Monday, March 27, 2017

The IAU--and Brown--Get It Wrong, Again



The Pluto/planet definition debate just took a turn toward the tenor of the 2016 US presidential election, with the most outrageous remarks coming from scientists.

It seems IAU Secretary General Piero Benvenuti and the scientist who discovered a planet but wants people to believe he “killed” one—Mike Brown—are tired of the debate and just want it to go away—or so they say.

Incredibly, Benvenuti thinks the debate has lasted this long solely due to Alan Stern! In a Canadian CBC News article dated March 24, 2017, he makes the following statement when asked why the debate has gone on for a decade after the 2006 IAU vote:

"Because of Alan Stern. Because of the Horizons team … Why am I not getting French schoolboys or Italian schoolboys or Iranian schoolboys writing to me about Pluto?"

There are so many things wrong with this statement that it’s hard to know where to begin addressing them!

Let’s start with the fact that the IAU describes its mission as “safeguarding the science of astronomy.”

Alan Stern spent 25 years tenaciously advocating an unmanned mission to Pluto. Because of his persistent dedication and effort, 7.5 billion people on Earth now have close up, high-resolution photos of Pluto. Because of the mission he fought for and put both brains and heart into for two-and-a-half decades, humanity has in-depth knowledge of the Pluto system, including its geology, its weather, its history, etc.

If not for the efforts of Alan Stern—along with those of the New Horizons team members—we would have nothing more than blurry pixelated images of this fascinating world.


One would think the head of an organization that bills itself as “safeguarding the science of astronomy” would give its highest commendations to a scientist who revealed a whole world and its system of satellites to the people of this planet.

Yet all Benvenuti can do is scapegoat and condemn Alan Stern—proof yet again that the IAU is more interested in safeguarding its self-appointed “authority” than the science of astronomy.

Galileo experienced a very similar reaction from the institution that saw itself as the “authority” of his day regarding astronomy.

Unfortunately for the IAU, the organization has no power to put Alan Stern under house arrest. Science by authority went out as of 1610.

Benvenuti does not even get the name of the Pluto mission right, erroneously referring to it as “Horizons” rather than New Horizons.

He claims French, Italian, and Iranian school boys—notice he did not even mention girls—are not sending him letters about Pluto. How do we even know this is true other than the fact that he says so? It’s quite easy to delete emails one does not want to read or send them to the spam filter. Benvenuti’s claim has no more to back it up than does Donald Trump’s claim that millions of illegal immigrants voted against him.

Even if schoolchildren of both genders aren’t writing to him, the reason is probably that they do not know who he is. People concerned about Pluto typically write to NASA, Neil de Grasse Tyson, and the American Museum of Natural History—the institutions or people they associate with either Pluto or astronomy in general. They are more likely to contact planetariums and observatories, especially those in their areas, than they are to write to the Secretary General of the IAU.

Benvenuti’s statement is a barely veiled claim that it is only Americans who care about Pluto’s status, and this is blatantly false. Support for Pluto’s planethood is not about American nationalism. It is about people looking at Pluto and seeing a planet.



If he thinks Alan Stern is the only reason the debate continues, he is sadly mistaken.

More than 300 planetary scientists signed the 2006 petition rejecting the IAU resolution. Numerous scientists have spoken and written against it over and over again for more than 10 years. And they have been joined by a large cohort of amateur astronomers, educators, writers, and members of the public around the world who continue to express their active opposition to the definition that states a dwarf planet is not a planet.

Even scientists not as vocal, such as Dr. Barrie Jones, author of Pluto: Sentinel of the Outer Solar System state they have no problem with the term “dwarf planet” but add that they reject the notion that dwarf planets are not planets at all. Many deliberately use the terms interchangeably as a quiet means of support for dwarf planets being a subclass of planets.

