Fight for Pluto !, A Campaign to Reverse the Unjust Demotion Options

[laurele]

I did not create this petition, and I am not pushing for Pluto only. If I had, I would have put in language urging the overturning of the IAU definition of a planet adopted last month and the adoption of a better definition that includes Pluto, Eris, and possibly Ceres and Charon as well. The point here is that the process by which the decision was adopted was flawed as well as arbitrary and capricious. This, not just the Pluto issue, is what Dr. Alan Stern seeks to correct with his conference next year.

It's not a matter of reinstating Pluto vs. adopting a better definition of the word planet. In no way are these goals mutually exclusive. And I am not wedded to having a nine-planet solar system. In fact, I have no problem with us having 50 or 100 planets or more, but the IAU members who voted on this decision did have a problem with that.

However, I do feel strongly that the definition of the word planet ultimately adopted should include Pluto. A round object that orbits the sun, has an atmosphere and three moons is a planet. There is no reason it cannot be both a planet and a Kuiper Belt Object. But it is different from other Kuiper Belt objects which are mostly much smaller and do not have any moons.

[Guest_Kevin Heider_*]

I am not pushing for Pluto only. I would have put in language urging the overturning of the IAU definition of a planet adopted last month and the adoption of a better definition that includes Pluto, Eris, and possibly Ceres and Charon as well.

If Pluto is a Planet because it is spherical, then Ceres deserves the same status!

The point here is that the process by which the decision was adopted was flawed as well as arbitrary.

The lower end of Planets will always be arbitrary. Nature does not confirm to our rules. Rather we define Planets as Spheroids (~400+km in diameter depending on mass), being at least as big as Pluto (2300+km), at least as big as Mercury (4878+km), or Dominant in their orbit, all of these definitions will have borderline cases. What happens when we find a Spheriod 480km in diameter (perhaps Huya?) that has too many tall mountain ranges on one side and on the other side has a small bite taken out of it by a collision with another object? Do we call it spherical by self gravity? Do we call it a former Planet (ie: it was a planet until that other object deformed it)??

Vesta looks too me as if it might have been spherical until an object came along took a bite out of it. Because Vesta has a differentiated interior, is it a former 'Dwarf Planet'?

I have no problem with us having 50 or 100 planets or more, but the IAU members who voted on this decision did have a problem with that.

The IAU had to come up with a definition of a Planet because of all the other TNOs (a group for which Pluto belongs to) being discovered. Since one object (Eris) was discovered to be bigger than Pluto they could infer that other objects would also be bigger than Pluto. The IAU either had to keep Pluto as a Planet and let many other non-dominant obects be included as Planets OR they had to remove Pluto as a Planet. Keeping Pluto as an exception to the rule would be unscientific.

But it (Pluto) is different from other Kuiper Belt objects which are mostly much smaller and do not have any moons.

Since "most stars are part of a binary star system, most planets have satellites, asteroids are known to have satellites, and some KBOs are known to have satellites", I find your statement that 'most do not have moons' to be inaccurate. Back in the 1960's no one thought Pluto had any satellites either. But since Pluto is one of the closest and most carefully studied KBOs they have found 3 satellites.

However, I do feel strongly that the definition of the word planet ultimately adopted should include Pluto. A round object that orbits the sun, has an atmosphere and three moons is a planet. There is no reason it cannot be both a planet and a Kuiper Belt Object.

Currently moons are defined by their surrounding DOMINANT (more massive) Planet. But currently (for better or worse) we define both planets and moons by their surroundings. If we want to define Planets by 'what they are' instead of 'where they are', should we also call spherical moons as Planets? That would add 19 moons as Planets.

"and ('c') dominates the neighborhood around its orbit clearing it of comparable objects." is as good of definition as any.

