[X] My Assistant

[odave]

In a name discussion over on Usenet's rec.arts.sf.written, a poster dug up this article on the Beeb's website, published just after Sedna's discovery:

Announcing the name Sedna, Dr Mike Brown, leader of the research team, said: "We knew it could end up being the coldest, most distant object in the entire Solar System.

  Early one day we decided it was appropriate to name any objects out of this region after Arctic mythology" 

I'm not well versed on Arctic mythology - anyone else?

I'd prefer Persephone myself...

[JRehling]

One thing I find terribly sad about the intersection of public education and the "what is a planet" debate is that no definition of "planet" is likely to include fascinating worlds like Io, Enceladus, or Miranda.

A pop science book I bought around 1981 came out and called the Galileans and Titan planets, although that author's notion did not become convention. Although the label "Lunar and Planetary Science" implicitly includes Phobos and Charon and Halley's Comet as "planetARY"... although oddly enough, the Moon is different enough that it needs its own half of the label!

Kids are taught about Pluto -- a place we've never been to -- but not about Titan, a world that's bigger and much more dynamic than either Pluto or Mercury.  In my book, "planets" are things that wander across the sky; "worlds" are places that we can (or have, or will) go to visit.

Sometimes tiny rocks like Tempel 1 and Eros get promoted to "world" status, and that's all right as far as I'm concerned.  Explain to a fifth grader (or even a second grader) that if they jumped off the ground on one of those worlds, they'd fly off into space -- they think that's pretty cool.  Especially if you jump up and down while you're explaining it to them.  (You can invite them to jump up and down, too, but then you have to get them to stop!)

Categories are powerful things -- people are surprised to learn that Reno is west of San Diego, and that Windsor, Canada is south of Detroit -- when the parent categories stand in one relation to one another, people assume that the members must all hold that relation to (CA west of NV; Canada north of USA). So, people assume that Mercury is more worth knowing about than Titan (and maybe it is -- that's debatable).

The analogy that I think of (maybe not the best for fifth graders) is of evidence at a crime scene. You want to understand the crime -- the best clues are not necessarily going to come from the largest objects in the room, or even the largest objects related to the crime. The killer's fingerprints (very small) may be more useful than his/her bootprints. A tiny drop of blood may be of more use than a discarded hat. In the same way, the isotopes of argon on Venus may tell us more about the origin of the solar system than do the bands in the clouds of Jupiter. And certainly some of the more exciting places in the solar system are smaller -- in fact, I don't know any solar system aficionados whose favorite world is the Sun -- and it's almost 1000 times more massive than everything else put together.

It's a pretty good bet that the largest US county doesn't have as much to see as Manhattan -- this could be an easy point to get across if you get past the "memorize the names of the nine planets" starting point. Maybe the best thing that can happen is that so many new planets are discovered that it becomes futile to learn their names and the rule of thumb becomes "Most planets are cold, barren iceballs; let's learn about the more interesting worlds."

That said, although the exciting worlds are usually the unique ones (Io, Europa, Titan) -- there's a lot to learn from comparing almost-alike pairs and sets of worlds, and the icy midsized moons plus the uranian satellites make a fascinating study on planetary evolution even though most of them are less than spectacular individually. The most interesting thing about Pluto -- and now Planet 10 -- may be comparing them to each other.

[SFJCody]

The 2003 UB313 discovery page now includes this:

"Though we tried earlier to measure the size using Spitzer, those observations failed due to a technical glitch. We are trying again! The new data will be down by the end of the month."

[Guest_Sunspot_*]

The 2003 UB313 discovery page now includes this:

"Though we tried earlier to measure the size using Spitzer, those observations failed due to a technical glitch. We are trying again! The new data will be down by the end of the month."

Didn't they base their size estmates on the fact that Spitzer was unable to detect it?

[odave]

Yes, but as I understand it, the lack of a Spitzer observation sets the upper estimate only.

