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Pluto Might Be Bigger Than Eris
astroengine writes "Look out, the battle of the dwarf planets is about to re-ignite! During last weekend's rare occultation of a star by Eris, astronomers managed to gain one of the most accurate measurements of Eris' physical size. When three Chilean telescopes watched the star blink out of sight, astronomers were shocked to find that Eris is actually a lot smaller than originally thought. So small that it might be smaller than Pluto. On speaking with Discovery News, Eris' discoverer Mike Brown said, 'While everyone is more interested in the "mine is bigger than yours" aspect, the real science is the shockingly large density of Eris.' The mass of Eris is well known, so this means the object is more dense than Pluto. Does this mean the two mini-worlds have different compositions? Did they evolve differently? In light of this finding, is the underlying argument for Pluto being demoted from the planetary club on wobbly ground?"
http://xkcd.com/473/
http://blindscribblings.com - Tasty pop-culture in conceptual fashion.
This sounds about right; the Eris is a fairly tiny phone.
Oh wait...
Living With a Nerd
I remember being so confused about the Pluto controversy. Maybe it's just because I'm not an astronomy nerd but I don't understand the uproar about correcting a miss-classification of a heavenly body... I remember Neil Desgrasse Tyson on the Colbert Report chiming in that it was just a simple fact. Any of you astronomy nerds reading that could explain the emotional reaction? (Not to assume, was it astronomy nerds that were upset? Maybe it was Astrology people that were upset.)
check out the Mp3 Garbler I built!
Size does not matter. Clearing its path matters. Per the IAU Pluto has not cleared its orbital path and can not be considered a planet by the current definition.
Sorry, I cannot find anything about the relative size of Pluto and Eris at any of those places. Indeed, it seems the Bible doesn't mention either at all.
The Tao of math: The numbers you can count are not the real numbers.
I have done this, so can you read how the Bible says to be right with God
Is it just my observation, or is eldavojohn an idiot?
Uh...something doesn't seem right here...
Living With a Nerd
Messed up quoting you, sorry about that. Still, I don't think quoting the bible and then shitting all over someone is going to help your cause...
Living With a Nerd
The argument was as arbitrary as any others. It was basicly "which property is common to both Pluto and Eris, but not found in the other objects traditionally considered planets?".
Pluto always was a weird object to be called a planet, with his density somewhere in the nowhere between the earthlike planets and the gas giants, and being pretty similar to the large moons of the gas giants.
But only when Eris was found, there was a second objekt thought to be similar enough to Pluto to define a new class of "plutolike objects", which allowed Pluto to be demoted from planet status.
So yes, the classification of Pluto in the class of "plutolike objects" (pardon, "Dwarf planets") seems to be on pretty firm ground, considering there are now more objects known in that class (Makemake for instance), though Eris now seems to be a weirdo within this class.
Well, as soon as you figure out a simple, reliable and accurate method to figure out something's radius from 14 billion kilometers away, tell the astronomers.
Have they found the Black Lion, and is Princess Allura okay?
Oh, wait, that's Arus.
I wasn't arguing how arbitrary it was. I was arguing that the people who created the definition were smart enough to define it in such a way that the classification can be determined on a case-by-case basis. A basis that won't be substantively changed by comparative measurements. Discovering anything about any new planetary body will not change Pluto's classification because the discoveries will not be about Pluto.
Professor: "I'm sorry, Fry, but astronomers renamed Uranus in 2620 to end that stupid joke once and for all."
Fry: "Oh. What's it called now?"
Professor: "Urectum. Here, let me locate it for you."
1. Fly 14 billion km measure, radio results back.
2. Continue flying for a few hundred years, then return in giant ship whose communications wreak havoc across your homeworld.
Degaussing scares the bad magnetism out of the monitor and fills it with good karma.
Ask just about anyone geeky and my age,, and they'll telll you so: "yes, Pluto is a Fucking Planet, now stop trying to change things".
