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Definition of Planet to be Announced in September
MasaMuneCyrus writes "After over seven years of debating, the International Astronomical Union announced that it expects to announce the official definition of a planet in September. After many-a-deadlock, they handed the task of deciding exactly what a planet is to a new committee, which includes historians and educators. 'They wanted a different perspective from that of planetary scientists,' said Edward Bowell, an astronomer at Lowell Observatory who is also vice president of the IAU's Division III-Planetary Systems Sciences group. If all goes according to plan, the wording will be proposed in their 12-day General Assembly meeting in Prague."
....or is it? :-P
Pluto?
I've been 50-50 on it myself. I'm a fan of anything Arizona (having lived there), but apart from the moon system, I'm hard pressed to call it a planet.
If Pluto sticks - then there's probably 100s of Kuiper Belt objects that qualify.
It's great that some random internationally sanctioned body is going to announce some arbitrary definition of a planet, but what does this mean to those of us who only care about a LIFE SUPPORTING planet?
... debian-legal will notice that Earth is not a planet under the new definition.
http://outcampaign.org/
The argument over the definition of a word reminds me of a quote from former president Clinton... "It depends on what the meaning of 'is' is."
I hope Pluto finally gets excluded from planet definition. It's too small (only twice the size as it's "moon", Charon, and a little less than a fifth as massive as Luna), it's out of the plane of the elliptic (a trait shared with objects like comets, but not any planets), and it's not even orbiting in a stable configuration with regard to Neptune (for part of it's orbit, Pluto is in fact eighth, and Neptune ninth).
Then there's the fact that it only really got counted as a planet in the first place because astronomers at the time of it's discovery were hung up on the idea of discovering a ninth planet. They thought they found a disturbance in Neptune's orbit, which they attributed to a ninth planet, but ended up being caused by the fact that they were working from bad data about Neptune's mass. Pluto's much too small to have any effect on Neptune's orbit.
This might finally put the final nail in the coffin of the idea of nine major planets in our solar system. We can only hope.
Planet: object orbiting a star, massive enough to be spherical under its own weight, but not enough to undergo nuclear fusion.
Major planets: the eight (Mecury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune).
Minor planets: the moon, all the spherical satellites of the major planets, Pluto, all the spherical asteroids in the asteroid belt and all similar spherical kuiper belt objects.
I think the most logical thing would be to consider "planet" a part of the name of a celestrical body, just like we do with "ocean" and "sea", and not use it as a classification word.
That's right, because it's important to know what kind of spin to put on the spread of a nation's doctrine. Will we be colonizing an asteroid, planetoid or is this celestial body a true planet? Most adviors agree that establishing an embassy will increase your cultural influence.
My Very Eager Mother Just Served Us Nothing?
Where does Xena fit into this mess?
As a planet candidate, I don't see the problem with having 20 planets in the solar system! I don't see why so many people are against having a lot of planets in our solar system...is it that difficult to remember a few more of us? Sheesh!
I'll form my OWN solar system! With blackjack! And hookers!
I don't even think this is a real "Sun" we have here. I'd say it was a "yellow dwarf".
OTOH the other two moons are small enough to be called moons.
The Raven
I meant "there are nuclear reactions going on inside the Earth's core" rather than fusion. Like I said, I can't remember if it's fusion or fission.
You seem to have a fundamental misunderstanding of the nature of proof in science. We've observed those planets about as well as we've observed many subatomic particles. Entities are posited to fit the observation. This is the case in any area of science. Not counting possible margins of error in measurements, we've observed these planets in much the same way as we observe subatomic particles. Would you like to stop believing in those?
If you would, would mind explaining exactly how all our predictions based on those particles ended up being right? Lucky guesses, the lot of them?
That's an awfully big leap of faith.
