Planet debate gets greater

Dennis M. Dwyer Hot Springs, Arkansas 71901 — Sat, 20 Sep 2008 01:04:45 GMT

Why all the fuss? The outer solar system (Oort cloud and Kuiper belt) are full of such bodies like planetessimals and comets and such. Relax. I am somewhat concerned about what will happen in Dec. 2012, when the sun and solar system cross over the galactic 'equator' into the Northern hemisphere of the Milky Way Galaxy.

Planet debate gets greater

Jon Brophy Cobbleskill, NY — Sat, 20 Sep 2008 01:39:05 GMT

Im not against having a scientific way of identifying and understanding things but I think that none of the gibberish is going to be of any consiquence untill we begin mastering the art of intergalactic travel.

Planet debate gets greater

Mike Witkoski, Enola, Pennsylvania — Sat, 20 Sep 2008 01:47:35 GMT

What will happen if we ever find an earthsize or larger body out there, at a great distance, say a couple hundred AU. Suppose such a body is a little smaller than Mercury? Where do we draw the line?

Mike Witkoski
Enola PA USA
mwitkoski@capitalareahomes.com

Planet debate gets greater

Peter Lauk, Atlanta, Ga. — Sat, 20 Sep 2008 01:48:29 GMT

Stern's take on the IAU's definition of planethood is compelling. As an armchair astronomer, I've never read or heard such an eloquent (and pithy) discussion of the matter.

Planet debate gets greater

H in State College, PA — Sat, 20 Sep 2008 01:56:17 GMT

The teacher was right; there are only eight planets... even if its still up for debate, the IAU has officially down graded pluto to a dwarf planet, even if it is temporarily. I personally believe that it should be a dwarf planet based on the fact that it has not cleared its orbit of major debris.

Planet debate gets greater

Jaipal Singh Datta, Ghaziabad, India — Sat, 20 Sep 2008 02:01:25 GMT

There are seven Planets. Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn. There are two others known as Rahu and Ketu, which moves in anti direction

Planet debate gets greater

Joe Blow, Pluto, New England — Sat, 20 Sep 2008 02:02:13 GMT

How many Blades of grass are on my front lawn?

How many Sea Shells are on Miami Beach as opposed to Daytona Beach???

How many Countries do we have named today in the World? How many Counties did we have named 1000 years ago????? How many Countries will there be in 400 years more???????

Planet debate gets greater

Albert B, Mexico city, Mexico — Sat, 20 Sep 2008 02:05:11 GMT

I kind of agree with the new definition (not the dwarf part, but the formal planets part) from Pluto and beyond the're just orbital oddities.

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Phillip Mulligan, Edmonton, Alberta, Canada — Sat, 20 Sep 2008 02:05:12 GMT

Just find us some earth like planets that we can settle on not some dirty iceburg in space. The astronomical community really has a lot of looking to do.

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Joseph Papierz Jr, Deerfield Beach, Florida — Sat, 20 Sep 2008 02:07:40 GMT

Some people have too much time on their hands
without any idea what to do. If it orbits a sun
it is a planet, large or small. If it orbits a
planet it is a moon. What's wrong with that?

Planet debate gets greater

Tyler, Purdue University — Sat, 20 Sep 2008 02:10:20 GMT

Jon, I agree with you. The phrase "until we begin mastering the art of intergalactic travel" just made me laugh though.

Planet debate gets greater

Jim Pacini Rio Rancho, NM — Sat, 20 Sep 2008 02:19:15 GMT

I had the pleasure of taking an astronomy class taught by Dr. Clyde Tambaugh at New Mexico State U. in the early 80s. He would be laughing at the indecision of today's astronomers. His goal was the pursuit of the unknown and instilling the joy of discovery in his students. It worked for me. And now I pass it on to my middle school students.

Planet debate gets greater

Dennis McClain-Furmanski, Marion, VA — Sat, 20 Sep 2008 02:32:53 GMT

Why all the fuss, indeed Dennis. Why not refer to the "9 traditional planets" if one wishes, or refer to each body with its name and measurements? If one must give them a label, "solar system objects" applies to anything inside the heliopause, and they can be classed as gas bodies, rock bodies or ice bodies. The argument here is one of scale in one or more measures, and any such argument is someone's slippery slope.

Planet debate gets greater

Dan Hilbert, McMinnville OR — Sat, 20 Sep 2008 03:04:36 GMT

Hey all you astro-physicists and astronomers, let's be fair about this. There are many satellites that would qualify as planets. If you call Mercury a planet then how about the Moon. It has a diameter only slightly less than Mercury's 3,600 miles. The Moon's diameter is 2,160 miles. There are also many other satellites orbiting Jupiter, Saturn, and Uranus that could also be categorized as being planets. How about Titan, the moon of Uranus with a diameter of 5000 km? And Gannymede and Callisto, both of which are larger than Mercury?

