A few years ago the solar system got a bit more crowded when astronomers at the Palomar Observatory spotted a tenth ‘planet,’ romantically named 2003 UB313, circling the sun out beyond Pluto’s orbit. Questions of whether this thing constituted a real planet or just an especially reflective asteroid should have been put to bed last year when some folks at the Keck Lab in Hawaii discovered that the rock, codenamed ‘Xena,’ has a moon.
Who’s an asteroid now, tough guy
Some people weren’t satisfied. Maybe it’s a big asteroid with a really little asteroid spinning around it, they said. Nope (Nature, subscription wall. you know the drill):
The recently discovered ‘tenth planet’ of our Solar System is substantially larger than Pluto, astronomers have found.
For many, the discovery that object 2003 UB313 is about 3,000 kilometres across will remove any doubt that it deserves to be called a planet.
…When astronomer Mike Brown of the California Institute of Technology in Pasadena unveiled 2003 UB313 to the world in July 2005, his team was already confident that the new object was at least as large as Pluto, and deserved the status of ‘planet’.
But UB313’s elongated orbit takes it almost twice as far away from the Sun as Pluto ever gets, making it very difficult to measure its diameter precisely. One clue to its larger size came from the fact that it is slightly brighter than Pluto; a larger mirror would reflect more of the Sun’s light. But an alternative explanation could have been that UB313 is simply made of a more reflective material than Pluto.
Using the Institute for Millimetre Radio Astronomy (IRAM) 30-metre telescope in Spain, Bertoldi’s team has now studied the radiowaves coming from UB313, which reveal how much of the Sun’s rays are absorbed and re-radiated as heat. Because very little reflected sunlight is emitted at these wavelengths, the object’s brightness in radiowaves depends only on its size and surface temperature.
Based on its enormous distance from the Sun, UB313 is calculated to be tremendously cold: a staggering -248 °C. Bertoldi and his colleagues combined this value with their measurements of UB313’s radiation to determine its reflectivity and size.
Assuming they’re about the same density (they’re not, but bear with me), that puts Xena at about 2.3 times as massive as Pluto and one-75th as massive as our own blue rock. The International Astronomical Union (IAU) hasn’t thought up a proper name yet, so if you have any ideas you can either leave them here or drop them a line yourself.
Steve
But lots of things are bigger than Pluto. It’s like taking the stats of the worst player in the Hall of Fame and saying anyone with better stats is therefore a Hall of Famer.
I was under the impression that there isn’t necessarily a fixed standard for calling something a “planet,” but I was also under the pretty clear impression that the only reason Pluto is still considered a planet is tradition.
Pb
Planet X. Duh.
Alternatively, how about Hoth?
Anyhow, sorry CIT-Pasadena, but I’ll be damned if anyone named “Mike Brown” gets a planet named after them, and “Brownie” is right out. Nothing personal, at least, not directed at you guys.
DougJ
Bush is announcing that, planet or not, 2003 UB313 has just joined the coalition of the willing. They’ll be sending three tons of ice to Iraq.
DougJ
New Jack Planet.
kl
Considering its density and inability to sustain life, I propose we call it Cindysheehan.
Bruce Moomaw
I hope they name it Persephone — she got badly cheated back in 1978 when Pluto’s first (and major) moon was discovered. The discoverer intended to give it that name — especially poetically appropriate since the two worlds are tidally locked and eternally keep the same face toward each other — but, by extremely bad luck, his wife was named Charlene and so he decided to honor her by instead naming it “Charon”. Apart from being harder to decide on the pronunciation of it, this immediately led to confusion (continuing to this day) with “Chiron”, the first outer Solar System asteroidal object, which had been discovered just the year before and was a major find in itself.
As for whether or not Pluto is a “planet”, that debate, God help us, is still going on; the only thing more impressive than its durability is its absurdity. I wrote an article on it back in 1999 and stand by my opinion then: since the size borderline between “planet” and “nonplanet” is ultimately arbitrary, the best thing to do is set the cutoff at 2000 km diameter — thus allowing Pluto (which is only slightly bigger) to retain its long-time historical membership in the Planet Club without letting all sorts of tiny riffraff in.
Steve
Surely there must be more Roman gods out there to name planets after. I always wondered why, of all the gods they could have chosen from, they picked the easy joke-fodder “Uranus.”
What I actually found out the other day is that apparently Uranus, which was the first planet to be discovered in the modern era, was originally named after King George by the British astronomers who found it. But no one outside of England was willing to call it “The Georgian Planet” (seriously, that was the name!) so eventually Uranus became the standard. England was the last country to actually give in and accept Uranus as the name, though!
Nutcase
That’s definitely a debate just now. Is Pluto a really small planet, or a really big asteroid, or…?
Marcy and Butler have decided that, OK, Pluto gets to be a planet, but that’s as small as they come.
tzs
Lessee, are we going to keep ourselves to the Olympian gods or allow other Greek deities into the soup?
I like Persephone, though. Makes me hope we don’t find anything else out there; we’re sorta short on chthonic gods…
StupidityRules
Pluto shouldn’t be considered a planet nor should this one.
Clever
Cthulhu
That would be awesome. I can just imagine grade school science professors trying to say it, then trying to explain what the hell it is.
For those not in the know: http://en.wikipedia.org/wiki/Cthulhu
Bruce Moomaw
The trouble with just kicking both Pluto and this one out of the Planet Club is that there is an excellent chance that there are other objects out in the Kuiper Belt (or in the Oort Cloud, several trillion miles from the Sun, where we may never find them even if they DO exist) that are clearly intermediate in size between Pluto and 2003 UB 313 on the one hand, and Mercury — the smallest unquestioned planet — on the other. (In fact, there may be some undiscovered objects out there as big as Earth.) So if you throw Pluto and this New Guy out of the Planet Club on size grounds but still keep Mercury in, you’ve just set another totally arbitrary size cutoff — but at a different point that’s more historically confusing.