Your comparison, by the way, entirely fails to hold water. The issue here is a historical mistake having been entrenched in the popular definition, and the lack of a technical definition. IUPAC doesn't have to deal with popular definitions confusing the issue, they're already developed technical definitions for anything within their scope.
to come up with "A massive body that reflects more radient engergy than it generates".
the earth is flat ! http://www.alaska.net/~clund/e_djublonskopf/Flatea rthsociety.htm
http://zapatopi.net/afdb/ and open yr mind 8)
bring bak the ponies ! xx
bring bak the ponies!!
for what it's worth (not much):
planet = mostly rock/metal sphere with a significant atmosphere (what "significant" means becomes a point of contention then of course)
asteroid = solid rock/metal object that is not spherical
moon = rock/metal sphere without an atmosphere
a gas giant should be considered as something different than a planet (mostly gas, obviously spherical)... a star is simply a gas giant that has achieved thermonuclear fusion... and in between you have your brown dwarfs and other objects occuring at the end of a star's life time/ before it's lifetime/ malformed and never quite stars, etc.
and comets should also come to mean any agglomeration of ice and rock and dust that is loosely packed, not just those we see streaming towards the sun on a regular basis... as we explore the oort cloud, we'll find plenty of these "dormant" comets
and most importantly: all of these objects should be defined independently of what they orbit
so mercury isn't a planet, it's a moon of the sun
likewise, pluto is a moon of the sun
and ceres and vesta are moons of the sun (small perfectly spherical "asteroids")
titan isn't a moon, it's a planet of saturn (it has a significant atmosphere)
the most important thing i think, no matter what nomenclature is agreed upon, is that as we discover weirder extrasolar objects out there, the "what it orbits" part of an object's identity should come to mean something totally different than "what it's made of"
and size should never have meaning
then of course, we have to come to grips with direction of orbit, orbits outside the elliptical, orbits with bizarre shapes, binary/ tertiary objects, binary/ tertiary/ quartanery star systems, etc.
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
10 bucks says the definition is broad enough to include Pluto but narrow enough to exclude any other "extraplanetary" bodies in our Solar System; they want to preserve the status quo of the Solar System, don't they?
This sentiment is baffling to me. You're living on a big hunk of emperical evidence. If the planets of our solar system can form it follows logically that planets can form around other stars. If our solar system is like even a small fraction of other solar systems we can use information about ours to look for other ones. There's several methods to find extrasolar planets, and quite often multiple methods can be used on the same system to verify the findings of other observations. Large planets cause a star to appear to wobble. This happens because the two bodies are orbiting their mutual barycenter. By keeping track of a star's periodic doppler shift it is possible to determine the mass of an orbiting planet or planets. This method can also be used to confirm findings from planetary transit observations. When a planet's orbit brings it between its parent star and us the light of the star will dim slightly and for a period of time related to the size of the planet and length of its orbital period. With this information the mass of the planet can be determined. If this meshes with the star's wobble you've got pretty good evidence of a planet orbiting that star.
I'm a loner Dottie, a Rebel.
A mass large enough to be gravitationally shaped into a sphere, and has not undergone fusion reaction at its core at any stage of its life.
Things are either black or white, up or down, good or bad. There are no shades of grey.
Can't we just say that there are different objects in the universe that have similar properties? What's wrong with saying an object is 30% like the planet we're on, but 70% like Jupiter?
Must everything have a category?
It's a real flaw in western thinking. We can't just simply let things be - we have to pin them to cork boards like preserved butterflies. Why not just describe what you find as you found it? Nature doesn't fit things into categories, why should we?
Weaselmancer
rediculous.
then there's probably 100s of Kuiper Belt objects that qualify.
Is it that important to have a precise definition of what is a planet and what is not?
Unless you are going to precisely define every single astronomical object. from dust to galaxy filaments.
I suspect that someone is going to claim the possession over those planets (apply the definition here).
Maybe Computers will never be as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]
Therefore whatever definition is used, Pluto will always be included as a planet.
Same reason why American's will always keep the penny. Ego and historical pride.
Recycle PCs and build a wireless community network www.hillsborough.org.nz
come on, alien must come from a planet ;)
Why not categorize and measure like G(ravity), N(ewton), K(elvin)?
If an object is one half earth's mass, just call it 1/2 Planet. If the object orbits around a planet, just call it satellite or moon or subplanet. After all, planet means "to wander". What doesn't wander around the universe?