Planet debate gets greater

Tim Fraser — Sat, 20 Sep 2008 03:21:41 GMT

In Dec 2012 i.e. after 4 years of McCain and Palin Adminsistration the mother earth will anyways be closer to nemesis...

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Dan Andersen, Chicago, IL — Sat, 20 Sep 2008 05:10:54 GMT

Why not call the Earth and it's "nearer" neighbors, ending with Neptune, the "Near Planets" and call all the rest within the sun's sphere of influence the "Far Planets?" That way, they all get to be called "planets" (based upon criteria already established before this Plutino-Schmeeno stuff.) Geez, you geeks: K.I.S.S. !

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Laurel Kornfeld, Highland Park, New Jersey — Sat, 20 Sep 2008 05:40:08 GMT

I attended the Great Planet Debate, and one of the things Stern and others emphasized is that the number of planets in our solar system is not important. It is likely to keep changing as we make new discoveries--the same way the number of known exoplanets keeps increasing. The worst thing about the IAU definition is that it states that dwarf planets are not planets at all, which makes no linguistic sense. Also, according to the IAU definition, the exact same object can be a planet in one location and not a planet in another. For example, Earth would not be considered a planet if it were in Pluto's orbit. How can we classify an object solely by where it is while ignoring what it is?

What I find especially disturbing is when students like Stern's son are told they are wrong when they include Pluto (or any other dwarf planets) as planets. This is an authoritarian style in which children are taught what to think rather than how to think. We do them a great disservice by giving them only one side of a debate and presenting it as reality. I'm happy to report that in some cases, students had lowered grades reversed after their teachers were made aware that there are many professional astronomers who do not agree with the IAU decision.

I do have one question though. Haumea is egg-shaped rather than round. Is it still considered to be in hydrostatic equilibrium? If its being in hydrostatic equilibrium--a requirement for an object's designation as a dwarf planet--is in question, then why was it given dwarf planet status? Was that decision made prematurely?

[ALAN ADDS: Hi, Laurel, I've noticed your comments on Mike Brown's blog ... From what I've read, Haumea is considered to be in hydrostatic equilibrium. It's supposedly spinning so fast that it bows out to create that egg/pumpkin/football shape. It's been compared to a spinning water balloon, which would be similarly bowed out ... until it goes splat.]

Planet debate gets greater

Kcpaull, Fort Mill, SC — Sat, 20 Sep 2008 05:58:42 GMT

Why don't we just go ahead and say if you can see it with the naked eye,and it's not the sun, moon or stars, it's a planet. This should fit right in with teaching other archaic ideas in school.

Planet debate gets greater

Heidepriem, Germany, Berlin — Sat, 20 Sep 2008 11:13:42 GMT

????Ich bin etwas besorgt darüber, was geschehen wird, in Dezember 2012, wenn die Sonne und Sonnensystem Kreuz über dem galaktischen "Äquator" in der nördlichen Hemisphäre der Milchstraße.????

[ALAN ADDS: Translation from German:]

I am somwhat concerned about what will happen in December 2012 when the sun and solar system cross over the galactic equator into the northern hemisphere of the Milky Way.

[ALAN AGAIN: These Web sites address the "galactic equator" urban legend:]

http://www.geocities.com/astrologyages/maya2012.htm

http://www.astro.uu.nl/~strous/AA/en/2012.html

Planet debate gets greater

Dennis Feuerstein, Grand Rapids, Michigan — Sat, 20 Sep 2008 12:38:29 GMT

Is "planet" to be a generic or scientific term? "River" is not a scientific term; the river analogy needs clarification. The USGS website states that all “linear flowing bodies of water” are classified as streams in the Geographic Names Information System (GNIS). Some of the generic terms that fit this are creeks and rivers. You might claim a creek must flow into a river, but such hierarchies do not exist. In Northern Virginia, Little River flows into Goose Creek.

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Ryan, Rochester, NY — Sat, 20 Sep 2008 13:37:42 GMT

Stern's river analogy was pretty good. I think he's dead on about the planet debate. I like the of having classes of planets. Gas Giants, Rocky planets, and Icy planets. All planets, and everybody is happy!!