What does being geeky have to do with being old and too set in your ways to listen to reason?
Give us an argument why the IAU's definitions of a planet and of a dwarf planet are unreasonable. Please avoid any Appeal to Tradition. Also, can you craft a definition of a planet that covers Pluto but not Eris and Ceres other than "just what we used to arbitrarily call a planet?"
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
Rupert:
A planet in Earth's solar system beyond the orbit of Pluto. Rupert was named Persephone, but nicknamed Rupert after "some astronomer's parrot." It was eventually settled by the Grebulons.
In 2005, an actual tenth planet fitting Rupert's description was discovered beyond Pluto (which was considered a planet then, as opposed to a dwarf planet now). In a poll of the public conducted by New Scientist magazine to search out potential names for the object, "Rupert" ranked #5, and "Persephone" was the top choice. The planet was, however, ultimately named Eris.
Can we get a "-1 Wrong" moderation option?
It's perfectly simple: Humans are not animals, Humans are fucking special. Ask just about anyone religious and my age, they'll tell you so: "No, humans aren't animals, now stop trying to change things".
See how ridiculous your non-argument sounds?
I thought the matter was settled when we learned it was a Mass Relay encased in ice.
the BIG YELLOW one is the SUN!!
It's not yellow.
Don't give Eris out yet. There was a lot of discussion on the MPML about this.
First, Eris is definitely more massive, by about 28%. They both have satellites with good orbits, so their masses are pretty well determined.
Second, it is not really that clear that Pluto is really larger than Eris. There have been a number of estimates of Puto's size; by the most recent one presented by Angela Zalucha at the DPS meeting (a radius fit to occultation measurements with a new atmospheric model), Pluto and Eris have roughly the same radius within the respective error bars (1146 +-20 km in diameter for Pluto versus 1170 km for Eris).
What is more interesting to me is that Eris is dense and very bright - could something as rare as Deuterium snow be covering its surface ?
I liked Xenia a lot better, and don't understand the sort of pedantry that disallowed it. Now it resides with the Brontosaurus in the land of cool, but abandoned, names.
If you want an odd body, look at Sedna, which may be a world from an alien solar system.
So, in other words, the question is not which one is bigger - Eris or Pluto, but which one is denser - Eris or the astronomers?
Why the insults? Why are people so emotionally attached to the old order in which the term "planet" didn't have a solid, scientific definition which included Pluto (but in which kids didn't learn about similar bodies like Ceres) that they are willing to lash out at astronomers for attempting to put some kind of reason and order into the system?
I honestly can't think of any better demonstration of why humans should never achieve immortality. Look at how attached people are as minor of a belief that they were taught in childhood as whether or not Pluto is a planet. It's like the whole "debate" is a microcosm of how irrationally attached some people become to resisting change in their understanding of the world.
And people wonder why politics is so entrenched and partisan. If people can't adapt over Pluto just think of how stuck they are on the things that actually matter.
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
I glanced at my RSS feeds and thought the story title was "Pluto might be bigger than Elvis". Now that would be really big!
There is this thing called a MAGNIFYING LENS (usually used as a collective system of same) which makes a distant object's apparent size large enough to measure its arc. Put a big enough one of those in orbit and your three qualifications are easily met. The one you don't mention - cost - might be a little problem.
Fuck you... allow me to elaborate.
Science progress, and you geezers* can stuff yourselves. For the record, I'm probably older then you. You can gave geeky, I'll stick with nerdy, because I actually know shit.
I'm sure there where people like you when the Greeks figured out the world was round, and there were people like you when the write brothers flew, and there where people like you when phones went cordless, and there will be people like you when we send people to actually walk on Pluto.
We don't need you're attitude, we will never need your attitude. You are an achor around the ankle of progress. But we are stronger then you, and science will continue no matter how much you want it to freeze in place.
*By Geezer I mean: unchanging, 'in my day', 'get off my lawn' wastes of space.
