||[Jul. 31st, 2014|07:02 pm]
Are there some people with vested interests in keeping the flawed IAU planet definition intact who would go so far as to suppress any attempt at further open debate?|
This question is not hypothetical. On July 29, 2014, Newsday posted an article by writer Delthia Ricks titled “Pluto Planet Controversy Rages on Among Scientists.” That article can be found here:
Because there were many issues raised in the article that needed to be addressed, I and several other Pluto advocates wrote comments in response to the article.
While my comment followed the site guidelines and did not involve inappropriate language or personal attacks or anything else that might disqualify a comment from being posted, it never saw the light of day.
Today, only two days later, the article notes “Comments are Closed.” At least one other comment was deleted, yet ironically, a spam comment with the typical “My aunt made money online, and so can you” remained posted.
The article and comments in response to it were discussed on the Facebook group “Society of Unapologetic Pluto Huggers.” In that discussion, I mentioned that my comment was never posted, but a spam comment was.
Several hours later, the spam comment is no longer there.
The article noted support from Astronomy magazine editor David Eicher for a debate on the topic of Pluto and planet definition, a challenge Stern recently issued to Tyson.
The writer then stated that neither Neil de Grasse Tyson nor Alan Stern could be reached for comment.
Something about this seems off. As busy as Stern is, he is known to be extremely reliable in following up with requests, especially by the media, to discuss Pluto.
Astronomers who did manage to get quoted in the article presented arguments one could accurately describe as less than stellar.
A Dr. Denton Ebel, who chairs the Earth and Planetary Sciences Department at the American Museum of Natural History in Manhattan, supposedly “cringes at the thought of ‘the Pluto discussion’ presents incorrect information four years out-of-date by stating that Eris is larger than Pluto. Presumably referring to Eris, he states, "There's an object in the Kuiper belt that is larger than Pluto, and it isn't a planet.”
In November 2010, a team of astronomers led by Dr. Bruno Sicardy obtained a more accurate measurement of Eris’s size and determined it is marginally smaller than Pluto though 27 percent more massive. More massive means more rocky and therefore more planet-like.
Why would an astronomer in such a prominent position at the American Museum of Natural History in New York “cringe” at the Pluto discussion? One would think astronomers would celebrate any public interest in astronomy, seeing it as a jumping off point to engage and interest the public.
The writer also quotes Dr. Fred Walter, a professor at the University of Stony Brook, who proceeds to attribute support for Pluto’s planet status to emotion, saying, “Clearly, it’s a touchy subject.”
Obviously a dynamicist, Walter goes on to say, "Pluto isn't gravitationally independent. It's gravitationally tied to Neptune."
There is nothing wrong with a dynamical view of the solar system. However, the author never mentions that the real debate is between the dynamical view, which requires objects to gravitationally dominate their orbits to be considered planets, and the geophysical view, which does not require this gravitational dominance and defines a planet as any non-self-luminous spheroidal body in orbit around a star, in orbit around another planet, or free floating in space.
Here, then, is either deliberate bias or a lack of awareness on the part of the writer. She presents the controversy as gravitational dominance versus emotion rather than quote a single astronomer explaining and advocating the geophysical planet definition. And that is a disservice to readers.
Walter goes on to say, "We haven't really fully demoted Pluto. The word 'planet' is still there," he said, referring to the term dwarf planet. "But if you were Pluto," he asked, "would you rather be the runt among planets, or the king of the dwarf planets?"
He seems unaware of the fact that the IAU definition specifically precludes dwarf planets from being considered planets. The “what would Pluto prefer” amounts to a straw man argument. The debate is not about what Pluto “prefers.” It is about what constitutes the best classification system, what definition best helps us understand the solar system and put objects in their proper contexts.
A definition that blurs the distinction between shapeless iceballs and rock (comets and asteroids) on the one hand, and a geographically differentiated, complex world similar to the terrestrial planets in all but size on the other hand constitutes a scientifically poor definition.
Walter’s presumption about “what Pluto prefers” is nothing more than a case of him projecting his own view onto Pluto.