The lower estimate was set by assuming 100% albedo, it would be about the same size as Pluto.

So if Sptizer does see it now, it may be even bigger than the original upper estimate...

[SFJCody]

Short IAU statement:

http://www.iau.org/IAU/FAQ/2003_UB313.html

Spitzer observation schedule for the last week of August (not yet up):

http://ssc.spitzer.caltech.edu/approvdprog...lan/week092.txt

HST proposal:

http://www.stsci.edu/cgi-bin/get-proposal-info?10545

[Jyril]

So to be consistent, shouldn't we say that the person who discovered Neptune was the person who first hypothesized its existence based on the perturbations of Uranus' orbit?  The actual visual sighting of Neptune was only the "confirmation" of its existence, using today's logic.

Depends what you mean by hypothesizing. Because Neptune was discovered near the position it was expected to be according to LeVerrier, he deserves the discovery credit. One would say that he discovered it by its gravity. Those who claimed that there should be additional giant planets (Lowell, Pickering et al.) don't deserve the credit even if one was found, because they did not make accurate/correct predictions.

[Guest_BruceMoomaw_*]

The observation that Neptune was discovered because people were trying to explain the disturbances in Uranus' orbit also brings to mind a debate we should have on what it means to "discover" a planet.  We have 100+ extrasolar planets that have been "discovered" but never observed directly.  Most of these "discoveries" are based solely on the inferred presence, size, and motion of an object based entirely on its effects on its parent star.  So to be consistent, shouldn't we say that the person who discovered Neptune was the person who first hypothesized its existence based on the perturbations of Uranus' orbit?  The actual visual sighting of Neptune was only the "confirmation" of its existence, using today's logic.

Nope. In the case of Uranus' subtle, slow orbital perturbations, they might well (like Mercury's) have been due to flaws in Newton's theory rather than to a new planet. In the case, of the extrasolar planets, however, we're seeing some stars do a persistent, circular jig while others do not -- and the only remotely plausible reason for that is that they are being orbited by large planets.

[Guest_BruceMoomaw_*]

Personally, as a kid I would have been far more interested to learn that the number of planets was really indeterminate, and dependent upon definition, than that it was a boring old nine. And, as John says, it's not the size of your world; it's how interesting it is.

[Jyril]

So if Sptizer does see it now, it may be even bigger than the original upper estimate...

That's right. Still, it seems to have Pluto-like surface (although it's not reddish like Pluto), so it may have relatively high albedo like the other two new giant KBOs.

[dvandorn]

OK -- here's a gedankenexperiment.

You have God's Magic Eight-Ball. You can only ask it the following question: "How many planets does this particular star have?" It can only give you a number back.

What answer is more helpful to you -- four, 12, or 33,117?

A classification system that is *too* inclusive makes it less useful.

-the other Doug

[SFJCody]

More information on the possible name:

http://www.sacbee.com/content/news/science...-14199188c.html

"We always use silly names," he said. There are two other objects he's been studying that are called Santa and Easter Bunny. When Santa was discovered to have a satellite, the scientists called it Rudolph, of course.

When it came to Xena, Brown said he liked the idea of another female planet in the solar system. "Only Venus is a female," he noted."

Perhaps this will carry through to the official name...

[TheChemist]

deleted double post apologies ...

[TheChemist]

Xena is female ?

[Jeff7]

Kids are taught about Pluto -- a place we've never been to -- but not about Titan, a world that's bigger and much more dynamic than either Pluto or Mercury.  In my book, "planets" are things that wander across the sky; "worlds" are places that we can (or have, or will) go to visit.

Unless you happened to know a lot about the planets when you were young. In 4th grade, the teacher exempted me from the platetary lessons, because she said I knew more about the planets than she did. I could tell you the orbital times of most planets, how many moons they had, and the names of some of the larger moons. I knew all of the Galilean Satellites, and of course, Titan. Miranda, Triton, Charon....fun times.