Correction:

"But now, at least according to [the TOTAL LOSERS at the] International Astronomical Union, there are only eight planets..."

Hey... I'm fair... I loved the definition they worked on for three years before the vote.  Even though it was a complete surprise that Charon and Ceres were listed as planets it made real sense: round bodies not orbiting another planet.  When that definition came out, there was a lot of fuss but no one said "it did not clear its orbit" because that is not an obvious (or clear) definition for a planet in our own system let alone an exoplanet in another system.  Lo and behold however, the "clearing orbit" criterion became law as if just to specifically exclude Pluto.  In their delusions the IAU also excluded potential JOVIAN planets that may have been captured as far out as 50,000 AU and would never EVER clear their orbit cause it takes  too darn long.  We see this in other systems where large JOVIAN planets are found 50 to 70 AU from their own sun... Ooops... I meat to say DWARF JOVIAN PLANETS that really aren't planets anyway... Duh!  What a load of bunk!

Err.. I am one of those "total losers", having voted at the IAU GA. Astronomers just love classifying stuff. Thats how you can tell the difference between an astronomer and a physicist. I am a quasar man myself, and like most people still there by the end of the fortnight, basically voted to MOVE ON. Any reasonable definition would do. The label isn't interesting. What matters is all those groovy new objects that Mike Brown and others have discovered. I am glad at least that he is getting some PR out of this !

Oh come on people! The IAU gets so excited when they find a new planet around Saturn and Jupiter but Pluto, Charon, Ceres and Eris are out because they are to small?!? Obviously, the IAU is grumpy and pissy! I think the new dwarf planets should be named: Fun Planets or Icebergs or Snowballs. I'm kidding about the last sentence. Anyway, if it circles the sun that is good enough for me and probably for the rest of the people.

I hope you don't mind Andy, but I'm going to have to call you on that. "basically voted to MOVE ON..." "Any reasonable definition would do..." "The label isn't interesting..." I'd have thought the IAU would have taken their job a bit more seriously. Try asking a elementary school student to memorize names like 2003 EL61. A label DOES matter! In fact, because it was improperly lumped together with millions of other "meter-wide" asteroids, I never even heard of Ceres before the vote. Few are even going to know or care about all these other incredible worlds we are finding. "Clearing an orbit" implies that you're dealing with a protoplanet which (after 4.5 billion years) I certainly hope is not the argument being made. It can be argued that the definition also doesn't work for planetary orbits that have been disrupted. I'd hate to see "Earth" declassified as a dwarf [not-so] planet should Jupiter one day migrate towards the sun (as they suspect happens with hot Jupiters) and throws us into some new orbit.

There was a better solution. Dont make a definition for planets at all. Chemists didn't suddenly call toluene methyl-1,3,5 cyclohexene, they left it as it was and accepted that it was a holdover from the past. They then went ahead and created a nomenclature for describing all possible compounds.

The same thing should have been done with planets. The nine planets recognized at the time should have been designated as such. The definition of a planet would have simply been "a member of the set of nine bodies that were historically called planets". It should have been accepted that the term planet has no scientific definition or meaning, and is simply a common term used to describe those nine bodies. They then should have created a sensible definition for the classification of everything else. The fact is, what we were calling planets had no really good way of defining them and any attempt at doing so, just made something arbitrary and senseless.

Just another example of people getting paid to much to not actually accomplish anything...say building homes,repairing, helping people..you know, work.

As my great, great, ever so great Uncle Will once opined,"A rose by any other name would smell as sweet!" Note to the Scots: I also trace my ancestry to the Lesleys of Aberdeenshire.

A small group hijacks a vote with an absurd premise. A couple of recent US elections or the IAU? Your choice! Gravitationally round, orbiting a star and not another planet (the Forest Moon of Endor comes to mind!). KISS!

I think the whole thing is silly. Isn't it obvious that Jupiter and Saturn are NOT the same sort of object as Earth, Venus, and Mars? If you are going to start really sorting things out, there is your next step.

