Happy Solstice!

Today is one of those days when I will deviate from the usual Pluto-centered entries to honor an occasion that has profound meaning for me and for many on this planet—the Winter Solstice, the original reason for the December holidays, though reversed in the Southern Hemisphere.

We hear a lot about miracles at this time of year. One powerful reason for this is that those of us in the Northern Hemisphere experience and take part in the greatest miracle of all—the return of the light after a long period of increasing darkness.

Long before anyone knew that the Earth orbits the Sun and that its axial tilt is the cause of our seasons, people dreaded the end of summer and the onset of darkness and cold. When there is no central heating and no possibility of growing one’s own food, survival is in question. As the Sun’s strength appeared to wane following the Autumn Equinox, people’s fears and anxieties increased as they faced the looming lean winter season.

Today, so much of the holiday season has become disconnected from the Winter Solstice, and much of the atmosphere of December focuses on what divides us instead of on what unites us. At a time when our actions are plunging us toward mass extinctions and environmental catastrophe, when we desperately need to reconnect with our planet and its web of life, we instead worship money and material things, which ironically are responsible for this disastrous course.

As an actress, I had a lot of outdoor performing gigs this year, and one of the benefits of this was the chance to reconnect with our planet and its seasonal rhythms. From rehearsing in winter coats in early spring, waiting impatiently for the warmth and the budding of new leaves, to all-day Renaissance fairs at the height of the Sun’s power, to an outdoor film set for three days in bright sunlight and 95-degree temperatures, to five weeks at a Halloween theme park along a trail, watching nature slowly go into dormancy, I experienced the year and each season of it vividly, profoundly, and powerfully.

The death part of the cycle, from late September to early November, was more serene than scary. Even though I was dressed as a ghost with white face paint along a haunted trail full of animatronics and fake monsters, what was most real was the sense of Earth going to sleep, which I could actually feel as I sat on the ground waiting to jump out and scare the next person.

When one has the opportunity to be one with nature, to feel the seasonal changes on a deep, intuitive level, it becomes a lot harder to take part in activities that harm the precious Earth with which we bonded.

That is why our society and so many people could benefit from celebrating the seasons as a way to understand, not just on a rational level, but on an experiential one, that we are not separate from the Earth, that, as one song states, “We live as she lives; we die as she dies.”

Myths and symbolism are another path toward attaining that understanding. Even though we know the Sun doesn’t change on our shortest day, the ancient story in which the Sun dies only to be reborn and begin a new cycle at the Winter Solstice, speaks powerfully to us with hope, affirming that there is no end to life, only an end to one cycle and the beginning of another.

An old Jewish legend says that Adam and Eve were created at the Autumnal Equinox, when the lengths of day and night were equal. However, they soon noticed that the daylight was diminishing more and more, and they began to seriously fear that the Sun would die, and the world would once again be plunged into formlessness and void.

When it appeared things couldn’t get any worse, Adam desperately prayed to God, who responded by telling him, wait and watch for three days, and after that, celebrate for seven days. He didn’t know what that meant but followed God’s instructions anyway. And on those three days, the Sun appeared to stand still, its southward movement stopped.

On the fourth day, the miracle happened. The Sun began to move again, but this time, it reversed course, moving northward. The days began getting longer. And Adam and Eve understood that the path of the Sun is a cycle, and such is the way of the world. And they celebrated for seven days, as people have done for thousands of years to this very day.

I am not a creationist or literal believer in the Bible or in any myth, but at the same time, I recognize symbolic truth hidden in these stories. From the beginning, human beings experienced the increasing darkness in fall, and felt the anticipatory terror followed by intense joy when the Sun appeared to return, bringing new light and warmth, the promise of spring.

Twenty-first century humans can be scientifically literate and still retain spirituality, the sense of the transcendent. Celebrating the Winter Solstice offers us this gift. To truly receive it, we need to get out of the malls and step into nature.

As our ecosystems face unprecedented collapse, as our planet faces the increasing perils of global warming and toxic pollution, we would do well to remember this, to understand beyond words that we are a part of the web of life and that whatever we do to that web, we do to ourselves.

"We’ll count all our blessings while the Mother lays down
With snow as her blanket, covering the ground.
Thanks to the Mother for the joy that she brings;
She’ll waken to warm us again in the Spring.”
~from “A Fire Is Burning,” a Winter Solstice song

Pluto Ornament Planet and Moon ornaments The Planetary Society

Pluto Ornament Planet and Moon ornaments The Planetary Society

Scientific Exoplanets Renderer (SER) First Look at Pluto

http://phl.upr.edu/library/notes/serfirstlookatpluto

Guest Blogger Thomas Wade: Pluto Lives

Thomas Wade is a high school physics teacher and a former construction engineer. Here is a terrific article he has written about Pluto's planet status and misstatements of science facts in Mike Brown's book. I hope his is the first of many guest blogs on this site:

Pluto Lives

It’s déjà vu all over again. The troglodytes at the International Astronomical Union (I.A.U.) have arrived at the Pluto party carrying their usual wet blanket and sharp stick. They threw the wet blanket over the fourth moon of Pluto, naming it Kerberos. The sharp stick went into the eyes of the 174,000 people worldwide who voted for Vulcan in a non-binding vote on names for Pluto’s newly discovered fourth and fifth moon. Cerberus, the second place finisher received less than 100,000 votes; and Styx, the third place finisher received less than 90,000 votes. The name Styx was given to the fifth moon, and the Greek version of Cerberus, Kerberos, was given to the fourth moon. Kerberos, of course, received almost no votes.

Despite having the second most logical person, William Shatner, to advocate for its name, Vulcan lost out on a technicality. Objects within the orbital radius of Mercury are called vulcanoids, so the IAU deemed it too confusing. Of course there already was an asteroid named Cerberus, but that did not deter the IAU from simply tweaking its name. Really!

This news came to me, almost to the day, of completing Mike Brown’s modestly named book How I Killed Pluto, and Why It Had It Coming. Easy reader, you don’t have to reach for the defib paddles. Pluto is still very much alive.

Brown is referring to the IAU’s Aug. 24, 2006, vote to reclassify Pluto. Brown had discovered another object, Eris, thought at that time to be somewhat larger than Pluto, orbiting farther out with comets and other objects in an area known as the Kuiper Belt. With all of the imagination of a warm grapefruit, the IAU chose to reclassify Pluto as a “dwarf planet”. Guys, if you haven’t noticed, you still have the word planet in your classification. They could have used an exciting acronym like K-BOMB; Kuiper Belt Object Moving Badly. As Dr. S. Alan Stern, head of the New Horizons Pluto project, pointed out in his 2006 space.com interview, there were only 424 votes (about 4%) cast of approximately 10,000 astronomers worldwide. That 424 also includes the 91 astronomers who did not want to deplanetize Pluto.

You see, the 9th planet of our solar system is a little quirky. Its orbit is so elliptical that it comes inside the orbit of Neptune twice as it orbits the Sun. It is smaller than Mercury, the next smallest planet, and its orbit is also about 20 degrees tilted from the plane in which the other planets orbit. It was booted out, however, because it has too much “clutter” in its neighborhood that it has not cleared out.

But quirkiness is O.K. . Everybody loves quirky. In fact, our solar system is full of “quirk”. The Sun radiates small particles called neutrinos, trillions of which penetrate our bodies every second at nearly the speed of light. Because general relativity tells us that time is gravity- dependent, time proceeds at different rates on the Earth, moon, Mars, and yes, Pluto. You would age faster on Pluto than you would compared to someone on Earth. My favorite, however, comes from Dr. Gabrielle Walker’s excellent book Antarctica. It turns out that not only is there a non-zero probability that the person sitting next to you is a Martian; there is a non-zero probability that You are a Martian. How is that for quirky?

Brown’s egotistical contention that HE killed Pluto comes from his aforementioned discovery of Eris. He had always thought Kuiper Belt objects should not be called planets. Finding an object bigger than Pluto, although much farther out, was enough for Brown and the IAU to get Pluto scraped. As a former engineer and physics instructor for the last 26 years, what bothered me about Brown’s book was his misstatement of scientific facts to convince the reader that the solar system needed deplutoing. See, I just made up a word, much like Brown makes up facts. On page 12 of his book, he states that planets go around the Sun in perfect circles, unlike Pluto’s elongated orbit. This would come as a surprise to the editors of Astronomy magazine and the students of any high school physics class. In Astronomy’s recent August 2013 edition, they named the 40 greatest astronomical discoveries of all time. Johannes Kepler’s discovery that all planets move in elliptical orbits ranked third on that list. In fact, the video series “Mechanical Universe” states that the only reason Kepler made this discovery with the naked eye observations of Tycho Brahe, was that the Mars orbit was elongated as much as it was. Pluto’s orbit, to be sure, is even more elongated than Mars. It is just quirky that way.

What kind of skullduggery would have a well-known astronomer stretching the truth to make a scientific point. It happens all of the time. Even the greatest physicist of all time, Issac Newton, bent facts to try to make his speed of sound formula, based on air density, match the best contemporary measurement for the speed of sound. Although it is done all the time, it is just not right.

Why the bullying of Pluto? I believe it comes from a dismissal of lay populations as uneducated rabble in need of constant guidance. “We IAU astronomers know better. Just follow our lead.” To be sure, there is a use for an IAU naming process. You don’t want to wake up to the news that Mars has been renamed Justin Bieber or Lima Bean. However, in the case of Pluto’s reclassification, and the veto of Vulcan, the IAU has used technicalities to thumb its nose at the regular folk.

The case for Pluto’s continuation as a planet remains strong. Although only about half the diameter of Mercury, Pluto has five moons; three more than the four closest planets to the Sun have combined. Its moon Charon is the eighth largest known moon in the solar system. If something happens to Earth, Pluto is one of only two planetary lifeboats available to humankind, Mars being the other (some moons like Europa, would probably work also). Whether it is runaway global warming in the near future, a possible asteroid impact, or the swelling of the Sun in a few billion years that will eventually incinerate Earth; Pluto may at some time become our most important neighbor. And then there is Pluto’s discovery….

In his metaphysical masterpiece Zen and the Art of Motorcycle Maintenance, Robert Pirsig resurrected a word that sums up the American spirit; “gumption”. In 1930, after excruciatingly tedious comparisons of millions of star images by hand, Clyde Tombaugh discovered Pluto. Brimming with the patience and gumption of a champion, Clyde Tombaugh was the only American (born in Streator, Illinois) to have ever discovered a planet. In fact, in Astronomy’s top 40 list, Tombaugh’s discovery came in at #14, beating out Einstein’s general relativity (#34) and coming in only three places behind Newton’s Principia, the bible of physics and calculus. As a true American hero, a portion of Tombaugh’s ashes are being carried to Pluto by NASA’s 2006 Pluto mission New Horizons, due to rendezvous with Pluto in 2015.

The most galling aspect of the Pluto-Vulcan bashing is the arrogance. At the end of Brown’s book, he actually creates a fictional conversation with his daughter when she will be in third grade.