Planet debate gets greater

Daniel Carrera — Sat, 20 Sep 2008 15:13:29 GMT

I disagree with Stern. Objects like Pluto are different from the 8 regular planets. It's not just size, as with rivers. Their history and formation is different. That said, the IAU chose very poor nomenclature. Any reasonable person would deduce that a "dwarf planet" is a type of planet. One option would be to call them planetoids. Another option would be to call them all planets, but make three classes of planets: dwarf planets, terrestrial planets and gas giants.

Planet debate gets greater

K. vonReubendale, Payson, AZ — Sat, 20 Sep 2008 15:28:37 GMT

The naming-mess has been created because the astronomical community forgot to figure out whether we're "lumping" or "splitting" as a first step. Then we can decide on definition of words like Planet. Although it would be a good idea to actually define our labels, for now why don't we just default to 8 "planets" with non-eccentric orbits, and a bunch of "kuipers" with eccentric orbits? After all, it's a semantic arguement----nature is a continuum.

Planet debate gets greater

Justin McCright - La Plata, MD — Sat, 20 Sep 2008 15:53:43 GMT

A minor correction (no pun intended)...the correct term for a dwarf planet orbiting in the Kuiper Belt is "plutoid", not "plutino". A plutino is any Trans-Neptunian object (dwarf planet, plutoid, or other) that is in a 2:3 resonance orbit with Neptune.

[ALAN ADDS: Yes, you're quite right ... plutino is the correct term, and I've made the correction above. Thanks for setting me straight, Justin.]

Planet debate gets greater

Mad mom, Temple city,ca — Sat, 20 Sep 2008 16:39:03 GMT

Why after so many years does Pluto be removed from the list of planets in our solar system is just stupid after all the millions of textbooks,reading books and etc. Its just another form of discrimation that someone has created for themselves. Our solar system has 9 planets, and I will fight the system that tries to punish my children for having the wrong answer.

Planet debate gets greater

Don Boyer — Sat, 20 Sep 2008 17:04:36 GMT

I think the whole debate is not based on a real scientific need for definition anymore but more on the rubbing of Ph.D. egos together, which isn't science. It is most common in astronomy and archeology, the two sciences that affect human perceptions of the species the most. If we were a space-faring species, using uninhabited lumps to mine resources, we wouldn't care if it was a "planet" or a "zopblorg". Silly. When science can't sit down and settle something like this within a few years, you know it's egos running the show, not science.

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Siobhan Elizabeth, Philadelphia, PA — Sat, 20 Sep 2008 17:43:28 GMT

Jon Brophy -- if you think this article is full of "gibberish" then when we do "master the art of intergalactic travel" (it's an art, not a scientific matter?!?), you will hardly understand any of that!

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Josh Levin, Marlton, NJ — Sat, 20 Sep 2008 18:21:24 GMT

Remember that the eight "biggies" fall into two classes -- the rocky or "terrestrial" planets (Mercury, Venus, Earth, and Mars); and the four giants -- gas giants Jupiter and Saturn, and ice giants Uranus and Neptune.

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Doug Irvin, Kerrville, Texas — Sat, 20 Sep 2008 19:02:41 GMT

As often as science imitates fiction, I think it would be appropriate to continue the tradition. Many SF novels in various genres class planets by letter. Each letter describes the general type of planet. For example, in the TREK genre, Earth would be a Class M planet, signifying it is habitable with an oxy-nitrogen atmosphere and a mass producing a 9.8m/s/s gravity. This type nomenclature would go a long way in cooling tempers about what is a planet. And help kids in school keep it straight as well.

For those who would decry the idea as juvenile, consider that outside of academia, SF has the highest number of contributors possessing masters and doctorates. They also happen to possess imaginations. And how many astronomers today got their interest started by reading SF? pay it forward!

Planet debate gets greater

Polar Bear, Somewhere Cool, AB, Canada — Sat, 20 Sep 2008 20:09:39 GMT

The example of rivers, has precisely the same problem as with planets. The terminology doesn't stop at rivers, it also has creeks, streams and other types of watercourses (some that don't even have water at times; wadi's for example.) It is likely that some creeks are larger than some rivers even. (Why is that so? Poor categorization or just the ad hoc manner in they way rivers and other watercourses were named?)

In any event, it is reasonable to categorize and label things, just as it is important to recognize that the categories and labels are not absolute and eternal dividing points, just humanity's way of organizing information into meaningful groupings.

It is always a question of drawing a line somewhere in the categories of physical objects. As long as there is reasonable agreement on the factors that define how an object is included in a category, then it doesn't particularly matter in the big picture.

