12 planets and rising

[Royston]

Due to a re-classification of what qualifies as a planet, our solar system could have 12 orbiting planets, compared to the age old and accepted 9.

 

According to this definition' date=' two conditions must be satisfied for an object to qualify as a planet:

 

The object must be in orbit around a star, but must not itself be a star.

 

It must have enough mass for the body's own gravity to pull it into a nearly spherical shape.[/quote']

 

This would end the debate over Pluto...

 

The proposal recognises eight classical planets' date=' three planets belonging to a new category called "plutons" and the largest asteroid Ceres.

 

Pluto remains a planet, but becomes the basis for the new pluton category.[/quote']

 

Please see the full BBC article below.

 

http://news.bbc.co.uk/1/hi/sci/tech/4795755.stm

[herpguy]

Darn, you beat me to it.

 

I'm just curious, does anyone here disagree with this decision?

[insane_alien]

i think that its a pretty solid definition. i'll go with it.

 

EDIT: woah, charon is classed as a planet now. its in orbit around pluto!

[JTM³]

Now we just need to start classifying planets like they do in Star Trek

[AzurePhoenix]

I'm happy with it, that's basically the definition I've shouted for before, but what about wandering planets that don't circle a star? What do they become now? Or do they remain planets because they originated around a star? There definately needs to be some sort of in depth classification system methinks

[Anjruu]

woah, charon is classed as a planet now. its in orbit around pluto!

 

Actually, IIRC, the center of mass of the Pluto-Charon system is outside Pluto, so they are saying that that doesn't count. Charon doesn't orbit Pluto, they orbit each other, and that they are a duel-planet system, or something.

 

I'm happy with it, that's basically the definition I've shouted for before, but what about wandering planets that don't circle a star?

 

Those must be pretty rare, though, I think. I mean, what sort of event would have to occur for a planet which formed as planets do, and then escaped from the gravity well of its sun, without being destroyed? Some sort of near-collision with an extremly large asteroid which yanks the planet from its orbit? Nova wouldn't produce these, the heat would destroy the planet, I thought, and anyway, there would still be enough mass. What else?

[AzurePhoenix]

Hmmm... when I said that I was thinking about a binary planet pair that I'd heard about on a science news show that mentions current stuff, but a quick look to wiki says that one of the two worlds is actually a brown dwarf. That's a little different than being a plain old starless planet. I feel so misled

 

wiki article on Oph 162225-240515

 

and it looks like some "rogue" planets actually formed coelescently themselves, not around a star. NOt much else I can find though.

 

interstellar planets

 

Those must be pretty rare, though, I think. I mean, what sort of event would have to occur for a planet which formed as planets do, and then escaped from the gravity well of its sun, without being destroyed?

getting caught and "flung" out by a gas giant seems the primary explanation

[darkangel199]

This is my newspaper's story on the planet thing:

 

"A story written in the Kansas City Star, By Faye Flam.

 

Looks like Pluto stays in the club, but Ceres, Charon, and Xena join, and so may 200 more.

 

 

To all the elementary -school kids who wrote impassioned letters begging astronomers to keep Pluto on the list of planets: Be careful what you wish for. To preserve Pluto's status, a select panel of seven astronomers, historians and others have agreed to stretch the definition of planet so far that, some say, about 200 objects may eventually be allowed in-many with only letters and numbers as names. An asteroid called Ceres, once considered a planet, was readmitted as was Charon, once classified as the moon of Pluto. An entire new class of planet was named- the plutons- and it includes both Pluto and Charon. The key point: Plutons are planets, too.

 

The panel, organized by the International Astronomical Union, has so far upped the list to 12, but it concedes that will grow fast as additional bodies are offically sanctioned and astronomers discover still more. The resolution, announced Tuesday, now goes before the organization for a vote next week among more than 2000 astronomers gathered in Prague. If approved, the new official list will read: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and UB313 ("Xena"). One factor in the what is a planet dispute might have to do with the fact that Pluto is the only planet discovered by an American: Clyde Tombaugh, a Kansan.

