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Analysis of Pluto’s Redefinition

On August 24, 2006, after hours of careful and often acrimonious deliberation, the International Astronomical Union (IAU) meeting in Prague redefined the concept of “planet” when Pluto became a dwarf planet because it could not “clear the neighborhood” with its own mass. Pluto became the lightning rod for criticism of the scientific community by the general public.  The thin veil, obfuscating the underpinnings of the seemingly well-oiled scientific method of problem identification, data gathering, hypothesizing, testing and concluding, had been lifted, and the mechanism that lay underneath wasn’t pretty; in the audience’s view, the method by which Pluto was redefined—by voting—did not appear “scientific” or “objective.”   The Pluto redefinition thereby lends itself to be a case-study of how and why the relationship between science and society has appeared so contentious in recent times.  How does the general public understand science and the scientific method to operate?  Is this impression accurate?  What can be done to help bridge the ever-widening gap, and alleviate the rancor between the public and the scientific community? 

The discovery of Pluto occurred during a period of what historian and philosopher Thomas Kuhn called “normal science" [1]. Given the instruments of the time, which recorded discrepancies between the predicted and observed positions of Neptune and Uranus, Percival Lowell and William Pickering predicted the presence of a trans-Neptunian object, Planet X. The planet, later named Pluto, was eventually discovered in 1930 by Clyde Tombaugh. The presence of Pluto was no surprise to the scientific community, and thus generated little internal dissent. Furthermore, it was found at a time when the public viewed science with an “attestive gaze”, so there was general acceptance of Pluto’s addition [2].

Seventy years later, the picture has completely changed. The public, which now has a more direct relationship with science and technology in its home, workplace, and at the doctor’s office, now views new developments with a much more critical eye. Thus, there was much more controversy when Pluto was demoted to a dwarf planet in August 2006.

The first rumblings of dissent among the astronomy community began when other trans-Neptunian objects close to Pluto’s size began to be discovered in the Kuiper Belt—Qaoar in 2002, Sedna in 2004, and an even substantially larger object, UB313, in 2003.  These new objects necessitated a shift of vision where they, and by extension, Pluto, could no longer be regarded as planets; if the definition of ‘planet’ was not narrowed, then the world would allow for any number of Kuiper-belt object to claim the distinction. The word “planet” would lose its meaning. Thus, astronomers had to redefine the category “planet”, and create a new category of “dwarf planet”. This is a normal process in science. In order to define an object, such as a new species, it has to be put into a category, and the category has to be defined (and sometimes, redefined.) The process of recategorizing Pluto, however, resulted in massive public attention and controversy. Why? At least in part, this controversy is the result of the public’s distorted understanding of the scientific process—in school, we learn about the progress of science according to an orderly scientific method, rather than the negotiations and redefinitions that occur at professional meetings and in the hallways of office buildings over pizza and soda.

Pluto’s perceived demotion to dwarf planet status has incited more than the cultural disorientation of a generation whose childhood fixity has suddenly been upended; Pluto’s redefinition is seemingly marked by increased erosion in the public’s faith in the credibility of science, and has also exposed the normative asperities grinding their way through the smoothly revving engine of the scientific method.  Although scientists may seem increasingly monolithic, embedded in an “us against Them” mentality, where they dole out indubitable expertise and attempt to close itself off to criticism, this expertise is still fashioned and deployed with an imagined audience in mind, replete with an audience’s expectations, beliefs and critiques.  For example, during the IAU meeting, it was evident that scientists envisioned different audiences when they interrogated Pluto’s planetary status. Many scientists were hesitant to radically change Pluto’s status because they considered the public’s reaction, but masked it by calling it scientific uncertainty.  This uncertainty over categorization and nomenclature of the planets was highlighted by Robert Williams, a member of the executive committee of the International Astronomical Union who said, “Nineteen experts wrestled with this for six months and didn’t reach a conclusion.  My recommendation is we’re not ready to move on this yet.”  He favored waiting until more was known about the edges of the Solar System.  Other experts chose what they deemed the objective route, and envisioned a public, savvy with the scientific method, that would easily grant acceptance to the new iteration of Pluto’s status.  Phrases such as “clearing the orbit” were even used specifically to facilitate public understanding.  Yet others paid no heed to what the public thought and did not seek out alliances with the public to facilitate the acceptance of the redefinition.  Brian Marsden, head of the Minor Planets Center in Cambridge, Massachussetts, said, “We should speak of eight major planets.  People say schoolchildren will be upset, but so what?  It’s our job to educate them.”  The question such a statement raises is how exactly children, and more broadly, the public, should be educated about the scientific process.

Educating the public with the “truth” must include acknowledgement of the messiness and social nature of the enterprise. Dogmatic commandments about the scientific method simply will not work in an era in which the public increasingly sees the messiness of science unfold before their eyes.  In fact, holding on to the objectivity of the scientific method can have serious unforeseen consequences. Immediately after Pluto’s demotion, Republican Representative Brian Palmer of Michigan, who chairs the Michigan Legislature’s House Education Committee, remarked, “In our lifetime, we all know Pluto was a planet. Today, now, Pluto is not a planet. The issues on global warming are changing from year to year on what supposedly may cause it, may not cause it, whether it exists or not. The bottom line is we want to make sure that the language is in there regarding critical thinking on all theories that are evident in science today.” Palmer used Pluto’s redefinition as evidence of the vicissitudes and inconstancy in science to weigh in on the adoption of new science guidelines for Michigan’s high school graduation standards and allow for the implicit teaching of intelligent design, and the explicit criticism of evolution. 

The scientific method is widely regarded by many as a very efficient, streamlined, logical and objective process.  This impression, indoctrinated from early childhood’s experiences in science education, where one memorizes the steps of the scientific method, is reinforced through scientific textbooks, journal and popular media articles, where complexities, contradictions and outliers are eliminated for ready access and consumption.  Therefore, when competing and conflicting studies and recommendations are disseminated into the public—who want the “truth” and the “bottomline”—the mixed signals are seen as evidence of science failing.  The answer of “we don’t know” is unacceptable.

Constructed as the greatest articulation of human thought and action, science has arguably been lionized as a panacea for every facet of society’s ills, whether they are social, cultural, economic, or political.  Indeed, scientists have traditionally been encouraged, allowed and expected to gain access to specialized knowledge for society’s benefit.  If science is the altar at which many pray, then science had better produce and practically apply the “correct” answers expediently and had better not betray anyone.  Confronted with the fallibility of science, many outside the scientific community, and in the Pluto case, the community of astronomers, are recalcitrant towards the special and privileged knowledge scientists seem to have.  The excerpts and rhetorical musings included above allude to not only an internalization of Pluto’s demotion, but also to an endemic frustration with the perceived elitism in science; not only did the astronomers who voted on Pluto’s status not seek out the public’s opinion, but if they were “wrong” before, what makes one think that they are not wrong again? 

In a culture where many clamor for stark binaries and easy answers, conciliatory and interactive approaches, which value public input and fears, better serve the scientists’ interests.  Rendering the scientific process more transparent may help placate public rancor and even garner public endorsement.  Although in the case of Pluto’s redefinition, it is true that sudden exposure cast a baleful glare on messiness and complexity of science—the background (what is artfully hidden) and foreground (controlled information presented) became miscible.  The plotline to which the public was accustomed became disrupted and the narrative changed.  However, this may lead to a new narrative where scientists and the audience communicate more honestly with one another and share authority, even if that means that scientists need to relinquish some of their power to keep it. 

By Monamie Bhadra and Shobita Parthasarathy

October 17, 2006

Last updated: January 25, 2007