-- Kevin Heider

[laurele]

[quote name='Kevin Heider' post='70120' date='Sep 27 2006, 03:09 PM']
[quote]If Pluto is a Planet because it is spherical, then Ceres deserves the same status!
The lower end of Planets will always be arbitrary. Nature does not confirm to our rules. Rather we define Planets as Spheroids (~400+km in diameter depending on mass), being at least as big as Pluto (2300+km), at least as big as Mercury (4878+km), or Dominant in their orbit, all of these definitions will have borderline cases. What happens when we find a Spheriod 480km in diameter (perhaps Huya?) that has too many tall mountain ranges on one side and on the other side has a small bite taken out of it by a collision with another object? Do we call it spherical by self gravity? Do we call it a former Planet (ie: it was a planet until that other object deformed it)??[/quote]

Why can't there be a subcategory of planets that are also Kuiper Belt Objects? Many asteroids in the Kuiper Belt would not fit this description, but setting a minimum size plus other factors such as having moons and an atmosphere would be a good start. Pluto is sufficiently larger and different than most Kuiper Belt Objects. Maybe we are discovering a whole new type of planets.

[quote][quote]Vesta looks too me as if it might have been spherical until an object came along took a bite out of it. Because Vesta has a differentiated interior, is it a former 'Dwarf Planet'?
The IAU had to come up with a definition of a Planet because of all the other TNOs (a group for which Pluto belongs to) being discovered. Since one object (Eris) was discovered to be bigger than Pluto they could infer that other objects would also be bigger than Pluto. The IAU either had to keep Pluto as a Planet and let many other non-dominant obects be included as Planets OR they had to remove Pluto as a Planet. Keeping Pluto as an exception to the rule would be unscientific.[/quote][/quote]

I'm not advocating keeping Pluto as an exception. I am advocating objects the size of Pluto or larger be considered planets. So far the only one found is Eris, but if others are found, they should be considered planets too. I think Vesta is a lot smaller than both Pluto and Eris. The IAU definition makes no sense because it creates a term "dwarf planet," which appears to be a noun modified by an adjective, but then says a dwarf planet is not a planet. That's like saying a grizzly bear is not a bear. They need to do better than this and have far more participation and deliberation in the process.

[quote]Since "most stars are part of a binary star system, most planets have satellites, asteroids are known to have satellites, and some KBOs are known to have satellites", I find your statement that 'most do not have moons' to be inaccurate. Back in the 1960's no one thought Pluto had any satellites either. But since Pluto is one of the closest and most carefully studied KBOs they have found 3 satellites.
Currently moons are defined by their surrounding DOMINANT (more massive) Planet. But currently (for better or worse) we define both planets and moons by their surroundings. If we want to define Planets by 'what they are' instead of 'where they are', should we also call spherical moons as Planets? That would add 19 moons as Planets.[/quote]

An uncontested portion of the IAU's definition is that a planet must orbit a star, not another planet. Therefore, moons do not count as planets. The only uncetain case is Charon. If Charon and Pluto orbit one another and the sun, both are planets, a binary system. If Charon orbits Pluto but Pluto does not orbit Charon, then Charon is solely a moon.

What other KBOs that we know about, other than Pluto and Eris, have moons? How large are these KBOs?

[quote]"and ('c') dominates the neighborhood around its orbit clearing it of comparable objects." is as good of definition as any.[/quote]

I disagree. Neptune does not clear its orbit of Pluto, and Jupiter does not clear its orbit of many asteroids. Even Earth does not fully clear its orbit of asteroids. The only way this provision holds is if we go back to size--ie, Neptune is bigger than Pluto; Jupiter is bigger than the asteroids in its orbital field. This definition is poorly worded and problematic because it sets up a double standard.



[/quote]

[Guest_Kevin Heider_*]

laurele: Why can't there be a subcategory of planets that are also Kuiper Belt Objects?

If we find only one object (as large as Mars) in the Kuiper Belt we might call it a Planet assuming that we do not find too many KBOs in the 400+km range. Whether such an object is a planet or not is a function of the mass of the belt vs the mass of the planetary contender. We currently do not call Pluto a planet for basically the same reason that we do not call Ceres a Planet. Ceres and Pluto are both Belt Objects surrrounded by many other comparable belt objects. The term 'Dwarf Planet' is not a bad way to make these large planetesimals stick out from the lesser asteroids.

Are you aware that from roughly 1801 to 1850 that Ceres, Vesta, Pallas, and Juno were known as primary planets? See: When Did the Asteroids Become Minor Planets? AND read about Planet Hygea


laurele: Many asteroids in the Kuiper Belt would not fit this description, but setting a minimum size plus other factors such as having moons and an atmosphere would be a good start. Pluto is sufficiently larger and different than most Kuiper Belt Objects.