The Kruger Dunning explains most post on
...Once we conquer gravity and develop some sort of gravity drive that doesn't require half a universe's worth of energy to lift off out of a gravity well.
A planet then will be something we can land on, and walk around upon, that is the most significant gravity well in easy distance.
This significantly matches the science fiction (fantasy fiction?) concept of what a planet is...
Is the world flat for you? does heavier then air flight exists in your tiny, stupid world?
The Kruger Dunning explains most post on
It seems perfectly acceptable for a religion that advocates the murder by magical bears of 42 children for the sin of pointing at a man, laughing and calling him bald.
cause they get more hits by bringing up the manufacturversy.
The Kruger Dunning explains most post on
At the end of the day, the whole "planet/not a planet" distinction isn't even particularly illuminating. It's much more useful, IMHO, to just look at the parameters and make up your own mind. How massive is it? What's its distance from the sun? What's its eccentricity? What's its inclination (please, no jokes about Uranus' inclination...)? What's its origin?
A binary planet/not planet distinction just doesn't tell you that much.
Not really. There's not enough light that far away from Sol to see much of anything. I tried to do the math, but it kept rounding to 0.
The other solution, waiting for it to transit another light source, is what just happened, and is not exactly an "on-demand" occurrence.
Fuck you... allow me to elaborate.
Science progresses, and you geezers* can stuff yourselves. For the record, I'm probably older than you. You can have geeky, I'll stick with nerdy, because I actually know jack shit.
I'm sure there were people like you when the Greeks figured out the world was round, and there were people like you when the Wright brothers flew, and there were people like you when phones went cordless, and there will be people like you when we send people to actually walk on Pluto.
We don't need your attitude, we will never need your attitude. You are an anchor around the ankle of progress. But we are stronger than you, and science will continue no matter how much you want it to freeze in place.
*By Geezer I mean: unchanging, 'in my day', 'get off my lawn' wastes of space.
You almost made a decent argument, although it was mostly emotional and not rational. Too bad you write like a fucking third grader.
Dilbert RSS feed
And ask anyone my grandmother's age and they'll tell you that they're not really convinced Pluto is a planet because when they were in school in the 1920's, it wasn't a planet, it was just a chunk of rock that nobody had ever seen.
Nostalgia's not what it used to be.
I'm sorry, but your definition of planets has gaping hole. Unless you believe that gas giants shouldn't be classified as planets?
> Who decides what the definition of "planet" is?
Everybody. We argue about it, use various conflicting definitions for a while, and eventually converge on a consensus. That's how natural language works.
> The IAU... ...determines what definition will be used in IAU publications. Their definition is influential but not necessarily dispositive.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
I wasn't arguing how arbitrary it was. I was arguing that the people who created the definition were smart enough to define it in such a way that the classification can be determined on a case-by-case basis. A basis that won't be substantively changed by comparative measurements. Discovering anything about any new planetary body will not change Pluto's classification because the discoveries will not be about Pluto.
Here's the definition: "The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune." The rest of the definition is noise because they failed to define "clearing the neighborhood".
Pluto is mostly made of various ices (like comets) and travels through the Oort Cloud (like comets). It's orbit is highly eccentric and at a tilt (like comets). Pluto is quite clearly a large comet that never made it to the inner Solar System. Also, because of it's companion, Charon, the center of gravity for the two is actually between the two. If it were a planet, it would also be unique in this respect as well.
*sigh*
http://www.youtube.com/watch?v=ORTLn-RDnQ4 at ~2:32 to set the stage, and then
http://www.youtube.com/watch?v=DAZQ0qX5iR0 at ~1:33
Yeah, so...I wasn't really trying to accurately describe the color of the big yellow one...
from the article summary:
"Look out, the battle of the dwarf planets is about to re-ignite! During last weekend's rare occultation of a star by Eris.
from the parent post:
Fuck you... allow me to elaborate.
from wikipedia
Eris is named after the Greek goddess Eris (Greek ), a personification of strife and discord.
