Sunday, August 17, 2008

It Shouldn't End

"It just won't end. Two years after the International Astronomical Union demoted Pluto from a planet to a dwarf, the bickering goes on."  So begins an online article by Nature.com on The Great Planet Debate.

There is a very strong case to be made that  it shouldn't end. We are continually discovering new data about Pluto, the Kuiper Belt, Ceres, Vesta, exoplanets, etc., all of which must go into informing our concept of what makes something a planet. I cannot understand this need to artificially end what is clearly an open discussion, largely because we just don't have sufficient data yet about some of these bodies to draw firm conclusions. What the IAU did was horrible--a linguistically nonsensical definition brought about through a highly flawed process that did not even adhere to the recommendations of its own committee. Should we just leave things in this mess because "the IAU has spoken" (well, four percent of them, anyway). What about the fact that most planetary scientists, those whose expertise and research specifically deal with planets, are not IAU members? Shouldn't these be the people making such a decision if it is made at all? There is a very real dichotomy between two strains of thought--dynamicists, who look at where objects are, and planetary scientists, who look at what they are. In an age where new knowledge is constantly pouring in, of course such definitions will be in flux.

What if we had decided to "cut off debate" and end discussion of what a planet is after the discoveries of Uranus and Neptune or after the 17th century revolution in which we realized the sun is the center of the solar system? How would we incorporate new information? What's wrong with the debate being ongoing???

Even more significantly, we have one spacecraft en route to Vesta and Ceres and another en route to Pluto.  Dawn will arrive at Vesta in 2011 and at Ceres in 2015, the latter being the same year as New Horizons' rendezvous with Pluto.   This means we know that within seven years, an entire new set of data will become available to us about these objects, data that is likely to surprise us and could very well change how we view and classify these objects. Knowing this data is coming makes the idea of shutting down the debate even more incomprehensible.

As for education, what is wrong with teaching that there are two schools of thought, and both are equally valid? What is wrong with discussing something that excites people about astronomy?  Like it or not, the subject of Pluto evokes passion.  Why not use that passion as a stepping stone to introduce astronomy to many people who have had little or no previous exposure to it?  NASA submitted sample lessons for teaching the controversy at the second through fifth grade level and again at the high school level.   The lesson plan for younger children calls for the teacher to introduce a new term, such as "dwarf planet," have the students explain the term in their own words, have them create a non-linguistic representation of the term, engage in activities that help them understand the term, discuss the term with one another, and engage in games that allow them to play with the term.

In another lesson, the students are asked to compare characteristics of Earth, Ceres, Vesta, and Pluto--location relative to other solar system bodies, size and shape, mass and gravity, density, presence or lack of water, internal structure, surface features, number of moons, presence or lack of magnetic field, length of day, length of year, and presence or lack of atmosphere--and are then presented with both the IAU definition and a contrasting definition based on an object's geophysical characteristics. This opens debate on the issue, followed by a written exercise in which students explain how their understanding of a planet has changed or not changed as a result of the lesson.

At the high school level, students are presented with the case of the discovery of a hypothetical planet and then given a list of that planet's characteristics as compared with those of the known planets, dwarf planets, various of the planets' moons and asteroids. They are then asked to classify the new object using these many characteristics.  The lesson then proceeds to a debate with some students representing the IAU viewpoint and others taking the opposing position.  Both sides are evaluated on clarity and coherence of their arguments and rebuttals, teamwork, and adherence to rules regarding each person's time to speak and their opening and closing statements.

Has our culture become so focused on needing and seeking "closure" to everything that we cannot comprehend the utility of discussion that goes on for decades, centuries, or even indefinitely?

One online comment in a forum discussing the Great Planet Debate is especially troubling.  The poster states that the IAU has spoken; they are the authority and the experts, and therefore, we should follow what they say. This sentiment was echoed by one of the dynamicists at the Great Planet Debate, who stated that while he would have preferred that the IAU come up with a better definition, one that includes dwarf planets as a subclass of planets, now that they have done something else, we need to recognize their definition and work with it to avoid chaos and a situation in which multiple planet definitions are used.

The same speaker said he believes some decisions by authoritative bodies are so wrong that they beg for revolution and/or resistance, but this one does not rise to that occasion.

We clearly have a cultural issue here, and it centers on how people respond to authority.  American education is supposed to prepare students to be active participants in democracy, which requires critical thinking skills.  Those skills can and do often involve the need to question authority, even to question the legitimacy of those who claim to be in authority. Development of these skills mandates that the goal of education be teaching students how to think rather than what to think.
Blind obedience to any authority is dangerous because it turns people into automatons, easily enabling the rise of dictatorships and the perpetration of all sorts of injustices. Opposition to such blind obedience is inherent in American culture and can be seen on both sides of the US political divide.  Whether the issue is the decision to have an abortion or the right to own guns, the American people largely do not like being told what to do.

However, resistance to blind obedience in general and to the IAU decision in particular are not, as some claim, occurring only in the US.  Astronomy educators in England and Australia have discussed their own opposition to the IAU's planet definition in online blogs and report just as much resistance to it from their own populations.

The writer of the article in Nature.com argues that the Great Planet Debate is about maintaining status for New Horizons and even about making money through books, T-shirts, and bumper stickers.  These arguments are highly questionable and sound a lot like ways of dodging the very real issue at hand.  There are always people who will use controversy to sell objects and make money; if this controversy didn't exist, they would likely find something else.  And the fact that so many people continue to buy items supporting Pluto's planet status is a statement in and of itself.  People vote with their dollars; their purchase of these items is their expression, through the market, of displeasure with the IAU decision.

As for New Horizons, the mission hardly needs to manufacture publicity.  It is already fully funded, and its stunning Jupiter flyby images speak for themselves.  NASA has active Solar System Ambassadors and Educators, some of whom specifically focus on educating the public on the New Horizons mission. This debate was not done to promote New Horizons.  It was done because there is a need for open, participatory debate on the issue of what constitutes a planet, a process not provided by the IAU.  In effect, the Great Planet Debate did what the IAU should have done but failed to do.

These discussions can and should continue, and they should involve not just professional astronomers but amateurs and members of the public as well.  The goal is to get people thinking, questioning, evaluating, and re-evaluating their positions on this topic.  If that results in a planetary version of the Boston Tea Party and a throwing of the IAU definition into bodies of water, so be it.

In short, it's all good.

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