 

The problem with keeping the usual nine planets stemmed from a discrepancy between how astronomers envisioned the solar system and how schoolteachers presented it. Icy Pluto had always been much smaller than the other planets- a pebble among basketballs, yet beloved underdog. By the 1990s, scientists were finding that Pluto had a family of its own, a swarm of similarly small, icy bodies in a region called the Kuiper Belt.

 

Keeping Pluto a planet in the textbooks didn't seem like too much of a problem until last summer, when Caltech astronomer Michael Brown and colleagues announced that they had found another Kuiper Belt object three times Pluto's size. At that point, it seemed arbitrary to keep Pluto as a planet without letting this new one in. It was enough of a problem that the International Astronomical Union put it above naming Brown's new planet/object. So far, it goes by UB313, but astronomy buffs nicknamed it "Xena". To Brown, the new classification looks unnecessarily complicated.

 

"I'm excited about the possibility of adding the thing i've discovered as a new planet", he said. And yet, he said science might have been better served by reclassifying Pluto as a non-planet. The new official definition of a planet would include all bodies big enough for gravity to shape them into an approximate sphere. Just how big depends on what they are made of. The largest asteroid Ceres, is spherical enough to get admitted to the pantheon. But objects made of ice can be much smaller and still qualify, because it takes less force to round them out. Just a couple of hundred miles around will do, said Brown. That means that many very small objects beyond Pluto will qualify as planets.

 

Under the new rules, planets must orbit a star. moons of planets don't qualify, with the new exception of Charon, which is so close to the same size as Pluto that they are really sister bodies rotating around each other and the sun, said Owen Gingerich, historian of astronomy at Harvard, who headed the committee. Brown said he is suprised at the arbitrariness of the new list of planets. "We know in the solar system there are at least 53 objects that are round, objects in the Kuiper Belt- that for reasons i can't fathom they decided not ot mention in their press release."

 

One, for example, called Sedna, was discovered in 2002. "The committee will look into those," Gingerich said. The panel recognizes that there are more than 12 objects that fit its definition- but these are considered sure-fire planets. The rest, he said "Have to get their accreditation."

 

Brown said that as an astronomer, he finds this all a bit bureaucratic- "a strange process," counter to the way science is supposed to work. "They're scared to demote Pluto." he said. Most of the planets were too obvious for any kind of official discovery. Mercury, Venus, Mars, Jupiter, and Saturn were known to ancient civilizations, Gingerich said.

 

It's not clear why there is so much pressure to keep Pluto a planet or whether the push is coming more from elementary-schoolteachers or grown-ups. "I think it's a total projection," Said Derrick Pitts, chief astronomer at the Franklin Institute. Children, in general, accept change better than grown-ups. "I'm convinced this love affair is because in 1930 Pluto the dog was first sketched," said Neil Tyson, chief astronomet for the Hayden Planetarium in New York."

_______________________________________________________________________________________________

 

How can a planet be an underdog? A lot of people call Pluto a underdog planet lol. a underdog of what? It seems this whole Pluton crap is nothing more than a bunch of scared astronomers trying to keep the masses happy. How can grown-ups be upset that Pluto might be removed? the New york observatory got thousands of letters from protesters saying its not right to remove Pluto lol. Hell my teaher friend said he was told by the princpal of the school he works at that if he values his career he should stop telling the kids Pluto is not a real planet. The principal said parents would cal lto the school because their kids would go home crying that Pluto is not a real planet. He said his wife, a college professor at UMKC ( a local college in Kansas City ) had her life threatened by people who are pissed that Pluto might be removed so she stopped saying it. crazy huh? And even crazier, some people think that since Pluto was discovered by an American, the rest of thew world wants to remove it out of spite lol. Even though the guy who started it works in New York.

[ecoli]

people don't like change darkangel. the nine planet thing is an axiom of sorts for elementary schools these days, and astronomy is one of the few branches of science that still seem accessable in the public eye. Anyone with a telescope in the backyard knows that pluto is a planet... changing that would ruin their neat sense of reality.

 

I wonder how people thought when pluto was first discovered and classed as a planet. Were people angry?