Brown-“Lilah, did you know that when you were born we thought there were nine or ten planets?”

Lilah-“You know, adults are so stupid.” (the italics were in the original)

The hubris required to put those fake words in the mouth of his small daughter is almost unimaginable. Pluto advocates, like myself, not to mention all of the IAU members who tried to keep Pluto in the planet club, are just plain stupid. We are just not smart enough to know better. As for Vulcan, your 174,000 votes are nice, but we would rather give it a name that got virtually no votes because we know better.

Wait a minute, timeout! It now appears that Brown’s Eris is suffering from that terrible malady that affected George Costanza in that infamous Seinfeld episode; shrinkage. It turns out that the early estimate of Eris’s size has continued to decline since 2006 and it now looks like it is about the same size as Pluto, not bigger as was advertised at the IAU meeting when Pluto was demoted. Mr. Brown wanted to replace the old planet memorization acronym with: Mean, Very Evil Men Just Shortened Up Nature. After the Eris SNAFU, I would suggest: Many Vile Envious Meglomaniacs Just Screwed Up Nice Pluto.

Did I mention that the original press release by Brown and Caltech about the discovery of Eris referred to Eris as the tenth planet. In his book, Brown actually blames this statement on his wife. She had advocated for keeping Pluto as the ninth planet and simply acknowledging Eris as the tenth. Mr. Brown, should have, as I have learned in 20 years of marriage, listened to his wife.

I have no animus towards Dr. Brown. His book does a good job of demonstrating the gumption needed by the serious astronomer. Astronomy is a very demanding profession. The tone of the book is downbeat, however. Brown starts out chapter thirteen with the phrase “Keeping Pluto dead has taken a lot of work.” No reader, Pluto is not dead. I, and other science educators around the world, teach Pluto and the controversy every year. I would suggest that Dr. Brown take his Schmidt-48 (a telescope, not a gun) and point it slightly past star SAO187108 . He will see a dim object , not a corpse, with five even dimmer objects orbiting it. The people of the world have named one of those objects, Vulcan; Spock-like in its cold remoteness. As for Pluto, it is, and always will be, alive in our hearts, minds, and imaginations.

Pluto's Atmosphere Never Completely Disappears

In a Scientific American article dated September 30, 2013, astronomer Dr. Ken Croswell reports the discovery by Dr. Catherine Olkin that Pluto's atmosphere never completely disappears during its 248-year orbit around the Sun. Interestingly, Olkin, of the Southwest Reserarch Institute in Boulder, Colorado, and Dr. John Stansberry of the Space Telescope Science Institute, both agree that Pluto IS a planet--as does Croswell himself. Read the article here: http://www.scientificamerican.com/article.cfm?id=air-apparent-plutos-eternal-atmosphere

The original research paper, to be published in the journal Icarus, can be found and downloaded here: http://arxiv.org/abs/1309.0841

Can't Keep A Good Planet Down

Seven years ago today, in a harried, last-minute highly political act, four percent of the IAU decided Pluto should be stripped of its designation as a planet and should instead be classified as part of a new group of objects, the dwarf planets—which, they said, are not planets at all even though the word “planet” is part of the category name.

It’s hard to believe seven years have passed since that ignominious day. And while some astronomers determined to keep planet Pluto “dead” are likely to gloat about the “new solar system” and brag about how this definition will last for another 80 or so years, what is even more incredible is the way Pluto’s status has remained an active topic of debate over the better part of a decade, at a time when members of the public are decried for their short attention spans.

In just the last year, we have celebrated the 35th anniversary of the discovery of Charon, Pluto’s large moon/binary planet companion, with New Horizons taking its first image of Charon. With its entourage of five moons and counting (four if you count Pluto-Charon as a binary system), this little planet never fails to generate intense interest and long discussions, both online and offline.

Meanwhile, the IAU has managed to stir public ire twice in 2013 alone, first by rejecting the name Vulcan, which received the highest number of votes in a contest sponsored by the SETI Institute that asked the public to suggest names for Pluto’s fourth and fifth moons, and then by condemning the private company Uwingu for launching a fundraiser through which people were asked to submit names for the exoplanet Alpha Centauri Bb and for the larger effort of creating a “Baby Book” of exoplanet names.

Each of these incidents brought people’s attention back to the IAU’s worst debacle seven years ago and reinforced the image of an elitist group out of touch with the general public.

That is likely the reason that earlier this month, the IAU reversed itself on the naming of exoplanets.

This reversal appears to be part of a slow, but inexorable change on the organization’s part, a recognition that its mission to “safeguard the science of astronomy” requires a respectful relationship with the public rather than a dictatorship.

One year ago, at its Beijing General Assembly, the IAU finally approved electronic voting, which will enable members who cannot attend future General Assemblies to have a voice in important decisions by voting remotely.

That rule change is laid out here: http://www.iau.org/administration/statutes_rules/statutes/ .

“15.a. To enable the widest possible participation of Individual Members the Executive Committee may decide that voting on certain issues of a primarily scientific nature, as determined by the Executive Committee, shall be open for electronic voting for not more than 31 days counting from the close of the General Assembly at which the issue was raised.

15.b. The Executive Committee shall give Members not less than 3 months notice before the opening of the General Assembly of the intention to open certain issues to electronic voting after the General Assembly.”

At this site, http://www.universetoday.com/104088/iau-revises-their-stance-on-public-involvement-in-naming-of-exoplanets-and-moons/ , Nancy Atkinson describes the change in policy regarding the assigning of popular names to exoplanets and on allowing members of the public to take part in that process.

The new IAU position, published online only ten days ago, states: “It is therefore in line with a long-established global tradition and experience that the IAU fully supports the involvement of the general public, whether directly or through an independent organized vote, in the naming of planetary satellites, newly discovered planets and their host stars.”

The announcement outlined a set of rules for public submission of exoplanet names that can be found in Atkinson’s article above.

Dr. Alan Stern remains skeptical of the decision, noting it still preserves IAU authority by requiring members of the public to submit exoplanet names to the organization. “Why should the IAU be a traffic cop?” he legitimately asks.

Stern points out that this statement contradicts an earlier one made by the IAU in April. In that statement, the IAU said: “These [naming] campaigns have no bearing on the official naming process — they will not lead to an officially-recognized exoplanet name, despite the price paid or the number of votes accrued.”

Readers of this blog may at this point see where I am going.

As the popular 1960s song goes, “The Times, They Are A’Changing.” The days of authoritarian decrees by a tiny unelected group are numbered. People interested in and involved in astronomy want to have a say in astronomical matters. They want to have input into names and yes, designations, of new discoveries. Chances are, the IAU leadership is making these concessions not because they want to, but because they see the way the wind is blowing and desperately don’t want their organization to become irrelevant and obsolete.

I may be overly optimistic here, but if the public and media can get the IAU to change its stance on naming exoplanets, maybe, just maybe, we can get them to reconsider the issues of planet definition and the status of all dwarf planets, including Pluto.

And if such efforts go unanswered, the IAU is not the only game in town. Astronomy today needs inclusive workshops and consensus building, not a “traffic cop.” As the late Patrick Moore often urged, the field needs an organization that includes amateur astronomers and both respects and welcomes their input.

Back in January, when I first learned of the new policy allowing electronic voting, I wrote to IAU Secretary General Dr. Thierry Montmerle asking for the IAU to reopen discussion on 2006 Resolutions 5a and 5b at its 2015 General Assembly, so that the 96 percent of members who were not in that room in Prague could have a say in the matter.

While noting that a group of IAU members would have to submit a draft resolution several months in advance of the 2015 General Assembly and specifically request it be subjected to electronic voting, as per IAU rules here
http://www.iau.org/administration/statutes_rules/working_rules/ , Montmerle went on to say,

“To be honest, I doubt that any group of astronomers will do what you suggest. There is no indication among the professional community of any will to reconsider the Prague Resolution, and now two GAs have passed without reaction. So personally I would see absolutely no justification (especially taking into account the progress made since then) in bringing up the same issue once again nine years later.”

It is disturbing to hear a high level IAU official dismiss reopening a relevant discussion three years in advance of the General Assembly. One gets the sense that the IAU leadership has made up its mind and does not want to be confused with the facts.

Then again, the events of 2013 illustrate that the IAU is capable of reversing its position if momentum in the astronomy community is clearly moving in a different direction.

Here are the points I noted in response to his message, in favor of a re-vote in 2015:

“I respectfully disagree with you regarding reason to bring up this issue nine years after the Prague decision. As I'm sure you understand, all understanding in science is subject to change based on our discovery of new information. At one time, astronomers thought all solar systems formed and are organized just like ours. Today, we know from exopanet discoveries that this is not the case. Similarly, several developments have occurred since 2006 or will occur by 2015 that could be regarded as compelling a reconsideration of the definition of planet.

1. The New Horizons flyby of Pluto and the Dawn flyby of Ceres will both take place in 2015, and the data these missions will provide will give scientists unprecedented understanding of the composition of small worlds that are large enough to be in hydrostatic equilibrium. These missions will show us two dwarf planets up close and personal, and their findings will likely trump all previous knowledge about such worlds. How could this new knowledge not compel a reconsideration of the concept of planet, including the question of whether dwarf planets should be classified as planets?

2. A huge number and variety of exoplanets have been discovered since 2006. Initially, the goal of creating a definition for the term planet was intended to include both planets in our solar system and in others. As Dr. Jocelyn Bell Burnell said at the 2006 GA, ‘You will notice that the heading of the resolution is definition of a planet in the solar system. We originally hoped to be able to define planet more widely, but we found it too difficult to manage appropriate wording on the timescale that we had. So today, we are talking only about objects in the solar system. We do know that there are other planets beyond our solar system. We are just not looking at them today.’

The IAU may not have had time to consider exoplanets in 2006, but the intention was never to not include exoplanets at some point in the future. Many giant exoplanets discovered today would not meet the criteria of ‘clearing their orbits.’ Only days ago, Formalhaut b was confirmed to have an extremely elliptical orbit that takes it through a disk of debris. Formalhaut b does not remove that debris when it crosses it nor does it capture the debris into its orbit. Therefore, Formalhaut b can be viewed as a world that does not ‘clear the neighborhood of its orbit.’

It is understandable that at first, a definition was created only for planets in our solar system. However, the Copernican principle reminds us that Earth and its solar system are not ‘special’ or at the center of anything. They are just one of many stellar systems with planets. Therefore, it behooves astronomers to standardize a planet definition that fits both our solar system and others rather than hold on to one that somehow gives a ‘unique’ or ‘privileged’ status to Earth's sun and planets.

3. Six years after the IAU vote, the planet definition adopted remains a matter of ongoing controversy and debate. Given the fact that only 424 IAU members voted on that definition, doesn't it make sense to revisit the issue now that electronic voting has been enabled? Many IAU members expressed dismay at having not had a voice in the 2006 debate because they were not present in Prague on the day of the vote. A group of professional astronomers, many of whom are IAU members, signed a formal petition rejecting the IAU definition and in 2009, asked the IAU GA to reopen the issue, only to be rebuffed. Why not include more voices and gain the type of strong consensus that will only strengthen a new planet definition? More voices, including more planetary scientists, can only enrich the discussion.

