Science and Society

Why don't they just call them big rocks?

Note from Ned--

Good thought, Mark--but if you were at the IAU you'd get an argument. Jupiter, Saturn, Uranus and Neptune aren't rocky. In space, nothing's simple.

You write that "new categories are needed as our understanding of the universe changes" - well, this may have applied to the introduction of the "dwarf planet" category but certainly not to the new subcategory which will always include every dwarf planet except one and provides no extra insights.

The sole reason for this was another IAU vote two years ago that defined this subclass - with Pluto as its declared prototype - as a kind of consolation prize for the disgruntled Pluto fans.

What's wrong with planetoid? or planetitse?

Personally, I prefer Altoids.

It is a curiously strong and refreshing term for celestial objects in our solar system that at least deserve MINTioning.

One proposal back in 2006 was "planetino" - actually pretty clever, since the neutrino is much smaller than a neutron, shares some properties (i.e. no charge) and yet is a different beast and not just a small neutron. But this proposal never came up for vote.

If we’re going to use technical terms than Charon, Hydra and Nix are not moons, but satellites. The term “moon” for those rocky things that orbit planets is colloquial, although certainly common in the scientific community. So Titan, Europa, Io, Phobos . . . all technically satellites, not moons.

cturple

Planetoids is what Ceres and its neighbors were called a long time ago. The notion that asteroids were pieces of planet, hence planetoids went out of favor. Surprise, its coming back!

Eh? I don't mind 'dwarf planets'. Far better sounding than 'Plutoids'. The new name just sounds too wierd and make it seems Pluto and others are the size of asteroids when they are not.

Gee, change it back, will ya, IAU?

What's in a name? Well, apparently, a lot, since the scientific community is having such a difficult time with this whole episode in astronomy. Frankly, I find it quite amusing watching and listening to a crowd of supposedly educated and enlightened people struggling with this. And, it will all be finished up by political wrangling, rather than a scientific consensus. What's wrong with calling them 'lumps?'

our tax dolloars hard at work ;-)

Planetini?

Yet more anal-retentive dissection of information into the increasingly trivial. How will referring to these types of celestial bodies as "Plutoids" rather than "dwarf planets" change anything or deepen one's understanding of the subject? A rose by any other name...

cturple
Planetini?
cute!

Planetchen?

The ancient Greeks named them Planets a.k.a. wanderers. Since they can't have a say in this matter, the original name should stand. There is no good reason not to considers Ceres or Pluto or Eris as Planets. Clearing orbits is actually pretty meaningless more so when the orbit is so large and erratic. Dwarf Planet I can understand as its just another way to say it is a small planet, just like calling Jupiter a gas giant, it is what it is.

BTW while moons are satellites of planets, planets are satellites of stars. Moon is an english translation of the original greek and satellite has a broader meaning. So calling natural planetary satellites "moons" is more accurate, but technically (by the ancient definition) they are also planets.

One word: planette

To Chuck who says "our tax dolloars hard at work" I know your statement is meant to be tongue in cheek, but just an FYI...the IAU is an international organization of astronomers. It doesn't have much to do with American taxes.

At least we didn't pay for the stupid name. :)

Pluto will always be a planet in my eyes.

Maybe it should be "Plutroid" the whole process has been a pain in the butt.

Gene

Clearing its orbit is actually pretty significant from a gravitational standpoint. Add to that the recent discovery that Pluto is actually losing its atmosphere as it orbits, plus the irregularity of its orbit, and it seems like Pluto might actually be more of a giant meteor than a tiny planet.

Also, defining terms is absolutely necessary. Claiming that a more specific classification scheme is unnecessary is like saying that there's no point in differentiating between Hepatitis A, B, and C. By clearly defining language, astronomers can more accurately describe what they're looking at. And when you consider how loose the 3,000-year-old Greek definition of "planet" was, anyone with a mind for detail can see how important it is to begin updating some terms that could work better for us.

and by meteor I meant comet, sorry

How about letting the ancient word "planet" apply to the whole group of wanderers in the solar system, by which I mean all the planets, asteroids, meteors, dwarf planets, this new Plutoid category, and so on. Scientists do need to every more finely distinguish things, but for us mere mortals, the old lingo works okay. And this is coming from someone who got his first telescope when he was about five years old -- me!

As HUGE as the universe is, I think scientists are going to end up with way more categories than they can handle, especially if they're getting nit-picky like this. I'm STILL offended on behalf of poor Pluto, which most of my lifetime was a planet -- and I really can't adjust. When it comes right down to it, what do scientists really know anyway? I've been sorting things and making lists all my life... There's ALWAYS the one little critter that defies definition and can't be pigeon-holed. So let it be. Don't mess with Pluto: he is what he is. Their categories and lists don't change Pluto any: the only thing that changes are the lists and categories.