Hmmmm...large bodies with their own circumsolar orbits whose mass is large enough to assume spherical shapes - large enough to land and walk around on, but they are not planets?  

I'm glad they are not in charge of zoology - they'd probably deny blue whales mammalhood because they're too big and go to the wrong sort of dentist.  

Let Pluto and Xena back in and cease this nonsense once and for all.

"...and a big 'shame on you' 
   to the bonehead IAU, 
'cause Pluto's always a planet to me!..."

Perhaps we should no longer regard the first four solar system bodies as planets because of the discovery of more distant and larger Jupiter and Saturn, for example.

There are many different types of stars. we classify them on basis of size, color, temperature etc.. why not have a similar system for planets. ie star trek (earth is an M-class planet)

Maybe I dont understand or am uneducated as to the scientific definition of what constitutes a planet. To me it should consist of a concentric orbit around a star, be uniformly spherical and have either a stable atmosphere, a waning atmosphere or no atmosphere. This would preclude Pluto because of its alternating solid to gas atmosphere and its elliptical orbit that does not have the Sun at its center but well off center. Perhaps a mathematical equation could provide the percentage of centeredness of orbit based on size and distance and ellipse of an orbiting object to help qualify it as a planet. A similar solution could also provide a range for the spherical uniformity (of the astral body) as well.

It seems to me the bias against Pluto being a planet comes from the obvious reality that it is clearly not like the other 8 planets in very significant ways. To use a poor analogy, It would be like classifying a monkey as human because it has similar physical characteristics regardless of the glaring descrepancies arising from any deeper comparison. Therefore specific criteria must be deliniated and edified as is the case in lifeform classification.  There are many different "species" of stars which belong in a differnt "kingdoms" or "Orders" than planets, moons and asteroids.

I think a classification system like this could designate pulsars and neutron stars, cepheids and black holes as well as quasars, nebulas, whole galaxies (perhaps galaxies[along with solar systems and such] belong in another classification analogous to anthropology as galaxies are collectives of smaller independent objects), and other astral bodies, all the way down to asteroids, comets and other cosmic debris. I am just a layman so I am only specualting. Perhaps a system like this has already been implemented.

'Classification' to a real scientist is second only to 'discovery.'  A planet becomes a planet when it is first formed and becomes a satellite of a star. A moon is a satellite of a planet, formed when the planet is formed.  Some moons are 'captured' by planets, and some planets are 'captured' by stars.  Classification only slots the body into its appropriate place in the hierarchy of things.  Pluto's ancestry is still under dispute, but the pattern of creation and dispersal throughout the universe needs definitions to make processes clearly understood.

Do you know what I had to go through to explain to a 7 year old why her beloved little Pluto was removed from her count of planets in our solar system? How do I explain that some people want to change the definition of history and discovery? Can you hear all the children arguing with each other that they know better now and that Pluto is not an ' official' planet but a dwarf-planet. My little one is now sad to see that her new books have omitted our beloved Pluto. The IAU should not take it upon themselves to govern history or change it- try explaining this to a 7 year old!

I agree with Des Emery.  The universe needs definitions to make processes clearly understood.  If gravitationally spherical body revolves around a star, regardless as to it's origin, then it's a planet.  If it revolves around a planet, it's a moon.  The only nuance with which astronomers and layman alike should have to struggle is whether gravitationally spherical and joined pairs should be considered planet and moon, or binary planets.

(If the center of gravity between the two does not fall within the sphere of one of the bodies, then they should be considered binary.)

KISS

I understand that there may someday be a reason why we are debating that Pluto is/is not a planet.  There's an awful lot of thought, time and money being put into what exists beyond our environment.  Is it that we are just such curious beings that we need to peer at and anlayze what might be out there?  But we as a species have been doing it for ever.  It's part of who we are as human beings.

Personally I don't really look past the Moon and the Sun much, as I am quite happy with the current planet I'm on, Earth.  Or has someone decided that Earth is no longer a planet?  Oh, okay, it still is?  Good.