Nothing in science is set in stone or decreed ‘forever.’ I ask you to take into account the above factors as compelling arguments in favor of revisiting this subject with much more data and significantly more input, nine years after 2006.”

In response, Montmerle said he saw no purpose in continuing this discussion.

What Montmerle didn’t acknowledge in his email to me is that the lack of motivation among the professional astronomy community to reconsider the Prague resolution largely stems from the fact that many astronomers are simply ignoring it altogether. One could argue that that is a much easier route than spending time wrestling with an entrenched bureaucracy, allowing professional astronomers to devote precious time to research rather than politics and procedure.

Dr. Stern confirms this in his most recent report on the New Horizons mission, which can be found here: http://pluto.jhuapl.edu/overview/piPerspective.php . He noted that during the Pluto Science Conference last month, many of the speakers, including some who do not view dwarf planets as planets, continually used the word “planet” in discussing both Pluto and Charon.

He writes, “Throughout the proceedings, scientists of all stripes, including some who don’t regard dwarf planets as planets, repeatedly referred to both Pluto and Charon (though never their small moons) as ‘planets.’ I wasn’t very surprised by this, since I hear it a lot at other conferences too, until one colleague asked me, ‘Why do you think [names withheld] referred to Pluto and Charon as planets when they didn’t sign the petition rejecting the IAU’s planet definition that excludes dwarf planets?’ I was surprised by her answer to her own question: ‘I think it’s because they subconsciously think of Pluto and Charon as planets, and they can't help but say it in when referring to them.’”

On the occasions when the 2006 IAU decision was mentioned at the conference, I couldn’t help but notice that it triggered amused laughter among many in the room.

With less than a year and a half to go until New Horizons begins transmitting its first close-up observations of Pluto in January 2015, Pluto is bound to be a hot topic of discussion in the near future.

That means two parallel discussions loom large on the public radar when it comes to astronomy. One is the role of the IAU in decision making while the other is New Horizons’ reconnaissance of Pluto. This is a good thing because ultimately the two topics are intertwined with one another.

So when a particular astronomer walks around saying that it takes a lot of work to keep Pluto “dead,” the reason for that should be obvious. Seven years after a decision the IAU, or at least four percent of it, desperately wanted to be the final word on the matter, the debate continues. Planet Pluto is very much alive and kicking. You just can’t keep a good planet down.

Dr. David Grinspoon: It's Not About Pluto: Exoplanets Are Planets Too

Dr. David Grinspoon, a signatory to the 2006 petition rejecting the IAU demotion of Pluto, argues in this Sky and Telescope article dated August 16, 2013, that the major flaw with the IAU planet definition is that it completely excludes exoplanets.

Go to http://web.ebscohost.com/ehost/detail?vid=3&sid=36c10510-93ca-425f-b49d-4495be45fc90%40sessionmgr104&hid=114&bdata=JmF1dGh0eXBlPWdlbyZnZW9jdXN0aWQ9Y2pybGMwODUmc2l0ZT1laG9zdC1saXZl#db=fth&AN=88458886 . On the left margin of the page, click on PDF Full Text to either open or download and save Grinspoon's article. He makes a lot of strong points, especially in light of the rapid rate of exoplanet discovery.

Pluto Conference Wrap-Up: Atmospheres, Magnetospheres, Predictions, and Resources--and Lollipops!

The last day of the Pluto Science Conference was only a half day, but speakers managed to get in a lot of discussion on the possible interaction of Pluto’s atmosphere with the solar wind, computer simulations of this interaction, X-ray emissions that might be seen from Pluto’s plasma (a state of matter containing charged particles, both positive and/or negative) environment, X-ray observations of Pluto by the Chandra Space Telescope (an X-ray telescope launched by NASA in 1999), predictions regarding Pluto’s wind structure, Pluto’s ultraviolet glow, and more, all connecting back to the New Horizons flyby in just two years.

Fran Bagenal, a huge Pluto supporter with whom I had fun comparing Pluto T-shirts, reported that Pluto interacts with the solar wind like a comet does, given its large atmospheric escape rate. The solar wind is a stream of charged particles released from the Sun’s upper atmosphere that varies in temperature, density, and speed with time and distance. Voyager 2 actually measured solar wind conditions at 30 AU, roughly Pluto’s distance from the Sun, even though it did not fly past Pluto, and found large variations in it.

Pluto has an extended, puffed up atmosphere, speaker Peter Delamere noted. This atmosphere presents an obstacle to the flow of the solar wind. New Horizons’ SWAP (Solar Wind at Pluto) instrument will look into the solar wind as it comes toward Pluto. Interestingly, the solar wind is currently a lot weaker than it was when Voyager 2 measured it.

On the day of its closest approach, SWAP will begin seeing ions from Pluto. As New Horizons departs, the instrument will likely get a good view of the long tail of ions coming from the planet.

Interstellar ions may also play a role in influencing just how the solar wind interacts with Pluto.

John Cooper questioned why some Kuiper Belt Objects appear red while others appear bright and still others dark. The cold classical KBOs are usually red. Objects created in cryogenic (very low temperature) material tend to be very bright.

Computer models have been utilized to study whether Pluto’s interaction with the solar wind is similar to that of a comet, as Bagenal stated, or whether that interaction is more like that between the solar wind and Venus. The solar wind can undergo many types of interactions with other objects. Four instruments on New Horizons—PEPPSI, REX, ALICE, and SWAP will provide data that could help answer this question.

X-ray observations will also assist in revealing the nature of the interactions between Pluto and the solar wind. This is because X-rays are very effective atmospheric probes and can tell us a lot about the escape rate of Pluto’s atmosphere. Such measurements have successfully been made of the interaction between comets and the solar wind. We can expect to see X-ray emissions from Pluto. During the New Horizons flyby, astronomers will seek observing time on the Chandra telescope, which can encompass Pluto and Charon with one pixel! This will enable very useful comparisons between New Horizons’ up close observations and ground-based observations from Earth.

With only two years until the flyby, excitement is building, and predictions abound. Angela Zalucha presented a computer model she created based on a Global Climate Model (GCM) used to study Earth’s climate. Her “Pluto GCM” assumes the planet has a dynamical core. The REX instrument on New Horizons will send radio waves through Pluto’s atmosphere while ALICE will measure the Sun’s light at Pluto as well as light from a background star shining through Pluto’s atmosphere. She emphasized that Triton is a very good analogue for Pluto.

Researcher Melanie Vangvichith also made use of a computer model, with the goal of creating a complete simulated 3D GCM of Pluto’s atmosphere for the years 1988-2016. Special focus was given to results for the years 2007, 2010, and 2015. Her model shows no troposphere (lowest atmospheric layer), unlike Triton; this is attributed to the abundance of methane on Pluto, which warms its atmosphere. Weather occurs when particles sublimate on the planet’s summer hemisphere and are then transported by wind to its winter hemisphere, where they subsequently condense.

While Vangvichith’s model produces results in agreement with Earth-based observations for this short period of time, it is uncertain whether it can produce the same accuracy when addressing changes over hundreds of years. This is largely due to difficulty in initializing Pluto’s surface and subsurface temperatures over such long periods, especially given its elliptical orbit.

A GCM model also based on Earth climate models created by Anthony Toigo produced its best results when its simulations of Pluto’s current climate assumed the existence of a relatively thick atmosphere. He noted that future studies of Pluto’s climate should focus on tides, general circulation, and surface winds.

To understand the evolution of a planet’s atmosphere, one needs to track the processes in that atmosphere. Nitrogen is the primary gas in the atmospheres of Pluto, Triton, Titan, and various large Kuiper Belt Objects. The ALICE instrument on New Horizons will analyze the composition and structure of Pluto’s atmosphere. It will also show the structure of Pluto’s darker regions against the interplanetary background.

The Cassini mission to Saturn observed ultraviolet airglow on Titan using a model known as AURIC, or Atmospheric Ultraviolet Radiance Integrated Code; New Horizons will use this model to measure ultraviolet airglow on Pluto. ALICE will make this possible by collecting atmospheric data in ultraviolet wavelengths. Interestingly, the AURIC model was initially created for Earth, then modified for Mars, Titan, and now Pluto.

ALICE’s observations are expected to show emissions of argon and nitrogen. Focusing on a profile of the planet’s limb (the outer edge of the planet’s disk) will reveal where the emissions are taking place.

New Horizons will encounter Pluto at a distance of 32.91 AU from the Sun (that is 32 times the Earth-Sun distance).

Stern closed the conference by reminding those present that this meeting was a follow up to a conference held 20 years ago at Lowell Observatory. That conference focused on turning the idea of a robotic mission to Pluto into a reality. Quite a few attendees at this year’s conference had attended that one, and to emphasize this, a picture of the 1993 group was displayed onscreen.

Papers presented at this conference will be published in a special edition of the journal Icarus.

The Pluto Science Conference featured more than just lectures. Two poster sessions were held, one on Tuesday and the other on Thursday, where attendees had the opportunity to view 30 posters and discuss them with the scientists who put them together. On Wednesday during lunch, a special “Triton Half Time Show” was presented, illustrating Voyager 2’s 1989 findings at Triton, which is believed to be a captured Kuiper Belt planet similar in composition to Pluto.

Looking ahead, Stern announced his goal of holding another conference in the summer of 2017 to digest and make sense of the findings of New Horizons, which will take approximately a year to be downlinked. The 2017 conference will lead to the compilation of a Pluto system book.
Abstracts of talks at this year’s conference are posted on https://dnnpro.outer.jhuapl.edu/plutoscience/Home.aspx . More detailed discussions of each speaker’s presentation can be found at Kimberly Ennico’s blog at http://blogs.nasa.gov/mission-ames/ . A summary of the conference and how it exceeded organizers’ expectations can be found here: http://www.spacedaily.com/reports/Pluto_Science_Conference_Exceeds_Expectations_999.html

Only time will tell how accurate the predictions at this conference are in matching what is actually going on. It is worth remembering that prior to the discovery of planets orbiting stars other than the Sun, astronomers generally assumed other solar systems would look like ours. That turned out to be incorrect, to the point of sending scientists back to the drawing board in determining how planetary systems form. Whether models and predictions for Pluto are accurate or way off base will not be known until we actually see the planet and its moons up close.

Finally, to reward readers who hung in there and stayed with me to the end of these conference discussions, here is something on the lighter—and sweeter—side. I always urge supporters of Pluto’s planet status to vote with our dollars. Thanks to Kate McKinnon, wife of astronomer Bill McKinnon, who took part in the conference, I learned that one can buy solar system lollipops that DO include Pluto! Kate highlights these lollipops in a blog post titled, “Take That, Mike Brown!” That post can be found here: http://katemckinnon.wordpress.com/2013/07/24/take-that-mike-brown/

To purchase these lollipops, visit the Colossal Shop, which is selling them as Solar System Lollipops, at http://colossalshop.com/products/solar-system-lollipops , for $22 a set. Choose from a variety of flavors, including cherry, guava, marshmallow, strawberry, blackberry, and cotton candy.