Ceci n'est pas une signature.
If it's not in the Holst suite, it's not a planet.
In other words, King Koopa's airship is a planet. Seriously: play "Mars" and then the Airship theme.
That protector of ours, Brennan-Monster is at it again !
nt
Give us an argument why the IAU's definitions of a planet and of a dwarf planet are unreasonable. Please avoid any Appeal to Tradition.
The definitions are unreasonable because no definitions are needed. Nature makes no distinction between "planets" and "dwarf planets." Celestial objects don't split into neat discrete types either by trajectories or composition or any other criterion. They all follow the same laws of physics. There's no separate sets of physical laws for the motion of planets and that of other objects (which is, by the way, the reason the ancients gave the "planets" a distinctive word to distinguish them from other "stars" (in the original sense)).
Basically, "planet" is an obsolete category that no longer does any work in astrophysics. You can exhaustively state everything that we can state about a celestial object without settling the non-issue of whether it's a "planet" or not.
Also, can you craft a definition of a planet that covers Pluto but not Eris and Ceres other than "just what we used to arbitrarily call a planet?"
Of course, since celestial objects differ from each other in degree on a large number of criteria. The only definitions of any interest is the traditional one—on account of being traditional. Stop pretending that we're making some sort of scientific progress by pointlessly redefining a term that's just not useful anymore. Leave the damn definition alone as a reminder of how we got to where we are today.
Are you adequate?
Oops. My plan is undone. Now I need a really bright collimated light beam to reach out to it ...
Why the insults?
No insults, just an incredibly lame pun. ^_~
Ezekiel 23:20
How hard could it be to bounce a laser off of it for illumination?
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
Actually, it's the general public that decides the definition of planet, not the IAU. The general public wins because they have the most votes and weapons if it comes down to either democracy or war over it. So get used to it: Pluto is a planet.
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
Who decides what the definition of "planet" is?
All interested parties, whether they are technically informed or not. See "Hacker" "Cracker" controversy.
The IAU decided that, at the same meeting where they threw Pluto off the list of planets.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Very, very, very, very, very hard. Do the math.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Bigger than 'Er arse? My arse? Yer arse?
'Er arse ain't 'alf bad, as 'tis!
"Flyin' in just a sweet place,
Never been known to fail..."
The rest of the definition is noise because they failed to define "clearing the neighborhood".
Noise?!
There's FIVE ORDERS OF MAGNITUDE difference in planetary discriminant (mass ratio between the body and all other masses in that orbit) between the highest value for a dwarf planet (Ceres) and the lowest value for a planet (Neptune).
When the difference is a factor of 10,000, there's absolutely no need to create a precise definition, and it would be foolish to do so.
It's like you're arguing that the definition of what is or isn't ocean is useless because it doesn't precisely define at what point of the tide cycle, or how far up a river mouth, it transitions from ocean to not ocean. But the question we're asking is whether Topeka, Kansas is in the ocean or not and the answer is obviously NO!
You might as well argue that it's completely arbitrary to say that you are alive and Benjamin Franklin is dead, because science has not precisely defined the exact line between dead and not dead. Um, I think it's still pretty clear which is which in this case.
You see, if they did actually define "clearing the neighborhood" in a precise manner, that would be the truly arbitrary choice. But when you look at the bodies in our solar system, and you see that there's a small set of objects which outweigh everything else in their orbits by at least a thousand-to-1, and then a great many objects which weigh less than the rest of the objects in their orbit, then yes that actually makes a clear dividing line. You don't have to draw it with infinite precision to see that it's there.
The definiton of Pluto as a planet is far more "noise" than the definition that it isn't. We only called it a planet because we didn't know it was so different from the other ones. It's like when we first discovered Ceres. Only we changed that one pretty quick, even though it's more planet-like than Pluto is.