Walter also notes that Pluto has “the most extreme orbit of any of the planets.” While that may be true in our solar system, he fails to mention that of the nearly 2,000 exoplanets now discovered, many giant planets, some bigger and more massive than Jupiter, have orbits far more eccentric than Pluto’s. Should those not be classed as planets?
Ebel is quoted with the old standby, "There are lots of objects out there and we are still finding new ones. But everything can't be a planet."
But everything in hydrostatic equilibrium, meaning rounded by its own gravity, and not a star, can and should be considered planets. Where is the science in arguing we cannot have too many planets?
In fact, every single astronomer the writer quotes presents the anti-Pluto view.
Amateur astronomer Ken Spencer, president of the Astronomical Society of Long Island, is quoted as saying, "In my heart, I know that it really can't be a planet anymore. I was really sad to see it demoted. But after reading why, it's hard to argue with those reasons."
Actually, it isn’t hard to argue with the IAU’s poor reasoning at all. It just seems the writer of this article found it too hard to locate and interview a single astronomer who can explain just why the IAU demotion is so flawed, using only his or her brain, no heart or feelings necessary.
The article ends with Walter citing anecdotal evidence that he believes supports his case, once more beating the drum of “it’s all based on emotion.”
He says, "It's only older people who think differently. This is a sociological issue, not a science issue because people don't want to give up what they learned in school."
This sounds a lot like Walter seeing exactly what he wants to see. Many astronomy educators and outreach people have experienced just the opposite, that children not even born when four percent of the IAU voted back in 2006 still strongly support designating Pluto and all dwarf planets as a subclass of planets.
Walter says, "I don't tell the students what Pluto is. I let them vote. And overwhelmingly they say Pluto is not a planet.”
I’m going to take a chance here and say that while he lets the students vote, he introduces the subject by sharing his view on it. Unfortunately, in many cases, students do not feel they can or should argue with their professors. The notion of “just give the professor what he/she wants to hear” to get a good grade is a genuine problem and likely serves to bias many students in favor of the position their instructors hold.
That part might be sociological, but the question of a dynamical versus a geophysical planet definition, as well as the need for a definition that includes exoplanets, most certainly is a scientific issue.
Assistant Professor of Earth and Atmospheric Sciences at the Georgia Institute of Technology Dr. Carol Paty is paraphrased as saying that even though New Horizons will present data about Pluto that scientists never before knew, she doubts Pluto will be reinstated.
How professional of her to draw a conclusion before the data is in. Maybe this is what she wants to happen--or not happen. She also fails to acknowledge that the IAU is not the only game in town. Another organization could very well form and come up with its own, better definition.
Interestingly, the last comment posted on the site, by an anonymous writer who simply identifies him/herself as “An Astronomer," reads “There is no debate. Astronomers say Pluto is not a planet by definition. A magazine editor and Facebook page creators have no standing to even suggest reclassification. The title of this article is incorrect and embarrassing. Pluto is not a planet. Case closed.”
So there we are. Once again, “Case Closed.” “No Debate.” “It’s Over.” “Astronomers Decided.” This is the same attitude we have heard from the IAU and supporters of its definition for eight years. It is the same mentality that led the IAU leadership to refuse to even consider reopening the debate at its General Assembly in 2009, when asked by a group of planetary scientists to do so.
Usually, decisions made once for all eternity are confined to religion, not science.
The bottom line, is there are those who have a vested interest in never reopening the debate. Those who want the IAU definition to stand and be the only one know its weaknesses will be exposed if the debate is reopened. They see themselves as the victors and so do not want any reconsideration, regardless of the science. Just shut down debate altogether. This is the type of mentality one expects from politicians, not scientists.
I am not personally upset that my comment was not published. There are many very articulate people who uphold the geophysical planet definition, whose comments would likely do a better job advocating it than mine. Yet not a single one other than David Eicher of Astronomy magazine, who called for the debate, was quoted. Not a single pro-Pluto or pro-geophysical planet definition was quoted, and the only pro-Pluto comments posted were very limited and general and did not address some of the weaknesses of the arguments made by the astronomers cited.
Plus, the closing of comments after only two days is highly unusual. Could some astronomers have possibly contacted Newsday, exerting pressure to close the comments section?