Planet debate gets greater

Talontbo — Sun, 21 Sep 2008 00:39:55 GMT

how much easier it would have been to just say...

regardless of size, if it has a defined atmosphere and its primary orbit circles a star it is a Planet... "as in, circles a star along an orbital plane".

of course their are more complex issues... but why create a new name...

whatever happen to a good ole "Planetoid"?

and I personally think if these larger than Pluto Bodies are housed in the outer Solar Shell and orbit the sun in a general way with all the other clutter found there... then they should be disqualified.. Pluto, though perhaps smaller.....

Has a defined atmosphere (seasonal), orbits a star and is separate from the other larger Solar Shell objects. And at times its orbit is closer to our sun than that of Neptune's... this cannot be said of other Kuiper Belt objects...

so call me old school... Pluto is a Planet.. I could careless what a butch of academics think or decide.. that don't have the ability to change my mind.

Planet debate gets greater

Dave BC WA — Sun, 21 Sep 2008 01:30:11 GMT

I’m not sure I understand all the arguments about Pluto being a planet. Decades ago it was determined to be the ninth planet. To me, that’s the way it is.
If you want to draw a line, let Pluto be that line. If it’s the same size or larger, it’s a Planet. If it’s smaller, it’s whatever.
If you can’t handle a hundred Planets, the solution is so simple: quit building better telescopes.

Planet debate gets greater

Kevin, Tokyo, Japan — Sun, 21 Sep 2008 01:44:58 GMT

One interesting point I had heard in this debate, and I apologize immensely to whoever said it for I cannot remember their name, but they said a dwarf planet should be considered like a person and a dwarf person. They may be smaller, but they are still people. Dwarf planets were tenacious enough to survive the birth of solar system and become round, or the case of Haumea roundish, and not become the moons of other larger planets. Though they haven't cleared their path, which is what the IAU wants a planet to do to be considered as such, if let's say the Earth was flung out into the asteroid belt in a freak accident, would it become a dwarf planet? If so, then it wouldn't fit the current idea of a planet and would be considered a minor body of the Solar System. As to whether or not they should be called Dwarf Planets is up for grabs. I believe they should in fact be considered in the same class of planets in one way or another.

Planet debate gets greater

Paul Hartley, Merida, Yucatan — Sun, 21 Sep 2008 05:33:30 GMT

Textbooks (and definitions of planets) reveal a basic flaw in our educational system: knowledge is not static.

Planet debate gets greater

Dan Dixon, Seattle, Washington, USA — Sun, 21 Sep 2008 07:06:52 GMT

You can see and experiment with Haumea and the other dwarf planets in Universe Sandbox, an interactive space simulator.

Explore the Orbit of Haumea:
http://universesandbox.com/

Planet debate gets greater

Jon Woods — Sun, 21 Sep 2008 11:19:31 GMT

I say go ask Steven Hawkings. He is clearly the smartest man on the planet and is well informed on planetary issues.

Jiff
www.anonymize.us.tc

Planet debate gets greater

Matthew McGee, Virginia — Sun, 21 Sep 2008 12:17:49 GMT

The argument concerning rivers is ridiculous.
We have rivers, creeks & streams, depending on it's size. In the case of the IAUs definition it makes things quite clear and easy to distinguish between a planet and a trans-neptunian object (dwarf planet) based on whether it is actually round due to gravity(size) and has it cleared it's orbit of debris and other similiar objects.

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dino — Sun, 21 Sep 2008 13:22:53 GMT

11 planets, as mentioned in holy quran.
i guess planet X was discovered , one more to find :)

Planet debate gets greater

Rick, State College, PA — Sun, 21 Sep 2008 14:09:57 GMT

I disagree with the author's take on the new separation between planets and dwarf planets. I feel that adding specificity to definitions is an important part of science that will help future classification and nomenclature.

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whatever — Sun, 21 Sep 2008 15:05:59 GMT

Stern was actually one of the people who came up with the "eight uber-planets, each dominating its orbit" standard in 2000 and justified it with a lot of fancy math. Now, as boss of a Pluto probe, he finds it convenient for his career to play to "PLUTO Iz A PLANET GODdAMNIT!!!1!!" crowd that can't handle the idea that not everything they learned in the second grade was actually sensible or true. Whatever goodies accrue to a technocrat when he lands a robot on a "planet," Stern obviously doesn't want to miss out, no matter what all the other astronomers have to say about it.

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sfumato420 — Sun, 21 Sep 2008 16:38:44 GMT

Personally, I defer to the precedence of history where Ceres was first called a planet, and then as more objects similar to it, like Juno, Vesta and Pallas, it was understood they were something different and new, Asteroids.

Pluto is the Ceres of the Kuiper Belt.

