Wednesday, August 24, 2011
Five Years Later: Pluto Hasn't Been Killed and Doesn't Have It Coming
It’s August 24, 2011; five years have passed since the debacle in Prague, and a few vocal people who insist our solar system has only eight planets are still acting like broken records, endlessly repeating “get over it.”
That’s because the decision that was supposed to be final, that was intended to once and for all end the debate over Pluto’s status and over how to define the term planet continues to be a huge #FAIL, as new discoveries keep the little world front and center and continue to amaze us.
Being a procrastinator is usually not considered a positive thing. Yet for me, as I continue to work on my book and on several other Pluto-related writings, the delays have resulted in unexpected benefits, specifically, a continual influx of new information about Pluto, dwarf planets, proto-planets, and exoplanets that, in each case, compels revisions and new topics of discussion.
As often said, a little knowledge is a dangerous thing, and discoveries in just the last year, never mind the last five years, powerfully illustrate the mistake made by four percent of the IAU in rushing through a resolution based on only a little knowledge, a resolution accurately and amusingly described by Alan Boyle in his book The Case for Pluto as looking like “it was stitched together by Dr. Frankenstein.”
Except Dr. Frankenstein’s monster “took.” The IAU definition, to the dismay of those who threw it together and then proclaimed victory in the debate, did not “take.”
Here is some of the knowledge 424 astronomers voting in Prague in 2006 did not yet have:
Pluto’s lower atmosphere contains methane gas, as revealed in March 2009 by ESO’s Very Large Telescope. This lower atmosphere is significantly warmer than Pluto’s surface, where the average temperature is –180 Celsius. Unlike Earth, Pluto has an “upside down” atmosphere where temperatures increase at higher levels by 3-15 degrees Celsius per kilometer.
Pluto might harbor a subsurface ocean that could host microbial life and could also drive a weak magnetic field. Pluto’s largest moon, Charon, may also host a subsurface ocean and shows evidence of cryovolcanism.
Contrary to popular belief, Pluto is once again the largest Kuiper Belt Object, as Eris’ occultation of a star in November 2010 helped astronomers obtain a more accurate measurement of its size, which was determined to be marginally smaller than Pluto’s. There currently are no known objects in either the Kuiper Belt or the main asteroid belt between Mars and Jupiter that are larger than Pluto. Eris is slightly more dense than Pluto, but if density is all that counts for planets, then Saturn should be demoted, as it is the solar system’s least dense world, to the point that it could actually float in water.
Outside our solar system, an incredible range of exoplanets has been found, most of which would never fit the IAU planet definition even if it specified planets have to orbit a star rather than our Sun. These include planets that orbit their star backwards (in the direction opposite the star’s rotation); a planet believed to have been formed the way stars form, directly from a molecular cloud, orbiting a brown dwarf; a Sun-like star with six planets all orbiting within a space equal to the orbit of Mercury; rogue planets not orbiting any stars; at least two systems with giant planets orbiting in the same 3:2 resonance as Neptune and Pluto, and even a star system with two planets that share a single orbit.
Such unexpected findings prompted planetary scientist Dr. Jack Lissauer to admit the data is “sending me back to the drawing board” when it comes to theories of solar system formation. Those who exclude Pluto from planethood due to its eccentric orbit should study exoplanets, many of which have orbits far more inclined and elliptical than Pluto’s. Apparently, astronomers’ theory that most solar systems formed the way ours did is being proven incorrect, as can be seen here: http://www.spacedaily.com/reports/Interstellar_Crashes_Could_Toss_Out_Habitable_Planets_999.html
In 2011, Pluto twice occulted a star, allowing astronomers to obtain more accurate measurements of its atmosphere’s pressure, density, and temperature via NASA’s Stratospheric Observatory for Infrared Astronomy. Contrary to expectations, Pluto’s atmosphere has not become thinner as the planet recedes from its closest point to the Sun, which it reached in 1989. No one knows why.
Pluto’s atmosphere changes very quickly, as can be distinguished from changes in the coloring on its surface. More on this can be found here: http://arxiv.org/abs/1104.3014
Vesta, a main belt body known as an asteroid since the mid-19th century, now being visited by the Dawn mission, is showing itself to be a highly complex, geologically differentiated world. It is not quite spherical, not quite in hydrostatic equilibrium but clearly very different from any asteroids except Ceres, which is not an asteroid at all, but a small planet, and Pallas, which is somewhat similar to Vesta. Some astronomers now refer to Vesta and Pallas as “protoplanets” to distinguish them from tiny, shapeless asteroids.
If having a tail makes an object a comet, then Mercury joins the ranks of the comets, as it has an elongated tail of glowing gas, as found by NASA’s Stereo mission.