They have currently confimed over 783 Kuiper Belt Objects, and are constantly confirming more. At least 16+ of them could be large enough to be spherical. What does having moons have to do with being a Planet? Nothing! Venus does not have any moons and no normal person is questening it's status as a Planet.

Mercury is so close to the Sun that it does not have much of an atmosphere even though it is 23x more massive than Pluto. Pluto has a non-circlier orbit that varies from 29-50AU from the Sun. Pluto only has an atmospehere when it is near it's closest point to the Sun. When Pluto drifts back out further into the solar system that very thin atmosphere will freeze to the surface. Pluto is estimated to be roughly 60% ice and 40% rock. If Pluto were orbiting were Mars is today, a lot of Pluto's mass would burn-off and escape Pluto's weak gravity. This scenerio could very well be another reason to compare Pluto to Ceres.


laurele: Maybe we are discovering a whole new type of planets

Asteroids (between Mars & Jupiter) are rocky planetesimals, were as, KBOs and Comets (due to their average great distance from the Sun) are often made of more ice than rock. But they are still planetesimals.


laurele: I am advocating objects the size of Pluto or larger be considered planets.

Why arbitrarily decide that Pluto defines what is a planet and what is not?

Planet: One of the seven celestial bodies, Mercury, Venus, the moon, the sun, Mars, Jupiter, and Saturn, visible to the naked eye and thought by ancient astronomers to wander in the heavens above a fixed Earth and among fixed stars. The word “planet” comes from the Greek word for “wanderer".

"Mercury (which modern science has shown to be the smallest planet) has been known as a Planet for thousands of years, were as Pluto has NOT even been known for 100 years."


laurele: The IAU definition makes no sense because it creates a term "dwarf planet," which appears to be a noun modified by an adjective, but then says a dwarf planet is not a planet.

When Resolution 5B failed to pass, it was decided that a 'Dwarf Planet' (compound noun) would be excluded from the list of 'Planets'.

Before 5A Section (3) passed we had 136,000+ Minor Planets.


laurele: An uncontested portion of the IAU's definition is that a planet must orbit a star, not another planet.

I wouldn't say it is uncontested. If every small spheroid (some possibly as small as 400km in diameter) is considered a Planet then I would hope moons that are spheroids (7 of which are larger than Pluto) would also be considered as being included in a new definition. You are talking about redefining the definition of a Planet and that means no reasonable idea can be dismissed.


laurele: What other KBOs that we know about, other than Pluto and Eris, have moons?

2003 El61 has 2 moons. But it, like Pluto & Eris, have been very closely studied objects. As we learn more about KBOs I am sure that we will find many more satellites around KBOs.


Kevin: "and ('c') dominates the neighborhood around its orbit clearing it of comparable objects."
laurele: Neptune does not clear its orbit of Pluto, and Jupiter does not clear its orbit of many asteroids. Even Earth does not fully clear its orbit of asteroids.

Neptune is 7500x more massive than Pluto, they are not comparable.
Jupiter trapped all those asteroids at lagrange points. Let's see Pluto do that.
Show me a NEA comparable to the Earth.

-- Kevin Heider

[laurele]

If we find only one object (as large as Mars) in the Kuiper Belt we might call it a Planet assuming that we do not find too many KBOs in the 400+km range. Whether such an object is a planet or not is a function of the mass of the belt vs the mass of the planetary contender. We currently do not call Pluto a planet for basically the same reason that we do not call Ceres a Planet. Ceres and Pluto are both Belt Objects surrrounded by many other comparable belt objects. The term 'Dwarf Planet' is not a bad way to make these large planetesimals stick out from the lesser asteroids.

Pluto and Ceres are not comparable, as Pluto is much larger. Pluto is also not comparable with the vast majority of Belt objects surrounding it , which are very small and often not spherical in shape. The same may be said of Ceres in relation to its surrounding asteroids. Again, we're back to the unresolved question of how large an object has to be to qualify as a planet.

There is no "we do not currently call Pluto a planet" because there is no "we." What we have today is an unresolved dispute among scientists over Pluto's status and still no clear definition of the word "planet." The small number of IAU members who voted on this and the fact that an almost equal number of scientists signed a petition against the IAU definition and said they would not use it make it very clear that this is still a debate in progress.


