My thoughts on the recent IAU debacle regarding Pluto and the other planets ... oh come on raise your hands if you really expected this geek not to eventually comment on how badly they dropped the ball? There now, that's what I thought...
All right first of all they had a golden opportunity to set down some good grounded scientific definitions which would be universal and well serve humanity on our first steps into the stars. Boy did they blow it. The condescending elitists of the astronomical community accuse those of us with some sense of sentimentality simply because we wanted Pluto to maintain its rightly deserved status of a planet. They will claim that we wanted it to stay the way it was because Pluto has been a planet since its discovery in 1930. However I suggest that matters are very reversed, that the entrenched elitists who pushed this "definition" through were violently opposed to the re-re-naming of the planet Ceres (which was named a planet upon its discovery in 1801 and only demoted to "asteroid" about 50 years later) as such and including the new planet, provisionally named, 2003 UB 303 as such. The elitists own deep entrenched sentimentality drove them to fear the rightly additions to our own solar system and fight to adopt a flawed definition of the term planet which will only serve to cause greater debate and confusion at later dates as we finally move towards a greater understanding of our neighboring systems when we find other smaller planets.
What I propose in remedy of this unfortunate mismanagement and to (hopefully) further prevent any future confusion and debates, I suggest nothing short of a complete reassessment of the celestial sphere.
We will start with an examination of the term "planet" itself. The term planet itself comes from an ancient Greek word meaning wanderer. Which meant any light in the sky that didn't move in a regular and easily predictable pattern across the sky, which the stars do. The "planets" compared to the relatively stable pattern and position of the stars do seem to wander. However given the ancient view of the world which gave rise to this term both the Sun (Helios/Sol) and the Moon (Luna) were also considered to be "planets" along with Mercury, Venus, Mars, Jupiter, and Saturn. Given the rise of the heliocentric model of our solar system and more modern understandings of astronomy Luna was demoted to be a moon and Helios promoted to being a star, along with the Earth (Terra) being demoted from the center of the universe to a wanderer following our star around. Then we built telescopes and started finding way too many other bodies out there wandering around our star. Clearly a better system of classification was and still is needed.
So we keep the term planet for the primary wanderers around our star. That's fine, there's a sense of classicism there, everybody is familiar with the idea of a planet. So lets define planet so everybody is on the same page. The IAU started out fairly good but they fumbled at the goal line.
"Is not massive enough to initiate thermonuclear fusion of deuterium in its core..." good start, if it can do that its a star not a planet, I think we all agree.
"Has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape..." that's a good one too, however one has to wonder what the definition of "nearly round shape" is? Is a body with 3% derivation from a perfect sphere nearly round, is one that's 30% derivation?
"Is in orbit around a star or stellar remnants..." that's where we really start to slip. There are bodies out there orbiting other massive planets that are far more massive than some bodies which are simply orbiting a star. If we're using physical characteristics to determine our definition then this seems fairly arbitrary and could be improved on.
"Has cleared the neighborhood around its orbit..." and of course this is where we all know that everything went from needs some polishing to OMG! You bastards killed Pluto! This is ball dropping low-light of the game. Where the IAU had a chance to categorically change the way we think about our solar system and others they let a few sniveling little whiners, who have a grudge against 2003 UB 313 just because some well meaning flakes call it Xena, hold them back and ruin a good thing they had going. Here the IAU had a shining chance to create a new broad and sweeping definition of the term planet that would include all obviously planetary bodies and then could further refine the broad category into smaller more specific classifications. Why are Mercury and Jupiter in the same class but Mercury and Ceres not? There is no reason. They should all be planets in the massive grouping, but each belonging to its own subcategory. Planetary astronomy could have taken the nod from taxonomy and developed a categorical classification system in which things with a few vague similarities are broadly classed together and then sifted out into their own unique sub-grouping based on more and more specific criteria. But they didn't ... and now the universe is a muddle.
Of course we'd also like to point out that Mars, Jupiter, Neptune and even Earth all have asteroids as neighbors. Jupiter itself has 50,000 Trojan asteroids, I wouldn't call that a clear neighborhood. So I guess Jupiter is now the biggest dwarf planet, seems silly doesn't it? But according to IAU's new rules Jupiter is now Ceres dwarf planetary buddy.
Our proposed new definitions are as follows:
* Galaxy, a huge gravitationally bound system of stars, interstellar gas and dust, plasma, (possibly) unseen dark matter, and other matter.
* Blackhole, an object predicted by general relativity with a gravitational field so strong that nothing can escape it, not even light. Formed in nature whenever a sufficient amount of mass gets packed in a given region of space, through a process called gravitational collapse.
* Star, any body large enough to have at one point in its life cycle supported a sustained natural fusion reaction for an extended period of time, that is not a Blackhole.
* Primary Star, any star around which another star orbits, or which is the only star in its system.
* Binary Star, any set of two stars where the center of gravity in their system is not inside one of the bodies but is in the space between them.
* Secondary Star, any star that is in orbit around another star where the center of gravity in that system is within the body of the larger star.
* Planet, any body not large enough to sustain a natural fusion reaction for an extended period of time AND had sufficient self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, within a 20% derivation from a perfect sphere.
* Jovian Planet, a large planet that is not primarily composed of solid matter, but will most likely have a rocky or metallic core, while the majority of its mass is in the form of gas (or gas compressed into a liquid state).
* Telluric Planet, a planet that possess a secondary atmosphere, an atmosphere generated through internal volcanism or comet impacts.
* Chthonian Planet, a planetary object resulting from the stripping away of a Jovian Planet's atmosphere. Such atmospheric stripping is a likely result of close proximity to a star.
* Mesoplanet, a Planet of sufficient size for its self-gravity to overcome its rigid body forces and become nearly round, yet not of great enough gravity to maintain an atmosphere in non-proximity to a star.
* Binary Planets, any set of two planets where the center of gravity in their systems is not inside one of the bodies but is in the space between them.
* Secondary Planet, any planet that is in orbit around another planet where the center of gravity in that system is within the body of the larger planet.
* Planetoid, any body with sufficient self gravity to nearly overcome its rigid-body forces so that it assumes a nearly round shape between 21% and 40% derivation from a perfect sphere.
* Cluster Planetoid, any group of planetoids where the center of gravity of the group is not in any of the bodies but in the space between them.
* Secondary Planetoid, any planetoid that is in orbit around a larger planet or planetoid where the center of gravity in that system is within the body of the larger object.
* Asteroid, a predominantly rocky body orbiting a star that is smaller than a planet or planetoid such that its own self-gravity cannot overcome its rigid-body forces.
* Cluster Asteroids, any group of asteroid where the center of gravity of the group is not in any of the bodies but in the space between them.
* Secondary Asteroid, any asteroid that is orbit around a larger solar system object, which is not a star, where the center of gravity for the system is within the larger object.
* Moon, any body which is in orbit around a planet and not a star, including other Planets, Planetoids, or Asteroids.
A logical derivation of terms not too far different from what we have come to learn and expect from our solar system and from others. While very closely related to current definitions and propositions we feel that this system is much more flexible and able to cope with new and coming discoveries of celestial bodies in ours and other systems.
[originally posted on my MySpace Blog]
Optimism