Pluto's Geology and Surface-Atmosphere Interactions

A point frequently cited in support of Pluto’s planet status is that it is a complex world with geology and weather. On the fourth day of the conference, these subjects took center stage, as researchers described what is known about the surfaces of Pluto, Charon, and the four tiny moons and the interactions between these worlds’ surfaces and atmospheres.

Issues addressed regarding surface geology included predictions of whether Pluto and Charon have plate tectonics (processes in which a planet’s crust and upper mantle divide into plates which float and travel independently over the planet’s mantle), predictions on the overall geology of Pluto and Charon, impact craters and the dust particles they eject, and the effects of gravity on the surface processes of the system’s four tiny moons.

PhD student Marc Neveu presented a study questioning whether “exotic sodas” or gas exsolutions (the processes of separating or precipitating from a solid crystalline phase) could cause cryovolcanism on Pluto and Charon. His talk was followed by Dr. Lynnae Quick, who presented her predictions for cryovolcanic flows on Pluto’s surface.

Also discussed in depth were landforms and surface processes on Pluto and Charon, using the seasonal caps on Mars as an analogue for Pluto regarding jets, fans, and cold trapping, mapping coordinate systems used for Pluto, the use of geologic mapping to investigate the geologic history of Pluto and its moons, and speculation about what Pluto will look like.

I felt very grateful to Swinburne for their insistence that students use at least some scholarly journals in our research, in order to familiarize ourselves with the level and format of articles by professionals in the field. Even if one has difficulty following all the equations and theories presented in these studies, the key is to understand the major points being made, the conclusions the researchers reached and how and why they arrived at those conclusions.

Both Pluto and Charon are likely to have impact craters on their surfaces. Such craters are ubiquitous throughout the solar system, and researchers can use the wide variety of craters to learn about the impacting bodies that caused them.

Because Pluto has an icy surface, craters there will appear like those on other icy bodies. The craters will likely be small and shallow since the impacting bodies likely traveled at low velocities.

Pluto’s smaller moons are likely to have surfaces akin to those of asteroids and other small solar system bodies.

Pluto and Charon are tidally locked to one another, meaning they rotate synchronously, with the same side of Pluto always facing the same side of Charon and vice versa. This tidal locking provides unique constraints on the bodies’ interior structure, thermal history, and likely patterns of tectonic deformation.

Cryovolcanism is possible on Pluto, Charon, and other large Kuiper Belt Objects if there is liquid below their surfaces and there are cracks in ice on these objects’ surfaces. The gases able to exert enough pressure to get to their surfaces are hydrogen, nitrogen, argon, methane, and carbon dioxide.

Other places in the solar system where cryovolcanism occurs include Jupiter’s moon Europa, Saturn’s moons Titan and Enceladus, and Neptune’s moon Triton. Many speakers emphasized the similarities likely between Triton and Pluto. This is useful because we have data on Triton from the Voyager 2 flyby of Neptune in 1989. Triton likely originated in the Kuiper Belt and may have been a planet with its own orbit around the Sun before being captured by Neptune.

Pluto and Triton have similar densities, surfaces, and atmospheric compositions, so Pluto’s surface is likely to look a lot like Triton’s. However, albedo contrast is very different for the two bodies. Triton has only modest contrast in the brightness of its surface areas while Pluto shows enormous contrast, with some areas very bright and others dark.

Almost all presenters at the conference made reference to computer models used to determine the outcomes of the processes they are studying. Some described computer models they created either individually or through a team.

Three possibilities were discussed for Pluto’s surface. The first is that Pluto is geologically differentiated with a floating ice shell and a subsurface ocean. The second also has Pluto geologically differentiated, but frozen down to its core, with no ocean present. The third is that Pluto has uniform density globally with a viscous (thick, sticky consistency between that of a solid and that of a liquid) interior and a rigid outer shell.

Scarps, or cliff lines caused by erosion, are also ubiquitous in the solar system; they can be found on Earth, Mars, Titan, and Triton and are also expected on Pluto and Charon, where surface material is moved via condensation (change of physical matter from gas to liquid) and sublimation (change of physical matter from solid to gas without passing through a liquid phase). Another process that likely occurs on Pluto and Charon is sedimentation, or the transportation of eroded particles over long distances in thin atmospheres via plumes.

Geologic mapping is a tool in which scientists take data from many different observations and use it to understand an object as a whole. It was first used on Earth to map geologic features and their ages and characteristics, but has since been used for other solar system bodies and will be an ideal tool for astronomers to use New Horizons data for the purpose of defining and characterizing the brightness, texture, color, and morphology (form and structure) of Pluto and its moons and teasing out their natural history.

The next series of talks centered on surface-atmosphere interactions, addressing issues such as seasonal variations on Pluto’s surface, seasonal transport of volatile organic compounds and the use of computer models to illustrate these phenomena, seasonal light curves, computer modeling of Pluto’s climate, processes driving sublimation and deposition on Pluto, global surface-atmosphere interaction on the planet, chemistry in Pluto’s atmosphere, a comparison of Pluto’s photochemistry (the study of chemical reactions that proceed with the absorption of light by atoms or molecules) with that of Titan and Triton, and three dimensional modeling of the methane cycle on Pluto.

It may come as a surprise to some that Pluto does have seasons! Pluto’s seasons are affected by its highly eccentric orbit, which results in seasons of different lengths for its northern and southern hemispheres.

A good research project for students involves examining the history of Pluto’s light curves, then taking new ones, and comparing the information from all of them to determine whether volatiles have been or are being transported across the planet’s surface. Triton’s light curve has changed significantly since the Voyager 2 flyby. Past light curves of Pluto show no volatile transport; however, in recent years, it has been difficult to obtain accurate data since Pluto has been passing through the plane of the Milky Way. Starting in 2014, Pluto will move away from that plane and data collection will become easier.

Many scientists believe Pluto does experience significant seasonal transport of volatiles. If this is the case, light curve measurements will best confirm these processes, as these measurements are good at detecting changes in albedo (brightness) patterns.
Photometry is a technique that measures the intensity of an astronomical object’s electromagnetic radiation; it has been used to monitor Pluto’s brightest regions. The planet’s color appeared constant until 1992, but after that it changed significantly. Pluto’s south pole has become brighter, and its surface has become more red. The only explanation for these changes is that there have been actual changes on Pluto’s surface.

Three factors control Pluto’s climate. These are its obliquity (axial tilt) of 58 degrees, resulting in its poles receiving more sunlight than its equatorial regions; the eccentricity of its orbit, and the fact that the nitrogen in its atmosphere is in vapor pressure equilibrium with its surface ices (meaning the pressure of atmospheric nitrogen in gaseous form and surface nitrogen in ice form are the same).

In discussing Pluto’s atmosphere, Dr. Kevin Baines compared it to Titan and Triton, describing Pluto as “a really alive planet—really a small Titan.” Dr. Vladimir Krasnopolsky noted that the chemistries on Titan and Triton are very different from one another. Triton is a far better analogue for Pluto. Titan is much closer to the Sun than Pluto; its surface temperature is 94 Kelvin. If it were moved to Pluto’s orbit, Titan would be much more similar to both Pluto and Triton.

A computer model known as the LMD Pluto Climate Model has been used to simulate Pluto’s atmosphere, surface, and subsurface temperatures between 1988 and 2015. The model is being used to determine whether methane that never sublimated will disappear from the surface of Pluto’s poles by 2015. On most areas of Pluto, the atmosphere is much colder than the surface; however, this is not true in the areas where sublimating materials are carried by wind.

This model will be a useful tool to the New Horizons community and to researchers investigating climates on other planets.

Rings, Interiors, Surface Composition--and One Man's Personal Agenda

Who would have imagined there is SO much to discuss about one small planet?

This five-day conference is truly a gathering of great minds, the most knowledgeable people in the world regarding Pluto. With every aspect of the Pluto system under intense analysis and discussion, those of us present are witnesses to the frontier of all we know about these worlds, at the same time knowing that in two years, that knowledge and understanding will dramatically change.

Today, discussion moved from satellites to rings, addressing the possibility of rings around Pluto and their potential sources. Most dust ejected by the small moons is thrown out of the Pluto system altogether while some lands on Pluto and Charon.

Naturally, computer simulations were conducted to determine potential hazards to New Horizons, as the dust particles present in planetary rings could destroy the spacecraft in the event of an impact.

Alternative flyby routes, known as Safe Haven Bail Out Trajectories, or SHBOTS, have been designed by the New Horizons team in the event such hazards are discovered. One such alternative, the Deep Inner SHBOT, actually presents opportunities not afforded on the original trajectory. This path goes through the best locations for higher density particles, meaning it potentially yields the best opportunity for discovery of moons and/or rings. But are potential hazards worth it?

There was much discussion on the process that drives the formation of rings, including the influx of material from the Kuiper Belt. Additionally, as Pluto passes the ecliptic plane twice during each of its orbits, it passes through a thick patch of dust.

The remote search for rings is done in two ways—by direct imaging and by measurements made when Pluto occults (passes in front of) a star. So far, no rings have been found. On its original path, New Horizons faces a reduced risk but is not entirely out of the danger zone.

From dust and rings, discussion moved to the composition of the surfaces of Pluto and its four moons. There is evidence for methane frost on Pluto; various researchers described spectroscopic studies in wavelengths ranging from the infrared to the ultraviolet in the quest to discover the makeup of these objects.

We know methane exists in a pure state and in a diluted state on Pluto; some of it is dissolved in nitrogen. It is distributed uniformly across the surface, as are nitrogen and carbon monoxide. Neptune’s moon Triton contains carbon dioxide, and there is clear evidence it also harbors water ice. Evidence has not been found for carbon dioxide on Pluto though the James Webb Space Telescope, once in operation, should be able to do a more thorough search for it.

What do we know so far? For one thing, ultraviolet light does not make it to Pluto’s surface due to the shielding effects of methane in its atmosphere. Methane is present in Pluto’s atmosphere and on its surface.

The surface of Charon is different from that of Pluto. Pluto’s surface is colored, meaning it has more material than pure ice, which is white. Charon does not appear to have carbon monoxide, carbon dioxide, or methane; it does have water ice and a hybrid form of ammonia. Pluto’s coloring is likely due to organic residue resulting from solar irradiation of its surface. Other hydrocarbons must be present, but we don’t have access to all parts of the electromagnetic spectrum to distinguish them.

Observations with IRAC/Spitzer confirm that Pluto’s surface is heterogeneous. Participants learned about the many methods used to identify what is on that surface through measurements of Pluto’s thermal lightcurve and observations at long wavelengths.

