Tuesday, June 16, 2009

"Moving On" Is Not An Option

Last week's planet definition discussion at the American Astronomical Society's meeting in Pasadena, California, started the latest round of Internet discussions on the question of what is a planet. A portion of the session can be viewed online at http://www.ustream.tv/recorded/1633104 via Ustream, thanks to Pamela Gay of "Astronomy Cast." This hour-long broadcast covers only the second half of the discussion. I am trying to find out if there are any online broadcasts of the first half and of the question and answer session following the entire discussion. If anyone reading this is connected with the American Astronomical Society and knows of links for these, please post them in the comments section of this blog entry.

Dr. Alan Boyle twittered notes from the entire discussion, which he put together on the following site:
http://family.boyle.net/plutonotes.htm . I encourage anyone interested in this debate to read these.
In a column written after the conference, which can be found here,
http://cosmiclog.msnbc.msn.com/archive/2009/06/10/1959870.aspx , Boyle quotes Neil de Grasse Tyson saying it's time to move on from the what is a planet debate and address the many categories into which solar system objects can be classified, based on aspects such as shape, composition, geology, and suitability for life. "This is what we should be thinking about now, not arguing over the fricking definition of a planet," Tyson is quoted as saying.

It is interesting that of all speakers, Tyson is the one who makes this comment, as he is the one who re-energized this debate in the first place when he chose to design the solar system display at the American Museum of Natural History's Rose Center with only eight planets. He has done speaking tours as well as radio and TV interviews on this subject. He wrote an entire book on it. But suddenly, he decides it's time to move on? What gives?

In response to Tyson, Alan Stern, as quoted by Boyle, emphasizes that the way we think of planets should reflect the diversity of the solar system. Objects like Pluto make up the largest class of solar system planets, he notes.

An important aspect of diversity is the concept that many very different items can be encompassed in a broad category. Just think of the terms "plant" or "animal," and this is obvious. Why then, do some insist that there can be only two classes of planets, the terrestrials and the jovians? If we artificially limit our definitions that way, we will be forced to create "wastebasket categories" to accommodate the objects that do not fit our narrow proscriptions.
"Moving on" from a bad decision such as the IAU planet definition by letting that decision stand is a terrible idea and makes no sense. The fact that this issue continues to be debated illustrates that the IAU decision satisfied few people and created tremendous confusion.

Jean-Luc Margot of the University of California at Los Angeles proposed sticking to the IAU definition but defining all round objects, whether they are gravitationally dominant or not, whether they are moons, planets, or dwarf planets, as "worlds." Using this concept," some worlds are planets, and others are not," he said.

Margot's approach does not really offer much that is new. By sticking with the IAU definition and then adding the term worlds plus the caveat "some worlds are planets, and some are not," he puts us right back at the problematic point we started from--the fact that the IAU definition classifies objects by where they are while ignoring what they are. If we're going to stick with the term planet, why not just come up with more adjectives to describe the many different types of planets we are discovering? Satellites like Titan and Ganymede can be referred to as "secondary planets" since their primary orbit is around another planet, and their secondary orbit is around the sun.

It is interesting to note that Mike Brown said he tries to avoid the discussion of whether or not Pluto should be classified as a planet altogether. He was for these small round objects being classed as planets before he was against it, and his blog title, "Mike Brown's Planets: Full and Dwarf" implies he considers dwarf planets a type of planet, which contradicts the IAU definition he now claims to support. Maybe he doesn't want to discuss the subject because he isn't sure which position he is taking on any particular day!