Are you aware that from roughly 1801 to 1850 that Ceres, Vesta, Pallas, and Juno were known as primary planets? See: When Did the Asteroids Become Minor Planets?.

They have currently confimed over 783 Kuiper Belt Objects, and are constantly confirming more. At least 16+ of them could be large enough to be spherical. What does having moons have to do with being a Planet? Nothing! Venus does not have any moons and no normal person is questening it's status as a Planet.

These Kuiper Belt Objects may be spherical but what is their size in relation to Pluto, Eris and even Ceres? Many KBOs are very tiny and in that way clearly different from these three. Also, linguistically, minor planets are still planets. They are a subclass of the larger category. The IAU's creation of the term "dwarf planet" and subsequent claim that "dwarf planets" are not planets at all whether major or minor, makes no sense.

Having moons is a characteristic of all but two of the major planets. In contrast, no asteroids have satellites.
Mercury and Jupiter have very litttle in common, yet both are considered planets, and no one is questioning this. Again, we're back to the uncertainty of what defines a planet. With the IAU definition clearly unsatisfactory, the question remains unresolved.

laurele: Maybe we are discovering a whole new type of planets

Asteroids (between Mars & Jupiter) are rocky planetesimals, were as, KBOs and Comets (due to their average great distance from the Sun) are often made of more ice than rock. But they are still planetesimals.
laurele: I am advocating objects the size of Pluto or larger be considered planets.

So is it the composition of the object that determines whether or not it qualifies as a planet? The gas giants have little in common with the terrestrial planets. If the Kuiper Belt contains planet-sized objects largely made of ice, perhaps that should establish them as a third type of planet, one which we are only now discovering. The word "planet" is a very broad term, and there is no reason it cannot have many subcategories including "minor planet." In fact, one of the IAU proposals stated that a planet must have a spherical shape and orbit the sun, with nothing at all about "clearing its orbit."

Why arbitrarily decide that Pluto defines what is a planet and what is not?

Planet: One of the seven celestial bodies, Mercury, Venus, the moon, the sun, Mars, Jupiter, and Saturn, visible to the naked eye and thought by ancient astronomers to wander in the heavens above a fixed Earth and among fixed stars. The word “planet” comes from the Greek word for “wanderer".

Then if we use the classical definition, Uranus and Neptune are not planets either since they are not visible to the naked eye, and ancient astronomers knew nothing about them. And the sun and moon would once again qualify as planets.

"Mercury (which modern science has shown to be the smallest planet) has been known as a Planet for thousands of years, were as Pluto has NOT even been known for 100 years."

So does the definition of planet center on how long we have known about an object? Again, that would likely exclude Uranus and Neptune.

Since Pluto's status is still unresolved, it's not clear that Mercury rather than Pluto is the smallest planet.

[i]laurele: The IAU definition makes no sense because it creates a term "dwarf planet," which appears to be a noun modified by an adjective, but then says a dwarf planet is not a planet.

When Resolution 5B failed to pass, it was decided that a 'Dwarf Planet' (compound noun) would be excluded from the list of 'Planets'.[/i]

What this means is that the IAU, or rather, the very small minority of scientists who took part in this vote, made a colossal mess. There is absolutely no sound reasoning to say a "dwarf planet" is not a planet. This has to be revisited. Anyone can pass or vote down a resolution, but the resolution is pretty worthless if it makes no sense. And why did the IAU only allow members present in the room to vote and wait until the last day to hold the vote? Are they incapable of voting by email? This was clearly a political move by those who wanted to demote Pluto and is thereby suspect. It was not a scientific decision; this view is held by many planetary scientists including IAU members not present on that day.

Before 5A Section (3) passed we had 136,000+ Minor Planets.

And what is the problem with that? Why not establish a list of major planets and another of minor planets, all the while recognizing both are planets of some type.


I wouldn't say it is uncontested. If every small spheroid (some possibly as small as 400km in diameter) is considered a Planet then I would hope moons that are spheroids (7 of which are larger than Pluto) would also be considered as being included in a new definition. You are talking about redefining the definition of a Planet and that means no reasonable idea can be dismissed.