In general, the physical properties of Trans-Neptunian Objects (TNOs) are not well known. Spectroscopy shows that Quaoar, which is probably large enough to be spherical, has a surface dominated by water ice. A current goal of Earth-based observations with ALMA is to obtain accurate information on the size and densities of medium-sized TNOs. Measuring in long wavelengths is important in determining these objects’ characteristics and surfaces.

Makemake, a small Kuiper Belt planet, is known to contain large slabs of methane. Quaoar and Eris also have methane on their surfaces. A total of 56 hydrocarbons have been identified on the surfaces of TNOs.

Pluto has also been measured in the mid-ultraviolet portion of the electromagnetic spectrum. Laboratory studies have been used to simulate conditions on Charon. In some ways, Charon’s surface resembles that of Saturn’s moon Tethys. No variation in Charon’s color or lightcurve has been seen since 1992. Charon is believed to have a reasonably cratered surface, and very subtle albedo and color features. The side facing Pluto looks different than the side facing away from Pluto. Cryovolcanism is possible; the presence of nitrogen is uncertain.

Speakers presented studies on the spectra and chemistry of Pluto’s ices, the formation of high mass hydrocarbons on Kuiper Belt Objects, and radiation chemistry on Pluto. A long-term goal is to obtain optical data for nitrogen, methane, and methane ices on Pluto.

A huge question explored is the possibility that Pluto harbors a subsurface ocean. The presence of an ocean depends on the presence of minor compounds and on whether the processes of convection and dehydration have occurred. Studies of the interiors of both Pluto and Charon play a crucial role in determining whether either body could have such an ocean.

To that end, researchers discussed constraints on the interior structures of both Pluto and Charon, mass determination for both objects by New Horizons’ REX instrument, the process involved through which Pluto’s interior structure evolved, and distinguishing formation scenarios for both objects based on the question of whether the impactor that created them was partially differentiated.

If Pluto and/or Charon have subsurface oceans, how did they evolve and cool?

One way that could help determine whether either body has a subsurface ocean is a look at the objects’ shape, which New Horizons will make possible. If Pluto and/or Charon show fossil bulges on either side, chances are no ocean is present. But if they don’t show these fossil bulges, there is a good chance an ocean exists. The formation of subsurface oceans depends on heat production and heat removal.

One of the most interesting subjects raised was presented as background information by Dr. Marc Buie, whose talk was titled “The Surface of Charon.” Buie revealed an interesting factoid. While Charon was discovered in July 1978, the late Brian Marsden, head of the IAU Minor Planet Center, did not officially recognize it as a satellite of Pluto until February 1985! Buie displayed copies of several IAU circulars issued between July 1978 and February 1985 that referred to Charon as an “unconfirmed” satellite of Pluto. During this time period, astronomers, despite IAU reluctance to recognize Pluto's moon, all recognized its existence and even referred to it by the name Charon—long before that name became “official.”

The display drew repeatedly drew laughter and recognition by those in attendance.

Did Marsden have a personal agenda? This is the same man who told the late Clyde Tombaugh that he “will torpedo your planet” and see that Pluto gets a minor planet number, even if Tombaugh did not live to see that. For decades, Marsden wanted Pluto under his auspices at the Minor Planet Center. And in 2006, it was Marsden who pushed hard for demoting Pluto.

It took seven years for an established astronomer to be certain that Pluto has a large moon, well beyond the time this was accepted as common knowledge, not just by astronomers, but by the general public?

More likely, Marsden didn't want to know that the object he was so determined to downgrade was actually half of a binary system.

Personal agendas should not come into scientific discussions. This is just one more reason that the minor planet numbers assigned to Pluto and the other dwarf planets should be removed—in spite of the fact that Marsden will not see it.

Atmospheres, Origins, and Moons Get Spotlight on Conference's Second Day

The second day of the Pluto Science Conference, July 23, brought more detailed and exciting discussion of Pluto, now focusing on the atmospheres of both Pluto and Charon and then proceeding to the subject of Pluto’s satellites—all five of them. In the evening, Alan Stern gave a public talk, “New Horizons to Planet Pluto: Exploring the Frontier of Our Solar System,” which can be viewed here: http://www.youtube.com/watch?v=iPyRAmviIuE&feature=c4-overview-vl&list=PL2335EF9F07B1DE5E .

Between staying late for Alan’s talk and having problems of my laptop constantly freezing on me, this post is actually a day late.

My friends and family find it hard to believe I found a five-day conference entirely about Pluto. Sure enough, participants continue talking about Pluto in between the sessions! If only this could be a regular thing, preferably closer to home!

Being here is an amazing, exciting opportunity. I am actually meeting people whose works I have read and whom I have watched online giving talks about Pluto and other areas of planetary science. Everyone here is incredibly friendly—while many don’t know me, not a single person has been negative, cold, or insulting. The conference is thankfully free of ego issues, a place where many people share the same interest, and a tremendous learning opportunity for all.

At times there is disagreement, but it is always friendly and respectful.

The discussion on atmospheres reviewed current knowledge, noting Pluto has a nitrogen-dominated atmosphere and also contains methane and carbon monoxide. Until 1985, no one knew this small planet has an atmosphere. This was revealed first when Pluto occulted a star in 1985. Three years later, mutual eclipses by Pluto and Charon of one another, enabling astronomers to obtained improved spectral measurements and observe ongoing changes, such as increasing pressure.

Talks addressed the interaction between surface methane and atmospheric methane on Pluto and the question of whether haze is present in its atmosphere. The size of that atmosphere has increased significantly between 1988 and 2012. And there is a difference between the planet’s upper and lower atmospheres.

Researchers presented their work and that of others in the form of spectral lightcurves (graphs of light intensity, plotted for celestial objects or regions as a function of time), data learned from occultations by Pluto of stars, and through observations using the world’s largest telescopes, including Hubble.

While we know little about Pluto just two short years before the New Horizons flyby, the information we have shows that Pluto’s atmosphere is fully formed and global.

Speakers addressed the issue of whether Pluto’s atmosphere will at some point collapse as it recedes from the Sun. Collapsing in this case means the nitrogen gets so cold that it falls back onto the surface.

The planet has volatile organic compounds (organic chemicals that have a high vapor pressure at ordinary, room temperature conditions) in its atmosphere, and these can condense and evaporate when clouds are present.

New Horizons will make map the distribution of volatile organic compounds in Pluto’s atmosphere through the REX (Radio Science Experiment) thermal imaging instrument. It will also the source of any hazes on Pluto and whether they come from condensates or from sources higher in the atmosphere.

Various researchers presented the findings learned from different occultations of stars by Pluto. A study this year used global circulation models to predict that the atmosphere would have much more cold methane than warm methane in localized regions.

The atmospheres of Pluto and Charon have been studied in the infrared and near-infrared portions of the electro-magnetic spectrum. Stern pointed out that comet impacts could cause a temporary, transient atmosphere on Charon. The large moon has no permanent atmosphere since it lost its volatile organic compounds long ago.

With Pluto’s moon count now up to five, there was no shortage of areas to discuss regarding Pluto’s origins and satellites. Pluto likely did not form where it currently is located. A model of the evolution of the solar system, known as the Nice model, proposes that the four giant planets, Jupiter, Saturn, Uranus, and Neptune, migrated to their current positions, having initially formed between 15 and 20 astronomical units or AU (one AU equals the distance from the Sun to the Earth, about 93 million miles). Jupiter likely formed closer to the Sun and moved outward, leading Uranus and Neptune to go unstable and scatter into the proto-planetary disk around the early Sun.

Where did Pluto come from? Dr. Hal Levison stated that Pluto was already in that disk, at least according to this model, when the giant planets migrated. Yet the model has flaws. The only way it works without resulting in total destruction of Earth and the terrestrial planets is if a third ice giant is added, a planet that subsequently was scattered out of the solar system altogether by Jupiter.

Pluto’s Kuiper Belt neighborhood should have more mass than it does. If all Kuiper Belt Objects are put together, they result in a mass less than 0.1 Earth masses. Far more mass is needed to have formed what is there now. Where did it go?

There are “cold classical Kuiper Belt Objects (KBOs) that have orbits of low eccentricity and inclination as well as plutinos, objects in various resonances with Neptune, and “hot” or highly eccentric KBOs with high inclinations, such as those in the Scattered Disk.

Astronomers presented different theories of planet formation to explain how these KBOs accreted. But do processes work the same at 20 AU from the Sun as they do at Earth’s distance (one AU)?

Notice how many talks end up with more questions than answers. That is part of the fascination of Pluto. We know a lot about this very cold, distant world, yet that knowledge is the tip of the iceberg, showing us how much we don’t yet know.

The New Horizons mission initially motivated the search for additional moons of Pluto. From 1978-2005, only Charon was known. Nix and Hydra were discovered through a deep exposure using Hubble. Pluto’s fourth moon, Kerberos, was found during an intense search for rings around Pluto in 2011, and Hydra was found a year later, its fifth, Styx, was discovered through use of a broader filter that allowed astronomers to probe even more deeply.

All five moons orbit roughly in the same plane as Pluto and Charon, and all are very close to being in mean motion resonances with Charon. Nix and Hydra are estimated to be about 50 kilometers in diameter while Kerberos and Styx are smaller, about 10-15 kilometers in diameter.

The position of these moons was discussed in the context of New Horizons and possible alternate trajectories in the event there is debris present that could destroy the small spacecraft on impact. New Horizons will measure the surface temperatures of Nix and Hydra and obtain high resolution images of all four small moons.

Also addressed were the origins of Pluto’s satellites, likely through an impact by another planetary body with “proto-Pluto,” similar to the impact believed to have formed Earth’s moon. It is unlikely that the small moons were captured rather than formed this way. Charon is thought to be composed of material from the impacting object.

That impact may have heated Pluto to temperatures between 50 and 100 Kelvin, causing Pluto to lose ice.

The orbits, physical properties, and chaotic rotations of Pluto’s moons were subjects of extensive discussion. Just about every speaker tied his or her talk to New Horizons, outlining how the mission will answer the many unresolved questions.

Current plans call for New Horizons to fly through an area interior to Charon known as the Charon Instability Strip (CIS), an area of about 2500 kilometers where no satellites are expected. Hubble will allow further constraining of that region, to less than 25 kilometers in one small area. The LORRI instrument will look for hazards upon approach seven days before the flyby. LORRI will continue to search for satellites, down to much more narrow areas.

From the flyby, there will be a “final answer” to the question of whether or not there are more moons of Pluto out there, Alan Stern said.

His talk that evening on the New Horizons mission was well attended and broadcast live online. One proud Pluto fan from India noted he got up at 5 AM (his time) to hear the talk live. During the question and answer section, a boy asked about planet definition and whether objects have to clear their orbits to be planets. Dr. Stern responded by confirming this is an ongoing debate, adding his view that the solar system now has a third region of planets where prior to 20 years ago, it consisted of four terrestrials, four gas giants, and one misfit, Pluto.

