Planetary Update

Things are happening fast and furious at the International Astronomical Union (IAU) regarding the upcoming planet definition vote that’s scheduled for this Thursday.

And Wikipedia’s on the story!

In the open-source information age, their 2006 Redefinition of Planet page has not only been created since last week’s announcement of a proposed definition but has been updated to reflect the current state of play.

I was particularly interested to see some of the criticism directed against the proposed definition. Not only have other critics agreed with me that one shouldn’t limit planets to just things that are orbiting stars, they have also made the same criticism I did of defining a moon based on where the barycenter of a planetary system is located.

In fact, they went beyond what I said and made new criticisms of this (dumb) idea:

[W]hile the Moon is defined as a satellite of the Earth, over time the Earth-Moon barycentre will drift outwards (see Tidal acceleration) and be situated outside of either body. This would then upgrade the Moon to full planet according to the redefinition. The time taken for this to occur is expected, however, to be billions of years.

In the extreme case, where a double body has the secondary component in a very eccentric orbit, this could lead to a drift of the barycentre in and out of the primary body, leading to a shift in the classification of the secondary body as a satellite or planet, depending on where in its orbit it is.

All of which underscores the point I made last time: What an object is rather than where the object is should determing whether it is a planet.

Now, I don’t know what the IAU will do this Thursday when they finally vote. Wikipedia reports that one group voted early with negative results:

According to Alan Boss of the Carnegie Institution of Washington, a subgroup of the IAU met on August 18, 2006, and held a straw vote on the draft proposal: only 18 were in favour of the draft proposal, and over 50 against. The 50 in opposition preferred an alternative proposal drawn up by Uruguayan astronomer Julio Ángel Fernández.

That alternative proposal would demote Pluto from planetary status.

Whether or  not the draft definition passes, I doubt that Thursday’s vote will see this kind of lopsided vote in favor of the Fernandez alternative. The group in question was (a) relatively small (68 people, when there are more than 2000 at the meeting) and (b) clearly highly motivated on the subject or they wouldn’t have held a preliminary vote like this. This strikes me more as an attempt to influence the course of events than a representation of what opinion in the IAU is on the topic.

A different indicator of opinion in the IAU is as follows:

Owen Gingerich, an historian and astronomer emeritus at Harvard who led the committee which generated the original definition, predicted the Executive Committee, "will undoubtedly come before the membership with a single resolution. They may make some adjustments." He added that correspondence he had received had been evenly divided for and against the proposal.

YEE-HAW!

Who doesn’t like a cliffhanger scientific scrap!

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Author: Jimmy Akin

Jimmy was born in Texas, grew up nominally Protestant, but at age 20 experienced a profound conversion to Christ. Planning on becoming a Protestant seminary professor, he started an intensive study of the Bible. But the more he immersed himself in Scripture the more he found to support the Catholic faith, and in 1992 he entered the Catholic Church. His conversion story, "A Triumph and a Tragedy," is published in Surprised by Truth. Besides being an author, Jimmy is the Senior Apologist at Catholic Answers, a contributing editor to Catholic Answers Magazine, and a weekly guest on "Catholic Answers Live."

29 thoughts on “Planetary Update”

  1. If only we had an astronomical pope, endowed with scientific infallibility. Then all could be sorted out…

  2. I still refuse to ascribe the title “planet” to Pluto on the grounds that Pluto got her planetary degree at Columbia Evangelical Seminary.

  3. “I still refuse to ascribe the title “planet” to Pluto on the grounds that Pluto got her planetary degree at Columbia Evangelical Seminary.”
    And I thought my scientific infallibility joke was funny!
    I guess I’m a sentimentalist. I like Clyde Tombaugh’s story. http://www.klx.com/clyde/ Demoting Pluto demotes his legacy?

  4. When I first heard of planet Xena, I thought, “What if planet Xena had a moon…they could call it Gabrielle!”
    I was shocked to find out that is indeed the case!
    http://www.gps.caltech.edu/~mbrown/planetlila/moon/
    At first I didn’t want the planet to be officially named Xena, since it’s going to have that name for the rest of human history. But to have Xena and Gabrielle…that is just too much to resist!

  5. Call me a sentimental stick-in-the-mud, but I think Pluto should remain a planet. What, would you seriously want to downplay the threat posed by Yuggoth at this moment? “Oh, don’t worry; it’s only a Pluton object”?
    I don’t agree that Ceres and Charon should be considered planets. As for Xena… meh. I’m willing to be convinced (besides, we need more planets named after female divinities besides Venus).
    Nine (Or Possibly Ten) Is The Natural Number! And are you seriously telling me that somewhere, someone has not trawled through the Bible to establish the holy and sacred and irrevocable number of planets in the solar system as established by the divine Will, any alteration to which is a sign of the impending End of Days, the Rapture, the Tribulation, and the Ascent of the Beast? I find that hard to believe.

  6. I have come up with a mitigating plan just in case they DO decide to go with the eight planet model.
    The Seventh Planet from the Sun shall henceforth be known as “Neptune” and the Eighth Planet from the Sun shall henceforth be known as “Pluto”. Thus, Pluto is still the farthest planet from the Sun and school teachers everywhere will be relieved of hearing the annual snickers at the word “Uranus”.