I am personally unhappy with anyone's decision to take Pluto off the list.  It has nothing to do with whether Pluto is a planet or not.  It has to do with the fact that we learned that Pluto is a planet, just like Earth, Venus, Saturn, etc. when we were kids.  That was what they taught us, and darn it, we got tested on that question!  Now they decide to just change that, "Oh, oops, let's change this..."  If we let them get away with just being able to change what they previously said, then there's a real problem there.  I have a problem with people trying to change history by just changing their story.

Can you imagine what happened when people finally found out that the Earth is round, not flat?  That you wouldn't just fall of the side of the world if you sailed too far?  They must've been really p***ed.

So the question remains:  Do we allow Pluto to go the way of the tooth fairy?  Or do we continue to believe that the world is flat?.....

When Xena was discovered and named by matriarchal men (apparently under the protection and guidance of the gods, that they received such divine inspiration) and Xena was found to have a moon named Gabrielle, patriarchal men, who seek to control and dominate women and who see women struggling for freedom and justice as being subversive to their unjust and unethical repressive "order", refused to allow this planet both its rightful status as a planet and her name and also the name of her companion moon.

To do this they were forced to denigrate the planet Pluto, but such was their fanaticism that they accepted this forfeit. This is despite the reality being that Pluto, the god associated with awful human destiny and death, and with the minerals under the earth, especially Plutonium and those other elements associated with the threatened death of all life on Earth, and with Plutocracy, the rule by men using the power of money or earth and the exploitation of Earth's hidden resources  has characterised or expressed its influence over the period from the discovery of Pluto in 1930 until the present. These vain men deny the reality of their own history and cultural experience!

Now these patriarchal men have renamed Xena and Gabrielle after "discord, strife" (Eris) and lawlessness (Dysnomia). (It is interesting that  "lawless"  is the name of the mortal woman, Lucy Lawless, who portrays the immortal Xena! - Is this not truth trying to assert itself under falsehood?) What these vain patriarchal men have done is to have Xena and Gabrielle depicted through their misogynist eyes - to bring justice in a world of evil men becomes "discord and strife and lawlessness" because these are the evil men whom Xena and Gabrielle struggle to overcome and who will kill "but there has to be a reason" and that is justice, the defence of the victims of patriarchal terror and exploitation. These men have defamed all women with their slur that when women fight for truth and justice they are bringing strife and discord and lawlessness to the world - this is misogyny, the hatred of all women made public to the whole world!

Now, just as Pluto characterized or influenced the world, (and perhaps the rationalists can look to Jung's theory of synchronicity for comfort in explaining that "coincidence") now we shall have a new age in which Pluto and Charon become superseded by Xena and Gabrielle. The Yang, or Joachim in the west, has become full and now is the time for Xena and Gabrielle to bring judgement upon evil men, for Yin, or, in the west, Boaz, to become dominant again, for the female principle to return to human history, for a new age of matriarchy to begin. That is the way of the Tao, and, in western ancient philosophy, when the pillar of Boaz is on the right hand side - the dominant position.

Let's see who is right and who is wrong!  

P.S. I am against globalism/monoculturalism/New W.(orld) Order as well so the IAU should be ignored as a body also, and let the United States have its great planetary discoveries. Let them be called Pluto and Charon, and Xena and Gabrielle and if the IAU complains about it let them all be arrested as a global sexist conspiracy by the global police and thrown in the global prison they really do belong in. (Isn't sexism supposed to be internationally outlawed under the Universal Declaration of Human Rights? ... That old fashioned idea of equality?!)

And the rest of us will do as we want, or as we are inspired - fight for truth and justice in a world of evil men (Michael brown and the other discoverers of Xena and Gabrielle excluded) or, seen through the anti-female glasses  of these evil, patriarchal men, cause discord, strife and lawlessness against self-proclaimed leGiTiMat3 male authority. But since these evil men, if justice exists and is done, will be in International Prison, who cares what they think - let them rot in their misogynist vitriol!