The Pluto Science Conference Day 1: New Horizons and the Kuiper Belt

Today was the first of a five-day Pluto Science Conference being held at the Johns Hopkins University Applied Physics Lab, the same site where the Great Planet Debate was held five years ago. I feel very lucky to be back here, in a town named Laurel in Maryland for five days of All Pluto, All the Time!

The conference is being held in anticipation of the New Horizons flyby of Pluto, now just five years away. Most though not all attendees are professional astronomers and/or members of the New Horizons team.

Day one focused on New Horizons itself, with separate presentations on each of the instruments on board the spacecraft. This comes only about a week after a successful nine-day rehearsal for the encounter held earlier this month.

We learned that New Horizons will be able to take images better than those taken by the Hubble Space Telescope starting in May 2015.

Dr. Alan Stern and several other speakers discussed the effort to get a mission to Pluto off the ground, an effort that goes back 20 years, conceived after mutual eclipses by Pluto and Charon of one another revealed that Pluto has an atmosphere.

“Pluto has received worldwide attention because it is a solar system body worthy of intense study,” Stern noted.

Dr. Tom Krimigis outlined the science objectives of New Horizons, divided into three groups: measurements required for the mission to be a success, known as group 1; highly desired measurements, group 2; and bonus/desired measurements, group 3.

Seven phases of the Pluto encounter were outlined. These include Approach 1, January 6-April 4, 2015; Approach 2, April 4-June 23, 2015; Approach 3, June 23-July 13, 2015; Near Encounter Period, July 13-15, 2015; Departure Phase 1, July 15-August 4, 2015; Departure Phase 2, August 5-October 22, 2015; and Departure Phase 2, October 22, 2015-January 1, 2016.

During the flyby, observations from Earth-based telescopes will be done to complement the data from the encounter. This means there will be two simultaneous studies of the same objects—one “in situ,” meaning at the site (Pluto), and the other from Earth.

While the most important data will be sent back first, it will take an entire year to downlink all the data from the flyby. Pluto will still be surprising us well into 2016.

The second part of the day focused on the context of the Kuiper Belt, including plans to fly by one or two small KBOs after Pluto. Because of fuel concerns, these KBOs must be in a narrow cone along the spacecraft's trajectory. Astronomers have been searching for such objects but have not yet chosen any specific ones although they expect to find two or three. This was also a goal of the citizen science Ice Hunters and Ice Investigators projects though both those projects have completed going through the data they had been given.

There was much discussion of the different parts of the Kuiper Belt—the area of objects in resonances with Neptune, the classical Kuiper Belt, and the Scattered Disk. The latter is the location of Eris and other KBOs with highly eccentric orbits.

Where did Pluto form—in its location, or somewhere else. Various theories attempt to answer this question. One theory, discussed by Dr. Renu Malhotra at the Great Planet Debate, and also discussed extensively in Malhotra's research publications, is that Neptune formed closer to the Sun and then migrated outwards, sweeping objects located closer to the Sun, including Pluto, with it.

The hope is that data from the flyby will answer questions such as what Pluto and Charon are made of, how both accreted, and what their internal structure is. What is known so far is that Pluto and Charon are dense, rock-rich worlds that accreted very rapidly. They probably formed closer to the Sun than their present location.

As I have noted many times in this blog, Pluto is believed to be about 70 percent rock and very likely differentiated into core, mantle, and crust just like Earth. The possibility of Pluto having a subsurface ocean was discussed as well.

Ceres is also estimated to be 70 percent rock and may contain materials brought from the Kuiper Belt region. The small planet is actually more like objects in the Kuiper Belt than like inner solar system bodies, to the point that some astronomers theorize Ceres actually came from the region beyond Neptune.

Also noted was a search for a system of small moons around Haumea, a small, football-shaped planet beyond Pluto in the Kuiper Belt. Haumea is known to have two moons, but as Dr. Luke Burkhart, who conducted a search for additional satellites, noted, no such objects were found.

“Haumea doesn't have a cohort of satellites; Pluto remains unique,” Burkhart said.

These are just the highlights of presentations that were far more intense, detailed, and at times technical.

Kimberly Ennico, New Horizons Deputy Project Scientist, is blogging from the conference, and her posts can be found at http://blogs.nasa.gov/mission-ames/ . You can also follow the discussion on Twitter here, https://twitter.com/search?q=%23Plutosci&src=hash and by following the hashtag #PlutoSci.

The conference has brought together an amazing group of scientists and others who share a fascination with distant Pluto. I personally recognized some from other conferences and many names from scholarly publications I have downloaded and read.

Little mention was made of the IAU. At the same time, debates and disagreements among scholars, such as the question of Ceres' place of origin, were noted genially and recognized as positives that are part and parcel of such discussions. Ideas rise and fall based on data from missions like New Horizons and from studies like those discussed by the speakers. They are not imposed by fiat.

This conference represents the kind of discussion astronomers and others interested in Pluto should be having, a healthy back and forth exchange of ideas. Those who reject such an exchange for simpler but largely unscientific “decrees from on high” will likely be left behind and consigned to irrelevance.

Two important notes: Tomorrow, July 23, Dr. Alan Stern will give a public lecture, “New Horizons to Planet Pluto: Exploring the Frontier of Our Solar System.” The talk will take place at 7:30 PM EDT in the Kossiakoff Center at APL. It will be webcast live at mms://a1232.l711157231.c7111.n.lm.akamaistream.net/D/1232/7111/v0001/reflector:57231

Second, there is a public campaign to get LEGO to make and sell a LEGO model of New Horizons. They have already done this for the Mars Curiosity Rover and for the Japanese Hyabusa cometary mission. We all can help make this happen! The LEGO program is called CUUSOO. A model is created, shared on the CUUSOO web site, and then must get 10,000 individual votes. At that point, it will be reviewed by LEGO and then possibly chosen for production as one of their products, meaning it will be sold online and in stores.

Cast a vote for LEGO New Horizons at http://lego.cuusoo.com/ideas/view/44093 .

First Image of Charon: New Horizons Camera Spots Pluto's Largest Moon

http://pluto.jhuapl.edu/news_center/news/20130710.php

Announcing the new names of Pluto's smallest known moons

Searching for Pluto: A Guide to the 2013 Opposition Season

Searching for Pluto: A Guide to the 2013 Opposition Season

NEAF: Neutral on Pluto and on Planet Definition Debate

As a follow up to a previous regarding the Northeast Astronomy Forum and my request that they present fair and balanced coverage of the Pluto debate by hosting a pro-Pluto-as-a-planet speaker alongside Mike Brown, I would like to share a friendly, respectful response from NEAF organizers regarding my request.

I am very happy to share that Lecture Series Coordinator Keith Murdock emphasized that NEAF supports open debate and does not take a stand on the Pluto controversy. In fact, organizers had reached out to Alan Stern to present the other side; unfortunately, logistics precluded Stern from doing so this year. NEAF organizers are already planning next year's event and hope to enlist Stern or another planetary scientist to present a geophysical perspective.

This is great news because forums like NEAF exist to promote open debate and discussion rather than to endorse any one perspective. I want to publicly thank and commend NEAF organizers for being so responsive, generous, and fair in addressing this issue.

As for this year's NEAF, now in progress, Dr. Ken Kremer, who is giving a talk on the Curiosity Mars rover, plans on making sure to add a plug for the planet status of Pluto and all dwarf planets.

Below is the text of the letter I received:

"Dear Laurel,
Thank you for your comments. We realize that Pluto's status is still a controversial topic, and would like to state that having Mike Brown as a speaker is not to be interpreted as an endorsement of his opinions on the subject. We are a forum, and have no objections to presenting valid arguments on the definition of a planet from the geophysical, rather than the dynamical point of view. We had in fact reached out to Alan Stern on the subject, but were unable to come to a speaking agreement with him.

We are already considering our speaking slate for next year and will strongly consider a planetary scientist with a geophysical perspective for next year's schedule.
Your opinion is important to us and we appreciate your recommendations on this issue.

Sincerely,
Keith

Keith Murdock
RAC Board of Directors
& Lecture Series Coordinator
RocklandAstronomy.com "

Uwingu Responds to the IAU, Extends People's Choice Alpha Centauri Planet Naming Contest | PRLog

Uwingu Responds to the IAU, Extends People's Choice Alpha Centauri Planet Naming Contest | PRLog

The deadline for nominating and voting on names for the exoplanet orbiting the star Alpha Centauri B has been extended one week, to Monday, April 22 at midnight, Eastern Daylight Time.

Make your voice heard, and participate by nominating a name and/or voting for any of the names already proposed.

To make a statement supporting Pluto's planet status, please vote for "PlanetPluto." The name will not be used for the exoplanet since we already have a planet Pluto in our solar system. But voting for this name will send a strong message to the IAU and the world that members of the public join hundreds of professional astronomers in continuing to reject the controversial 2006 IAU planet definition and its resulting demotion of Pluto.

One more thing to note: According to the IAU planet definition, none of the nearly 900 confirmed exoplanets qualify as planets. Why? Because the IAU definition requires a planet to orbit the Sun rather than simply "a star." Even a requirement to orbit a star would preclude rogue planets, which are planetary bodies floating in interstellar space and not orbiting any star.

Vote and make nominations here: http://www.uwingu.com/vote-on-planet-names/#.UWw-uaKG1ac

April 15 Deadline, and It's Not Taxes: Vote "PlanetPluto" in Uwingu's Exoplanet Naming Project

Uwingu is a company presenting a new way to fund astronomy research and space exploration. It makes use of crowd-funding online to motivate people discouraged by federal cuts to NASA's planetary program and cuts to space research by other Western governments to donate small amounts that will hopefully add up to enough money to fund large grants to scientists and research institutions.

The IAU wrongly condemns Uwingu as a "scam" and unfairly compares it to real scams such as the International Star Registry or projects that "sell" people land on the Moon.

Uwingu is nothing like this. Donors know they are not buying a certificate or an exoplanet; they are voluntarily funding scientific research that too many governments are unwilling to fund.

The IAU should be applauding this effort to get more funding for astronomy and get more people actively involved in the field, but instead, they are condemning an effort that actively promotes the science of astronomy and enables all of us to do so as well.

Is the IAU response really about Uwingu or exoplanets at all? Or is it a thinly-veiled attempt to "get back at" the leading astronomer in the world who has opposed and continues to oppose their flawed planet definition and demotion of Pluto? Decide for yourselves.

The IAU claims it is the only legitimate organization with the power to name and classify celestial bodies. Why? Because they say so? The truth is, the only authority they hold is by consensus, and if that consensus erodes, so does their authority.

As a way of sending a message to the IAU, I have been asking Pluto supporters to vote for "PlanetPluto," which has been nominated as one of the exoplanet names on Uwingu's site. You can vote as many times as you want, and a vote costs only 99 cents, which will go toward astronomy research.

As of this moment, PlanetPluto interestingly has 14 votes, which, if one counts Pluto-Charon as a binary system, equals the current number of planets in our solar system according to the geophysical planet definition, which includes terrestrials, jovians, and dwarf planets.