The enemies of Democracy are
"Hail Pluto!"
Doesn't work, does it?
Quidnam Latine loqui modo coepi?
It's perfectly simple: Pluto is not a Dwarf Planet, Pluto is a Fucking Planet. Ask just about anyone geeky and my age,, and they'll telll you so: "yes, Pluto is a Fucking Planet, now stop trying to change things".
And you'll be as wrong as those who resisted reclassifying Ceres from planet to non-planet.
Oh, what's that, you don't think Ceres is a planet? It's pretty obvious that what just happens to be the biggest asteroid in a giant asteroid belt that's total mass is 3 times this one body is cool, but not a planet?
Yeah, that's exactly what geeks will be saying about Pluto in twenty years.
Tradition, not any salient facts, are the only reason people resist reclassifying Pluto. Tough. Science moves on. We know things about (Ceres|Pluto) that we didn't know when we discovered it. You can adjust to this knew information, or you can stamp your foot and refuse to change.
Which is fine. But the world will change with or without you.
The enemies of Democracy are
I thought the definition of Dwarf Planet was: Large Enough to be round (that is enough mass to create a Spheric shape). Both meet this requirement even if Pluto is bigger Orbit the Sun. Only Pluto Have a clear Orbit no on Pluto and no on Eris Ceres is the only other object that is unquestioned as a Dwarf Planet. If Pluto is seen as bigger than Eris, then given that it is dose not have a clear orbit for as much as I know.. which is not much, means it should not be listed, or never should have been, as a Dwarf Planet.
I think the word "planet" comes from a Greek word meaning "roaming star". This was assigned to stars that seemed to move in a direction different from the other stars in the sky. So if you want to really think of the classic definition, Earth isn't a planet either. ^.^
(I remember reading about the sphere thing, also. That one sounded good to me.)
If we are not Animal, then are we Plant, Fungi or Mineral? I know a few people that might count as Fungi. Tim S.
My money is on Scrith.
Harder than bouncing a laser beam off of the nail on your left pinkie from the Moon.
There's FIVE ORDERS OF MAGNITUDE difference in planetary discriminant [wikipedia.org] (mass ratio between the body and all other masses in that orbit) between the highest value for a dwarf planet (Ceres) and the lowest value for a planet (Neptune).
You do realize that nothing significant comes within 11 AU of Pluto aside from Charon and possibly an occasional rare visit from Eris? That's more than a third of the distance to the Sun.
The goddess of discord is certainly living up to her reputation.
"So you think you have me all figured out, do you? Heh, heh, heh."
So how long will it take to get there, how big of a dish will it take to get a signal back, and how much plutonium to power the instrument package and radio to find out what is really going on out there?
Here's the definition: "The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune." The rest of the definition is noise because they failed to define "clearing the neighborhood".
The problem I have is that Pluto crosses the orbit of Neptune, therefore making Neptune a non planet by the same definition.
I think the editor is mixing up "impetus for discussion about the definition of planet (which ended up excluding Pluto)" with "reasons for the final definition of planet (which excludes Pluto)".
What actually happened was: we discovered Eris, and the IAU said "huh. It seems likely that there are hundreds of objects large enough that we'll have to decide if they're planets, where before everything we found was clearly either a planet or an asteroid/comet. Not to mention all these planets we're finding around other stars... We need a good definition of planet to go forward with." The final definition agreed upon excluded Pluto.
What the editor appears to believe happened is: we discovered Eris, and the IAU said "huh. This is bigger then Pluto, so either both are planets or neither are. We don't want to increase the number of planets, so lets go with 'neither'."
At least, I don't see any reason why someone might think an adjustment to the size of Eris would cause a reconsideration of Pluto as a planet unless something like the second was what happened.
Does a line appended to your comment give your post meaning in and of itself, or only in relation to those without?
What about plutonium? The element was named after a planet. If Pluto is no longer a planet what then, rockonium?