I won't be insulting myself with their sexist planetary names, so for all my life they will be referred to by me as the Planet Xena and her moon, Gabrielle - and I encourage other like-minded people to disobey these misogynists and do the same.

If men are so bad. Why dont women start making more discoveries and inventing useful technology.(Not to mention fight the wars) Oh ya you are all busy having babies(you know, ensuring the proliferation of the species). Men cant have babies so we have to find something else to do to be productive. So women like you can have the safety and security from which to undermine the efforts of men at every turn. You are a real shining example of exactly why men run the world.

The war for women is against men who oppress, demean and discriminate against women, and that is human history.

Men raise armies to fight wars against other men who raise armies, and the system requires downward pressure on women to make the babies men require. "Baby Making Machines" is what women were recently referred to as in Japan, where women aren't making enough product for Japanese men!

Men control technology and drive women off of the internet with misogyny and out of I.T. by turning it into a male preserve:  I was the only female in some of my I.T. classes of about 20 students each - and living in Australia, the land of the Ocker with its dry, conservative dry-masculine business-culture attitudes helps to drive women out of IT too. That is my personal experience!

Equal opportunity is dead! Men want to run the world, not share it, and it takes two to share, in this case, two sexes. So the alternative choice is forced upon humanity - the continuation of male-rule, the domination of women and the repression of imagination and of Eros ... or matriarchy, women holding the reigns, and ruling with wisdom, the wicca-women, or wise-women having the authority that men have shown that they are unworthy of.  That is the choice human beings are faced with. There is nowhere left to go but down the path to liberation from patriarchy, and female rule.

This is the natural order of things, human sanity, deep. underlying human psychology, as shown in the "THE LOVERS" VI in the Major Arcana of the sacred Tarot and as exposed in Geoffrey Chaucer's "The Wife of Bath's Tale".

And this is the time for this long conflict to come to a head. Women's struggle for equality is over. In pouring scorn on women all over the world and in writing their misogyny and patriarchy in the heavens for all the world to see, patriarchal men have declared that they reject equality and see women as troublemakers who must be brought under male power and authority. This is the meaning of "Eris" and "Dysnomia".

Dysnomia sounds like a psychiatric label! Is being female a patriarchally-defined mental illness now? That is another implication of this  global cultural and spiritual issue, that human sanity is being defined by men, in male terms, in order to prop up a male system, which is inhuman, completely mad and irrational, and which contains no element of justice in it. "Dysnomia"?! "Lawlessness"? Is this how men want to depict women - as mad and delinquent?! This is not how women see the world - this is the evil-male view of the world imposed opon women. It is a lie.

Some men are rational and support truth, but the men who get power are the ones who do not - and that is why women do not have power, because it means becoming a beast in order to rule. What good is that? And that is why matriarchal men are not in power, because they can't be bothered with all the beast-politics and bullying they would have to endure. And that is why the very basis for society has to change - to be reversed! Patriarchy is bad for women, for most men (though many may not know it) and only supports the beast-men who rule. I am not a Christian, that is for sure, but " you shall judge them by their fruits!".

If I was an American I would be very angry that the two American planetary discoveries (though Michael Brown is English, like me) had just been obliterated by global patriarchal interests. And all American women should be doubly offended. So why doesn't your President do something good for the United States and declare Pluto and Xena to be planets and Charon and Gabrielle to be their moons, by an act of law, for justice, for human culture, for all humanity?! That would strike a powerful blow against these "evil men".  They have no right to do what they have done.

Otherwise this will be a wound that will not heal.

