We are two weeks into the International Year of Astronomy, and already there have been fascinating new developments in the field, including the imaging of exoplanets’ atmospheres; the presence of methane on Mars, indicating it is not a “dead planet”; new information revealing that our Milky Way galaxy is far bigger than previously thought, and much more.
Significantly, today is the third anniversary of the launch of New Horizons, which is now six and a half years from reaching Pluto.
However, one Pluto-related news item this month turns out to be driven far more by the desire for press and public relations than by the quest for knowledge. Specifically, I am referring to the latest book by Dr. Neil deGrasse Tyson, director of the Hayden Planetarium, titled The Pluto Files: The Rise and Fall of America’s Favorite Planet.
Rise and fall? To paraphrase Mark Twain, rumors of Pluto’s “death” have been greatly exaggerated.
Pluto is about as “dead” as a soap opera character who is presumably killed under mysterious circumstances, yet there is no body to prove the person is truly dead. Of course, everyone already knows the character mourned by others on the show will inevitably return in a few years when the actor renews his or her contract.
Tyson, whose presentation at the Great Planet Debate involved far more show than substance, appropriated the “Pluto is not a planet” stand about eight years ago when the Hayden’s Rose Center for Earth and Space re-opened in 2001, gaining him notoriety for his exclusion of Pluto from the planet display.
Since then, Tyson has used his stand on Pluto to catapult him to celebrity status, conducting tours, lectures, and TV interviews around the country proudly bragging about the hate mail he received from third graders when his exclusion of Pluto from the Rose Center became public knowledge.
Tyson is not a planetary scientist. In fact, he is not a research scientist at all. His interviews are characterized largely by sound bytes, theatrics, and wild statements such as “Pluto is happier with its Kuiper Belt brethren than as a planet.” I guess he has a direct line to Pluto since he comments with such certainty about how the planet “feels.”
In his presentations, Tyson frequently comments on Pluto having an elliptical orbit, claiming “that is no way for a planet to behave,” arguing that such an orbit is more typical of comets. Does he ever consider that maybe planets have a much wider range of behavior styles than he or anyone else has previously thought? Many of the giant exoplanets we have found, most of which are significantly larger than Jupiter, have very elliptical orbits. Does that make them comets instead of planets?
Tyson also likes to argue that if it were placed closer to the sun, Pluto would grow a tail like a comet. That is true, but it is only half the story. Any planet brought close enough to the sun (or to its parent star), including Earth and even Jupiter, would grow a tail due to sublimation and outgassing. Of course, Tyson won’t tell that second point to his audiences.
He also loves to portray “Plutophiles” as ignorant of the fact that there are moons in our solar system larger than Pluto. “How many of you know that?” he questions Pluto supporters in his audience, with the assumption they do not know.
Those who have spent any time studying the solar system are aware of this. However, many of us recognize that the round moons of planets are planets themselves in every way—they are in hydrostatic equilibrium and geologically differentiated, just as the primary planets are. Tyson’s claim that no one has proposed calling them planets is false. Nineteenth-century textbooks referred to them as “secondary planets”; this takes dynamics into account by still defining them as planets but as ones with a secondary orbit around the sun and a primary orbit around another planet.
Referring to these moons as secondary planets immediately does away with the size-based argument used against Pluto.
At the Great Planet Debate, Tyson proposed doing away with the term “planet” altogether and adopting a wholly new classification system where objects are grouped with other like objects. However, he never presented a comprehensive alternative schematic other than to articulate two groups of objects, the terrestrial planets and the gas giants.
If we are to group objects with those like one another, Pluto cannot be grouped solely with other Kuiper Belt Objects just as Ceres cannot be grouped solely with other bodies in the asteroid belt. To do this is to ignore the fundamental characteristic of hydrostatic equilibrium, that is, of being spherical and therefore geologically differentiated.
Tyson never explains why he is okay with glossing over this crucial difference between planets and asteroids. This is a major weakness in his arguments.
Supporters of Pluto’s demotion often discuss how even as children, they viewed Pluto as not fitting into either of the two categories of planets, the terrestrial planets and the gas giants. Quoting Sesame Street, they argue, “one of these things is not like the others.”
But what if there are more than two classes of planets? What if there is a third class, the ice dwarfs, which may lie among a belt of objects but have compositions that significantly distinguish them from most of the other objects in those belts? Isn’t it a disservice to not even consider this possibility?
Personally, I question Tyson’s motivation in his “demote Pluto” quest. A look at his web site shows a list of public appearances and TV interviews across the country. One can be reasonably certain that Tyson will repeat the same lines, practically verbatim, in each one of these presentations.
Those who buy his book or attend his lectures deserve to know that he is being paid well to do the lecture circuit and be the astrophysicist version of a celebrity. There is nothing illegal about this; however, it cannot help but lead many to question how much of this is about Tyson’s celebrity status. Much of his latest book is about himself. Has he been attaining money and fame at Pluto’s expense? Clearly, he benefits personally from this public stand. Could that be at least part of his motivation in being so adamant about categorizing Pluto as a non-planet? The public has a right to know.
Meanwhile, in spite of Tyson’s theatrics, there is a significant backlash underway to get Pluto’s demotion overturned, possibly even at this year’s IAU General Assembly this summer. The January 3, 2009 issue of
The Independent article “Planetary Storm Over Status of Pluto,” which can be found here,
http://www.independent.co.uk/news/science/planetary-storm-over-status-of-pluto-1222862.html describes efforts underway to get Pluto’s planet status reinstated.
New York Times science writer Ken Chang, in “How Many Planets Do You Want in the Solar System?” which can be found at
http://tierneylab.blogs.nytimes.com/2009/01/10/how-many-planets-do-you-want-in-the-solar-system/ , published on January 10, 2009, makes clear that Pluto’s status is still very much part of an ongoing debate and notes that he has not met anyone for whom the IAU definition clarifies this issue. I will note that I have a personal appreciation for Chang, who actually quoted me in the text of his article!
Yet a commenter who identifies himself only as “Wayne,” makes what I believe is the most important point in this debate when he points out that we are arguing over something subjective rather than objective. He says:
“It astonishes me that people talk about this as a matter of scientific inquiry, like the discovery of a new species or new information about the atom. This is nothing more than a matter of subjective definition that has no right or wrong to it. Some people say “I choose to define ‘planet” as such-and-such,” while others say “I choose to define ‘planet’ as so-and-so.”
Nobody can say that Pluto is or is not a planet in the same sense that s/he can say that the Earth does or does not revolve around the Sun (emphasis mine). Opinions on this sort of question are just as subjective as whether or not Citizen Kane was a great movie (not). That doesn’t mean we can’t argue about it, but we should let go of the idea that we are pronouncing something of scientific objectivity when we make up our mind about our own opinion on the matter.”
Far from having “fallen,” Pluto continues to inspire children and adults, as can be seen from a new 13-minute film titled “Naming Pluto.” Produced by Father Films, it documents the naming of Pluto by British schoolgirl Venetia Burney in 1930 as well as her first view of Pluto through a telescope on her 89
th birthday. Information on the film and how to order it can be found here:
http://www.fatherfilms.com/films/namingpluto/
In the words of Tim Ophus and Chuck Crouse, who respectively wrote the music and lyrics to “Dwarf Planet Nothing (The Pluto Song),” which can be found here,
http://www.youtube.com/watch?v=jlkYe6i3Dns&feature=PlayList&p=C928956660965F3A&index=1&playnext=2&playnext_from=PL
"Pluto’s going to rise once again!!!"
May it be in 2009.