(Jim doesn't know about Pluto and plutonium. The element is now called rockonium. Travelling back in time, they are looking for fuel.)
"Sir, we'll need rockonium to power these old engines."
"Scotty, we cannot use rockonium, this thing called plutonium is all we have."
"But sir... it will take weeks to adapt these engines. Even if I'm able to do it, we might all blow-up."
"Scotty, you have 4 hours."
"...but..."
"Here's the plutonium."
2 Hours later
"Jim, the engines are ready."
Views expressed do not necessarily reflect those of the author.
In fifty years, your grand kids will learn in school that there are 8 planets, and many smaller objects in the asteroid and Kuiper belts.
And when Grandpa says "Hogwash! Pluto's a planet dag nabbit!" they'll just roll their eyes.
The enemies of Democracy are
See the guy who did it talk about how it happened.
He rebuilt the Hayden Planetarium's exhibit to account for the new stuff being discovered. They wanted to present generally what's out there, so they grouped like with like: the inner planets, the gas giants and the Kuiper belt. Pluto plainly is not a gas giant at all and looks a lot like what's in the Kuiper belt, so wtd?
Apparently, when you're looking at how much crap really is in orbit around our sun , there isn't much question what to do, but it seems like a much bigger deal to people who haven't yet looked. .
As always, all IMO. Insert "I think" everywhere grammatically possible.
Maybe the term "planet" has just outlived its usefulness. It's an overly broad and difficult to define category of celestial objects. Maybe it's time to invent some new nomenclature. I give you our new solar system:
Mercury, Venus, Earth, and Mars will now be known as Rocky Planetary Objects (RoPOs).
Jupiter, Saturn, Uranus, and Neptune will henceforth be known as Large Gaseous Objects (LaGOs).
Any objects which are smaller than Mercury but large enough to compress itself into a sphere will now be called Quasi-planetary Small Objects (QuaSOs).
You're welcome IAU.
Does this
We could call them Dwarf Brown Dwarfs. Or since they are after all giant gasbags, Politicians.
Does this
It's like you're arguing that the definition of what is or isn't ocean is useless because it doesn't precisely define at what point of the tide cycle, or how far up a river mouth, it transitions from ocean to not ocean. But the question we're asking is whether Topeka, Kansas is in the ocean or not and the answer is obviously NO!
But the land that is now Topeka, Kansas was at times covered by ocean waters, including at least during the early Cretaceous. So maybe Eris once cleared its neighborhood, before a lot of "less desirables" moved in and it went down hill? Or perhaps it was a small neighborhood that was cleared, then bought-up via eminent domain then redeveloped? Or maybe the rules are different with such long orbits?
You might as well argue that it's completely arbitrary to say that you are alive and Benjamin Franklin is dead, because science has not precisely defined the exact line between dead and not dead. Um, I think it's still pretty clear which is which in this case.
But science has not definitively proven that time only flows in one direction, so the past and future are equivalent, which must make the instant of the present irrelevant. Then maybe Ben Frnaklin is as alive as us, and we are as dead as him.
Just kidding, I felt like being an argumentative moron. Too bad the minor planet advocates don't understand the statistical significance of orders of magnitude.
This is a hacked account, for which the owner can not be held responsible.
When the difference is a factor of 10,000, there's absolutely no need to create a precise definition, and it would be foolish to do so.
Well if the IAU was going for an IMPRECISE definition they couldn't have done better. Science is all about definitions. Precision is important. The current definition is an utter mess. I couldn't care less that Pluto was named after a Disney character. If we want to be precise it belongs in a different category BUT
1) They created pair of definitions where a "dwarf planet" is not a "planet. That is confusing and ridiculous.
2) They mention "the sun" and therefore the definition as written excludes extrasolar planets. So now we have "dwarf planets" that are not planets and "extrasolar planets" that techincally also are not planets.