Personally, I think ego and emotion are ruling this debate rather than science, but can you blame them, who wouldn't want to recognition of discovering a new planet. But should that drive science.

As for there still being a planet further out, I'm sure there is, one that actually follows the new definition. Or even a Brown Dwarf laying out there somewhere orbiting our sun. Look for that rather than make exceptions to the rule.

In the end though, be it one year or a hundred years, the truth will be revealed as we understand more, test the theories, and make more discoveries.

I think every one is over-reacting, and that is not science, it is a mob.

Honestly, this is turning into the abortion debate over when life actually begins, and I think it is tarnishing science.

Planet debate gets greater

robstuk666 — Sun, 21 Sep 2008 20:04:46 GMT

Well, as we pass into the southern hemisphere of our galaxy as we have done before in the past, there will be widespread radiation exposure, and cell mutations. This has been a key step in evolution-and/or de-evolution. It's just that this time will be different. The very outter layers of our atmosphere will be weaker than ever before in part to project H.A.A.R.P. and others like it around the world. H.A.A.R.P. is in Alaska, V.P. candidate Palin is also from Alaska. So will you be ready for the flood? 2010-2012 r.i.p

Planet debate gets greater

N A , BC , Canada — Sun, 21 Sep 2008 20:48:32 GMT

Cool Kevin.Lets consider the Dwarf Planets like dwarf people! Then we can have Dwarf Planet tossing events!

The word planet means 'wanderer' and referred to any object seen to move against the sky except for the sun and the moon.

The need to classify the plutoids comes from some astronomers' OCD disorder gnashing with the general publics perception that anything that looks like a planet should be called a planet.

In this case that means anything made round by the force of its own gravity should be a 'planet' to the general public. Isnt this good enough for the astronomers? Yes it means you have to rewrite your textbooks because the number of planets went up. Yes , for you, it means change. Get with the program. The debate seems asenine to a large portion of us.

Planet debate gets greater

Carl Hayes — Sun, 21 Sep 2008 22:08:55 GMT

The purpose of science is to discover the facts of reality. Whether we call Pluto a planet, an asteroid, an ice-cream cone, a Chevrolet, or a Democrat, or don't call it anything but "Pluto", the facts of reality are the same: there's a body of such size, with such composition, in such orbit. So why the wasted wind about the definition of "planet"? It's the same kind of mindless fuzz as the grade-school question, "If a tree falls in the forest and no one hears, did it make a noise?" In that case, everyone agrees what happened -- a tree fell, causing pressure waves to propagate in air. The evil is, thaqt the unintelligent are fooled into thinking they're arguing about what happened in the woods, when really they agree on that and are only talking about the definition of a word. The question in the case of Pluto is equally vacuous -- people think they're arguing about what's out there in space, when really there is no question what's out there, or even about its name (everyone agrees it's Pluto). They're arguing only about the definition of a word, though many of them think they're discussing a fact of reality. People whose brains work no better than that ought to be shut away in institutions.

Planet debate gets greater

John F. St. Louis, Mo. — Sun, 21 Sep 2008 23:12:49 GMT

There a 10 planets. Pluto and Eris are 9th and 10th respectively. Case closed.

Planet debate gets greater

Styler G., annoyed 9 yr. old, Byram, MS. — Mon, 22 Sep 2008 01:45:56 GMT

If one of the classifications of being a planet is to have cleared everything out of its path, then no planet with an atmosphere and/or a moon is not a planet; this is because 1. The atmosphere of a planet is not technically a part of that planet, merely some gases released by the planet/whatever lives on it or grabbed at random by the gravity of said planet, and this means that, since the atmosphere of a planet surrounds that planet and therefore is inevitably in the planet's path, it has not been cleared from the planet's path; 2. It is extremely rare for a planet to have a moon that never crosses into a position that, if the moon suddenly became stationary, would be in the planet's path.

Planet debate gets greater

CBCRonin, CT — Mon, 22 Sep 2008 02:08:29 GMT

"Plutoids" sounds like a layman's term for hemorrhoids... which is what the IAU's decision is becoming for them.
Instead of attempting a comedic jibe at those who disagreed with their "definitive" position, they should have left the comedy to comedians... because the "joke" isn't funny anymore.

Planet debate gets greater

C.J. Ohio — Mon, 22 Sep 2008 02:20:05 GMT

Aw, c'mon. Simply grandfather Pluto's status as a planet. Be nice. Refer to everything else as asteroids, comets, moons, IAU objects, etc.

