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

[mars loon]

Dear Friends,

Today I am extremely dissapointed that the Pluto Demoters have triumphed.

I respect their opinion, but disagree with it.

I strongly agree with Alan Stern's statement calling it "absurd" that only 424 astronomers were allowed to vote, out of some 10,000 professional astronomers around the globe.

This tiny group is clearly not at all representative by mathematics alone.

I believe we should formulate a plan to overturn this unjust decision and return Pluto to full planetary status, and as the first member of a third catagory of planets, Xena being number two. Thus a total of 10 Planets in our Solar System

Please respond if you agree that Pluto should be restored as a planet.

ken

Ken Kremer
Amateur Astronomers Association of Princeton
Program Chairman

[laurele]

[font=Times New Roman][size=4]

I strongly object to the demotion of Pluto by a small group of scientists voting based on very narrow criteria. There is no way I will accept this decision. If children I know are taught in school that there are eight planets in our solar system, I will correct this misinformation and teach them that there are nine (at least). This is revisionist history that would make George Orwell proud. Pluto orbits the sun and has three moons. The requirement that its orbit be on the same plane as Earth's is just one more example of human arrogance. In the long run, I believe this decision will be overturned. In the meantime, please count me in as an advocate who will do whatever I can to restore Pluto's rightful place in our solar system. You can also view my blog posting "In Defense of Pluto" at http://laurele.livejournal.com

[ugordan]

to restore Pluto's rightful place in our solar system.

It's not like anyone actually kicked Pluto out of our solar system or anything. Why don't you stand in defense of Ceres being reinstated as a planet, too? The decision to demote it could have also been considered "revisionist history". Why stop at Pluto? Why is it so special?

[laurele]

It's not like anyone actually kicked Pluto out of our solar system or anything. Why don't you stand in defense of Ceres being reinstated as a planet, too? The decision to demote it could have also been considered "revisionist history". Why stop at Pluto? Why is it so special?

I have no problem with Ceres being reinstated as a planet. In fact, I think the 12-planet scheme originally considered by the IAU is much more appropriate.

[ugordan]

I have no problem with Ceres being reinstated as a planet. In fact, I think the 12-planet scheme originally considered by the IAU is much more appropriate.

Then why aren't you pushing for that, instead of demanding that only Pluto be reinstated?

[laurele]

Then why aren't you pushing for that, instead of demanding that only Pluto be reinstated?

First, I would like to see this travesty of a decision by the IAU overturned, as I see it as a giant step backwards. I do and will advocate for the 12-planet alternative. Dr. Alan Stern is convening a conference of over 1,000 astronomers next summer to address this issue, and I'm pretty certain this scheme will be considered.

[ugordan]

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.

[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