LITBMueller
Halliburton
Otto Man
Rusty Griswold: Hey, you got Pac Man?
Cousin Dale: No.
Rusty Griswold: Space Invaders?
Cousin Dale: Nope.
Rusty Griswold: You got Asteroids?
Cousin Dale: Naw, but my dad does. Can’t even sit on the toilet some days.
Paul Wartenberg
If it’s bigger than your SUV and has something slightly smaller orbiting it, it’s a planet. Okay? Argument solved.
My deal is, we’re kinda running out of Greco/Roman nomens for planets. Any chance we could start getting the Norse gods involved? Fenrir, the wolf of the final winter of Ragnorok. That’d be a good name for a cold world.
Joey
Yes.
“There isn’t enough life on this rock to fill a space cruiser.”
Pb
Paul,
Good call. Maybe Jotunheim would be a good name for a planet. :)
ACT
I nominate Urrectum!
StupidityRules
Then I’m guessing that neither of Mercury and Venus would be planets…
Anyway. Pluto is a Kuiper Belt Object.
Steve
If A, then B. Does it necessarily follow that if not-A, then not-B? Of course not.
StupidityRules
Since it was if A AND B then C.
If it had only been if A then C then every astroid between Mars and Jupiter bigger than a SUV would be a planet… And there’s a lot of them there that’s bigger than a SUV….
Anyway… I belong to the group of people who doesn’t count astroids nor kuiper belt objects as planets.
Joey
That still doesn’t disqualify A or B from being C by themselves, just that if they are together it is most definitely C.
Steve
If a woman is gay AND has no bisexual urges, then she’s not going to be attracted to me.
Does it therefore follow that every other woman in the world is attracted to me? If only.
Perry Como
Naming planets after pagan gods is an assault on Christianity. Why can’t it be called Moses? Or Abraham?
Joey
Heh, nice.
StupidityRules
Ok. True. It should have been stated: if and only if A and B then C.
But if it isn’t exclusive then this rule can’t be the only one to decide if something is a planet or not…
Anyway, lots of new planets… :)
StupidityRules
Also, most people won’t think of the difference between “If A and B then C” and “If and only if A and B then C”…
Joey
That’s because most people have poor logic skills.
demimondian
For non-planetary bodies, we’ve never required Roman names — at least one of the major Kuiper belt objects is named after a Mayan diety, for instance. (That, by the way, is what I expect to see happen — Kuiper belt objects of significant mass will we referred to as “major”, and we’ll simply be silent on whether they’re actually planets or not. After all, all the ones we’ve found are sufficiently anomalous — highly eccentric orbits, primary/satellite mass ratios of .89, etc — than we can say “whether or not they’re truly planets, they still deserve a sategory of their own.”)
Krista
Being a Galactica nut, I propose we name it Kobol.
demimondian
More Dungeons and Dragons references…
canuckistani
I think the only solution is to set the planetary threshold over the tens of thousands of KBO’s, but allow Pluto to keep its planetary status by some kind of grandfather clause. That means we don’t need to memorize thousands of obscure god names to help our kids with their science projects.
Joey
Also very good. Battlestar is far and away the best show on tv, sci-fi or not. Though I still like Hoth slightly more. It just fits with the freezing temps and everything.
Krista
How about Iset? (Norweigian for “icy”)
Steve
All of this will become irrelevant when the GOP rehabilitates Ptolemy’s geocentric theory.
Bruce Moomaw
Actually, they have started using non Greco-Roman mythology to name Saturn’s flock of newly discovered “irregular” satellites (tiny captured asteroids, some of which orbit the planet backwards). The only member of the flock known until a few years ago was Phoebe; but now there are about a dozen, and they’ve started using not only Norse mythology (one of them is named Ymir), but even Eskimo mythology.
And the moons of Uranus were always an exception — Herschel himself named the first two after the fairies in “A Midsummer Night’s Dream”; the next two in the mid- 19th century were named after a character in the “The Tempest” and another in Alexander Pope’s “The Rape of the Lock”; and so every Uranian moon since then has also been named after characters from those three Shakespeare and Pope fantasy plays or poems. Of course, those are going to run out VERY soon.
Caleb
Man,
I can’t believe no one has come up with the most obvious name for this new planet…….Goofey.
:-)
Caleb
Of course it would help if I had a spell check.
Make that…..Goofy.
Gary Farber
Blogged about Xena’s moon, Gabrielle, January 2nd.
Blogged about the size finding yesterday in a post with a bunch of other science-related stuff I thought interesting or amusing.
Gee, I read you guys more than once a day, usually, and link to you with some mild frequency. But I’m much more boring, I guess. Oh, well.
John Cole
I propose we call it Dobsonia, because it is fucking out there.
DougJ
There’s a big scandal brewing at NASA. Heck of a job, Brownie, part 2?
The Disenfranchised Voter
Speaking of being fucking out there…
I nominate we call the new planet, “Boner” the name of the new majority leader Johnny Boehner.
Seriously, the way his name is spelled, it should be pronounced “Boner”. From here out I will refer to him as Rep. Boner.
Krista
Very nice.
Or, we could call it Coulter, because it’s cold, loopy, and is nowhere near planet Earth.
Yakboy
I gotta go with Libitina, the goddess of the dead. Fitting for being way the heck out there, especially as Pluto (god of the underworld) is the next one in.