Planet debate gets greater

Michael,kent oh — Mon, 22 Sep 2008 06:44:02 GMT

"Some people have too much time on their hands
without any idea what to do. If it orbits a sun
it is a planet, large or small. If it orbits a
planet it is a moon. What's wrong with that? "

That does not work.What about all the asteroids in the asteroid belt? Those have never been thought of as planets. Of course the real problem is,its not a good definition at all. Planets should be the nine bodies that have traditionally been called planets. Then astronomers should come up with a nice classification system to describe all the bodies that orbit the sun. Its even ok to use the word "planets" to describe some of them if that's whats chose. In such a system,"The Planets" or "A Planet" (with a capital "P") would refer to the nine bodies that were traditionally recognized as such. (much as the word god,with a lowercase g,referes to a deity suck as the Greek god Hermes,and God with an uppercase "G" refers to the Hebrew monotheistic god which).
The problem is,if you try to make a definition of "planet" that makes sense on its own and is consistent with the previous definition you run into a lot of trouble. (and probably a lot more as we find bodies that orbit other stars.) Suddenly the definition becomes rather useless. We COULD define a planet as anything that orbits the sun. Then it would include all the planets,and the asteroids,which most people would agree are not planets. The problem is,that description is just too simplistic. I say that xyz is a planet,so what. We still no nothing about it. Virtually anything you find in our solar system is a planet,it orbits the sun.

Planet debate gets greater

Singe — Mon, 22 Sep 2008 07:27:34 GMT

One could make the argument that Jupiter, 250% more massive than everything else in the solar system combined (except the sun) is the only real planet and the rest is just debris. :)

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JP Boulder CO — Mon, 22 Sep 2008 09:26:36 GMT

It's amazing to me that anyone cares one way or the other!

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Mark in Time, Lakeland, Florida — Mon, 22 Sep 2008 14:29:37 GMT

"All Science is either Physics or stamp collecting."
- Ernest Rutherford

This debate appears to be in the realm of the latter.

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Keith W. Fagan, Ponca City, Oklahoma — Mon, 22 Sep 2008 14:42:59 GMT

It seems to me that we're all dancing around the real issue here, which would appear to be fear (seemingly verging on absolute terror for some) over having to have kids memorize more than 9 names.

First off, this is nonsense, since even my 3-year-old daughter can tell you the names of the 9 traditional planets, plus Ceres, Eris, Sedna, and Quaior, and the Galilean Moons of Jupiter. Secondly, it misses the point entirely. Kids should be learning science, not rote memorization just to pass some test. They should be learning ABOUT planets- their types, formations, compositions, and histories, not simply their names and orbits.

If we were to apply the logic of many involved in this debate, we shouldn't teach kids about asteroids at all, since there are thousands of them, far too many to memorize. There are an awful lot of names for animals too, perhaps we should discard them with the bathwater as well?

Unfortunately, education will likely always trail significantly behind our current state of knowledge. Heck, when I was first taught the planets back in 2nd or 3rd grade in 1980 or so, my teacher was using a book published in the 1940's! I can also remember being quite disappointed over how little time we spent on the lesson, and how little was said about Uranus, Neptune, or Pluto. I wanted to learn more, indeed, already knew more than was being said.

So how many planets are there in the Solar system? Depends on your definition, but the important thing is not how many are out there, but rather that what KIND of things out there gets taught- Rocky Bodies, Icy Bodies, Gas Giants, Rings, Moons, Asteroids, Comets, Kuiper Belt Objects, etc.

Obviously, I've opted to include the Dwarf Planets in my discussion of planets with my daughter, even to the point of including objects the IAU has yet to formally classify as Dwarf Planets, such as Sedna and Quaior. I resisted Varuna because I couldn't find any real listing of size at the time, but it looks like I should introduce Makemake and Haumea now.

Planet debate gets greater

Rick — Mon, 22 Sep 2008 14:45:08 GMT

Really, the only thing that matters is that there is ONE class M planet in this system.

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T.R. Stone — Mon, 22 Sep 2008 14:57:57 GMT

I just don't understand all this fuss about "what constitutes a planet" and what doesn't. Jiminy poke, people! A solid definition shouldn't be THAT hard to cook up. I for one favor a definition where a "planet" is a body that

(A) Has a star as the center of its orbit;
(B) Has sufficient mass to gravitationally assume
the shape of a spheroid having an oblateness not
in excess of (an agreed-upon value).

Now, I grant you: that last bit in parentheses will be a bone of contention amongst a good many astronomers, but by settling on a sufficiently small oblateness, you get an essentially (and easily recognizable) oblately spheroidal body, effectively excluding potato-shaped monstrosities like asteroids. Since everyone insists a line MUST be drawn, how hard could it be to come up on a reasonable, universally-accepted value? And just to cover another possible point of contention, one may exclude PROLATE spheroidal bodies, which would effectively be the "potato-shaped monstrosities" I mentioned before.