  7. I have come up with a mitigating plan just in case they DO decide to go with the eight planet model.
    The Seventh Planet from the Sun shall henceforth be known as “Neptune” and the Eighth Planet from the Sun shall henceforth be known as “Pluto”. Thus, Pluto is still the farthest planet from the Sun and school teachers everywhere will be relieved of hearing the annual snickers at the word “Uranus”.

  8. Woops! Sorry about the double. Forgot my name and I didn’t realize I already hit post.

  9. Nine planets.
    Not nine and a half.
    Not twelve.
    Not Pi.
    Not nineish.
    Nine.
    Damn Byzantines.

  10. Those who are a part of the Greek Catholic Church might take offense at your post Some Day.
    Many Ukrainians were martyred for allegance with Rome and they use the Byzantine Divine Liturgy of St. John Chrysostom. Not to mention the Byzantine Catholic Church of America whose Metropolia is in Pittsburgh and is in full Communion with the Roman Pontiff.

  11. The number nine does have a nice trinitarian ring to it. Three threes, you know. Twelve is good too though. More would be too many though, and I don’t like the prospect of calling the moon a planet. To me planets will always at the end of the day be the wandering stars.

  12. Sigh… taking the word planet out of vocabulary to discribe these worlds will degrade them to just objects of foating matter, the word palnet always had a powerful meaning to it, it made a mere object into something more, something close to earth. They should leave the word planet to how well it suits our imagination of what a planet is rather than how it is technically defined.
    I don’t care what they think pluto is he will always be a planet to me, a little guy who got himself lost in outer orbit trying to find a home, trying to find a name to call himself, wondering who am I? will I ever be as good as my brothers?. Pluto has always struggled with this issue of identity and I blame the scientist’s over expectations.

  13. Mars was such a glory hog too, taking the little guy’s thunder. Uranus never helped too he just always criticized and nitpicked bitching about using coasters becuse it left a little water ring on the table.

  14. Nine (Or Possibly Ten) Is The Natural Number!
    “Three shall be the number thou shalt count. Four shalt thou not count. Five is right out.
    When thou countest three, thou shalt pull the pin, & lob the Holy Hand Grenade at thy foes, who being naughty in my sight, shall snuff it”.
    (If CAF isn’t back up soon, it will only get worse….)

  15. I would object to calling any planet “Doc” if it does not have a Ph.D. from an accredited University.
    Seriously, I would like them to name the dwarf planets after the Eddic dwarfs, especially those whose names were made famous by J.R.R. Tolkien’s The Hobbit. See my post on “Isn’t that how its spposed to be?” for those dwarvish lists.

  16. Grrrrr…I’m pretty ticked off at the “official” decision to demote Pluto. When I was a kid, Pluto was (and still is) my favorite planet. In kindergarden I even wrote a song:
    Pluto is my favorite planent
    It’s too far away from Earth
    It’s much cuter than Mercury
    I would even take a spaceship and fly to it
    That’s still my sentiment, and so I refuse to acknowledge the decision of the IAU. They have no power over me. As long as I and my descendents roam the Earth there will be men and women who continue to call Pluto a planet.

  17. I have a private fascination (perhaps weird in someone who generally hates math) for reflections, including numerical reflections, of the trinity in Creation.
    I mourn and question the legitimacy of the loss of a number of planets that can be traced to the Trinity. Nine and twelve (via the interesting number four) can, but eight? Two fours? Thats really pushing it. I have an intution that a more correct way of looking at something as important as the solar system would involve a number related to the trinity. Probalbly it should involve one or more of the following numbers: three, four, seven, nine, twelve, fourty, 144. Those numbers, especially three, follow you so well, as only one example, going down to the atomic and subatomic level (three basic kinds of elements, three kinds of subatomic particals, three quarks in a proton or neutron, etc.), why not going up to the astronomical level?

  18. As an idea, you could have “normal” planets, gass giants, and “dwarf plants” as the three kinds of solar satilites (planets, yes I think where the object is is as or more important than what it is. Consider the difference between a helium nucleus and an alpha partical). Of these three kinds of planets, there are four “normals”, four gass giants, and how many dwarf planets? Four if you count Charon. I would tend not to, in which case if we discovered one more dwarf planet this idea would work. Then we would have twelve planets, three catagories of four. That’s as neat as I could expect, though I am still unclear on why the number four is given almost as much prominence in nature and the Bible as three.
    I hope no one minds silly speculative posts littering the comboxes.

  19. Twelve by the way if you do not follow that is three times four, and seven is three plus four, hence the importance of those numbers (not that seven seems to come into play here)

  20. Sorry to bother y’all again. But I just saw an interesting article:
    http://scotlandonsunday.scotsman.com/scitech.cfm?id=1263692006
    Some astronomers are saying that Neptune doesn’t qualify as a planet under the new “official” definition:
    ‘Harold Weaver, from the John Hopkins University Applied Physics Laboratory and a New Horizons project scientist, said: “Since many ‘Plutinos’, including Pluto, cross Neptune’s orbit, I’d say Neptune’s neighbourhood still needs some clearing.” ‘
    Since only 400 out of 10,000 members of the IAU voted for this thing, I’m hoping the new definition will be ousted pretty quick.
    Regardless, I’m moving forward with my revolution and have had several people sign on to teach their children to keep calling Pluto a planet regardless of what the IAU says. The revolution will last for generations to come!

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