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A New Definition Would Add 102 Planets To Our Solar System -- Including Pluto (washingtonpost.com)
The Grim Reefer quotes a report from The Washington Post: Is Pluto a planet? It's not a question scientists ask in polite company. "It's like religion and politics," said Kirby Runyon, a planetary scientist at Johns Hopkins University. "People get worked up over it. I've gotten worked up over it." For years, astronomers, planetary scientists and other space researchers have fought about what to call the small, icy world at the edge of our solar system. Is it a planet, as scientists believed for nearly seven decades? Or must a planet be something bigger, something more dominant, as was decided by vote at the International Astronomical Union (IAU) in 2006? The issue can bring conversations to a screeching halt, or turn them into shouting matches. "Sometimes," Runyon said, "it's just easier not to bring it up." But Runyon will ignore his own advice this week when he attends the annual Lunar and Planetary Science Conference in Houston. In a giant exhibit hall crowded with his colleagues, he's attempting to reignite the debate about Pluto's status with an audacious new definition for planet -- one that includes not just Pluto, but several of its neighbors, objects in the asteroid belt, and a number of moons. By his count, 102 new planets could be added to our solar system under the new criteria. USA Today reports: "In the mind of the public, the word 'planet' carries a significance lacking in other words used to describe planetary bodies," the proposal states. "In the decade following the supposed 'demotion' of Pluto by the International Astronomical Union, many members of the public, in our experience, assume that alleged 'non-planets' cease to be interesting enough to warrant scientific exploration."
He's a dog!
-=This sig has nothing to do with my comment. Move along now=-
Academic politics is so vicious because the stakes are so low.
What prevents us from using a spectrum of overlapping well-defined concepts covering the wide range of objects in the system surrounding a star? Oh, and we already have it!
It's all about who owns the word planet. And my funding dick is larger than your funding dick.
It's going to make calculating a horoscope very complex. The *only* way will be with computer software, and you'll need large-format plotters to print charts.
How about this?
Require hydrostatic equilibrium and that the object orbits the sun. That eliminates most asteroids and things like that. If two bodies are in hydrostatic equilibrium and the center of mass is outside of the center of either body (the Pluto-Charon system), it's a double planet. That seems logical to me. Unfortunately, the definition that's been proposed would include moons as planets, even though they clearly orbit a planet.
No. Nothing can be a planet unless it is larger than Neil deGrasse Glactus's ego. A dwarf planet is no more a planet than a dwarf person is a person.
I'm an American. I love this country and the freedoms that we used to have.
I can't remember the names of 102 planets. What the fuck?
because this shit definately doesn't matter.
Anons need not reply. Questions end with a question mark.
how the hell are they supposed to learn a mnemonic that's 110 words long, they can't even handle the (current, and still bitter about it. #savePluto) eight word "My Very Eager Mother Just Served Us Nachos"
I'm sorry
Didn't Old Bill ask, "what's in a name? That which we call shit by any other name would stink as bad"
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Nothing should be called a moon if it doesn't have the gravity to produce plasticity in the rock.
She makes at least two excellent points in the article:
1. the word 'world' is scientifically recognized and fits pluto & the others just fine
2. classification must be useful, dammit !
whatever you want/need to do that helps identify different classes of astro bodies best.
(Someone had to say it. C'mon.. we were all thinking it!)
Excuse me nice gentlemen. I don't mean to interrupt but, I've been searching news articles trying to find my cat. Have you seen my cat?
... always a planet.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Has anyone asked Pluto how it identifies itself? I bet none of you have checked your privilege and even thought of it!
640k planets ought to be enough for anybody.
And then Ptolemy's geocentric model put Sun and Moon in a special group, because differently than the other planets, they never change direction in the sky, which the others do. Thus, the trajectories of Sun and Moon were easy, while the other planets needed cycles and epicycles to describe. This was one of the reasons, Nicolaus Copernicus came up with the heliocentric model, because then it made sense why Sun and Moon were "circular" wanderers, while the other planets were "epicyclic" wanderers, So, Sun and Moon were no longer considered planets, a position already shaky in the Ptolemian model. But it added Earth as a new planet. Copernicus' system didn't come up with good predictions of the planetary positions though, thus it wasn't widely accepted and even considered heretic by the Catholic Church. Johannes Kepler improved on the predictive power of the Copernican system, but Ptolemy's model was so finely tuned by now that it still was preferred for practical reasons. Galileo Galilei's discovery of the Iovian Moons gave credibility to the Keplerian model, but for navigational and other purposes, Ptolemy was still more exact. And it created a new class of celestial bodies: Suddenly, there wasn't one Moon, there were several moons out there. From a classical point of view, all moons were planets too: no fixed positions within the stellar constellations. At the end of the 17th century, Isaac Newtons Theory of Gravity gave a better model, Ole Roemer's discovery of the Speed of Light added some clues, and finally, the heliocentric model was better at predicting planetary (and lunar) positions than Ptolemy. But then a flood of new discoveries of celestial bodies clouded the view again: Uranus, Ceres and finally Neptune were discovered, and then all the other asteroids circling the Sun between Mars and Jupiter. Somehow the size of the Earth moon was used as a cut-off: Everything larger than the Moon circling the Sun was considered a planet, everything else an asteroid (which literally means "star like"). It was as arbitrary as anything else, but the Moon was close by and well studied, so for practical purposes, it made sense.
