elliptical orbit means that Pluto behaves more like a comet or an asteroid than a planet.

 

The issue of rewriting the school textbooks is only an issue for countries who spend so much money on education that schoolchildren learn from books written AFTER 1930, so Britain has saved some money there

[Kret]

What I'm going to find funny is if they ever discover another planet similar to Jupiter that behaves in a similar way to pluto, it's going to be classified as a "dwarf planet" and a "gas giant". I find the redifinition of "planet" quite flawed and conveniently adapted to "kick out" pluto from such category.

[Pete]

But shouldn't we know if Pluto's a planet or not? Don't we mine plutoonium there?

 

Thank you, thank you. I'll be here all week

[uriaheep]

What flavour is it? I know the moon is made of green cheese, but what flavour is Pluto?

 

I mean if it's chocolate or ice cream we really need to keep it.

 

 

................... What's everyone looking at?

[Accounting Troll]

Looks like the fisticuffs over the downgrading of Pluto have already begun link.

 

And if you live in the USA you can get your "Honk if Pluto is still a planet" bumper stickers here, if you don't mind everyone knowing how eccentric you really are.

[Snakeman]

If Pluto is not a planet, then that makes it a planetoid right? Does that make its moons planetoidlets then?

[Kernel]

What makes me laugh is that, by their own definition of a planet, it means that Jupiter, the Earth and Mars also can't be classified as planets.

[Zombie]

If Pluto is not a planet, then that makes it a planetoid right? Does that make its moons planetoidlets then?

Pluto is now called a "dwarf" planet. I have even heard it called a "minor" planet on the news too. Not sure if the meanings are identical, but the point is the same. Satellites circling a celestial body orbiting the sun are still defined as "moons". Doesn't matter if the satellites are larger than the actual planet either. I have yet to hear what binary planets will be called as this would foul up the definitions.

 

The problem with this mess is that the definitions of a planet are arbitrary. The stricter the standards, the less planets there will be. Not that any of this matters in the long run as there will just be another class of planet-type objects to memorize.

 

- Zombie

[Snakeman]

I presume they did this not just to define what a planet is, but to even do so in the first place, they must have had to agree on a diameter of a body to fit the definition. I brought up the word planetoid because I'd heard it before (so it has to be a word right?!? ) so I figured that had to be one competing element to defining a planet besides orbital circumstances.

[Ego Terrorist]

Okay, here's my problem, as I understand it Pluto is no longer a planet (it's a small or dwarf planet) because it hasn't cleared a path in its orbit.

 

It crosses the path of neptune...

 

...by that thinking... Neptune hasn't cleared a path in its orbit as it crosses Pluto's orbit...

 

Is it me or is there a problem here?

[Crazy Gringo]

Neptune is not a planet!

Otherwise it would have cleared out Pluto and Charon....

[Accounting Troll]

It takes Pluto exactly the same time to orbit the Sun twice as it does for Neptune to orbit the Sun three times. They are never at the same location when Pluto crosses Neptune's orbit and they never will be assuming that no external force interferes with their orbits.

 

If clearing an orbit is a criterion for becoming a planet, then all the planets (even Jupiter) fail because of all the asteroids and comets in the solar system.