It's not a matter of being spheroids but of orbiting the sun and not orbiting another object.


[url=http://en.wikipedia.org/wiki/2003_EL61]2003 El61[/url] has 2 moons. But it, like Pluto & Eris, have been very closely studied objects. As we learn more about KBOs I am sure that we will find many more satellites around KBOs.

What is the size of 2003_EL61; where is it located in relation to Pluto and Eris, and is it similar to both of them? If so, it may very well be another Kuiper Belt Object that is also a planet.


Neptune is 7500x more massive than Pluto, they are not comparable.
Jupiter trapped all those asteroids at lagrange points. Let's see Pluto do that.
Show me a NEA comparable to the Earth.

Does trapping the asteroids mean clearing them of its orbit? Why is "clearing an area of its orbit" a qualification for planethood, and how is such a phenomenon defined?
You go back to size when talking about how much more massive Neptune is than Pluto. That indicates your criteria is size, not clearing its orbit since no matter what the size difference, Neptune does not clear its orbit of Pluto. There is no way of getting around that fact. This goes back to the motive of the IAU minority who approved this definition, which was very specifically to exclude Pluto individually.

[Guest_Sedna_*]

The way I see it you're pushing for a petition to reinstate Pluto, not demanding the IAU to make a better definition. If the petition was for a better, less sloppy definiton of a planet, I'd gladly sign it. This merely looks like someone god pi**ed about their favourite pet planet not being a planet anymore. How's that for "human arrogance"?

IMO, the time of a nine-planet solar system has passed. Either we have 8, hack it down even more to 4 or we have 12 or more. Pushing for Pluto only is wrong and IMO shows you're not interested as much in a good planet definition, but are interested in Pluto only.

Good reasonement. What is Pluto? A dwarf planet, for humans of planet Earth (or for IAU, the AUTHORITY, though it may hurt to somebody...). Does it really matter what it is for us? Not really... I think it's not a planet. I'm not really in agreement in the new definition of "dwarf planet", I would set apart just planets and minor planets (or KBO's and Asteroid Belt big bodies with another name, maybe...), not intermediate bodies. Anyway, Pluto is Pluto, regardless of what we, just humans, say about such a body, or bodies like Pluto. It was doubted that Pluto was a planet when discovered, and it has been ruled out as such. An historical error has been corrected. New Horizons will now visit a new kind of body never (not even by Voyagers...) visited before. I find out that this is even more interesting that before, not the opposite.

[laurele]

Good reasonement. What is Pluto? A dwarf planet, for humans of planet Earth (or for IAU, the AUTHORITY, though it may hurt to somebody...). Does it really matter what it is for us? Not really... I think it's not a planet. I'm not really in agreement in the new definition of "dwarf planet", I would set apart just planets and minor planets (or KBO's and Asteroid Belt big bodies with another name, maybe...), not intermediate bodies. Anyway, Pluto is Pluto, regardless of what we, just humans, say about such a body, or bodies like Pluto. It was doubted that Pluto was a planet when discovered, and it has been ruled out as such. An historical error has been corrected. New Horizons will now visit a new kind of body never (not even by Voyagers...) visited before. I find out that this is even more interesting that before, not the opposite.

I have already stated that I want a better definition of the word "planet," and this is not just about Pluto. As for the IAU, I question who made them the "authority" on this? What about the equal number of planetary scientists who signed the dissenting petition? The process the IAU conducted was highly unprofessional and represents a very small portion of its entire membership. The way they went about making this decision detracts from their credibility. It's not a matter of anyone being personally hurt, but a matter of the havoc the IAU has created by going about its decision so poorly. Dr. Alan Stern described it as "sloppy science that would never pass peer review" and "an embarrassment to astronomy."

I'm glad you see the flaws with this "dwarf planet" definition and agree with the obvious statement that our perceptions and labeling do not change what Pluto is. At the same time, I have a serious problem with the IAU's designating it a number as just another asteroid, which it clearly is not.

Again, I repeat, Pluto has not been ruled out as being a planet. This debate will continue at Dr. Stern's conference next year, the IAU conference in 2009, and the New Horizons visit in 2015. I just think it's premature to assume this is a "done deal" when it clearly is not.