The opinions expressed at this conference reflect similar views expressed online covering the full spectrum of this debate. I am going to print one comment, written in response to a comment by me in the journal Nature in response to a June 3, 2009 article, "Quaternary Geologists Win Timescale Vote." The author sought to use the Pluto issue to illustrate an example of scientists reaching consensus, saying, "In 2006, astronomers reached a decision on the planetary status of Pluto; now, geologists may have done the same for the status of the Quaternary, the time period in which humans evolved and live today." The site is here: 

When, in the comments section, I pointed out that saying "astronomers" reached a consensus on the status of Pluto is incorrect and disingenuous (given that, clearly, a consensus has not been reached), one respondent accused what he called the "Pluto is a planet gang" of hijacking the entire thread! Here is what he said:

"Incredible to see the Pluto-is-a-planet (because it was discovered by an American) gang highjack (sic) this item. Please, people, get over it! The decision has been made by the acknowledged international organisation (sic) in question. Feel unhappy about that? Your problem only! And don't come with that crap again about 'only a minority voted.' Only a minority seemed to be really interested to come to the vote. If this was important to you, you should have been there and have voted yourself. Every IAU voting member could have voted if he/she wanted. And those 'many astronomers' and the public said to be opposing the vote result: this is almost solely an American phenomena. It has much to do with the fact that Pluto was the only of the former 'planets' discovered by an American. The anti-movement regarding the IAU decision doesn't have a strong international footing at all..."

Another commenter said, "The reclassification of Pluto, it seems, is an accepted part of the curriculum and new teaching materials have already been produced. These things happen. Scientists redraw old conclusions based on new evidence. I can't see how correcting an error, even if it means some level of relearning, is a bad thing.

Unfortunately, the comments section was closed before I could respond to the remarks by the poster who repeated the false claim that it is only Americans disturbed by the IAU ruling--the writer who accused the "Pluto is a planet gang" (I'm in a gang?! Wow, I didn't know. Are pro-Pluto T-shirts going to be outlawed in schools now???) of hijacking the discussion.

Hijacking is an interesting choice of words given that the writer of the article chose to evoke the Pluto example to illustrate scientists reaching consensus. She brought the subject up, meaning it is fair game for comments. She should have known that Pluto is most certainly not an example to use of successful scientific consensus.

The author of the first comment (which is actually the last one on the page; I chose to quote it first because it is so outrageous) may be an expert on geology but clearly is out of touch when it comes to astronomy and public perceptions of it. He provides absolutely no proof to back up his statement that it is only Americans  who oppose the demotion. He would know this is not true if he took the time to join the many astronomy communities online, composed of both amateurs and professionals. On these sites, intense debate continues, and opposition to the IAU definition is expressed by people all over the world.  At Swinburne University, in Melbourne, Australia, which runs an online astronomy program, students from all over the world come together, and in the class I just completed, "Exploring the Solar System," many non-Americans clearly stated their unhappiness with the IAU planet definition.

"The decision has been made by the acknowledged organization," the commenter says. Has it? What makes the IAU the acknowledged organization? Many planetary scientists do not belong to the IAU. Most IAU members are not planetary scientists. The writer believes the claim that only a minority of IAU members voted is "crap." Maybe he is used to Iranian style votes. The fact is, out of 10,000 members, 424 voted. No absentee voting was allowed, so if for some reason a member could not stay until the last day of this two-week conference, he or she could not vote. Additionally, most of the original 2,500 attendees left assuming the resolution on the table would be the 12-planet one recommended by the IAU's own committee. How were they to know that one particular group of astronomers would violate the organization's own bylaws by proposing a new resolution without first vetting it by the appropriate committee as required, and then putting it to the floor of the General Assembly for a vote?

The other commenter reflects a sentiment that makes equally little sense--the view that what's done is done. "These things happen," he says, as if he were talking about a natural disaster such as a tornado or earthquake, something over which we have no control. He can't see how correcting an error is a bad thing? Then he should have no problem with voiding the IAU definition, which most certainly is an error. Why is it that when it supports his view, sticking with a problematic definition is okay, but when it does not support his view, the "error" must be changed?

I could not personally have been there and voted, as I am not a professional astronomer. But that raises yet another issue. There are up to 20 amateur astronomers for every professional. Amateurs do actual research and make discoveries. They are the ones who do most of the communication of astronomy with the public.  Many amateurs are as well-versed in the field as their professional peers. Several such people are active my astronomy club in Cranford, NJ, alone.