Well....It seems like a reasonable set of criteria to me....

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Nameless — Mon, 22 Sep 2008 15:02:21 GMT

Is the classification really necessary? Or is it just their habit to make things more complicated for the rest of us? This debate is trivial at best, if not pointless since its not like any of us will ever go to that planet in our life times.And isn't calling Pluto a dwarf planet a contradiction? Dwarfs being small and planets being large.

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xorlack, Third rock from the Sun — Mon, 22 Sep 2008 15:08:41 GMT

Apparently none of us want to work today. How about we leave politics and religion and the galactic trans-hemispheric migration(how's that for a name)out of this one. Though, we could ask Tom Cruise to consult Xenu and his Thetans about what we should do.
Several good points have been made about size differentiation. There are a crapload of different types of dwarfism as far as people go. There are rivers, streams, brooks, etc. There is a difference where wire becomes cable. Boat to ship. Car to Truck. Blah blah blah.
What do we refer to Alderan as now that the Death Star blew it up? I don't even know where I'm going with this.
AND NO STUPID, THE SUN IS NOT A PLANET.

Planet debate gets greater

aaron g, van wert, oh — Mon, 22 Sep 2008 15:24:12 GMT

Isn't a dwarf planet still a planet? If not why is "planet" still in the name? As far as I'm concerned, the planet list is still growing. What makes people feel like EVERYTHING must be strictly categorized? Come on... a planet is a planet regardless wheather it is a dwarf or not..

Planet debate gets greater

Lovettsville, VA — Mon, 22 Sep 2008 18:04:22 GMT

Hey, if Pluto is not a planet because it has not cleared out all the stuff in its orbit, what if we find some stuff in Earth's orbit 10 years from now. Will we then de-classify Earth as a planet?

Planet debate gets greater

PAQ Pepperell MA — Mon, 22 Sep 2008 19:16:44 GMT

Planets Shmanits. . Let’s call them resource objects and use something akin to the automotive vin number that is coded to designate its characteristics, size, composition, spin, orbit and whatever. That way some time in the future after the people of faith are gone and humanity can progress again we will be able to find resource objects that can be used to make mars suitable for human habitation by adding water and mass. Earth could probably use a nice ice moon as a resource object for our space program.

Planet debate gets greater

psychic readings — Mon, 22 Sep 2008 23:25:34 GMT

I have a large interest in planetary activity, and I found this article very useful. Thank you.

Planet debate gets greater

Jack, Compton, CA — Tue, 23 Sep 2008 02:09:57 GMT

There are only 4 planets: Mercury, Venus, Earth, and Mars...the "giants" are just big balls of gas and to not fit the definition of planets. Pluto is more of a planet the the gas giants....

Planet debate gets greater

Jane Doe — Tue, 23 Sep 2008 17:23:22 GMT

2012, isn't' that the date that the Inca calendar stopped as they could not see anything beyond that?
What a time to be had by all. PARTY,PARTY,PARTY, LIKE THERE IS NO TOMORROW! Who knows, maybe there won't be.
I agree with the river analogy, but it depends on who names it. It is a river or a creek? They are both exactly a like, just one bigger.
I like to think that Pluto is still planet, and always will. So sue me!

Planet debate gets greater

Jeff Brumbaugh, Bedford, TX — Tue, 23 Sep 2008 18:24:26 GMT

To borrow on the rivers concept, why not consider lakes. The United States has an untold number of them. Yet only 5 are considered Great Lakes. Why not call them all planets and designate the 8 as Great Planets?

Planet debate gets greater

Tim, San Diego CA — Wed, 24 Sep 2008 01:45:26 GMT

>Perspective<
Our complete solar system doesn't even measure on the scale of it all! Why focus so much effort on these local specks of dust when there is so much more out there to discover! BTW: I like Stern's river analogy - smart! Also, to Dan Hilbert, I agree with your viewpoint regarding moons the size of planets. However, Titan is a moon circling Saturn, not Uranus.

Planet debate gets greater

Sean O'Donnell — Wed, 24 Sep 2008 06:20:55 GMT

Here's an idea. Poll children in grades 1 thru 8 and ask them how they want to handle this issue.
You can ask:
1)Is Pluto a planet?
2)If so, is everything the size of Pluto and bigger a planet?
They are the ones who will be dealing with this problem in the future so let them make the call. Then the textbooks can just be updated with new objects each year like historical dicoveries are added.