Here are just a few of the planetary scientists and science writers other than Stern who publicly and actively reject the IAU planet definition:

Kirby Runyon
Mark Sykes
Stephen Maran
David Grinspoon
Cathy Olkin
David Weintraub
Alan Boyle
Gerard Van Belle
Ken Croswell
Philip Metzger
Hal Weaver
David Rabinowitz
William McKinnon
David Aguilar
Fran Bagenal
Al Witzgall
Mark Showalter
Mike Buckley
Jim Bell
Carolyn Collins Petersen
Kevin Schindler
Tod Lauer
Will Grundy
Michael Summers
Kelsi Singer
Rob Gerardi
David Eicher
George Musser, Jr.
Ken Kremer
Mike Luciuk
Jason Schilling Kendall
Steve Russo
Jesús Martínez-Frías
Dennis Chamberland
Orkan Umurhan

This is just a short list, and I’m sure I will be adding more scientists and science writers to it.

There is also a huge movement online, sometimes humorously referred to as the “Pluto Resistance,” composed of thousands of people who have joined groups on Facebook and other social media opposing the IAU decision. Most also advocate planet status for the other dwarf planets, Ceres, Haumea, Makemake, and Eris. The largest such group is the Society of Unapologetic Pluto Huggers on Facebook.

Additionally, there are numerous websites such as plutoisaplanet.com, plutoisaplanet.org, plutoisaplanet.us, and many more, including this blog. These have stayed active for more than 10 years! Leading the “Pluto Resistance” for amateur astronomers and members of the public are Mike Wrathell, Raj Pillai, Bruce Reed, Carl Bergmanson, Michael and Nomi Burstein, Ed Murray, Janet Ivey-Duensing of Janet’s Planet, Steve Colyer, Andrew Brown, J. Richard Jacobs, Siobhan and Kevin Elias, Al Tombaugh, Annette Tombaugh-Sitze, Steven Raine, George Lewycky, Mark Andrew Holmes, Twila Gore Peck, Lawrence Klaes, Anthony Hallowell, Doug Turnbull, Scott Hedrick, Yael Dragwyla, Richard Hendricks, Gene Mikulka, John Bowman, Sr., and many more!

When Mike Brown says, “It's the same small group of people loudly complaining over and over the past decade” and claims the number of scientists who reject the IAU definition are “a vocal minority,” he is dead wrong.

His claim is the typical strategy of someone trying to discredit a movement by denying its popularity and attributing the position he opposes to only the outspoken people in the forefront. Like a typical politician, he simply repeats the same claim over and over again, with no proof whatsoever of its veracity.



Incredibly, Brown goes on to describe some of the pro-Pluto arguments as “insane!”

Of course, he does not say which arguments he deems insane. That would require him to give voice to those arguments and actually refute them. Ironically, he accuses the pro-Pluto side of being motivated by nostalgia and emotion when his tone makes it clear that his comments are driven by the emotion of frustration—frustration that he cannot get the world to accept his view of the solar system, even after more than a decade.

He, too, demonstrates ignorance regarding the New Horizons mission, stating, "If they can't make the case that the object that they sent their billion-dollar spacecraft to is interesting without having to co-opt the word planet, then they should have their spacecraft taken away from them. I mean, that's insane."

New Horizons’ total cost was $700 million, not billions of dollars.

Notably, JPL, where Brown is based, competed with APL in Maryland for a Pluto mission proposal in 2001. APL ultimately won the contest, which may be the source for the statement about taking the spacecraft away from the New Horizons team.

One thing supporters of the IAU definition have jumped on is the geophysical proposal’s inclusion of spherical moons as planets. The media has not helped, depicting the idea as far-fetched when that is hardly the case. Some of the top contenders for hosting microbial life in our solar system are spherical moons. These could someday be destinations for solar system colonization.

Even the evasive “Earth 2.0” could end up being the large moon of an even bigger exoplanet.

Spherical moons have been referred to as secondary or satellite planets for centuries. Their scientific classification as planets does not mean people cannot continue to refer to them as “moons.” It simply distinguishes those moons large enough to be rounded by their own gravity from the smaller, irregularly-shaped ones.

Brown exploits the issue of moons when, presuming to speak for everyone, he audaciously claims, “Nobody wants the Moon to be a planet” and laughs about it.

Since Brown personally and financially benefits from the Pluto debate by selling books and giving paid talks, one could question whether he really wants it to “go away.”

