Thursday, August 24, 2006

And then there were eight: Pluto no longer a planet

After a week of clashing over the essense of the cosmos and drinking Pan-Galactic Gargleblasters, leading astronomers declared Thursday that Pluto is no longer a planet.

The International Astronomical Union stripped Pluto of its planetary status, which it had held since it was discovered in 1930. Disney's dog was named after the planet, not the other way around.

Finally, there is a definition of planet: "...a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a... nearly round shape, and has cleared the neighborhood around its orbit."

Pluto is automatically disqualified because its oblong orbit overlaps with Neptune's, CNN reported.

Pluto is now reclassified in a new category of "dwarf planets," similar to what long have been termed "minor planets." Personally, I would have held out for the word "planetoid." So much cooler.

Another new category has been created as well: "small solar system bodies," a term that will apply to numerous asteroids, comets and other natural satellites.

Atrologers will be happy that they can now drop the difficult to account for Pluto from their readings. For now, planets are back to the eight "classical" ones: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Oh, right, astrologers consider the Sun and the Moon planets, too. Oops.

The conference of 2,500 astronomers from 75 countries had us fooled. Last week there was a proposal on the table to not only keep Pluto, but to add its moon and two other objects as planets, bringing the count up to 12. Before the change in definition, even Earth's Moon would have been called a planet under one proposal.

Once before a celestial body has been de-planetfied. In the 1800s, Ceres, now considered an asteroid, was considered a planet.

Pluto was quoted as saying, "I had a good run... 76 years... and you can't take THAT away from me."

And in 2003, Xena, an icy object slightly larger than Pluto discovered by Michael Brown of Cal Tech was hyped as the 10th planet. Now, it's the largest of the dwarves.

And poor Charon, the largest of Pluto's three moons, is no longer under consideration for anything. It had such high hopes, but even its parent Pluto has been dissed.

Image: Pluto and two of its moons.

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  1. Math is fundamental to all science. Lewis Carroll demonstated a basic mathmatical principle when he wrote, '"When I use a word,"Humpty Dumpty said, in rather a scornful tone, "it means just what I choose it to mean -- neither more nor less."' I think math trumps the IAU.

    We should use the Humpty Dumpty definition for what a planet is and not the IAU definition.

    Spread the word, Pluto is a planet whether the IAU likes it or not. In fact I now know there are 12 planets, Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Neptune, Uranus, Pluto, Charon, and 2003 UB313.

  2. Astrologers, drop Pluto? Oh no, never. To an astrologer, size doesn't matter, it's all about the power of the planet. See, Plutos effect on the orbit of Neptune is what lead to it's eventual discovery, exactly where it was predicted it would be discovered. Astronomers like to deny that today, but whatevuuhhh-


    Yep, Pluto may be a little fella, but he still packs a planetary punch.

  3. Copernicus Smiled
    By S. Alan Stern

    Planetary science is awakening to the realization that our solar system contains many more planets than any 20th century textbook ever envisioned. It's not your father's solar system.

    A real revolution is afoot in planetary science. The first shot was fired in 1930, with the discovery of Pluto, but almost no one realized its import. The second and third shots came in the late 1970s, with the discovery of distant objects called Chiron and Charon, but again, few recognized what they would portend. Rapid-fire volleys began in the 1990s, as myriad discoveries of icy bodies 100s to well over 1000 kilometers across occurred in the Kuiper Belt, just beyond Neptune, became an observational reality. But it was only this year, with the recently announced discovery of 2003 UB313-a world larger than Pluto-that we have heard the equivalent of the American Revolution's "shot heard round the world."

    When I was a boy in the 1960s, in college in the late 1970s, and in graduate school in the 1980s, we were taught that our solar system contains four rocky planets on the inside, four giant planets on the outside, and one spit of a planetary misfit called Pluto, moving in a markedly elliptical, and oddly inclined orbit beyond Neptune. Like many people, I recall thinking: What an odd bird that lone Pluto is.

    Today, however, we see a very different picture of our home solar system is emerging, one which reveals Pluto in context-as a nearby example representing what is almost certainly the most populous class of planet in our solar system-the "ice dwarfs."