[Guest_Sedna_*]

I have already stated that I want a better definition of the word "planet," and this is not just about Pluto.

So do I, as a minor planet or such maybe...

As for the IAU, I question who made them the "authority" on this? What about the equal number of planetary scientists who signed the dissenting petition? The process the IAU conducted was highly unprofessional and represents a very small portion of its entire membership.

The authority made itself. Who made the President of the United Stated, or UK, or Spain such a President? People did. With IAU, astronomers did, one year ago, or 100 years ago...

The way they went about making this decision detracts from their credibility. It's not a matter of anyone being personally hurt, but a matter of the havoc the IAU has created by going about its decision so poorly. Dr. Alan Stern described it as "sloppy science that would never pass peer review" and "an embarrassment to astronomy."

Maybe you are pertaining to IAU, or you were in the Assembly... I wasn't yet, unfortunately... and, from my first news, I was decided to accept IAU's decision, even the first one of 12 planets... though I was eager to find out Pluto to be ruled out as a planet (why not Ceres if the opposite)? We all know that this Assembly was not decided to promote Ceres to planet status, but the opposite for Pluto, or to decide Pluto's status, not Ceres'. Is Ceres a planet? Maybe, but I stick to IAU's resolution, and neither Ceres nor Pluto are planets... A pity... Not, probably, but if the IAU decides to promote Ceres and Pluto (both of them, not just Pluto!) to the status of planet, I will have to accept it, regardless of my personal opinion. "Some people" can not be in agreement, but it's their business... Regarding IAU, will you accept "Eris" for 2003UB313, or will you find a better alternative name?... IAU is the authority, not decided by me, of course, but by most of astronomers... And, finally, Pluto was assigned a MP number. It was offered "10000" as a honour, but was not accepted... now they/we have to accept this second one, no other chance...

[laurele]

So do I, as a minor planet or such maybe...
The authority made itself. Who made the President of the United Stated, or UK, or Spain such a President? People did. With IAU, astronomers did, one year ago, or 100 years ago...
Maybe you are pertaining to IAU, or you were in the Assembly... I wasn't yet, unfortunately... and, from my first news, I was decided to accept IAU's decision, even the first one of 12 planets... though I was eager to find out Pluto to be ruled out as a planet (why not Ceres if the opposite)? We all know that this Assembly was not decided to promote Ceres to planet status, but the opposite for Pluto, or to decide Pluto's status, not Ceres'. Is Ceres a planet? Maybe, but I stick to IAU's resolution, and neither Ceres nor Pluto are planets... A pity... Not, probably, but if the IAU decides to promote Ceres and Pluto (both of them, not just Pluto!) to the status of planet, I will have to accept it, regardless of my personal opinion. "Some people" can not be in agreement, but it's their business... Regarding IAU, will you accept "Eris" for 2003UB313, or will you find a better alternative name?... IAU is the authority, not decided by me, of course, but by most of astronomers... And, finally, Pluto was assigned a MP number. It was offered "10000" as a honour, but was not accepted... now they/we have to accept this second one, no other chance...

The IAU made itself an authority? So what is to stop an alternative group from making itself an equal authority, as is likely to happen with Dr. Stern's conference of 1,000 astronomers next summer? What happens if the IAU is itself divided? The comparison with the president of the US doesn't hold because the president was elected in a very specific process laid out in the US Constitution. If that process were conducted in a manner inconsistent with the Constitution, the election would be voided and a new one held.

I was not present at the Assembly, but I do not choose to blindly accept whatever the IAU or any other organization or individual, for that matter, decides upon at any given time simply because they are considered an "authority." It's not even clear the group who voted represent a consensus within the IAU. We're talking 424 out of 10,000! It's not just individuals' business if they are not in agreement. We are talking about definitions and classifications that impact the entire world. If two groups of scientists are equally qualified to make the determination, why should one group's view take precedence over the other's? As far as Eris, I am more interested in it obtaining planet status than what its name is. Like I said, I think the 12-planet scheme is far more accurate.

