All this stuff reminds me of the Grand Fenwick egg-breaking debate...

Adding the "dwarf" modifier to "planet" does nothing for science.

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What brings us together is stronger than what pulls us apart

Well, it Dwarf's it doesn't it?

Yeah, it dwarfs science.

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What brings us together is stronger than what pulls us apart

I would say "Primitive Ice Belt Dwarf Planet" sums up most of the Bigger TNOs.

After the the Sun swells into a red giant thus destroying Mercury, Venus, and the Earth, were those ever truely real Planets?

Hopefully after the Sun goes Nova it will destroy Mars, and thus give us only 4 true Planets (Jupiter, Saturn. Uranus, Neptune).

Will the Suns Nova encourage Jupiter to enlarge into a Brown Dwarf? Will the Nova cause a new planetoid belt?

At least I know they will have to revisit the question of how many local Planets there are in 4.5 to 5 billion years.

-- Kevin Heider

The sun won't go Nova. Red Giant and then after a few flicks of Helium flashes it's down to White Dwarf.

I am not sure the planetary nebula will shed enough to make for a new belt, I suspect not.

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The impossible often has a kind of integrity which the merely improbable lacks.

Jupiter and Saturn might pick up some pretty nice ring material from all the inner system material blown outward. The intensity of the Sun's emissions might not destroy any asteroids, but will certainly give their dustier side a good puff.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

The Space Review: Inside the planet definition process

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Correcting myself in regards to the Suns future 'planetary nebula' instead of a nova.

It does appear that 4 is a interesting number.

We have 4 terrestrial planets.
We have 4 Jovian Planets.
Jovians have 4 major moons. (Triton and other KBOs may have messed up Neptune's moon system).

Even the masses of the 'Jupiter + 4 Galilean moons' is basically proportional to Uranus and its 4 largest moons.

There are 4 Large Plutinos: Pluto, Orcus, Ixion, Huya.

So in 5 billion years Mars might be the old ball planet, since the 4 Jovians will survive.

They say the Red Giant Sun will boil off most the atmosphere of the outer planets. So is it possible that Saturn or Neptune will be the most massive planet in 6 billion years?

-- Kevin Heider

I can't see how you got that number. Unless you don't count one of the Galileans or Titan as a "major moon".

I would qualify all spherical moons (Mimas and up) as "major moons".

Huya is not particularly large (~ 500 km). There are certainly larger plutinos waiting to be found (and some of the unnumbered/unnamed may be larger).

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

I always forget about Saturns Iapetus, probably because I forget how to pronounce it. So Saturn has 5 significantly large (1000+km) moons. One of them could be a captured KBO.

Why the comment on the Galileans? Jupiter only has 4 very large moons.

I agree. But for the sake of simplification, the Jovian Foursomes (Saturn+1, Neptune messed up by Triton) dwarf the other Jovian moons.

-- Kevin Heider

"Odd ball"? you mean, after the other three are burnt up?
Ah, you meant each Jovian planet has four, not there are four total!

I thought you meant the largest moons (i.e. Moon, Galileans, Titan, and Triton, two of which disqualify).

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Heh, the very first phrase of that article is already problematic.

"It just didn’t feel right..."

Did it feel right when Earth was found to be round? Did it feel right when Earth was no longer the center of the universe? Did it feel right finding out the Sun, the Milky Way are no different from countless other entities?

Since when does feeling have a place in science? Something is what it is, regardless of what is the popular or past conception. This is why it is ridiculous to "grandfather" Pluto in and leave out other similar objects. Dismissing them altogether is equally flawed in my opinion, since orbital status really shouldn't be factored in the main definition of planet. The idea of using orbital "clearing" is just an easy way out to avoid too many planets to memorize and (even they admit) only caters to our solar system.

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This space is for rent.

Yes. Perhaps I should have stated myself differently.

It is interesting to note that "the mass of Pluto + the mass of Uranus's 4 biggest moons" = roughly the mass of one Triton.

It is also interesting to note that Uranus's moon Miranda is roughly the size of Ixion and Huya (two of the larger Plutinos).

-- Kevin Heider

You're giving too much credit to the IAU here by lumping their planet definition, which is simply a classification scheme, with observable facts like the roundness of Earth.

While people are still discussing this whole definition thing, I say someone either rename Kuiper Belt Objects to just "Kuipers", or rename asteroids "Asteroid Belt Objects". Is it too much to ask to have a little bit of consistency in how Small Solar System Bodies are classified?