The term "dwarf planet" is one concocted by astronomers with a specific agenda to demote Pluto. It makes no sense, as the IAU defines a "dwarf planet" as not being a planet at all. The IAU's conception that this is a "compound noun" rather than a noun modified by an adjective is an attempt to make up its own rules of grammar to fit this specific agenda, an agenda imposed by 424 out of 25,000 IAU members worldwide. They had to "move on? Any reasonable definition will do?" Moving on for the sake of moving on is nonsense. So is adopting an unreasonable definition that makes no sense and was in fact created largely by astronomers who are not planetary scientists. The August 24 decision did not end this debate--in fact it immediately generated a backlash among astronomers, virtually assuring this is not the last word. Even the discoverers of Eris are not united on this issue. While Mike Brown is of the "eight is enough" camp, co-discoverer David Rabinowitz signed Alan Stern's petition refusing to use the new planet definition. Both Pluto and Eris as well as some of the larger KBOs should be counted as planets, just planets of a different type than the first eight. To Pam in Boston, please tell your seven year old that it is perfectly okay to still count Pluto as a planet and that some of the leading experts on Pluto in the world have signed a petition to this effect. Led by Dr. Alan Stern, Principal Investigator of NASA's New Horizons robotic mission to Pluto, they plan to hold a conference of 1,000 astronomers this summer to address this issue. There are many scientists and lay people who still believe that when all is said and done, Pluto will be rightfully restored to the official list of planets.

Laurel - err that "specific agenda" part is a bit off...what does that mean ? Or were you thinking of a specific agenda to maximise publicity for New Horizons ? Hopefully there will be just as much publicity for the Dawn Mission to Ceres, which will be launched soon and will get to Ceres before New Horizons gets to Pluto. Could be a really nice bunfight.

ps I love the way this comment stream is degenerating into rant. Isn't the web great.

I think I was pretty clear in describing the "specific agenda" of those who insisted on demoting Pluto. The dynamicists, most of whom are not planetary scientists, are the ones who maintain that an object has to "clear its orbit" to be considered a planet. They created a definition clearly meant to target one object--Pluto. From the definition they came up with it's not even clear if their objection to Pluto maintaining planet status is its size or the fact that it crosses the orbit of Neptune. One has to question why such a major decision would be done in a backroom deal fashion on the last day of a ten-day conference with no allowance for Internet voting. Are you suggesting some sort of publicity competition between New Horizons and the Dawn Mission to Ceres? That would indicate this is a political rather than scientific issue. New Horizons had already been funded and launched by last August so Stern and his colleagues did not need further publicity for the mission. I have no problem with both missions getting equal publicity, which is a completely separate issue from the flawed process used by the IAU in this decision last summer.

I really do feel sorry for Ceres. Hey, it was a planet when it was first discovered in 1801 .. and then Pallas, Juno and Vesta joined the list.. and eventually as more and more tiddlers got found astronomers realised this was getting a bit silly .. so invented the new class of "asteroids" , and booted Ceres out of the planet list, after it had been there for about fifty years. Sound familiar ? The world got over it. But I guess the Internet Petition wasn't around, otherwise Ceres would have been "saved" and we would have had about eight gazillion planets by now. Hmm. Maybe that would have been great.

Note, I am a professional astronomer, which is why I use technical terms like "gazillion".

Ceres is significantly smaller than Pluto; however, I don't see any problem with classifying it as well as Pallas, Juno, Vesta, and some of the larger asteroids as "minor planets," another subcategory of the larger category "planet."  You say the world "got over" the demotion of Ceres but look what happened.  Most people were never taught about Ceres in school, and knowledge of it disappeared into oblivion.  That was not a positive outcome.

If the solar system ends up having thousands of planets, then so be it.  Why is that a problem?  Arguing that we need to limit the number of planets because human beings cannot handle a large number is hardly a scientific argument.

Laurel - this will be my last comment as we shouldn't really have a two person debate on somebody else's blog. I just wanted to stress that the points you made in your last comment are all very interesting and valid, and much more useful and fair than painting "scandal" and "plot" over a perfectly fair IAU process. If you seriously want the label "planet" re-instated for Pluto, lets all concentrate on why that would be a good idea. Good luck.

could somebody help me? i am a yr 10 students and im doing a case study on planets. Do any of you think that Ceres, Charon and Eris should NOT be considered as planets? if so, why not?

Message (please, no HTML tags. Web addresses will be hyperlinked):