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IAU Classifies Pluto & Eris As "Plutoids"
Kligat writes "The International Astronomical Union has decided that Pluto and Eris should be classified as "plutoids," alongside their 2006 classification as dwarf planets. Under the definition, the self-gravity of a plutoid is enough for it to achieve a near-spherical shape, but not enough for it to clear its orbit of its rocky neighbors, and the plutoid orbits the Sun beyond Neptune."
Reader FiReaNGeL links to a
similar story at e! Science News.
My uncle had a problem with his plutoids, and he had to sit on a big doughnut and use lots of ointment.
pluto contracted plutoids from minnie
How they are classified means what to whom? Someone needs their grant pulled for gross misuse of time.
Eris, which measures about 70 miles wider than Pluto, is the farthest known object in the solar system at 9 billion miles away from sun. It is also the third brightest object located in the Kuiper belt, a disc of icy debris beyond the orbit of Neptune.
"Kill 'em all and let Root sort 'em out"
It's a stupid debate altogether. I image all the astronomers involved feel really good about themselves for making an impact. Why couldn't they leave well enough alone? Pluto will always be the ninth planet to me, despite Eris. Definitions be damned!
*sigh*
The new definition of "planet" was quite good. Clear, straight to the point, and easy to apply to any object. Now, they add a new category that applies only to our solar system?
Okay, we won't be seeing objects this small on other star systems, but the point remains. We are already at a time when we know these objects should exist in many other places in the universe. The classification shouldn't depend on their position inside our solar system, it should be generic enough that we won't have to change it (again) when we see one of those around Alpha Centaurii. I thought this was the single most important thing to come out of the previous discussion about what should be considered a "planet".
In college I knew a 'dancer' who had named her 2 breasts "Alex and Nikki"!
As I recall, they each had "...a near-spherical shape, but not enough for it to clear its orbit of its rocky neighbors..."
-I suppose naming them "Pluto and Eris" would have worked equally as well...
my award-winning 5th grade planet mobile becomes even more irrelevant.
They didn't do any more research. Nothing scientific was done. No more information was found out or cataloged. Nothing interesting happened. Just a bunch of people with too much time on their hands gave yet another name to a celestial body that orbits the sun. Frankly, who cares?
When Pluto lost its status of planet a couple of years ago I was shocked reading that the USA was lobying against that definition just because Pluto is the only planet discovered by an american scientist. Please, oh please, tell me that IAU hasn't produced this new denomination just for political reasons. It would be very sad...
I'm not sure why but they seem trying to purposefully exclude Ceres which is spherical in shape (able to overcome hydrostatic force) and exists in the asteroid belt
The summary fails to mention one further requirement: For an object to be considered a true Plutoid, it must posses a "curiously strong" flavor.
plutoids classify you!
Why is this thus? What is the reason for this thusness?
First it got demoted, then given a brand new (and largely meaningless) title. I expect Pluto to get a pink slip any day now.
If you haven't been down-modded lately, you aren't trying.
Sacred cows make the best hamburger.
Pluto isn't large enough to clear it's orbit of "rocky neighbors". Well, here's a news flash - neither Earth, nor Mars, nor Venus, nor Mercury have orbits that've been cleared of rocky neighbors. So apparently the bias only applies to the outer regions of our solar system?
For that matter, if you want to be REALLY pedantic - Pluto's orbit overlaps Neptune's, so Neptune apparently isn't large enough to clear it's orbit.
There! We've whittled it down to two planets total: Jupiter and Uranus. That'll be easy to remember...
#DeleteChrome
Let's be honest here. We all know the reason Pluto was re-classified to throw off the Tom Tom of our, now lost, Galactic Overlords.
Galactic Overlords: "Tom Tom! Where is this "Earth"?!"
Tom Tom: "Make a left at the 9th Planet."
Galactic Overlord: "WTF?!?! There IS NO NINTH PLANET, Tom Tom!"
Galactic Overlord's Mother-in-law: "I told you, Rory! You should have made a right at Uranus! If you can't find a PLANET, HTF were you able to find my daughter's birth tube?!"
Galactic Overlord Jr.: "Are we there yet?"
Galactic Overlord: "Dammit! Don't make me pull over this Star Destroyer!"
Galactic Overlord Jr.: "I gotta pee!"
Sig Follows: "Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." -- Mark Twain
WTF is a plutoid? We already have a definition that could easily fit pluto and other celectial bodies like it
http://www.go-astronomy.com/glossary/astronomy-glossary-p.htm
"A large asteroid or other celestial body, also called a minor planet."
Call them planetoids. Therefore still remaining a planet but one that is not large enough to remove debris from its orbit. Then throw on mercury and mars and we can have a solar system of six planets and four planetoids (minor planets). This crap about removing debris from its orbit is farcical, how do they not know given another billion or two years it won't remove remaining debris?
Many (but not all) of the observed dynamical features of the Kuiper Belt can be explained by giant planet migration.
Pluto officially defined as Pluto.
Eris officially seen as similar to Pluto.
Who really gives a flip?
There are objects out there of every size shape and configuration possible.
See my blog at Who's Who
By saying this you (and people agreeing with you - yes, you know who you are!) show you didn't put any effort into understanding what "clearing neighbourhood" in planet definition means.