The reality is that the IAU and advocates of its definition haven’t “won.” The debate still goes on eight years later not because of emotion, but because their decision did not do the subject justice and continues to be undermined by new data we learn about worlds in this solar system and others.
My comments on the Newsday article constitute mostly what I said here, but I am reposting them for anyone interested. I have contacted the writer about these issues and will keep readers of this blog informed of any responses I get.
The issue hasn't gone away because people inherently understand that the IAU definition makes no sense. It also makes no sense for the IAU leadership to dig in their heels and continually refuse to reopen the discussion, as they have done so far. Here are several other points that also need to be considered:
The IAU definition says planets must orbit the Sun rather than "a star," meaning it automatically precludes exoplanets from being planets.
The IAU definition does not allow for rogue planets, which do not orbit any star and float freely in space. A planet cannot "clear its orbit" if it has no orbit to clear!
Even if the IAU definition did allow for exoplanets, a large number of these, including worlds larger than Jupiter, would not meet its definition because they have orbits far more eccentric than Pluto's, are in 3:2 resonances with other planets in their systems, plow through belts of asteroids during their orbit, share their orbit with another planet, etc.
One of the original motives for demoting Pluto was a perceived need to keep the number of solar system planets small. That has no scientific basis whatsoever. We already know the universe has billions of planets. If our solar system has nine, 90, or 900, then that is what it has. We can distinguish the different types of planets through the use of multiple subcategories.
Ebel is incorrect when he says there is an object in the Kuiper Belt larger than Pluto. His data is nearly four years old. In November 2010, Eris, the object to which he refers, initially thought to be larger than Pluto, was found to be marginally smaller than Pluto when it occulted a star.
Opposition to Pluto's demotion is not based on emotions, and you do a disservice by attributing the position to feelings. Opposition to Pluto's demotion and support of its planet status is based on the scientifically sound geophysical planet definition, the one adhered to by Dr. Stern and many professional astronomers who view dwarf planets as a subclass of planets. According to the geophysical planet definition, a planet is any non-self-luminous spheroidal body orbiting a star, orbiting another planet, or free floating in space. If an object is large enough and massive enough to have attained hydrostatic equilibrium, meaning it is squeezed into a round shape by its own gravity, according to the geophysical planet definition, it is a planet.
Significantly, Stern is the person who first coined the term "dwarf planet," and he did so with the intention that it would refer to a third class of planets in addition to terrestrials and jovians, not to non-planets.
Regardless of which is bigger, both Pluto and Eris are well beyond the threshold for being in hydrostatic equilibrium, meaning according to the geophysical planet definition, both are planets.
In fact, it is the supporters of the IAU definition whose decision is based on emotion, specifically, the position that our solar system cannot have too many planets because kids will not be able to memorize their names. Our solar system has whatever number of planets it has, and memorization is not important for learning; what is important is an understanding of the different types of planets and their characteristics. We don't ask kids to memorize the names of all the mountains and rivers on Earth or of all Jupiter's 67 moons.
This debate remains ongoing because people ranging from children to professional astronomers understand that the IAU definition, adopted by only four percent of its members, most of whom are not planetary scientists, is a very poor one and was adopted in a flawed process that violated the IAU's own bylaws. Significantly, an equal number of professional astronomers signed a formal petition rejecting the IAU definition.
The media erred in reporting one position, the IAU view, as fact, when what it really is is one view in an ongoing debate. To adherents of the geophysical planet definition, Pluto never stopped being a planet, and our solar system does not have eight planets; it has a minimum of 14 and counting.
Walter is also incorrect about an "age divide." Scientists strongly on either side of this debate tend to see what they want to see from the public and students. I and many amateur and professional astronomers have done a lot of outreach over the last eight years and have found that people of all ages overwhelmingly support Pluto's status as a planet.
Notably, unlike the overwhelming majority of Kuiper Belt Objects, Pluto has most of the same features that larger planets have. It has geology and weather; is differentiated into core, mantle, and crust; and may even harbor a subsurface ocean. As Dr. Stern says, "And I can’t think of a single distinguishing characteristic that would set apart Pluto and other things that you’d call a planet, other than its size. So I like to say, a Chihuahua is still a dog."
For more on the case for Pluto, visit my Pluto Blog at http://laurelsplutoblog.blogspot.com