    Consider that less than 2% of the Kuiper Belt has been thoroughly catalogued, yet over a thousand plus rogue worlds and worldlets have already been spotted there. And among just those bodies catalogued to date, we know that half a dozen (like Sedna and Quaoar) already rival-and in the case of the just discovered 2003 UB313-exceed Pluto's size. Moreover, most of these new worlds follow orbits that are as cockeyed as Pluto's-some even more so.

    Now we can see just how naive our 20th
    century perspectives were: Pluto is no misfit. Instead, once the advance of technology allowed us to probe deeply enough, it is becoming clear that Pluto was the advance harbinger of a populous new region of the solar system lying beyond the giant planets.

    Modern simulations of planetary formation, performed by different research groups around the world, led to broad agreement that in the process of forming the giant planets, some hundreds to thousands of smaller worlds, ranging from a goodly fraction of Pluto's size to at least Earth's size, were also formed. Most of these bodies were dwarf planets, like Pluto, with steeply declining populations at larger and larger sizes, so that only a few or few tens of bodies Earth's size were formed.. These simulations also show that most of these bodies were ejected from the giant planets region to more much more distant orbits as Jupiter, Saturn, Uranus, and Neptune, neared their current sizes and gravitationally cleared out their formation zones, some 4+ billion years ago.

    Importantly, these numerical models are supported by some solid forensic clues that are scattered about the outer solar system, and which lead us to similar conclusions: One such clue is the fact that Pluto's moon, Charon (itself half of Pluto's size) seems to have been formed by a giant impact with a body nearly as large as Pluto itself. What is most important in this finding is that, in order to make such a collision probable, there must have been hundreds or more 1000-km diameter bodies orbiting in the ancient outer solar system. A second clue comes in the form of Triton, a 2700 km diameter moon, which circles Neptune on a retrograde orbit that is the hallmark of gravitational capture from a previous orbit around the Sun. Triton is compositionally much like Pluto, but a tad larger. Apparently, it is one of the "many Plutos" that once formed, and it seems to have escaped ejection by becoming caught in a long-lasting orbit around Neptune. Yet another clue comes from the polar tilts or Uranus (98 degrees) and Neptune (30 degrees). The only viable mechanism known to be able to generate such extreme tilting of these gargantuan (15 Earth mass-class) planets, are off-center collisions with bodies of one to several Earth masses. Crucially, calculations also reveal that in order for both Uranus and Neptune to have had a high probability of suffering such collisions, as many as a few dozen such Earth-mass objects may have once orbited in their region of the solar system.

    As a result of the modeling capability that modern computers give us, combined with the forensic observational clues just discussed, and now the discoveries of rivals and even successors to Pluto's throne, we are slowly but surely coming to a simultaneously jarring and exciting new conclusion: that our solar system formed not just the nine planets we were taught to name in school, but many dozens, if not hundreds of others as well!

    A revolutionary aspect of this emerging, new paradigm is the dawning realization that the long-known eight rocky and giant planets, Mercury through Neptune, now seem to be the misfits.

    Indeed, from today's 21st
    century perspective, the solar system seems likely to be dominated by a huge population of rock and ice planets ranging from dwarf sizes like Pluto to perhaps super-Earth's. Most of these new worlds are expected to follow elliptical, highly-inclined orbits, like those of Pluto, Quaoar, Sedna, and UB313. Further still, of all the planets now expected to orbit within our sun Sol's grasp, most orbit between ten and a thousand times farther than do any of the planets we were taught about in school. It's not at all your father's solar system.

    Less than two centuries ago it was discovered that all the stars one can see by eye, and their innumerable brethren seen by telescope, are distant Suns, with numbers too great to count. Similarly, it was just under a century ago that our galaxy, the Milky Way, was realized to be but one of literally billions of galaxies. Both of these realizations, like the 16th
    century realization that the Sun (not Earth!) is the center of our solar system, jarred perceptions and changed textbooks in revolutionary ways. Just as jarring to us now is the newly emerging view that our solar system made, and is still littered with, very many distant planets, most of which are nothing like the familiar planets that orbit close to the Sun, like Earth. In a real sense, we are seeing a new chapter unfold in the revolution that Copernicus wrought when he displaced the Earth from the center of everything. Another slice of humble pie, anyone?

    Alan Stern is a planetary scientist at the Southwest Research Institute and the Principal Investigator of NASA's New Horizons mission to Pluto and the Kuiper Belt.