Pluto has been found to have a fourth moon, P4, estimated to be 8-21 miles in diameter. Current thought is the Pluto system was formed via a giant impact. If that sounds familiar, it should. That is how Earth’s moon is believed to have formed.
Three new dwarf planets were discovered in the Kuiper Belt, objects smaller than Pluto but large enough to be over the threshold for hydrostatic equilibrium, 250 miles or 400 kilometers wide. Scott Sheppard of the Carnegie Institute of Washington, who led the study that found these bodies, recently noted, “There could still be Mars- or even Earth-sized objects way out there, at hundreds of AU (astronomical units; one AU is the distance between the Earth and Sun, or 93 million miles), that would be too faint for us to detect.”
In spite of this, Mike Brown continues to discourage the notion of searching for more KBOs Pluto-sized or larger, claiming that if such objects existed, they would have already been found.
A most encouraging development, begun only two months ago, is Ice Hunters, a Zooniverse project in which citizen scientists can actively take part in the search for KBOs; discoveries made through this program could end up being targets for New Horizons after it flies by Pluto. No longer is KBO hunting or even planet hunting restricted to professional astronomers who can obtain coveted time on large telescopes. Anyone reading this who wants to take part in this exciting project, which is being run in conjunction with the New Horizons mission, should visit http://www.icehunters.org .
All these developments have served to strengthen support for Pluto’s planet status and for the planet status of all dwarf planets. Online discussions clearly show a tide turning in small planets’ favor. Arguments such as the claim that we cannot have too many planets because it would be too hard for kids to memorize all of them, or that the term “planet” is devalued by having a large number, or that “the experts have spoken, and it’s over,” or that support for keeping small round objects as a subclass of planets is based on sentiment and emotion are more and more frequently falling flat on their faces.
Scientific principles rise and fall over time, not through a vote. For more than 100 years, people have failed in attempts to prove Einstein’s theory of relativity false. In just five years, the IAU planet definition has not only failed to take hold, but has lost ground and continues to do so as new evidence shows just how premature the decision was.
Of Pluto and the IAU’s increasing irrelevance in the discussion, Alan Stern recently said, “I believe that most planetary scientists know it’s a planet, and we don’t need the IAU to tell us it is.” Neither, for that matter, does the general public need that.
From a cultural standpoint, support for Pluto’s planet status is as strong as ever. While teaching of the solar system is not standardized, the best teachers continue to teach the controversy. Students of all ages have eagerly embraced Pluto as an exciting topic for research. Two personal examples are noteworthy here. One member of my astronomy club, who just completed her freshman year in high school, proudly informed me of the A+ she received for her paper discussing the controversy. In July, when I met the family of my brother’s fiancée, I was impressed to hear her niece, who had just completed seventh grade, emphasize that her teacher absolutely would not come down on either side of the issue, instead teaching it as an ongoing debate.
Elon University Physics Professor Tony Crider has combined astronomy with another favorite interest of his and of mine—role-playing games—to create a game in which students role play astronomers at a 1999 debate and at the 2006 IAU General Assembly. As a new school year begins, I encourage teachers and students to use this original, fun, and informative lesson, which was introduced earlier this month at a meeting of the Astronomical Society of the Pacific. The game can be found at http://facstaff.elon.edu/acrider/acrider/The_Pluto_Debate.html , and I hope to post a review of it shortly.
Constantly enticing us with new data, Pluto is proving more popular than ever. In spite of a recession, Pluto-themed objects, including T-shirts, amazingly continue to sell online, even after five years. At a recent podcast I did about Pluto for the Online Astronomical Society, significant support was expressed for establishing an organization of amateur astronomers that could operate as an auxiliary to the IAU, enabling substantially more public input into decisions and facilitating better communication between professional astronomers and the public.
I am thrilled to announce that I am now a co-administrator for the Facebook Cause “Bring Pluto Back,” whose membership now stands at 1,634, nearly four times the number of people who voted to demote Pluto. If you’re on Facebook and want to join, please visit http://www.causes.com/causes/241322-bring-pluto-back .
Psychologist Carl Jung believed that symbols and myths connect people with subconscious levels of meaning that transcend logic and reason. Such symbols and myths inspire art, literature, music, and imagination. I believe Pluto has become one of those enigmas larger than itself and larger than life, compelling, motivating, inspiring people of all ages and levels of education. This is the je ne sais quoi phenomenon that those who keep repeating louder and louder that Pluto is dead and that we should “get over it,” do not comprehend.
Having performed in two Renaissance festivals, I’ve lately become fascinated with all things from that time, the age from which modern astronomy emerged. So on this fifth anniversary, my message to the IAU, whose members clearly made a premature decision based on a little knowledge and insufficient data five years ago, I will convey some Renaissance wisdom, from William Shakespeare:
“There are more things in heaven and earth than are dreamt of in your philosophy.” A good number of them are planets.