Science cannot be dictated by fiat. Ultimately, we are the "deciders"; we have the power to accept or reject names and definitions, to provide our own input, and to be part of astronomy research--not just by donating money but also by taking part in the many online astronomy research projects now open to all who are interested.

There is a deadline to nominate and vote on planet names, and that is Monday, April 15. While there is no guarantee any name will be used, Uwingu will create a "baby book of names" with the top 1,000 vote getters, which will be distributed to astronomers for possible use in naming any of the almost 900 exoplanets that have been discovered so far.

So take a break from doing taxes and vote here: http://www.uwingu.com/ . If you want to send a statement to the world affirming that Pluto is a planet and that the debate on planet definition is not over, cast one or more votes for "PlanetPluto," which you can find here:
http://www.uwingu.com/vote-on-planet-names/#.UWorZKKG1ac .

IAU Issues Response To Uwingu’s Exoplanet Naming Campaign

“I think it is diminishing that the IAU is holding onto their claim that they own the Universe...
This is like some 15th century European academic club claiming that since Columbus discovered America, they own all the naming rights. That’s BS.”~Dr. Alan Stern

IAU Issues Response To Uwingu’s Exoplanet Naming Campaign

An Open Letter to Organizers of the 2013 Northeast Astronomy Forum (NEAF)

Dear Ed Siemenn, Keith Murdock, and Mies Hora,

As a writer and amateur astronomer, I am contacting you to urge you to add a speaker to the NEAF 2013 program who represents the opposing view to that of Mike Brown, specifically, the position that Pluto and all dwarf planets are a subclass of planets that never have been "killed" along with the broader case for a geophysical planet definition.

I find it disappointing that NEAF would invite Brown specifically referring to him as the "plutokiller." This is a very unprofessional designation he has bestowed upon himself, and it really has nothing to do with science. It is about selling books and seeking money and fame. Significantly, even Neil de Grasse Tyson has moved away from referring to himself as a "plutokiller" and from the notion that Pluto is not a planet, toward a more neutral position in which he admits the debate over what a planet is remains very much ongoing.

Brown, on the other hand, regularly misinforms his audiences by stating that the debate is over and that no astronomers except a few "fringe" types still view Pluto and dwarf planets as planets. This is blatantly untrue, and it is misleading and unprofessional for him to state it as fact! Brown also engages in ridiculous practices such as beheading stuffed Disney Pluto dogs before his talks. Is this the way an astronomer should present himself to the public, including children?

Brown has also engaged in other unprofessional behavior, such as belittling the accomplishment of Clyde Tombaugh in discovering Pluto by saying "Tombaugh just got lucky," and by wrongly guiding astronomers interested in finding undiscovered large Kuiper Belt Objects in telling them that no such objects are left to be discovered when this is not the case.

Because of my active opposition to his position, he has also made personal attacks against me online and maligned me to other astronomers, referring to me as a "nutter" and a "stalker." I have never stalked anyone. All I have ever done is tried to get fair and balanced coverage of Pluto and the planet debate.

Why not present Brown as "Eris discoverer" instead of as "plutokiller?" Too few people are aware of Eris' existence because Brown has so focused the issue on "killing" Pluto rather than on the discovery of additional planets like Eris in our solar system.

Since you are inviting Brown to speak at NEAF, I respectfully request you add a speaker representing the other, pro-Pluto as a planet side. There are plenty of fantastic speakers and accomplished astronomers who can do a great job of this on short notice. One is Dr. Kenneth Kremer, who has given presentations at prior NEAF events. More than 300 professional astronomers, led by New Horizons Principal Investigator Dr. Alan Stern, signed a formal petition rejecting the IAU definition, adopted by four percent of its members. You can find their names here: http://www.ipetitions.com/petition/planetprotest/ . Please consider inviting one of them to present the other side of this issue, the case for a geophysical planet definition. Other good speaker choices are Alan Boyle, author of the book The Case for Pluto, Dr. Ken Croswell, author of Ten Worlds, Dr. David Aguilar, author of Thirteen Planets, and New Jersey's own Alan Witzgall, an outstanding speaker and knowledgeable astronomer who has been doing presentations locally in the tri-state area for more than 25 years and is a leading member of the Cranford, NJ-based Amateur Astronomers, Inc. (AAI) club.

I would be happy to get you in touch with any of the above potential speakers and/or any of the astronomers who signed the petition rejecting Pluto's demotion. I would also be happy to do such a presentation myself, as I have done for AAI and for various astronomy groups on quite a number of occasions.

I invite you to visit my Pluto Blog, advocating a geophysical planet definition and the planet status of Pluto and all dwarf planets, at http://laurelsplutoblog.blogspot.com .

NEAF is a terrific program, and its attendees deserve a fair and balanced discussion that presents them with both sides of this issue so they can draw their own conclusions after hearing all legitimate viewpoints on this subject, which continues to fascinate so many people. I therefore, in the strongest possible terms, urge you to add a speaker to this year's event who can and will present the view that our solar system has created many more planets than eight or nine, and that Pluto is one of them.

Sincerely,

Laurel Kornfeld, Highland Park, NJ, aka @plutosavior on Twitter and Facebook

Could Pluto Have 15 Moons?

Today is the 83rd anniversary of the announcement of Pluto's discovery by the Lowell Observatory. The date was chosen because it is the birthday of Percival Lowell, who first started the search for a Trans-Neptunian planet and founded the Lowell Observatory, and because it is the anniversary of the discovery of the planet Uranus by William Herschel in 1781. Significantly, Herschel first thought his discovery was a comet because no one could conceive of the idea of planets beyond Saturn.

This anniversary is an especially appropriate time for the latest research on Pluto, which shows that the small planet may have up to 10 more moons, which could bring its total number of moons to 15! More information can be found here: http://www.space.com/20181-pluto-moons-new-horizons.html


The paper discussing this can be found at http://arxiv.org/pdf/1303.0280.pdf

Discovery of the New Moons of Pluto - Mark Showalter (SETI Talks)

In a Google+ Hangout, Dr. Mark Showalter discusses the process by which P4 and P5, Pluto's fourth and fifth moons, were discovered, and worldwide participation in the contest to name them. This is very informative and definitely worth watching.

Update on Petition for New Horizons Commemorative Stamp

http://www.change.org/messages/private?message_id=84149076&ue=emn&utm_source=supporter_message&utm_medium=email

"Greetings New Horizons Pluto Stamp supporters,

First, a warm thank you to all of you who signed the petition last summer that was sent to the U.S. Postal Service requesting the issuance of a stamp to commemorate the NASA New Horizons space mission to Pluto.

Recently, we were issued a letter from the USPS informing us that the New Horizons mission stamp proposal will be submitted for review and consideration before their Advisory Committee! We have cleared the first hurdle!

Next it will be put on the agenda for the meeting of the Citizens' Stamp Advisory Committee. Based on USPS guidelines, we know that proponents are NOT advised if a subject has been approved by the Postmaster General for issuance until a general announcement is made to the public. And this entire process can take up to 3 years. So we will most likely not know if a stamp is approved until around the time when New Horizons reaches Pluto in 2015. But please be patient and keep your fingers crossed!

Also, we will no longer be sending updates to this change.org mailing list, so please visit the New Horizons website and sign up to receive updates on the mission at http://pluto.jhuapl.edu/

And join us on Facebook! https://www.facebook.com/new.horizons1?fref=ts

Once again, thank you all for your support! Go New Horizons!

This message is from Con Tsang. For Information, Go To "New Horizons" who started the petition "Citizens' Stamp Advisory Committee of the US Postal Service: Honor New Horizons and the Exploration of Pluto with a USPS Stamp," which you signed on Change.org.

View the petition | View and reply to this message online

Unsubscribe from updates about this petition"

Responding to the IAU: Pluto and the Developing Landscape of the Solar System

Today is the 83rd anniversary of Planet Pluto’s discovery by 24-year-old Clyde William Tombaugh at the Lowell Observatory in Flagstaff, Arizona, on February 18, 1930. As such, it is an ideal time to write an entry I have been intending to do for a while: a point-by-point response to the IAU “official” statement, “Pluto and the Developing Landscape of Our Solar System,” which can be found at http://www.iau.org/public/pluto/

The Discovery of Pluto

The description of Tombaugh’s discovery is accurate. However, one important detail is missing. The IAU statement says, “Tombaugh was searching for an elusive planet—planet X—that (Percival) Lowell had believed (incorrectly) to be responsible for perturbing the orbits of Uranus and Neptune.”

Not mentioned is that Lowell was far from the only astronomer to believe that an unknown gas giant planet was perturbing the orbits of Uranus and Neptune. Many astronomers of the late 19th and early 20th centuries believed this as well because the two giant planets’ actual orbits didn’t match the orbits astronomers had calculated they should have. But the reason for this was not the existence of another gas giant beyond Neptune. It was simply human error, erroneous calculations. This fact was not recognized until 1986 and 1989, when Voyager 2 flew by both these planets, confirming that nothing was perturbing them.

There is some irony in that the source given as a reference several times in the IAU statement is the book Pluto and Charon: Icy Worlds on the Ragged Edge of the Solar System, by Dr. Alan Stern and Dr. Jacqueline Mitton. Stern, Principal Investigator of the New Horizons mission, is one of the most vocal opponents of the IAU planet definition. It seems the IAU has no problem relying on his work as a reference when doing so is expedient, while at the same time repeatedly ignoring his input on this issue for six-and-a-half years.

The Changing Landscape of the Solar System

While the IAU accepted the name Pluto for Tombaugh’s discovery, it was the Lowell Observatory that named it Pluto, partly at the suggestion of young British girl Venetia Burney. By the time the IAU “officially adopted” the name, it was already a done deal. Why does this matter? The answer is, the chain of events leading up to Pluto being named was not driven or controlled by the IAU. At that time, the IAU did not even concern itself with planets and planetary science. The IAU did not have the type of power its leadership wants people to believe it has always had, and there is no reason for it to have the final say on planetary matters.

The statement goes on to say that, “The view of our solar system’s landscape began to change on August 30, 1992, with the discovery by David Jewitt and Jane Luu from the University of Hawaii of the first of more than 1,000 now-known objects orbiting beyond Neptune in what is often referred to as the trans-Neptunian region.”

Yes, the first trans-Neptunian Object other than Pluto was discovered in 1992, but many astronomers long suspected the existence of such objects, so the discovery was not that much of a surprise. The famous astronomer Dr. Harlow Shapley, in 1930, only months after Pluto’s discovery, questioned whether Pluto was the first in a new class of solar system objects and wondering whether similar bodies remained undiscovered in the outer solar system. In 1943, Dr. Kenneth Edgeworth suggested the existence of a reservoir of comets beyond the orbit of Neptune. Eight years later, Dr. Gerard Kuiper suggested a large region of icy bodies existed out to 120 astronomical units (AU) beyond Neptune. While the existence of this region was not confirmed until 1992, it certainly was anticipated long before then.

