August 25, 2006
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Why this "science-wonk debate" matters
Yesterday, the International Astronomical Union (convened now in Prague, the Czech Republic) voted to accept a resolution that not only expelled Pluto from the family of planets in our solar system, but also denied entry to a dozen other planetary applicants.
This is a fascinating debate that I've been following for a week now. It delves deep into issues only a space wonk like myself would enjoy, but a nice short introductory article can be found here.
Who cares whether we call all those big rocks flying around the sun "planets" or "dwarf planets" or "plutons" or "trans-Neptunian Objects", etc.?
Names carry power. The IAU, which most folks have never heard of, has great power because it is the official naming body for all astronomical bodies. If ever the name for "star" is changed to "gasball", or "Earth" becomes "Terra", it's this body of astronomers who will make that decision. Whatever they decide, that's what goes in the news services and textbooks and encyclopedias and star maps... and those names will color how people thing about the things that are named.
In past generations, the IAU and its predecessors happily rocked the scientific worldview of their various times by adding new planets as they were discovered: Saturn, Neptune, the Asteroid Belt, Pluto, and most recently the round asteroid Ceres as a "minor planet" (since it is the only known asteroid to achieve hydrostatic equilibrium). These successive discoveries have always increased our sense of wonder, mystery, and yearning to explore our solar system-- it gives us humans a sense that even in our own astronomical backyard, there are unexpected treasures to discover. Now to decrease the number of planets in our solar system, for the first time since astronomers began to understand and seek them, is a huge step backward.
Naturally, the solar system itself isn't affected by the IAU's arguments and debates. But our PERCEPTION of our solar system, and what awaits us there, IS affected by their decisions.
Names suggest or deny possibilities. What a thrill for my children's generation to learn that an extra three or twelve or more planets may lurk in the dark foothills of our solar system! What an unstated challenge to go find out about them-- and when most of them give up the idea of a space career, that fascination and hope may endure in whatever field they do choose.
But how sad for my kids to learn in school that the old folks were wrong even about nine planets: there are really only eight. Those others are (dismissive wave of the hand)... oh, plutons or KBO's, uninteresting motes not worth your notice. That dismissive attitude is contagious: they learn to draw their circles tighter, exclude the small and the distant.
Curiously, those closest to the debate but not actively involved in it don't seem to see the power of names. Louis Friedman, executive director of The Planetary Society, actually thinks "The classification doesn't matter." According to AJS Rayl, "...in the big picture, the new definition may mean little since the IAU notes that it will only apply to planets in our solar system."
What do you think? Am I a starry-eyed idealist, putting too much weight on this?
Comments (4)
No, no...I hear you. As an amateur astronomer, I and my friends are disappointed that instead of "adding" designations, we seem to be taking them away. Something vaguely disturbing about that. I wonder if Clyde Tombaugh, the guy who discovered Pluto, is rolling around in his grave?
I guess I prefer to look at the positive side. Instead of losing a planet, we've gained four dwarf ones! We're not 8, we're really 12! Welcome to the family, Pluto, Charon, 2003UCB and Ceres!
Clyde was pretty humble... I'll bet he'd be one of those, like Louis Friedman, saying "okay, dwarf planet, whatever... a mysterious celestial body by any other name would beckon just as sweetly!" Problem is, they do NOT necessarily beckon just as sweetly by another name. It's up to us to put a positive spin on the IAU's decision, maybe write some intriguing short stories about the outer solar system: "Pirates of the Plutons" etc. And if Kuiper Belt Objects and Trans-Neptunian Bodies formally take the mantle of "outer solar system", it will make the gas giants and their wonderful moons seem that much closer to us, and maybe folks will be more willing to shell out the cash to explore them.
And by the way, let's go ahead and call her "Xena", not 2003 UB 313!
Okay, here's a brief rundown on the "planets" of the solar system as we knew it a few weeks ago (the yet-to-be-confirmed discoveries of new plutons omitted). Planet's names ought to appear on the far left, then diameter, distance from the sun, and when discovered. This is tab-delimited, so I have no idea how it will appear in your browser... stretch your browser window bigger and hope for the best. Info culled from The Planetary Society somewhere and edited by me.
Diameter Avg.distance When Discovered:
(in miles) (from sun in mi.)
Mercury 3,000 36 mill. Known by ancients
Venus 7,500 67 mill. Known by ancients
Earth 7,900 93 mill. Known by ancients
Mars 4,200 142 mill. Known by ancients
Ceres 592 258 mill. 1801, Giuseppe Piazzi
Jupiter 88,800 484 mill. Known by ancients
Saturn 74,900 886 mill. Known by ancients
Uranus 31,800 1.8 bill. 1781,William Herschel
Neptune 30,800 2.8 bill. 1846,Johann Galle
Plutons:
Pluto 1,400 3.7 bill. 1930,Clyde Tombaugh
Charon 737 3.7 bill. 1978,James Christy
UB313 1,400/1,600 3.5-9 bill. 2005,Michael Brown, David Rabinowitz and Chad Trujillo
...so HALF the current "planets" were known to the ancients... HALF of them have been discovered since 1800, the latest one just last year. We aren't sure of its exact diameter yet but it's certainly bigger than Pluto, which was once welcomed warmly into the family of planets. If we stick to the previously-agreed simple definition of "planet" (i.e. "if it's big enough to be round and orbits the Sun"), the numerical size of the solar system might double again in the next decade or so.
Wouldn't that be thrilling?! Inviting?! Ah, we can only hope.
Drat, we can't call her Xena anymore. Although after hearing Brown's rationale for the new official name, I like it, I like it!
<bThe Politics of Astronomical Naming
By John Johnson Jr., Times Staff Writer
3:27 PM PDT, September 14, 2006
Eris: goddess of discord.
Could there be a better name for the recently discovered dwarf planet that threw our ideas about the solar system into a cocked hat?
Apparently not.
The executive committee of the International Astronomical Union decided this week to designate the object known as UB313 after the minor goddess of Greek mythology.
Eris, the story goes, was so miffed at being excluded from a fancy wedding that she stirred up the Trojan War.
UB313 aroused scientific discord after its discovery last year by Caltech stargazer Michael Brown. That's because UB313 was at least as big — and quite possibly larger — than Pluto.
Either UB313 was a planet or Pluto wasn't. Simple as that.
Astronomers fought for months before voting in Prague this summer to kick out little Pluto, leaving eight planets and lots of unhappy fans of the dethroned ninth planet.
Brown and his team came up with the name Eris with tongues firmly planted in cheeks.
"It was too good," Brown said today.
The IAU also took Brown's suggestion for the name of Eris' tiny moon, Dysnomia. In Greek mythology, Dysnomia is Eris' daughter, the goddess of lawlessness.
Astronomers love inside jokes and riddles. Two are hidden in the name Dysnomia.
You might get one if you know that before it was Eris, UB313 was nicknamed Xena. Think of the star of the TV show "Xena: Warrior Princess." Lucy Lawless.
Students of astronomical arcana might get the second one too. They may know that the wife of the discoverer of Pluto's moon Charon was named Charlene. Now, can you guess the name of Brown's wife?
Diane.
The new satellite is affectionately known by Brown's team as Di.
john.johnson@latimes.com