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"The plan does not involve mayonaise."
"... I knew there was a catch."

You can't take the sky from me.

Let's call 'em Edgeworths

It sounds Pratchettwise, to me.

What about other asteroids?

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Um, most people who are against Pluto's demotion justify their opinion only by their feelings...

When Pluto became a planet, it was thought to be much larger. Like Ceres, it was thought to be alone. After the discovery of the Kuiper belt it became clear that Pluto is not unique as thought before. Now it is not even the largest known Kuiper Belt object, and not a single property makes is unique (large moon: Orcus has one, and most giant TNOs have satellites; atmosphere: 2003 UB313 and maybe 2005 FY9 have similar transient atmospheres; it has more satellites than others, but it doesn't sound unreasonable that 2003 EL61 or others have more).

What I was against, is to demote Pluto a minor planet. It is far more complex world than the small cometary nuclei which are abundant in the Kuiper Belt. That's why it is great that Pluto became a dwarf planet. It received a minor planet number, but it is still a dwarf planet.

So in this sense the IAU definition is almost as good as possible. The real problems are the unfortunate wording ("orbital clearing" part) and that the definition covers only the Solar System planets.

So don't say the definition was a step backward when it takes into account the recent discoveries.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Well, we know how much female celebs like Paris Hilton love their dwarf dogs, so maybe dwarf planets will become the in thing in Hollywood.

Seriously, I think the IAU decision is a great thing for astronomy; when was the last time an IAU meeting even made international news coverage? It got a lot of ordinary people thinking about such things, even for a couple of minutes.

The idea that this somehow changes the science that New Horizons is going to do, or makes Pluto less important, seems silly to me. Birders are constantly changing classifications of birds, as do other areas of biology, as new information comes along about the relationships among species and sub-species (such as genetic information).

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009
All moderation in purple

hmm, that´s the problem...

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What brings us together is stronger than what pulls us apart

Unfortunately, the ordinary people are thinking, hey we're spending a lot of money there...

That's quite common when an expert considers something within his field (as is the opposite 'it just felt right'). It just means an instinctive response based on their knowledge and experience.

Engineers say a design just didn't look right. Accountants say a set of accounts just didn't hang together. Detectives say an alibi didn't smell right.

Sometimes it takes them a little time to figure out just what it is that doesn't seem right to them.

As for the new definition itself, apart from Stern's slightly-hysterical reaction, this appears to be being accepted rather quickly. I suspect there may be a bit of tweaking of the 'cleared the neighbourhood of its orbit' to clear up some of the ambiguity, but the basics will remain.

Detectives don't usually go public with it

"and (c) dominates the neighborhood around its orbit clearing it of comparable objects."

-- Kevin Heider

WADDA WE WANT...PLUTO
WADDA WE CALL IT?...A PLANET
WADDA WE WANT...PLUTO
WADDA WE CALL IT.......
There are a few of us

I thought I was concerned about this but now I realize it doesn't matter to me. I'll still call it a planet just like I still call the LM the LEM. Eh besides it's still classed as a dwarf planet so it 's not like they started calling it and asteroid or something. It's still a planet of sorts, just a tiny, cute one like it's always been.

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You're a coward and a liar and a thOOF - Bart Sibrel

Goodbye, Pluto. It was nice knowing you.

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If I set the budget, we'd have Ares and more. Unfortunately, I don't set the budget, and Ares is just too expensive and too far out for us to accomplish our goals within the budget we were given.

If we halt the ISS, all versions of Ares, and transport Orion and Altair aboard DIRECTv3's Jupiter family of Shuttle-Derived Launch Vehicles, we just might make it back to the Moon by 2020.

Since the IAU have voted in the stricter definition for planet, let's use the word "world" to take on the more looser definition - "any sub-stellar body that has sufficient mass to overcome rigid material forces so that it takes on a hydrostatic equilibrium (nearly round) shape". We may only have 8 planets now, but there are atleast 35 worlds. The set of worlds will include the planets, dwarf planets, moons (round satellites), and rogues. In school text books it would be wise to not only mention the planets but to also mention the worlds - like Io, Europa, Titan, Pluto, and EL61.

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Will 2003 EL61 and 2005 FY9 EVER get names!!

Planet would suffice. Thousands, millions of them.

I´m expecting "planetary" nebulas to change "classification" any time now.

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What brings us together is stronger than what pulls us apart

Yes, some are not spherical, but I suppose many have a cleared orbital path, with some interruptions now and then, and orbit around a central black hole, I think.

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Lighten up! This is a stellar board!