They call stars by a letter class, why not planets? Class A planet, and so forth. But...Plutoid?

" . . . and that have not cleared the neighbourhood around their orbit."

Could someone please explain how, in the name of Apollo, this represents an objective measure?! What is the neighbourhood? Is it an objective distance from the planets center of gravity?; because, if it's the same for Jupiter as it is for us, then one of us isn't a planet. How is it cleared? Our Moon is escaping! Earth certainly hasn't cleared the Moon from it's orbit . . .

This bit of linguistic catagorical garbage is nothing but brainy politics. The man who discovered Eris wanted to name it Xena, after the Joss Whedon show; and, while this shows the man to be an irretrevable dork with horrendous taste and little respect for posterity, it is the right of the discoverer of a PLANET to name it what he wants; so, the IAU, as a body of mostly tasteful people, wanted to not have a planet named after a card-board charecter in a rediculously poor fiction; so, they said: "Wait a minute, that's not a planet; because, um . . . it's too small! That's the ticket! It's too small to be a planet; so, it's not a planet, and it isn't named Xena, it's named Eris." Then the jerk who discovered Eris pointed out that if his planet was too small to be a planet, then so was Pluto; so, the IAU had to make a decision as to what is planet, exactly, a question never before formally addressed; and, rather than voting in favor of sense and calling Eris, Pluto and Ceres planets, they came up with this rediculously unscientific definition to avoid having a planet named Xena. Considering all the strife it's caused, Eris is certainly a fitting name for the newest PLANET discovered in the Sol System.

Moon does not come the Greek, neither is it any sort of translation. Moon is from Middle English mone, from Old English mona, from Old High German mano, from Old Norse mani, from Gothic mena, all which are words for the Moon. Mena itself comes down from the Proto-Indo-European word *me- meaning a unit of time, out of which grew the Greek mene, meaning moon, and the Latin mensis, meaning month. The word moon was first used to describe the satilites of other planets when they were first discovered.

Posted by: Quietman - They call stars by a letter class, why not planets? Class A planet, and so forth. But...Plutoid?
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I'm all for this. But what would be the defining features? Size? Atmosphere? Mass? Composition? When you start to actually think about it, it begins to sound like an enormous undertaking just to establish the classes. Where is Carl Linnaeus when we need him?

I thought Plutoids were fans of Mickey Mouse's famous dog.

Finnbjorn
Good explanation. If I may add, moon is a description of an extraterrestrial body, what people commonly call "the moon" is actually "Luna" just like "the Earth" is actually "Terra", hence the common words derived "Lunatic" (not moonatic) and "Terrestrial" among others.

Ned
If there are only 2 plutoids what is Sedna? A Sednoid?

I was disappointed when Pluto was relegated to something less than a planet. So now science, in its love of reductionism, has rendered Pluto into plutoid. I think plutoid should enter the vernacular as a general pejorative of sorts.

It could be used to describe a petty, small, and insignificant person or kind of behavior. Such as s/he is such a plutoid with an attitude. Or instead of saying someone is minimizing an issue, it could be said they're plutoiding.

The IAU criteria doesn't use gaseous composition as a criteria for plutoid. That's a shame because its usage could become more colorful. After downing a couple of Margaritas and green enchiladas, one could express , " Man, I'm feeling plutoid!"

I can't help but see potential for plutoid to become a rising star for noun, verb, and adjective usage.

I wonder if this will add to some theories of how life may have gone from mars to earth...maybe these plutoids act as linking planets allowing life to travel from planet to planet.

this is amusing......

A rose by any other name... What really is a shame are people who want to keep things static because of the emotional relationships. Like the world is flat, stars revolve around the earth, and Pluto is a planet. Wishing it doesn't make it so...

It has been obvious to anyone that it is simply illogical for there to be inner rocky planets and gas giants farther from the intial source, the sun, then a small pair of icy rocks. The discovery of the Kuiper Belt ended the question years ago, some people just couldn't change their belief system of birth signs and other man made nonsense. Few remember there used to be several more "planets" before improved technology indentified them as part of an asteroid belt between Mars and Jupiter.

I find the IAU classification system confusing. For one thing, how universal (pun not intended) could it be for other solar systems? Also, one of the criteria for a Plutoid states that it isn't large enough to draw in objects nearby. Pluto obviously has the mass and gravitational pull for 3 moons or satellites. In addition, Pluto fits the typical schema of a planet because along with the moons, it has a topography and an atmosphere, albeit a scant methane one. The IAU classification system, for me, is as clear as the stars on a humid, cloudy night in an urban center.

As long as humans do science there will always be an emotional element. Moving the sun to the center of the solar system allowed for a huge step forward in our understanding (Kepler's Law). Moving a spherical object orbiting it's nearby star to anything other than "planet" contributes nothing.