3) The clearing the path part of the definition is an arbitrary requirement and a kludge. It is possible we will discover extrasolar planets that cross each other's orbits in a stable way. Fortunately extrasolar planets aren't planets anyway.
There are other things wrong with the definition, but lets just leave it at that shall we? The definition is beauracratic and in terms of science it is PURE JUNK. Science is about understanding things. We humans do this by classifying them, so definitions are important. However in this case everyone was more focused on whether or not Pluto is a planet and was bending the definition to fit their preference.
These posts express my own personal views, not those of my employer
HEY FATASS! Move it, you're crushing my plums!
Justice is the sheep getting arrested while an impartial judge declares the vote void.
Was it really named after the planet or was it named after the Roman god of the underworld?
Justice is the sheep getting arrested while an impartial judge declares the vote void.
I really fail to see how Pluto is so much more different from Earth than Earth is from Jupiter. This planetary discriminant as a way to measure the cleanliness of an orbit is an interesting metric, but it is a bit strange to define an object according to its surroundings. A much more relevant metric to characterize an object would be its mass. There are two to three orders of magnitude of difference between the mass of Pluto and Earth, and there is about the same order of magnitude difference between Earth and Jupiter. Likewise, the composition of Earth and Jupiter are totally different, but that does not preclude them from both being called planets.
You do realize that nothing significant comes within 11 AU of Pluto aside from Charon and possibly an occasional rare visit from Eris? That's more than a third of the distance to the Sun.
Er, apart from the fact that Pluto's orbit crosses that of Neptune?
It seems to me that once in a while those two ought to come fairly close, no?
Do you also ask these questions of people who classify spiders and insects together as "bugs"? Or do you reserve your strawmen solely for people who disagree with astronomers on what to call a frozen ball of rock over 4 light-hours away?
For the record, Eris will always be Xena to me.
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
http://en.wikipedia.org/wiki/Eris_(dwarf_planet)
"Eris, formal designation 136199 Eris, is the most massive known dwarf planet in the Solar System and the ninth most massive body known to orbit the Sun directly. It is estimated to be approximately 2300-2400 km in diameter,[14] and 27% more massive than Pluto or about 0.27% of the Earth's mass."
It is the object that finally lead to pluto's "demotion" from planet to dwarf plant.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
All depends what education authorities do. If they decide to follow the IAU (which is likely as afaict there is no other organsation of similar standing pushing a rival definition) then that is what kids will be taught.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
Er, apart from the fact that Pluto's orbit crosses that of Neptune?
If I recall correctly, the distance of closest approach is somewhere around 17 AU (that is, how close Pluto actually gets to Neptune). Uranus gets closer than Neptune does. That's because Neptune and Pluto are in resonance.
Pluto has an eccentric orbit, it's between 29 and 49 AU. I was referring to closest approach. BTW, if the mass estimates for the Kuiper belt objects are correct, there's something like 5-50 times Pluto's mass in total in the area where Pluto orbits. It is likely then that at any given time, a relatively large amount of mass is within a third of Pluto's current distance to the Sun even if no major planets ever are.
Kuiper belt masses were initially estimated on the assumption that all KBOs have albedos of 0.04, like the nuclei of the Jupiter-family comets. These initial estimates gave masses 0.1 M [that is, 0.1 Earth masses - khallow] (Jewitt et al., 1998). Recent measurements of large KBOs suggest albedos on average about three times larger but it is not known if this is generally true or if the high albedos apply only to the largest KBOs (we cannot yet measure the smaller ones directly). In any case, 0.1 M is an upper limit to the total mass. With mass scaling as (albedo)^(3/2), the derived mass is 3^(3/2) 5 times smaller than first thought, corresponding to a few percent of an Earth mass. These estimates are still quite uncertain because we possess few reliable determinations of the albedos, because we do not know the densities of most KBOs and, especially, because we have meaningfully sampled only the inner regions of the Kuiper belt. For all these reasons, the relative masses of the various components of the Kuiper Belt are uncertain. A reasonably safe conclusion, however, is that the mass of the scattered disk objects is larger than the mass of the other components of the Kuiper belt (Trujillo et al., 2000).