I will admit I'm unfamiliar with the issue of Pluto being offered "10,000" as a number. Who made such an offer; who rejected it, and why does Pluto need a number at all? Why can't it simply be known as Pluto? And why do you say there is "no other chance" regarding this? There is always a chance to revisit an issue if the first decision was flawed. I'm curious; if next year Dr. Stern's group of 1,000 decides on a different definition of planet and adopts the 12-planet scheme, how will you decide which view to accept?

[Guest_Sedna_*]

The IAU made itself an authority? So what is to stop an alternative group from making itself an equal authority, as is likely to happen with Dr. Stern's conference of 1,000 astronomers next summer? What happens if the IAU is itself divided? The comparison with the president of the US doesn't hold because the president was elected in a very specific process laid out in the US Constitution. If that process were conducted in a manner inconsistent with the Constitution, the election would be voided and a new one held.

IAU made itself in the sense that, when it was constituted, astronomers arround the world accepted this association as the ruling one in astronomical affairs, such as definitions or naming issues. Will Dr. Stern constitute an alternate association? I don't know... A star could be, for instance, be named in two different ways or weird things like this... I think that this also "applies" somehow to the president of any country. Of course a big law baggage is set behind, but where you asked if you even wanted a president to be elected? Maybe you don't want ANY president, but you are told to elect one... IAU should be respected in the decisions it takes, even if those are not in agreement with our thoughts... Is a "coup d'etat" the solution for an unpopular decision of a goverment?

I was not present at the Assembly, but I do not choose to blindly accept whatever the IAU or any other organization or individual, for that matter, decides upon at any given time simply because they are considered an "authority." It's not even clear the group who voted represent a consensus within the IAU. We're talking 424 out of 10,000! It's not just individuals' business if they are not in agreement. We are talking about definitions and classifications that impact the entire world. If two groups of scientists are equally qualified to make the determination, why should one group's view take precedence over the other's? As far as Eris, I am more interested in it obtaining planet status than what its name is. Like I said, I think the 12-planet scheme is far more accurate.

424 members voted. Why not all of them?, it's their business, ask them... I think Pluto is not a planet, but if IAU had taken the decision to establish the 12-planet scheme, I would have accepted it... BTW, Eris seems to be a good name, doesn't it?

I will admit I'm unfamiliar with the issue of Pluto being offered "10,000" as a number. Who made such an offer; who rejected it, and why does Pluto need a number at all? Why can't it simply be known as Pluto? And why do you say there is "no other chance" regarding this? There is always a chance to revisit an issue if the first decision was flawed. I'm curious; if next year Dr. Stern's group of 1,000 decides on a different definition of planet and adopts the 12-planet scheme, how will you decide which view to accept?

I will accept, IAU's, for the time being. This is a serious thing, this is science and an authority is needed, like IUPAP in Physics or IUPAC in Chemistry. Why to give Pluto a number? Well, why do the asteroids "Pizarro" (4609) or "Valencia" (5941) need a number? Science needs to clasificate things, among many other things. Now Pluto, or 2003UB313 are "Minor Planets" and, as such, they have been given their numbers.

[JRehling]

A star could be, for instance, be named in two different ways or weird things like this...

If you mean "defined" when you say "named", this is already true of the word "star" (in a celestial sense, even, not counting the Hollywood/sports senses or the pointy-shape sense, etc.).

From the Random House dictionary:

1. any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night.
2. Astronomy. any of the large, self-luminous, heavenly bodies, as the sun, Polaris, etc.
3. any heavenly body.

Note the word "Astronomy" qualifying the 2nd definition. #1 and #3 also refer to bodies in the sky; #2 is "scientific". But #1 would be the sense used when someone at a campground points to Jupiter and asks a friend, "What's that bright star?" This kind of situation begs pedants to deny definition #1 and unilaterally enforce definition #2 and tell the person, wrongly, that it isn't a star. Jupiter is a star... of the kind definition #1 designates.

Here's what's so terrible about what happened in 2006. It's not that Pluto was demoted. It's that a terribly boneheaded approach to definition has been held up as a standard. It is taken for granted that planet, unlike "star", unlike "work", unlike "set", unlike most of the words in any language, should henceforth have just ONE definition. (Note to committee: WRONG.) And that it should be decided by committee (Note to committee: WRONG.)