When Pluto was discovered, it became planetary status, because at first, its size could not be determined from direct observation, only because of the brightness (15 mag), it was at first considered to be Earth sized. So it got the planetary status. Later there were better pictures with larger resolution, and the estimated size shrank down to ~2500 km in diameter, and in the same way, the estimated reflectiveness (albedo) increased, so in the 1980ies, Pluto was considered a "dirty snowball", consisting mainly of water ice mixed with planetary rock. Thus the cut-off point "Moon size" was crossed, and doubts about Pluto's nature as a planet arised. It was speculated that it was a former Neptune moon losing its orbit. And when the next transneptunian objects were discovered, like Eris, with about the same size than Pluto, the whole "what is a planet" question became virulent. Simple enumeration as in "The planets are those nine celestial objects we call Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Pluto" didn't work anymore, and a meaningful definition which included Pluto, but not too many other newly discovered objects, wasn't readily available.
"...have fought about what to call the small, icy world at the edge of our solar system."
I have a name for it.
Irrelevant.
Not good enough? Need more clarity? OK, here's some more.
Uninhabitable. Worthless. Pointless.
Until we start landing space mining equipment there to bring back an argument of value, perhaps we could find something else to discuss. This "religious" discussion is reduced to nothing more than textbook revenue when they need to re-write millions of them, which makes it rather cheap and not very scientific.
Diane Duane wrote a very fun series of books starting with "So You Want to Be A Wizard". In "Games Wizards Play", our heroine had a long chat with Pluto, who was attending a wizard's competition, about his status as a planet, and also about relationships among the planets, both socially and romantically.
Diane writes fun stories. She actually made a good story about X-Com, with actual plot, and portrayed the history of Vulcan, including the courtship of Spock's parents, in her book "Vulcan". Her stories about Vulcan and about Romulans are not considered canon by Paramount, but they make *sense* as cultures and about people with powerful intellects, powerful wills, and powerful tragedies. I always look forward to when she publishes something new.
The last time this was discussed on slashdot there was a very interesting series of comment posted by Rei that shed a lot of light on what the issues surrounding this are and how the situation (and redefining what a planet is) came to be.
(you should know the music...)
9 planets orbiting around the Sun. 9 planets.
Take Pluto down, pass it around, 8 planets orbiting around the Sun...
The proposed definition can be found at words 765-799 of the article.
A planet, he says, is anything massive enough that gravity pulls it into a sphere (a characteristic called “hydrostatic equilibrium"), but not so massive that it starts to undergo nuclear fusion and become a star.
The preceding 764 words are a useless regurgitation of how people feel about definitions in general and Pluto in particular. Spare me.
"We reject as false the choice between our safety and our ideals." --The American President (20.1.2009)
I like the definition of planet based upon any body of sufficient mass to be round (or nearly so to some mathematical measurement). That is, it is a planet based on size/mass and what it is within itself, and it is what it is no matter where it is (in the inner solar system or floating between stars).
The definition of having cleared it's neighborhood means that when it first formed, Jupiter wasn't a planet because it hadn't had time to clear it's neighborhood, and obviously this would include all of the other planets during formation. At some point, we'll probably find a distant solar system where there are two planets that orbit each other. Since they wouldn't have cleared their orbit of their twin, could they even be considered a planet under the 2006 definition even if they were far more massive than Earth, and even had an earth like eco-system? Would you like to be the astronomer that had to be pedantic an tell journalists that these weren't planets because it's hadn't eliminated it's binary partner?
So, moons (not counting Mars', perhaps they would be called asteroid moons) are planets (or planetoids) that orbit larger planet. If you want to have a distinction for planets that do what the re-definition did in 2006, add some modifier like solar planet (indicating that the planet is considered to be a part of a star's main planetary system) and give it the additional requirements that were voted on 2006.
My Very Excellent Mother Just Served Us Noodles with a side of broccoli, but my younger brother did not like to eat his broccoli so he decided to have pizza instead going to the pizza place around the corner asking toni if he offered pizza with tuna to which tony replied that he...
I am sure that there is a fat mom joke in there somewhere. Where is it?
Don't fight for your country, if your country does not fight for you.
Pluto traditionalists are the root cause of all ills in society
People should stop whining about semantics or personifying a planetary body as if it was a person. smh
My Very Eager Mother .....
This is gonna get long, folks, be back in a bit.
"Planet" and "moon" should be declared lay terms with no scientific or technical meaning. All non-stellar bodies are "satellites" which are referenced to their gravitational primary. Earth is a "solar satellite". Phobos is a "Martian satellite". Pluto is a "solar satellite", as is Ceres, Vesta, Jupiter, etc. Dactyl is an "Idanian satellite", which is in turn a "solar satellite". If you just want to get size involved then reference other known quantities. Pluto is a ".177 Lunar mass solar satellite", Jupiter is a "317.8 Earth mass solar satellite".