But contrary to his claim, Pluto is not just “one of many thousands of objects in the outer solar system.” It is one of a class of planets most numerous in our solar system and very different from those thousands of tiny KBOs.

Ironically, the world will get to know small planets, KBOs, and the outer solar system thanks to New Horizons’ extended mission.

If Benvenuti really wants the debate to “go away,” he should ask the IAU to rescind or suspend the 2006 resolution based on new data about Ceres and Pluto as well as the ever increasing number of strange exoplanets being discovered. Such a statement could simply acknowledge that it is far too early in our exploration of planets to come up with any specific definition, especially one so polarizing and exclusionary.

The IAU seems to want people to blindly follow its edicts. Maybe they need a reminder of Albert Einstein’s admonition, “Unthinking respect for authority is the greatest enemy of truth.”

We are not going away. The Pluto Resistance continues…


Tuesday, March 14, 2017

Pluto: Science has not spoken, and no one has to move on


The case for Pluto’s planethood is not at all grim--in spite of statements to that effect in articles published this month in the Australian-based publication Science Alert and in Forbes.com.

Both articles—the Forbes.com one by astrophysicist Ethan Siegel and the Science Alert one by writer Fiona MacDonald--are statements of interpretation rather than fact because they begin with a foregone conclusion that science somehow precludes Pluto—and dwarf planets in general—from being considered a subclass of planets.

This premise, written in wording that makes it appear to be factual rather than interpretive, is misleading and assumed to be true from the outset when this is hardly the case.

Consider the articles’ titles: Siegel writes “The Science Has Spoken: Pluto Will Never Be A Planet Again.” Using Siegel as an authority, MacDonald states, “An Astrophysicist Says Pluto Will Never Be A Planet Again, and We All Need to Move On.”

But science has not spoken. Ethan Siegal, one scientist whose field of study is not planets has spoken, and claimed to do so in the name of “science.”

And contrary to MacDonald’s claim, he hardly “penned a thorough takedown” of the argument for Pluto’s planethood.

Like most of the four percent of the IAU who voted for the controversial 2006 planet definition, Siegel is not a planetary scientist. His fields are galaxies and cosmology. This should not be at all understood as disrespectful to him. It just means he is not the go to person for determining what a planet is any more than Alan Stern is the go to person for defining the Big Bang.

In saying, “When it comes to planetary science, geophysics isn’t enough. In astronomy, the three rules of real estate also apply: location, location, location,” he self-identifies as a dynamicist. There is nothing wrong with that. What is wrong is his inherent assumption that his side of the planet definition debate is the only scientifically legitimate one, when this is not the case.

The same is true for MacDonald’s statement that “trying to make it (Pluto) a planet again could hurt scientific progress going forward.”

Legitimate debates between those holding conflicting perspectives—in this case, dynamicists versus geophysicists—do not hurt scientific progress. What does hurt such progress is blind acceptance of one self-appointed group as the only “authority” on an issue.

In a February 20 article about the proposal for a geophysical planet definition being presented at the Lunar and Planetary Sciences Conference, writer(s) identified as BEC Crew state, “Of course, nothing changes until the IAU makes a decision…”

Therein lies the real problem. Such a claim amounts to circular reasoning: A thing is true because the IAU says it is true, with no room for anyone, including those who actually study planets, to legitimately disagree.
For geophysicists, an object’s intrinsic properties, not its location, take precedence when it comes to definition.

Siegel’s primary objection to the proposed geophysical definition is that it would make over 100 objects in the solar system, including moons and asteroids, planets. This objection is based largely on the notion that our solar system cannot have “too many planets,” that having a large number somehow devalues the term “planet.”

An understanding of the geophysical definition makes it clear that an asteroid can never be a planet and vice versa. If an object in hydrostatic equilibrium is classed as an asteroid, that classification is wrong. If an object classed as a moon is in hydrostatic equililbrium, it is both a moon and a (satellite) planet. The two are not mutually exclusive, and it remains perfectly fine to refer to such objects as moons. Also classing them as planets simply distinguishes these moons from those not large enough to be in hydrostatic equilibrium, such as Mars’ moons Deimos and Phobos.