The IAU statement goes on to say, “With so many Trans-Neptunian Objects being found, it seemed inevitable one or more might be found to rival Pluto in size.” What is not explained is why the existence of an object of similar size would influence Pluto’s classification. How does it make sense to classify one body by the characteristics of another? Pluto’s classification should be based on its own characteristics, not those of Eris or Ceres, or any other celestial body. Would the existence of other “Earths” change the designation of our own planet?

The discovery of Eris is accurately credited to the team of Mike Brown, Chad Trujillo, and David Rabinowitz, yet the references at the bottom of the page cite only Brown, and nowhere in the article is acknowledgement that Rabinowitz opposed the IAU decision, as evidenced in his signing Alan Stern’s petition of 300 astronomers on August 30, 2006. Additionally, the article does not acknowledge that the initial view of Eris being larger than Pluto has been proven incorrect. Eris is described as being “around 2500 km across.” In November 2010, when Eris occulted a star, that measurement was revised downward to approximately 2340 km., in comparison with Pluto, whose size is estimated at 2344 km. Why was this information never updated on the IAU page? Eris is believed to be about 27 percent more massive than Pluto, which only indicates it is more rocky and therefore, more like the terrestrial planets. Pluto is estimated to be 70 percent rock, a fact often lost by people describing it as an “iceball.”

The IAU article notes that Eris, too, was found to have a satellite. Yet Pluto is now known to have five satellites, or moons (four if you count Pluto-Charon as a binary planet system), yet the IAU leadership insists this changes nothing and refuses to reopen discussion on the issue. Does having moons make a difference in an object’s classification? Based on this article and subsequent reactions to new discoveries, one can only conclude that it matters when the IAU leadership decides it matters but means nothing when that same leadership wants it to be irrelevant.

“With an object larger and more massive than Pluto now beyond Neptune and ever more of these Trans-Neptunian Objects being discovered, astronomers were beginning to ask: ‘Just what constitutes a planet?’” Over two years have passed since the discovery that Eris is not larger than Pluto, yet the IAU has never updated this information.

And astronomers have been asking, “just what constitutes a planet” ever since Galileo in 1610 discovered four “planets” orbiting Jupiter. Inherent in the IAU statement is the bias that “we cannot have too many planets.” More and more galaxies have been discovered as the Hubble Telescope has peered further back into the universe, yet no one has argued a need to determine what constitutes a galaxy because we now have too many. Never mind that to this day, no object larger than Pluto has been discovered in the Kuiper Belt. The sentence clearly turns away from scientific analysis to a subtle favoring of one interpretation.

A New Class of Objects and How to Define A Planet

Dr. Owen Gingerich, who served as chair of the IAU Planet Definition Committee, is quoted saying, “On the scientific side, we wanted to avoid arbitrary cut-offs simply based on distances, periods, magnitudes, or neighboring objects.”

But the IAU definition does everything Gingerich urges against! Its decision is clearly based on distances because the further an object orbits from its parent star, the larger an orbit it will have to “clear.” If Earth were in Pluto’s orbit, it would not “clear” that orbit of Kuiper Belt Objects either.

Similarly, the IAU decision is definitely based on neighboring objects! Pluto is classified not by its characteristics but by the existence of other objects—tiny Kuiper Belt Objects—in its orbit. The debate over Pluto’s status came about because of another object—Eris.

And Gingerich himself was kept out of the loop, never told that his own committee’s resolution would be rejected in favor of another one hastily thrown together. At the Great Planet Debate, he admitted that had he known this was going to happen, he would have canceled his early flight and stayed to the end of the conference.

While the article says the IAU has been responsible for the nomenclature of planetary bodies since the early 1900s, we already know this has not exactly been the case. The Lowell Observatory sent the suggestion of the name Pluto to the American Astronomical Society and the British Royal Astronomical Society, but not to the IAU.

Subsequent discussion describes the IAU as having created a committee representing a broad range of scientific interests to create a new definition of planet. What is not stated is that at the 2006 General Assembly, the IAU rejected the draft resolution created by that very committee and instead threw together an alternate resolution at the last minute, completely bypassing that committee and violating IAU bylaws, which require all resolutions to first be vetted by the appropriate committee before being placed on the floor of the General Assembly.

Former IAU president Ron Ekers, who opposed the 2006 decision, is quoted as having said, “Such decisions and recommendations are not enforceable by any national or international law; rather they establish conventions that are meant to help our understanding of astronomical objects and processes. Hence, IAU recommendations should rest on well-established scientific facts and have a broad consensus in the community concerned.”

The IAU leadership accurately claims its decision is not enforceable but has spent more than six years insisting that educators, textbooks, and the media use its definition as the sole “official” planet definition.

What about the need for decisions “to rest on well-established scientific facts and have a broad consensus in the community concerned?” Well, the IAU document has erroneous, outdated statements when it comes to scientific facts, and over more than six years, the organization has never allowed the discovery of new facts to influence its decision. As for a broad consensus in the astronomy community, that never happened. When 300 professional astronomers sign a petition rejecting a decision, when those same astronomers ask for the discussion to be re-opened three years later and are denied, when the leading expert on Pluto in the world and the head of the only space mission two years from rendezvous with Pluto repeatedly describes that decision as “an embarrassment to astronomy,” it is clear no such consensus exists today or ever existed.


The Final Resolution

The chaotic and flawed process by which the resolution demoting Pluto was crafted is whitewashed with the words, “a new version slowly took shape,” which was “more acceptable to the majority…” In what universe does slowly taking shape equate to something thrown together over a few hours? Many astronomers at the Closing Ceremony, where the vote took place, did not see the text of the resolution until it came to them for a vote that day. As for a majority, well, the majority of the 2,500 attendees had already gone home assuming the resolution recommended by the IAU committee would be voted on. Those not attending the conference weren’t eligible to vote. In whose math is 424 equal to a majority of 2,500? And of those 424 (really 423 since one astronomer has since admitted to having been warned of “consequences” to his/her career if he/she did not vote against Pluto), 91 voted in favor of Resolution 5b, which would have established dwarf planets as a subclass of planets.

There was no majority. A total of 333 IAU members, most of whom came with the agenda of creating a definition that excluded Pluto, determined that dwarf planets are not planets at all, misusing the term first coined by Dr. Stern in 1991.

Dwarf Planets, Plutoids, and the Solar System Today

We already know that it was never “agreed” that planets and dwarf planets should be two distinct classes of objects although one could accurately say it was imposed. Even fewer astronomers had input into the creation of the term “plutoids,” which was done in a classic backroom deal. Planetary scientists interviewed by the media, including Brown, who supported the IAU decision, all said they knew nothing of how that decision was reached or that it had been under consideration. Just who did come up with this term? Why is such a term even necessary when these objects can be characterized as trans-Neptunian dwarf planets?

Does the term “plutoids” help our understanding of astronomical objects? We have a separate class of dwarf planets that does not include Ceres. Some dwarf planets are “plutoids”; others are not. Objects that share Pluto’s orbital resonance with Neptune are called “plutinos,” but these are tiny, non-spherical objects, not dwarf planets. Are you confused yet?

Planets, Dwarf Planets, and Small Solar System Bodies

Get ready to be more confused. Here we have a big mess. Dwarf planets are supposed to be a class separate from Small Solar System Bodies, the new name for asteroids and comets, often referred to as “minor planets.” However, the IAU assigned all dwarf planets minor planet numbers! If these objects are not minor planets, why give them minor planet designations, completely blurring the distinction between tiny, shapeless asteroids, comets, and Kuiper Belt Objects on one hand and the complex worlds rounded by their own gravity that dwarf planets are on the other hand.

There are clearly more objects beyond Neptune large enough to be in hydrostatic equilibrium, but to this day, none has been given the designation of dwarf planet by the IAU. The IAU statement describes how Ceres was considered an asteroid for more than a century, but never clarifies that it no longer should be classed as such because it is now known to be spherical. Pluto is described as residing “within a zone of other, similarly-sized objects known as the Trans-Neptunian region,” yet the overwhelming majority of Kuiper Belt Objects are nowhere near Pluto’s size, and the other trans-Neptunian dwarf planets do not orbit anywhere near Pluto. Eris orbits in the Scattered Disk, the furthest region of the Kuiper Belt.

New data from the Dawn mission that calls into question Vesta’s status as an asteroid is not even mentioned.

Should Charon be considered a dwarf planet? With the discovery of Pluto’s fourth and fifth moons, both of which are in resonance with Charon, the answer is likely yes. The IAU statement says this may be considered later, but don’t hold your breath. Discussing the dwarf planethood of Charon inevitably brings up the subject the IAU leadership is doing everything to avoid discussing—the planetary status of Pluto and all dwarf planets.

As of yet, there have been no discoveries of objects larger than Pluto in the outer solar system. Some researchers believe there could be a gas giant orbiting the Sun far beyond Pluto’s orbit, yet to be discovered. According to the IAU definition, that object likely would not be considered a planet either because it would inevitably have tiny Kuiper Belt Objects in its path.

In a Q and A, the IAU poses the question of how new discoveries will be classified, whether as planets, dwarf planets, or small solar system bodies. The answer: "The decision on how to classify newly discovered objects will be made by a review committee within the IAU. The review process will be an evaluation, based on the best available data, of whether or not the physical properties of the object satisfy the definitions. It is likely that for many objects, several years may be required to gather sufficient data."


If the IAU isn’t even using the “best available data” and seeking input from leading planetary scientists now, how can we trust they will do so in the future?

Why can a spherical satellite of a dwarf planet not be considered a dwarf planet itself—because Resolution 5b says so? That doesn’t sound like scientific reasoning to me.

In plain language, an equally legitimate scientific definition of planet is, a planet is an object orbiting a star and large enough to be rounded by its own gravity. Some planets clear their paths around the Sun; some do not. The latter are dwarf planets. An object may not even need an orbit or a host star to be a planet, as astronomers have now seen “rogue” planets wandering in space not orbiting any star.

According to this, the geophysical planet definition, our solar system has 13+ planets: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Haumea, Makemake, and Eris. Charon could very well be considered a dwarf planet, and so should the other known spherical Trans-Neptunian Objects. Spherical moons of planets should be considered “satellite planets.”

None of this information is new, and all of it has appeared in other blog entries. But with educators directing students to the IAU site for a discussion of the Pluto question, these responses need to be reiterated, if only to bring fairness and balance to the debate.

Happy 83rd anniversary of Planet Pluto’s discovery!

References:

Boyle, A., 2009, The Case for Pluto

Petition of 300 Astronomers Rejecting IAU Decision, August 2006: http://www.ipetitions.com/petition/planetprotest/

Stern, S.A., and Levison, H.F., 2000, Regarding the Criteria for Planethood and Proposed Planetary Classification Scheme, Transactions of IAU

The Great Planet Debate, Johns Hopkins University Applied Physics Lab, August 2008: http://gpd.jhuapl.edu/

Tombaugh, C.W., and Moore, P., 1980, Out of the Darkness: The Planet Pluto


Weintraub, D., 2007, Is Pluto A Planet