A planet is any object in orbit around a star, of sufficient mass to reach hydrostatic equilibrium, has not reached critical mass to achieve stellar fusion, and is the most prominent body in its orbit and neighborhood. That definition is going to add a few more planets but not many.
The suggested definition from TFA is just as terribly obtuse as the 2006 definition. Even worse is the suggestion to change the word 'planet' to become an all encompassing term that now also means most smaller bodies as well (but not all). It makes things unnecessarily confusing. This just seems tantamount to two-year-old logic where one word now means everything.
And look, my suggested definition expands.
A moon is any object in orbit around a planet, of sufficient mass to reach hydrostatic equilibrium, and is the most prominent body in its orbit and neighborhood.
A moonroid (haha maybe?) is any object in orbit around a planet, has not reached critical mass to achieve hydrostatic equilibrium, and is shares its orbit and neighborhood with other objects of similar mass.
An asteroid is any object in orbit around a star, has not reached critical mass to achieve hydrostatic equilibrium, and is shares its orbit and neighborhood with other objects of similar mass.
And so on. The hydrostatic equilibrium is critical to defining celestial bodies but it shouldn't be the only requirement to define a planet.
..should count as planet #103, big & round.
At least try a more promising way to make Pluto a planet again. Why would anyone want to have 200 planets?
I remember always thinking that Pluto was odd as a planet. In elementary school they'd explain how all of the planets orbited along the ecliptic plane, and keep to their own orbits, except for Pluto. Its orbit isn't on the same plane as the other planets, and it crosses into Neptune's orbit. For me, that's what makes it not a planet.
"I was big enough for your mom." -- Pluto
"I believe in Karma. That means I can do bad things to people all day long and I assume they deserve it." : Dogbert
Everyone knows the song "my very educated mother just served us nine pizza pies" Adding 102 planets would be impossible for kids to remember LOL.
Yeah, your mom was excellent. I'm just curious how you would come* to know that.
*no pun intended
We keep trying to come up with rules which include those objects want to include and exclude all the others. The rules are arbitrary too, the result of a majority vote by some group. This is not science; it is semantics.
Pluto was well established as a planet years ago in the irrefutable context of song.
Pluto- 2 Skinnee Js: http://youtu.be/heRn5n6z-Ck
I ignore Anonymous Coward posts. If you want to discuss something, that's awesome. Log in.
We can't let these bad hombres into the United Planets of Solar System! We need to build a wall and Mexico will pay for it!
That is very true. Any scheme that puts Earth and Jupiter in the same class is highly suspect.
From the article, musing about how an alien visitor might classify them...
"Which of these would they consider a “planet” — or whatever the alien term for “planet” might be?"
Maybe a more useful classification would be to classify them by the characteristics of the body itself, irrespective of its orbit. Their word that we'd likely translate as "planet" might only apply to Venus, Earth, Mars, and Titan. (Rocky bodies with significant atmosphere.)
Most of the arguments for 102 extra planets in our solar system seem to be based on the public being excited about having a planet. I don't think it'd work that way. Having 110 planets would water the concept down. The problem is that an object is perceived as less interesting because of it, and that's not true at all.
There's nothing to stop a moon from being as large and complex as any planet. Ceres is categorized as a dwarf planet, and it's got surprising geology, even a chance of harboring water and life. The surface of comet 67P has proven to be amazingly interesting. Pluto didn't need planetary status to knock our socks off in 2015. We *are* going to find more rogue planets floating through space with no parent star that we can see. We are likely to find Planet 9 soon, and there's a chance it's not a planet which Jupiter and Saturn kicked out during our system's formation, but a captured exoplanet. These are all fascinating objects!
It's a question, though, of where they form, how they exist, what bodies they're interacting with. It makes no real sense to me for Europa and Ganymede to not be moons. Their primary gravitational attraction is to the planet they've formed around. That planet is something formed together with its parent star from the same disk, because of the gravitational eddies and changes that produced that star. They're all made from that system. That's what seems to be behind all the particular stipulations of what a planet is.
I'm okay with that!
Only Flat objects in space (such as the earth) are allowed to be considered planets, all spheroids are moons, anything irregular is an asteroid
On the Internet, no one can tell you're just a dwarf planet.
I'm a linguist, and I don't understand this controversy. Why should anyone care how the IAU defines 'planet'? They can't keep you from using the word any way you want, and their definition obviously makes no difference whatsoever to Pluto itself, nor does it have any legal standing (you won't lose your health care depending on which way they define it). So what's the big deal?
That 2006 vote came when most of the scientists had packed up and gone home. So the vote wasn't really a vote. They shouldn't have voted in the first place. After the uproar the should have admitted they made a mistake. From what we know about Pluto, it should be classified as a planet. They should admit it was a mistake.