[Dr. Dalek]

Darn' date=' you beat me to it.

 

I'm just curious, does anyone here disagree with this decision?[/quote']

No,

For me it is an exicting new prospect. I was getting sick of just the nine planets. Also there are more objects in the kepler belt that meet the "sphere, orbiting sun" requirment so there might be more than twelve.

NEW PLANET CANDIDATES

Trans-Neptunian Objects

2003 EL61

2005 FY9

Sedna

Orcus

Quaoar

Varuna

2002 TX300

Ixion

2002 AW197

 

Asteroids

Vesta

Pallas

Hygiea

EDIT: woah, charon is classed as a planet now. its in orbit around pluto!

Pluto dosn't dominate chirons orbit because they are closer in size than other planet/moons.

Pluto and Charon swing around each other like a sine wave in orbit. So they are less like a planet-moon system and more like a double-planet system.

[woelen]

I would most like a definition system, where there are 8 planets (Mercury ... Neptune), asteroids, mainly between Mars and Jupiter, and Oort-cloud objects. Pluto belongs to the latter class, and possibly hundreds of Pluto-sized other objects and maybe thousands or even millions of smaller objects. The Oort-cloud extends far far beyond Neptunes orbit and who knows what is all inside that area of the solar system. Maybe even earth-sized objects, but still I would not call them planets.

[darkangel199]

people don't like change darkangel. the nine planet thing is an axiom of sorts for elementary schools these days' date=' and astronomy is one of the few branches of science that still seem accessable in the public eye. Anyone with a telescope in the backyard knows that pluto is a planet... changing that would ruin their neat sense of reality.

 

I wonder how people thought when pluto was first discovered and classed as a planet. Were people angry?[/quote']

 

 

yeah but this woman works at a university! and the other guy is a teacher. lol today i was talking about it with a friend in Borders the bookstore, and this woman heard me say Pluto shouldnt be a planet, maybe its a comet that just has a a planet like orbit? cause if it ventured closer to the Sun it would get get a tail, much like regular comets.

 

she went on and on about how "WE scientists " (mind you i am not close to being any kind of scientist) are trying to "take away Pluto" we should "leave it alone!" lolol. me and my friend just laughed. I just think it would have been easier to set better conditions for planethood, not fix the system to keep Pluto in to make people happy. Hell by the new definition their are at least 50 planets in our solar system alone! and if this is the new rules, then why isn't Sedna included as well?

[Dr. Dalek]

yeah but this woman works at a university! and the other guy is a teacher. lol today i was talking about it with a friend in Borders the bookstore, and this woman heard me say Pluto shouldnt be a planet, maybe its a comet that just has a a planet like orbit? cause if it ventured closer to the Sun it would get get a tail, much like regular comets.

I think I read somewhere that the Earth has a tail. Just not a very visible one.

 

I just think it would have been easier to set better conditions for planethood, not fix the system to keep Pluto in to make people happy. Hell by the new definition their are at least 50 planets in our solar system alone!

In science the best explanations, solutions, and definitions are simple, generalised and can be applied broadly. "A planet is any object massive enough to assume a roughly sphereical shape and orbits a star, however a planet cannot be a star." This seems simple and generalised enough.

The thing is the whole thing about this new definition is they are not technically "fixing it" for Pluto. We already had a definition for planet when Pluto was discovered that Pluto apparently fit into. Seems more like someone tried to change the definition of planet to get rid of Pluto and failed, more so then someone trying to save Pluto in the face of harsh scientific scrutiny.

 

and if this is the new rules, then why isn't Sedna included as well?

Actually Sedna is a candidate for a planet that might very soon be defined as one, but you can't do these things all at once.

[Anjruu]

I think we should get rid of the term 'planet' entirely. Or at least sub classify even more. Have 10 different types of planets, or something, ranging from brown dwarf-sized, super-jovian planets which orbit at 1/10 the distance of mercury, to Pluto-sized planets which orbit as far away as can be imagined, and everything in between. If we want, we can still call them all planets, but the term alone is too vague. That's my two, uneducated, opinionated cents. I know you all didn't ask for it, but you got it anyway.