/. summary is to be trusted, is specific to our system.
Specifically, it doesn't say that no other bodies in vicinity are present, but that all of them are dominated by gravitational influence of a planet. And that's definatelly the case with Moon and near Earth asteroids. But not with Pluto - it's in orbital resoncance with Neptune.
I actually really like this definition, fairly precise, universal, and avoids waking up one day in a Solar System with 20 or 30 planets, once we start discovering more Pluto-like objects. But somehow we have this nonsence of people attaching sentimental value to the notion of Pluto beeing a planet, which makes the whole deal unpopular.
And BTW, I don't like this latest "plutoids" thing; looks more like PR stunt. Definatelly doesn't really resolve anything, and if
One that hath name thou can not otter
We call rocky planets also terrestrial or telluric. We call the other ones gas giants or jovian planets.
Sometimes my arms bend back.
There's no hard limit as a number, but there has to be some limit, otherwise every dust particle that orbits the sun should be classified as a planet.
I think the current definition is pretty good. Although I feel some sympathy for Pluto, I feel it's not quite right to classify a small body whose orbit intersects the orbit of a gas giant as a planet.
The irony of it all is that Pluto would never have been considered a planet if it wasn't for some error in observations that led people to believe its perturbation of Neptune's orbit to be much greater than it really is.
You have to draw the line somewhere, especially if there's a chance that we'll end up with a lot more than 30 (it shows the signifance of given object for the Solar System as a whole vs. the significance of a lot of objects as quite homogonous group). For example, Ceres was ALSO initially considered a planet...right until the point when we started to discover the rest of asteroid belt.
;P ) hint that Pluto is simply a similar "first", discovered by chance because it was back then close to eclyptic and close to predicted position of Planet X (Uranus/Neptune - like object predicted by perturbations in Neptune orbit - later measurements shown them to be non-existent)
All signs on heaven (and...only on heaven
One that hath name thou can not otter
There isn't any such limit. but it dillutes the usefulness of 'planet' as a term. This is astronomy, a science, it benefits from clear, precice, and _useful_ definitions. We can call everything that orbits the sun a planet if we like and lose its usefulness as a term, or we can just drop 'planet' as a scientific term and demote it to an historical anachronism. But neither of those are very good. If 'planet' is to be a useful term, it needs to have a precise and useful definition. There wasn't any such one that covered both pluto and the 8 planets. It's as simple as that.
In a lot of ways science _is_ terminology. You can't think about things (in a critical scientific way) or talk about them or advance your understanding of them until you name them. When Maxwell's equations were originally formed, they required pages and pages of equations and could be understood only by top mathematicians of his time. Now we can write them in a few dozen characters and they are easily understood by advanced high school students. Why? Because we gave the concepts names, and symbols. As math advanced, we recogonized that vector spaces were useful enough to get their own terminology, making complex concepts simple. As we learn about the solar system, and astronomy, we also find that new things are useful and refine the old terminology.
Of course, this is a fertile ground of discussion and there are various takes on the issues
http://en.wikipedia.org/wiki/Philosophy_of_science
http://notanumber.net/
If the definition some of us preferred had been adopted, a certain Italian would have gotten his planet back, too.
You and GP are begging the question. Yes, classifications are "useful" to catalog objects orbiting other stars. But, what is the use of cataloguing objects orbiting stars, in the first place? What does it tell us? Does the classification of an object predict any properties of it that beyond those that were required to successfully classify it?
Two subpoints here:
The response to this is that classifications aren't properties of things in themselves, but rather, are context- and purpose-dependent distinctions that people impose on them.
I've not seen anybody come even close to doing this for "planet." Once you observe all the things you need to observe to decide whether a celestial body is a planet or not, you're not in a position to predict anything else about the object.
This doesn't mean that scientists can't use non-predictive classifications for genuinely useful means; non-predictive classifications can be quite useful for communicating with other people (if somebody says "planet," it may not allow you to predict a lot about the object, but it helps you guess what the other person may be talking about). But usually, those classifications don't really need to be very precise.
In this case, the problem is pretty simple. The ancients charted the movements of the lights in the night sky, and were concerned with formulating laws to explain their motion. The problem you hit right away when you start doing this is that a handful of those lights move in a manner that's very different from the vast majority of the others. Those weird, "wandering" ones are the so-called "planets," in the original sense. This goes back to point (1): the classification of some celestial objects as "planets" responds to the purpose of formulating and solving this problem.
Guess what? We're not the ancients. We don't have their problems in explaining the motion of those things. We have super-powerful telescopes that show us all sorts of funny rocks in space that they could never hope to see, moving in all sorts of weird trajectories. We have a theory of Newtonian mechanics that explains their trajectories as a specific case of more general laws, without having to formulate laws of weird-space-rock-motion. Why are we keen at all to try to get a precise fit between what we see and their vocabulary? The reason we have problems with deciding whether something like Eris is a "planet" is because we know a lot more than the ancients did. Insisting too eagerly on the classification just demonstrates a failure to appreciate how very different and superior our understanding is.
Are you adequate?
eris, also known as the reason pluto is no longer a planet.