Planet debate gets greater

Matthew Goodwin, Bendigo, Victoria, Australia — Thu, 25 Sep 2008 03:39:33 GMT

Planet isn't a scientific term. It tells me nothing about the objects, structure, formation, or relationship to other objects. It is a pop cultural term only. We need to develop a Scientific Nomenclature for these "things" out there that will also cover "things" in the gravity well of other stars.

Planet debate gets greater

Rodney Sibert, Trussville, AL — Fri, 26 Sep 2008 03:39:03 GMT

(Jaipal, India
Answer to your non-question is SUNday, MONday, Tuesday (MARteS in spanish), Wednesday (MiERColes in spanish), Thursday (JUeves in spanish), Friday (ViErNES in spanish), SATURday.)

I have changed my mind on Pluto being acknowledged as a planet. I think it should be, as well as Eris, etc... Pluto orbits the Sun, so classify it as a planet. I don't care if there are 30 more out there, name them, and we'll get used to it. We have got to get past this adolescents of "no change" that we are in.

I take it back, Pluto is not a planet. If it was as close to the Sun as the Earth, it would have a tail. Now call me crazy, but don't we already have names for objects with tails?

Just because Pluto is not classified as a planet, doesn't mean it is no longer there. It's still out there.

Planet debate gets greater

Rodney Sibert, Trussville, AL — Fri, 26 Sep 2008 03:54:42 GMT

-Singe-
Jupiter is a failed star, with it's own little solar system going on. Look at all of it's satellites, kind of reminds you of the Sun and all of it's 8 planets orbiting.
Saturn as well. You give Saturn a few more years (thousands), and it's rings will be gone. It is very similar to Jupiter.
Also Jupiter is not that much bigger than Saturn. If you add the rings as part of the planet, Saturn is larger than Jupiter. But that would be like calling Pluto a Planet, lol.

Planet debate gets greater

Norman Fields, Bullhead City, Arizona, USA — Sun, 28 Sep 2008 19:18:52 GMT

The problem with the IAU definition of a planet is that it leaves only two panets in our solar system, because only Mercury and Venus are spherical by the force of their own gravities, and only they have cleared their orbits. The rest have moons..

I agree that the only reason for this change in definition is that a group of scientists needed to have their names appended to a newly published definition. If that were not so, they would have included all the spherical Kuiper belt objects as planets; they would have worried about truth in classification, rather than worrying about a cutesy mnemonic to memorize the planets' names (My Very Excellent Mother...).

Singe's point about the mass of Jupiter is well taken, but does not go far enough. Compared to the Sun, the rest of our solar system is dust, so let's ignore the planets. Beyond that, the universe is almost completely empty, so why not ignore everything in the universe as a little dust?

Planet debate gets greater

Joel(age 14), Hermitage, Tennessee — Mon, 29 Sep 2008 01:56:55 GMT

i agree with Joseph if it orbits the sun its a planet, if it orbits the pre-existing orbit it is a moon, its not that hard. and come on shouldn't we worry more about discovering planets and possible life out side of us not arguing over weather a celestial body is a planet or not!!!!

Planet debate gets greater

Emiel De Baere, Behramkale, Turkey — Fri, 14 Nov 2008 02:54:59 GMT

Don Boyer : You made me smile in recognition. You obviously understood the nature of egos in debates such as this one. Thinking ahead of our era just a bit...just a bit...
I wonder what Kurt Vonnegut, who is now in heaven... and looking at both us humans and the Kooper belt , would have to comment on all this.
Can anyone guess ?

Nonetheless, if Mad Mom, says there are nine planets as Pluto is a written fact and that we are discriminating ourselves because it is printed already in millions of textbooks, than for the sake of her children...I would I would suggest a massive book burning bonfire.
Kids love that stuff.

From all I understood from this debate, there is a big soup out there. But especially the following : a "higher" filosophical debate could be an option as to how our human minds work in order to classify and to name things.
It might occur to us then, that this debate is of minuscule importance to any one of us.
What we all already know I guess

Thanks for the entertainment. The world still looks pretty flat from what I've read about this issue.

Planet debate gets greater

John Doe, Smithfield NC — Tue, 18 Nov 2008 06:09:24 GMT

Is this a political debate or scientific? It certainly isn't going in the direction that was initially intended. Aparently know one knows how many "planets" exist in the Milky Way, however, It was nine until Pluto was recently eliminated... Seems to me that simple math and not speculation should be improvised here.

Planet debate gets greater

neneh linda, bujumbura burundi — Sun, 04 Jan 2009 15:13:56 GMT

I just want to know if other planets have added.I tell him of nine he says some have added.please I really want to know.