"Planet" should get no worse than the treatment Random House gave to "star". There is an inalienable sense in which Pluto is most certainly a planet, and committees don't touch that definition; they don't have the authority to. And the reason why Pluto qualifies by that standard is precisely the same reason why Europe is a continent and a starfish is a "fish" (Random House's definition #2 of "fish", not the scientific one at #1): because people call it one.

A committee may have the right to lay down ONE of the definitions of "planet"... if there's one that is useful and makes sense. The IAU's definition of 2006 (both of the proposed ones, actually) fail on both counts. Unlike definition #2 of "star", this definition of "planet" is NOT scientifically useful. That, it has become clear, would be true of any attempted definition. It also makes poor sense, whereas a definition that laid out an objective standard like a minimum diameter of 2000 km would at least make sense, and would only have two glaring problems with it (not scientifically useful; not for a committee to dictate as the only definition of "planet").

In whatever small way it matters, I call Pluto a planet. I won't stop doing so. I call Eris a planet. I won't stop doing so. I make no bones about having any standard other than "I know it when I see it" -- exactly the way I handle "mountain", "boulder", and "river". Every now and then I'll call something a mountain and someone else will call it a hill. Oh, well. I'm not going to be the only one calling Pluto a planet, and the committee is not going to own the term. They might get to own one of several definitions of "planet". That's all the power over this they deserve. Pluto will remain a planet according to other definitions and it will finally hit people over the head that, like "river", that's the kind of concept that "planet" is.

"Prime number" has a fixed, rigorous definition. The facts around the matter support that. "Planet" never will because the facts around it don't support that.

When New Horizons flies past Pluto, I guarantee that the rejection of the "planetness" of Pluto will be significantly crumbled. Whether this re-planetization has an in-committee component or just a grassroots component is hard to say. But the demotion is not going to stick.

[djellison]

This thread is getting overly heated ( as it was obvious it would )

I'm not going to close the thread - but I will if it continues like this. I've had complaints of insults from both 'sides' (despite only seing some a few days ago and deleted threads at that time)

Might I suggest that Sedna and Laurele BOTH step away from this discussion - if you continue to post in ways that draw complaints - I will not hesitate to suspend both of your accounts.

Doug

[Greg Hullender]

Since Mike Brown, discoverer of the erstwhile "tenth planet," truly had the most to lose from this, I really do think it makes sense for people to read his thoughts in support of the eight-planet definition:

http://www.gps.caltech.edu/~mbrown/eightplanets/

This is quite short -- fewer than 2,000 words -- and fairly easy reading even for a non-technical person. I have a lot of respect for someone who can sacrifice his own self-interest in favor of what he thinks is the best thing to do scientifically. People who want to argue the contrary (that "Planet" should include more than 8 planets) really ought to respond to his arguments first and foremost.

[Alan Stern]

Since Mike Brown, discoverer of the erstwhile "tenth planet," truly had the most to lose from this, I really do think it makes sense for people to read his thoughts in support of the eight-planet definition:

http://www.gps.caltech.edu/~mbrown/eightplanets/

This is quite short -- fewer than 2,000 words -- and fairly easy reading even for a non-technical person. I have a lot of respect for someone who can sacrifice his own self-interest in favor of what he thinks is the best thing to do scientifically. People who want to argue the contrary (that "Planet" should include more than 8 planets) really ought to respond to his arguments first and foremost.

My reply to Mike Brown is in an interview we did together for Air & Space, see: http://airspacemag.com/issues/2006/october...PlutoDebate.php

Everyone can form their own opinion of his evolving thoughts from this....

[Greg Hullender]

Thanks Alan. That was great! (Except for the Snapple ad on the first page obscuring the text -- I had to copy and paste that part of the article to read it.)

You two don't actually sound all that far apart in this article. Especially at the point where you want to make a term for "planetary bodies." Is there any special reason not to push the term "planetoid" for that? I know Mike Brown has proposed it at least once.

http://www.gps.caltech.edu/~mbrown/whatsaplanet/revolt.html

I realize it's an old term for an asteroid, but surely that usage has long expired. Non-fusing bodies large enough to be in hydostatic equilibrium really deserve a sexy name -- and at the moment they've got none at all. Heck, it would even be easier to explain to kids, "Well, you know scientists usually talk about planetoids, not planets, because planet is also about location, and location doesn't really matter that much."