*Middle English, from Old French planete, from Late Latin planta, from Greek plants, variant of plans, plant, from plansthai, to wander.
ref. dictionary.com
"Don't let fools fool you. They are the clever ones."
"Not a star."
Debating about what is and is not a planet. "Planet" is just a word. Deciding that some object is or is not a planet doesn't advance science. Why don't we just say, "our solar system has nine planets. Things outside the solar system that are similar to our nine planets will also be called planets. Pluto is traditionally called a planet. Other things smaller than Pluto may be called planetoids, small planets, mini-planets, or asteroids. Things outside our solar system that are gas giants are planets. But things that used to be stars, like brown dwarfs, will not be called planets. Agonizing over whether Pluto really is a planet or not is sort of like agonizing over whether Superman could beat up Batman."
How hard is that?
a brief glance at the discussion shows a strong geo-centric thinking.
if its so popular whyn't go a logical step further?
Every Earth is a planet, everything else is NOT.
The real planet has water, oxygen, and it is 150 million km from the sun.
Dunno, Mars, brother, what you are. You dont even qualify for a piece of rock.
you have to change your name to something that's pronouncable by those of us with only one mouth.
I've read about this debate numerous times, and I've seen size, atmosphere, orbit plane, eccentricity, composition, mass, shape, whether it undergoes fission, what it orbits, and probably other things considered as factors. One factor I've never seen mentioned before is whether or not the body lies in a unique orbit.
I think the following definition should suffice: a planet is a non-fusioning body (or system of two (or more) near-mass bodies in close orbit) in orbit around a star (or system of two...), massive enough to maintain a spherical shape, lying in an orbit that is unique, except for its satellites (or twins).
This definition includes the current nine planets, none of their moons, and none of the "belts." I dont think the composition, presence of an atmosphere, orbital plane or eccentricity, or size should be important, but it should be in a first-order orbit around a star, and it should be able to maintain a spherical shape, and probably most importantly, it should be the only body that follows its orbit, unless it has satellites. As far as I know, there aren't any currently known objects that fit this description besides the nine planets and the three or four bodies that have recently been discovered beyond pluto, and I have no problem calling those planets.
I have always considered Pluto a Micky Mouse kind of planet. And I think the IAU should consider the impact of their decision on the Cartoon universe as well.
Disclaimer:
I know nothing about astronomy.
Wouldn't it be easiest to just state that anything that exists in the solar plane is a planet and anything that isn't is just a captured satelite?
I know that this would exclude Pluto and all other Ort Cloud objects.
This is a complicated question, but what is wrong with an easy answer?
"The price good men pay for indifference to public affairs is to be ruled by evil men." ~Plato (427-347 BC)
...but I know what I like! :)
:)
But what I really want to know is this: planets orbit stars, and moons orbit planets, right? So what would you call something orbiting a moon?
Actually, I think we should have three categories: star, planet, asteroid. It shouldn't matter what it's orbiting. If it's big, round, and burning, it's a star. If it's big, round and not burning, it's a planet. If it's not so big and not so round, it's an asteroid. Luna, Ganymede, and Titan are both moons and planets. Phobos and Deimos are both moons and asteroids. Ceres and Pluto are planets. Comets are mostly asteroids, but some of them may be planets.
Fortunately for all of you, nobody listens to me.
Dear IAU, You suck. Love, Merriam-Webster
By the pricking of my thumbs, Something wicked this way comes: Open, locks, whoever knocks!
- Four terrestrial planets
- Four jovian planets
- The Kuiper Belt objects
- and the remaining comets, asteroids, dust, etc.
(Yes, I know I'm using the word planet, but the actual dispute is being driven by the discovery of a Kuiper belt object larger than Pluto and farther from the Sun).Planet: Biggish piece of rock.
/*ducks
Moon: Smallish piece of rock.
Meteor: Really tiny little bastard.
U.K: You don't want to know.
It honestly doesn't matter. The astronomers have purposefully tasked non-astronomers with agreeing on a definition of "planet".
This way, astronomers can continue to deny and decry that definition, because it wasn't done by them.
Science, meet Mr. Politics.
- RG>
Hey pal, this isn't a pleasantforest, so don't waste my time with pleasantries!