[I had to manual edit the exponentials because superscripts aren't supported by Slashdot. So there's up to 50 times as much mass (Wikipedia is claiming 5-50 Pluto masses worth, using current estimates for Pluto's mass). Anyway, with that much mass swimming around, it's very likely that Pluto has at least a Pluto's worth in mass of other Kuiper belt objects within the neighborhood I specified. Which would mean it is not a planet even under a different definition of neighborhood.
The battle over the status of dwarf planets has never subsided. Pluto and Eris are both planets and Kuiper Belt Objects. One does not preclude the other. They are planets because they are large enough to be rounded by their own gravity. They are Kuiper Belt Objects because they are located in the Kuiper Belt. Ceres too is a small planet because it is large enough for its gravity to pull it into a spherical shape. The IAU misappropriated the term "dwarf planet," which was first coined by Dr. Alan Stern, Principal Investigator of NASA's New Horizons mission to Pluto, to indicate a third class of planets which are large enough to be rounded by their own gravity but not large enough to gravitationally dominate their orbits. He never intended for "dwarf planets" to be classed as not planets at all. The IAU did not "have" to do anything other than allow Eris's discoverer to name it while holding off on any additional classification until more information is discovered about remote planets in this solar system and all planets in other solar systems. Significantly, there are quite a few exoplanet systems in which multiple planets orbit the host star in various different planes. Some have orbits far more eccentric than Pluto's, yet they are giant planets the size of Jupiter or larger. According to the IAU definition, none of these objects are planets! Saying there are more differences between Pluto and the eight closer planets to the Sun depends on what aspects one considers. Earth actually has far more in common with Pluto than with Jupiter. Both have surfaces on which we can place rovers and landers. Both have a large moon formed by giant impact; both are geologically differentiated into core, mantle, and crust, and both have nitrogen in their atmospheres. Other than orbiting the Sun, what do Earth and Jupiter have in common? It is premature to pronounce declarations that these faraway objects are definitively not like the other planets or that one is larger than the other. We just do not have enough data at this point to do more than make educated estimates. What we really need to do is send robotic missions like New Horizons to Eris as well as Haumea and Makemake. Yes, that will take time and money, but it is a far better investment than the black holes the endless wars in Iraq and Afghanistan have become. Also, memorization is not important. It is much more important to teach the characteristics of each category of planet than to ask kids to memorize a bunch of names. We don't ask them to memorize the names of rivers or mountains on Earth, so why do so with planets, and why allow a need for convenient memorization to determine how we classify them?
Simply do away with the term "planet" as an astronomical term, and refer to everything out there as a "class [x] celestial body".
Those elements form a series, each further away from the earth: Uranus, Neptune, Pluto, America.
Here's the definition: "The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune." The rest of the definition is noise because they failed to define "clearing the neighborhood".
Actually the original list when the term "planet" was coined was "Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn". At the time, Uranus was apparently unknown to European scientists, though it was known to people with good eyes in other parts of the world with clearer skies. Neptune wasn't known until 1846.
The current list of eight planets is the result of several revisions that had less to do with science than with the media. At one point, the revision was basically to exclude Ceres, which fit the previous definition, and hardly anyone wanted that. We can expect further revisions in the future, and they'll be as inconsequential as the earlier revisions. This won't stop people from discussing the topic endlessly.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
Hummmmm... noodles.
Tradition, not any salient facts, are the only reason people resist reclassifying Pluto. Tough. Science moves on.
The term "planet" has no scientific use. It does have a traditional one, and by tradition, Pluto is a Fucking Planet. Add Eris too if you like, but you can't take Pluto from me!
Socialism: a lie told by totalitarians and believed by fools.
Actually, failed stars was more my vote, but yes, it was an intentional gap.