Why not give amateur astronomers a say in this discussion as well? This could easily be done through organizations such as the Astronomical Society of the Pacific or through establishing a new class of IAU membership for amateur astronomers. These people give many hours to astronomy with no compensation, simply for love of the subject, and they are the ones who are left trying to communicate the IAU's sloppy definition with a very confused public.

So much of this comes back to education and the concept that planets are names of important things to memorize. Before the age of space exploration, we knew little about the planets in our solar system, and even less about their moons. Children were taught to memorize because there was not much else to teach. The film "Universe," made in 1960 and once shown in introductory college astronomy classes, does no more than mention Uranus and Neptune by name as the planets between Saturn and distant Pluto.

That is far from today's reality, which is of a diverse, active solar system with a multitude of objects, certainly too many to memorize, but all of which have unique, fascinating features. Today we can substitute an in-depth education about the solar system and the different ways objects can be classified, as Tyson mentioned above, for simple memorization. It is less important that students be told that we have four jovian planets than that they understand what makes an object a jovian planet. Some say this is asking too much, especially of kids, but frankly, that is a cop out. Kids are smarter than we think. As many have said, children interested in dinosaurs learn, on their own, the many different names and types and what the characteristics of each type are. My nephew, not quite six, is fascinated by marine life. One day, he saw me wearing a dolphin T-shirt and pointed to one of many images on that shirt saying, "that's an electric eel!" I had owned the shirt for years and had never noticed this!

And unlike those who voted in Prague, he recognizes a planet when he sees one. One day, we were looking at pictures in Galaxy, a coffee table book I have with beautiful pictures of stars, planets, nebulae, galaxies, star clusters, etc. We looked at the section on asteroids and at several different asteroids, all with irregular shapes. Then we looked at Vesta, which is mostly spherical except for its south pole, which likely was knocked off by an impact with another asteroid. I asked him how this one (Vesta) is different from the other asteroids. "It's round," he answered immediately.

Even my younger nephew, age two-and-a-half, knows what a planet looks like. He cannot pronounce the letter "L," but he can look at an astronomy-related T-shirt I'm wearing, point to the round object, and say "panet."

And the older one understands fully well that Pluto is a planet not because his Aunt Laurel says so, but because it is round and circles the sun.

Charles Beichman, Executive Director of NASA's Exoplanet Science Institute, said, significantly, that he is all for teaching that there are 359 planets, counting exoplanets as well as those in our solar system.  

Mark Sykes emphasizes that any definition must be useful, noting that the geophysical definition that classifies an object as a planet if it has attained hydrostatic equilibrium, is much easier to both teach and understand than the dynamical definition. The latter is a subset of the former, but the opposite is not the case. And as my little nephew demonstrates, even a two-year-old can recognize something round.

Avoiding this topic will not make it go away. A mistake was made, and it must be corrected, whether by the IAU, by another body, or by public consensus and usage. There are many people, including professional astronomers, amateur astronomers, and lay people who will never accept the IAU definition and will continue to fight it. I'm proud to be one of them.  We are nowhere near "the last word" on this topic, and as Weintraub said, we shouldn't be, as we know far less about the many types of planets out there than many so-called experts think.

Weintraub hit the nail on the head when he said, "the decision should be made by people in the trenches, not the IAU." That could be understood to include amateur astronomers, planetary scientists who are not IAU members, educators, planetarium directors, writers, and more.

Meanwhile, I encourage everyone to express your views on planet definition by commenting on science blogs when this topic comes up. You can arrange to get Google alerts for "Pluto," which will give you links whenever the subject is mentioned.

And keep supporting Pluto's fans in the arts! If you haven't done so already, consider purchasing Elias Fey's "Tribute to Clyde Tombaugh and the New Horizons Mission," an inspiring song that can be purchased online or as a single CD, from here:

And don't move on!

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