The definition should be based on surface gravity, or average surface gravity, that way the definition of a planet would be usefult. The watershed could be say, an average surface gravity that would make it feasable to build a facility of some kind where a long term human prensence can be sustained without major risk to health.
This would also be useful as objects could be classed with a relevance that would be important to any future explorer. Even non elliptical objects could still be given a metric to judge their habitability.
"Sir, object is a Class G planetoid! Our noses will be crushed by our feet if we set foot on it."
"I see"
"However sir, the Halo Ring, despite not being isomorphic to a sphere, does qualify as a planet due to a reasonable average surface gravity."
"Cue music. We're going in.
But even dyson spheres could qualify as planets.
May the Maths Be with you!
A planet must:
Revolve around a star
within a certain maximum aphelion
having a maximum elliptic
Be large enough in volume
Not be artificial in nature (this provides that any intelligence in this universe creating an object that would fit the prior criteria would not be allowed to call it a planet)
Define maximum aphelion and maximum elliptic and minimum volume. What else is there?
Web 2.0 == Giant Blogspam Circle Jerk
Maybe they should break the deadlock over Pluto by playing one (1) game of Rock, Paper Scissors.
www.wavefront-av.com
-- nt --
Wikileaks, no DNS
As Jesapoo points out, it's not about size, but as important as orbit eccentricity is material composition. Planets are historically categorized into two buckets based on their composition -- "terrestrial", which are mostly rock (mercury, venus, earth, mars), and "jovian", which are mostly gas (jupiter, saturn, uranus, and neptune). And then there are comets, which are mostly dirty ice and frozen gas with some rocks.
Pluto is cometary in composition, which has led some to classify it as a comet rather than as a planet. Frankly I can see the argument. Perhaps the best way out is to define "planet" such that some comets can be planets?
-- TTK
The IAU issued a press release stating that the definition would be delayed until next year while they change to the metric system. They also noted that when it is finally released, it will be the most awesome multiplayer online definition of a planet that the world has ever seen.
The IAU has offered its Division III-Planetary Systems Sciences group $500,000 in the form of a promissory note if the definition sees commercial release by December 31, 2006.
steampunk web design
Just call everything a fucking moon and be done with it!
Seriously, this entire "is Pluto really a planet" debate is getting very old. The word is just a word and no matter what you call Pluto it's still going to play the same role in our solar system. I can't believe that intellegent people with serious educations have a hair up their ass about simple terminology.
Dedicated Cthulhu Cultist since 4523 BC.
Any objective observer looking at the solar system from a stellar perspective [see note below] would describe the Earth and Moon as a double planet system. Each of these planets has significant dynamic features that cannot be accounted for without acknowleding the tidal effects of the other.
The taxonomy of astronomy is not going to make any sense until astronomers openly accept this, despite their personal, historical and cultural biases. It is now time for scientists to accept the Moon as a planet in its own right, and take the next significant step in completing the revolution in thought that was started by Copernicus 500 years ago. I mean come on, that's half a millenium! Isn't that enough time to take the next step and recognize that not only does the Earth go around the Sun, but that the Earth and Moon dance a dosido with each other? Gee, it isn't as if we're all Galileos facing a Church Inquisition for having bad thoughts! It is time to wake up and feel the gravities of the situation!
Astronomy has a much more serious problem than deciding what to call small distant objects. Until astronomy acknowledges that the Earth and Moon are a double planet system, the other sciences are not going to acknowledge it. Yet the advances that can be made in meteorology are limited if the tidal distortion of atmospheric envelope is not recognized in the models. Similarly, a full understanding of geology is not possible without recognizing that the Earth-Moon baricenter lies outside the Earth's core-- and that there is a significant amount of stress placed on the lithosphere due to this.
About five hundred years ago, a few astronomers dared to buck traditional thinking and in doing so not only freed astronomy from the limitations of traditional thinking, but also showed the direction to greater truths that the other sciences could take. It would be good if astronomers would again rise to the challenge, and take the next step.