Objections to more than a limited number of planets go back several centuries. Galileo’s reference to the four largest moons of Jupiter, which he discovered, as planets, raised major objections beginning with the church, whose position was there could only be seven perfect planets—the seven known since ancient times, which include the Sun and Moon but not the Earth.

When William Herschel discovered Uranus in 1781, his first instinct was to consider his discovery a comet, again due to the strong societal belief that no planets could exist beyond Saturn.

Contrary to Siegel’s claims, one can be honest and reject the notion that “there are very clearly eight objects that are different from all the others” in our solar system, as this is far from the case.

Earth actually has much more in common with Pluto than it does with Jupiter. Both Earth and Pluto have solid surfaces and are geologically layered into core, mantle, and crust; both have large moons formed via giant impact; both have nitrogen in their atmospheres; both have floating glaciers; both have volcanism, and like Earth, Pluto may harbor an ocean (though a subsurface one). In contrast, Jupiter is composed largely of hydrogen and helium, much like the Sun, and has no known solid surface. It has its own “mini solar system” of rings and moons. Putting Earth and Jupiter in the same category while excluding Pluto makes no sense.

Ceres, Jupiter’s moon Europa, Saturn’s moons Enceladus and Titan, Neptune’s moon Triton, and Pluto have different dynamics in terms of what and where they orbit, yet they all are similar in being “ocean worlds” with heat sources that allow for subsurface liquid water that could potentially be home to microbial life. Should these similarities in their intrinsic properties be rejected because their locations are different?

In terms of location, Pluto may well revolutionize our notion of what a star’s habitable zone is. No one expected a world orbiting so far from its star to be capable of hosting life, yet with an underground ocean, Pluto may do just that.

Even a rogue planet that orbits no star is still a planet based on its intrinsic properties.

Siegel cites dynamicist Jean Luc Margot’s 2015 schematic to emphasize a dividing line between planets and non-planets based on orbit clearing. However, Margot’s graph is clearly based on a 2002 paper by Alan Stern and Harold Levison that acknowledged a distinction between objects that gravitationally dominate their orbits and those that do not but never used that distinction to determine the latter are not planets.

Take a look at Margot’s graph, and notice the similarity to the one by Stern and Levison below it:






With the exception of Eris, which had not yet been discovered when Stern and Levison’s paper was published, and the latter’s inclusion of Earth’s Moon, Margot’s dividing line is essentially the same as that of Stern and Levison, who designated objects above the line as “uber planets” and those below it as “unter planets” but never said the latter were not planets at all.

Scientifically, we can recognize this division without precluding those below the line from being considered planets. How? By recognizing that some planets gravitationally dominate their orbits while others do not. The former are called classical planets while the latter are called dwarf planets. Both, based on their intrinsic properties, fall under the broader umbrella of “planets.”

The IAU definition is insufficient in that it puts location over an object’s intrinsic properties. Maybe what we need is a planetary classification system that incorporates both intrinsic and extrinsic properties. Redesignating dwarf planets as a subclass of planets is an easy way to move in that direction. Some scientists have considered establishing a planetary classification system similar to the Herszprung Russell Diagram for stars or to the Star Trek system, that establishes multiple planet subcategories based on both an object’s intrinsic properties and location.

As for the hypothetical Planet X possibly lurking in the outer solar system, its discovery, mass, and orbital parameters do not change anything about Pluto or dwarf planets. Finding such a world would actually strengthen the position of those who recognize our solar system can and does have many planets.

Advocates of a geophysical planet definition do not need to “move on” or be patronized with statements telling them to do so.

All scientists—unless they just arrived from Vulcan—have biases and opinions. Good science is about acknowledging the difference between fact and interpretation, not imposing interpretation on the world and calling it fact. That is a disservice to everyone.

Thursday, March 9, 2017

Hope for Pluto—Should We Re-Redefine Planets?

Hope for Pluto—Should We Re-Redefine Planets?: Planetary geologist Kirby Runyon is lead author of an abstract that proposes a new, geophysical definition of what a planet is.