  4. Prague - The international committee of astronomers decided this week to remove Pluto from the list of planets. A spokesman released this statement, "We're awfully sorry to have to let Pluto go, but this restructuring is necessary to move this solar system forward. We've got to tighten our asteroid belt and make difficult decisions. We've really enjoyed working with Pluto in the past and wish it no ill will. We look on this event as a great opportunity to revitalize our system."

    Behind the scenes however, things were reportedly more heated. Rumors abound that Pluto orbited slower than other planets, often appearing sluggish and possibly intoxicated. Some have reportedly complained about off color jokes directed at Uranus. Lawsuits by several asteroids demanding inclusion in the solar system reportedly also motivated the committee to take a hard line on planet definition. An original plan to use the world "Pluton" was rejected by their lawyers as demeaning and discriminatory.

    Others have defended Pluto, claiming the decision to downsize was based on unjust discrimination. One anonymous insider claimed, "It's a new solar system, and if you're not wearing rings, or you're too small, you're just not flashy enough for the kids today. Besides, the committee was always uncomfortable with the attraction between Pluto and its long-term partner, Charon. It's just prejudice I tell you."

    Pluto's press agent released this statement, "While Pluto is saddened by this turn of events, it's not bitter, rather Pluto looks on this as an oportunity to explore new and exciting projects."

    [Courtesy Mark Hoolihan and the Hoolinet ( Copyright 2006 Boniface Bugle Productions. All Rights Absurd.]

    The Tao of Masonry

  5. CPluto -- Another
    Astronomical Voting Folly
    By Mary Sparrowdancer
    Copyright 2006 - All Rights Reserved

    In what is surely destined to be remembered as one of the biggest, most highly publicized scientific clunkers of all time -- one giant step backward for mankind -- a handful of scientists in the International Astronomical Union (IAU) voted last week to limit the size of our solar system to no more planets than can be counted on two God-given hands. Our ninth planet, Pluto -- the only known binary planet in our solar system -- was therefore given the boot as were the other recently discovered, problematic planets that were exceeding the apparent "count on two hands only" limit.

    "Eight is enough," has become the popular new mantra being chanted by some, although it seems more appropriate for a Monty Python skit than for a learned conclusion drawn by those whose job it is to study is the universe. Even grade school children are now confused. "Is Pluto still there?" one child recently asked. "But what if eight is not enough?" another asked. Indeed. What if eight will never be enough, because as we continue our space explorations we will continue to discover that there is more, not less, to our solar system and universe than previously known.

    Dr. Alan Stern is a planetary scientist at the Southwest Research Institute and he is Principle Investigator of NASA's "New Horizons." Having lifted off in January of this year, New Horizons is our first robotic spacecraft that is at this time majestically en route to Pluto and beyond. On board is a compact disk containing the names of more than 430,000 people who wanted to somehow be a part of this extraordinary mission of exploration to our ninth planet, even if only in name. It would seem that such numbers alone indicate something of a consensus among humanity that we recognize Pluto as our ninth planet. The question of the day then becomes, how did 428 scientists in the Prague decide for the entire world that there are only eight planets, removing planetary status from Pluto and others recently discovered?

    Dr. Stern, who is among the many scientists who were unable to cast a vote in the Prague meeting on August 24, 2006, explained in an email that of the 8,900 members of the IAU, only 428 were actually permitted to cast votes on Pluto's status for the simple reason that only 428 people were physically present in the room. Those unable to be present in the room in Prague on August 24, 2006 (following what has been described by other astronomers as a "contentious debate") were unable to vote. Dr. Stern described this as a "farce," likening it to the chaos that would result if all Americans were required to travel to Washington, D.C. in order to vote for a president. "It won't stand," he said of the lopsided vote.

    Astronomers are calling for a petition requesting a revote and a more realistic method of voting - something that much of the entire world appears to be badly in need of at this time.

    In the meantime, Yes, Virginia, there is a Pluto. It is still there and it is very real. A few scientists will simply be pretending for a while that it no longer exists as our ninth planet. The rest of us, however, can continue to believe in the obvious.


    Mary is a science, health and spiritual writer who lives in Tallahassee, Florida. She is the author of the Love Song of the Universe. She can be reached at

    Website of Dr. Alan Stern --

    New Horizons --


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