The Moon is a planet. Let's acknowledge that.
note: A stellar perspective is significantly larger than a mere global perspective. From any stellar perspective, it is impossible to resolve the image of the Earth without also resolving the image of the Moon: if you can see one, you can see the other. Our stellar observer would not be able to plot the orbit of either without taking the other into account: the Moon is no mere satellite of the Earth; it is the somewhat smaller partner in a long term marriage.
it is what it is what it is
o ughtosupernova"
t ohavenaatmosphere"
nobody said anything about the need to capture the why of something being the way it is in a naming convention
you call something a "white dwarf", for example
you don't need to capture the idea it is a white dwarf because the star was not massive enough to supernova, that's not something you capture in the name of an object
you don't call it "whitedwarfleftoverfromdeathofstarthatwasnotbigen
you don't say "thisisamoonnotaplanetbecauseitistooclosetothesun
these deeper meanings are not things anyone tries to capture in any naming convention
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
"Fall heavy towards the moon, and the moon falls also towards you." -- Nietzsche
Hammer and feather are dropped simultaneously from equal heights (as measured by distance from the center of the moon), separated laterally by a distance substantially less than the moon's diameter. Both hammer and feather experience force from the moon's gravity proportional to their mass, and hence both accelerate at the same rate. Meanwhile, the moon is also accelerating towards the other two objects, but unevenly so: the hammer exerts a greater gravitational pull due to its greater mass. The moon is therefore subject to a torque, causing it to accelerate more rapidly towards the hammer.
The hammer is first to hit the ground.
Anyone who denies this truth is a spatially absolutist lunocentric whose refusal to recognize the validity of hammer mechanics/experience places him wholly beyond the help of Galilean metaphysics. Such hammer (feather) rejectionists ought to be banished to the stars, for their own good and for the good of not only hammers and feathers but all subjugated smaller objects, everywhere, who find themselves victims of this scientifically perpetrated emassculation.
--
a756f345ec354225c08ff1a10a43162a
First, "spherical" isn't exactly the right word. Ellipsoid is probably correct. The key thing is that the gross geometry is determined by gravity. We are indeed seeking an arbitrary cutoff, so that's no problem.
A brown drawf fusing deuterium is damn well undergoing fusion. It's a star. I think we also need to exclude anything that majorly violates newtonian physics, like a neutron star or black hole.
Last week we got a name for "rogue planet". It was something like "planemo", starting with "plan" and ending in "mo". (not that "intersteller planet" is a bad name though) Smaller intersteller stuff could be "astroidimo" or just plain "intersteller rock".
I'd also add: it can not be a planet if the center of it's orbit lies within another planet. This makes Pluto-Charon a binary system with 4 moons.
So maybe we have a dozen planets or even several dozen. No problem.
Need a new mnemonic, people! Mary's very eager mouth joyfully sucks until nut.
I, for one, do not expect a very intuitive definition. Just remember that a second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
We often refuse to accept an idea merely because the tone of voice in which it has been expressed is unsympathetic to us
But if they exclude Pluto from the planets, what does that mean for Sailor Pluto?
Will she become Sailor Kuiper? Would she be the first of the Outer Outer Senshi, to be joined by Sailor Oort at a later date?
i'd hit it so hard, if you pulled me out you'd be the king of britain [bash.org]
...Derrida? You cannot come down to one meaning of a word because words have play...Although this doesn't stop them from doing it anyway.
It will be interesting to see the "definition" they arrive at that will somehow define Mercury and (possibly) Pluto as "planets" and yet keep Luna from turning Earth into a dual-planet system. Not to mention the "moons" around Jupiter that are massive enough to have their own atmosphere. For the record I believe our Moon isn't really a moon, it should qualify as another planet... however there is too much inertia built up in human history to make that radical of a change to what people "believe".
Goes round the sun and is > 1000 Km. Allows Pluto, denies Ceres. Also allows that new largest TNO.
A plane is known today as any livable area, in soil composition to support farming. Is a planette the feminine or neuter of plane, or vis versa? I would like to see experimentation to a honey-bee colony built around an anti-gravity device, for that matter of agriculter in mobilizing collection and manufacture from the product. As usual, that is the purpose of colonialism (to prepare an area to sustain a society). When honey-bee colonies interlap their jurisdiction, the dispute can be moved away from stressing one-another's livelihood. Yet, looking to the etymological dictionary, I have defined a State and not a Colony: a state is prudent from the earth and up into the sky, while a Colony is privily difined as to the soil and below. Looking at America, the colonies charterd were for reproving the soil, and the charters were sealed upon dispute with the States united in a federal forum known as the United States.
Looking at the heavens, it is plausible to know that there is no such condition of being for a body to have no orbit. An Orbit is a reflection of relativity to the origin of its gravitational behaviour. All had an origin that split, then there was some locomotive force to continue those separate bodies in their own way, while others revolved around one-another or collided. Today, we see celestial bodies appearing to have no orbit, when in fact their orbit is changing every moment they enter the gravitational field of another that has more influence on the gravitational field prior. If it were that the celstiale bodies had no certain orbit, by discord from their foundation, even by law this would exhibit how the United States are no longer of North America. There is a "United States" in the District of Columbia, then there is a "United States" in Puerto Rico, then there is a "United States" in Guam (as well as territories that subscribe to its services.
Perhaps, given that "territory" applies to sea as well as land, we would know the difference between a "territory" charter as opposed to a charter in area in a vaccuum that is devoid of substrate/insulation (such are prime induction for the movement/conduction/semi-conduction of energy). In manner of colonial charter, energy is measured in gold Dollars, while in that of a state energy it is measured in dollars composed of people (not capital-D, but little-d dollars). I like that: capital-D Dollars as opposed to little-d dollars.
Thanks for the intriguing thoughts. What do you think?
without prejudice
A friend wrote this on the same topic. I call this limit the "Burton Radius", after my pal, Burton.
- size-limit-of-planet-my-two.html
30 seconds spent thInking of a good definition for the lower limit of whAt can define a planet leads Me to tHink "planet" should be defIned as "any celestial body that orbits a star, off of which a typical human could not jump themselves into orbit". if you can Go jump into orbit, it's not a planet. if you can't, it is. i define an orbit as moving 2*pi or greater rotations (in radians) around another mass to which you are gravitationally bound without touching the ground.
Just so.
taken from:
http://burtonmackenzie.blogspot.com/2006/06/lower
Demonstrant's Open Source Tools
The original definition of the word "planet" is wanderer. I suppose anything that wanders along the ecliptic can be a planet.
[Crow:] "I mean, you're the same Lewis that runs this place?"
[Lewis:] He shrugged. "Nobody runs this place that I know of." He paused, took a sip from his jug. "I do, however, own this rock. Have for a long time." He turned again to Lya. " Raised it from a pup. Boulder to you. Yep," he continued, patting the turf fondly beside his leg, "boulder first then he became, uh..."
"Bigger?" Lya offered.
"Right," he nodded. He eyed her with scrutiny. "Hey, you know an awful lot about this sort of a thing for a hussy. So where was I? Oh, yea. Boulder, then a bigger boulder--all easy so far. But next comes the toughie when he got to be an asteroid." He shook his head. "Ugly, ugly, stage in life, le me tell you, is that adolescent asteroid period. No respect at all. No values."
"But with a will of iron," broke in Lya, "and the determination of a god...."
Lewis looked delighted. "Golly, that's pretty! Oh, yeah. With iron will and the determination of a god, I..." he paused, right index finger poised, "I did it."
http://en.wikipedia.org/wiki/Armor_(novel)
[Fuck Beta]
o0t!
Congradulations, we now no longer have a moon, we have another planet that people mistakenly refer to as "The Moon". And we are no longer a single planet going around the sun, but a dual-planet system as out respective gravities have a pronounced effect on our ("The Earth" and "The Moon") orbits.
Then go on to apply any number of arbitrary designations to them. such as the primary satelites we know of can be called 'larger/smaller than earth & local Sol Sats' Kuiper belt objects can be 'small & distant Sol Sats' Pluto can be a 'small & local Sol Sat' and comets can be 'small and transitory Sol Sats'.
axis discrepancy indicates hexagons beyond control anomaly
Geez, if these eggheads ever stopped looking up for a few minutes and looked down at what they're standing on they could've saved themselves years of arguing...
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