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2003 Ub 313: The Incredible Shrinking Planet?, No bigger than Pluto?
Guest_BruceMoomaw_*
post Jan 31 2006, 09:20 PM
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(Thanks to Emily Lakdawalla):

http://sciencenow.sciencemag.org/cgi/content/full/2006/127/1
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Guest_BruceMoomaw_*
post Apr 12 2006, 12:09 AM
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Robert Roy Britt, in his blog on this subject ( http://www.livescience.com/blogs/author/robbritt ), positively DEMANDS that both Pluto and 2003 UB 313 not be called "planets" yet, unless the IAU gives us permission to do so. Who died and made YOU King of the Solar System, Robert?
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Stephen
post Apr 12 2006, 03:37 AM
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QUOTE (BruceMoomaw @ Apr 12 2006, 12:09 AM) *
Robert Roy Britt, in his blog on this subject ( http://www.livescience.com/blogs/author/robbritt ), positively DEMANDS that both Pluto and 2003 UB 313 not be called "planets" yet, unless the IAU gives us permission to do so. Who died and made YOU King of the Solar System, Robert?

Well, to be fair he is trying to make a legitimate point:
"Objects like Pluto and 2003 UB313 should be called minor planets or dwarf planets or something else that denotes their relative insignificance compared to the four inner terrestrial planets and the four outer giants. And therein lies the precedent: We already have terrestrials and giants. Just add dwarfs."

That sounds like the very solution astronomers used to resolve the pesky problem of Ceres and the asteroids (aka "minor planets") back in the 1800s.

Unfortunately, given we already do have a class of astronomical bodies dubbed "minor planets" you have wonder whether it would be wise to either extend that name to Kuiper Belt objects or invent a special term ("dwarf planets") for KB objects that could well end up be confused for the other one.

In particular, I notice astronomers themselves seem to be at pains to avoid using the word "asteroid" for KB objects. Yet if they did start using "minor planet" as a label for such objects, or a name which could well be confused with it (eg "dwarf planets"), then the existing association in many people's minds between "minor planets" and "asteroids" may well eventually lead to the "asteroid" label being applied to KB objects also, even if only by lay folk.

***

One further point on the more general issue of "is it/is it not a planet?"

The whole debate seems to depend not on the nature of the object but on its size. Yet in a sense it is not just size that seems to matter either. It is arguably as much about numbers. So long as there was only one body in the asteroid belt or out in the Kuiper Belt nobody--including astronomers--seemed to much mind calling both "planets". It was only when asteroids and Kuiper Belt objects started to proliferate like rabbits that astronomers started getting cold feet about the term.

Yet curiously this need to distinguish Pluto and Ceres from planets does not apply to two other general terms: stars and moons.

There are red supergiants out there and there are red dwarfs, but at the end of the day they are all termed "stars". (Only with "brown dwarf" does there seems to be a reluctance to use the word; and then it's arguably because of their nature: brown dwarfs are seen as failed stars.)

So too with "moon". While we sometimes hear the term "moonlet" bandied about, nobody seems to be (yet) suggesting we reserve that prestigious term "moon" for the larger objects circling planets and use some other label ("minor moons"? "dwarf moons"? "lunar objects"? "orbital rubble"?) for the riff-raff. (Although maybe astronomers are holding fire on that debate until Cassini or some successor probe actually images a few of the house-size "moons" in Saturn's rings.)

That raises the question of whether this present "is it/is it not a planet" debate--as well as the one back in the 1800s--doesn't involve more than modicum of--er--snobbery. Or to phrase the issue another way, I cannot help feeling the only reason this debate has arisen at all with "planet" is because Earth just so happens to bear the label "planet"; and despite all that has come and gone there is still a subconscious wish, even amongst some astronomers, for Earth to be part of a group with a certain degree of--shall we say--exclusivity.

Meaning that if Earth had been a moon rather than a planet would we now be arguing over whether to admit Janus to the hallowed ranks whilst not giving two hoots about using "planet" for Pluto and Ceres?

Thus, it is all right for Jupiter to be called a "planet". That then puts Earth among the giants. smile.gif We are even prepared to tolerate midgets like Ceres and Pluto being one--so long as there was only just one of each. Once there start to be too many of such small fry the feeling seems to be that the term "planet" is losing its currency. Hence, while nobody seems to mind labelling Janus or Miranda "moons" were they orbiting the Sun rather than Saturn & Uranus nobody would be calling them "planets". Similarly with Pluto or (say) Ida. Were Pluto or Ida in orbit around a planet astronomers would be quite happy to label both of them "moons". Only when they start circling the Sun does size suddenly become an issue.

======
Stephen
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Posts in this topic
- BruceMoomaw   2003 Ub 313: The Incredible Shrinking Planet?   Jan 31 2006, 09:20 PM
- - elakdawalla   QUOTE (BruceMoomaw @ Jan 31 2006, 01:20 PM)(T...   Jan 31 2006, 09:36 PM
|- - SFJCody   QUOTE (elakdawalla @ Jan 31 2006, 09:36 PM)Ac...   Feb 1 2006, 12:19 AM
||- - Rob Pinnegar   QUOTE (SFJCody @ Jan 31 2006, 06:19 PM)There...   Feb 1 2006, 02:12 AM
|- - AlexBlackwell   QUOTE (elakdawalla @ Jan 31 2006, 09:36 PM)Si...   Feb 1 2006, 05:48 PM
|- - JRehling   Incidentally, don't forget that Pluto "sh...   Feb 1 2006, 07:17 PM
|- - TritonAntares   QUOTE (JRehling @ Feb 1 2006, 09:17 PM)Incide...   Feb 2 2006, 12:27 PM
|- - Rob Pinnegar   QUOTE (TritonAntares @ Feb 2 2006, 06:27 AM)A...   Feb 3 2006, 07:18 PM
||- - ljk4-1   For what this is worth, Sky & Telescope is now...   Feb 10 2006, 04:52 PM
|- - angel1801   QUOTE (TritonAntares @ Feb 2 2006, 09:57 ...   Apr 12 2006, 02:01 PM
|- - Planet X   QUOTE (angel1801 @ Apr 12 2006, 09:01 AM)...   Apr 12 2006, 04:48 PM
- - MichaelT   I just read that the Max-Planck-Institute for Radi...   Feb 1 2006, 10:32 AM
- - SigurRosFan   Here's the detailed press release: - http://w...   Feb 1 2006, 01:19 PM
|- - David   QUOTE (SigurRosFan @ Feb 1 2006, 01:19 PM)Her...   Feb 1 2006, 01:34 PM
|- - Rob Pinnegar   QUOTE (SigurRosFan @ Feb 1 2006, 07:19 AM)A j...   Feb 1 2006, 02:46 PM
- - Big_Gazza   I have heard a rumour that one of the Mormons secr...   Feb 3 2006, 11:01 AM
|- - Bob Shaw   QUOTE (Big_Gazza @ Feb 3 2006, 12:01 PM)I hav...   Feb 3 2006, 01:24 PM
||- - AndyG   QUOTE (Bob Shaw @ Feb 3 2006, 01:24 PM)Do you...   Feb 3 2006, 03:35 PM
|- - JRehling   QUOTE (Big_Gazza @ Feb 3 2006, 03:01 AM)I hav...   Feb 10 2006, 05:50 PM
||- - punkboi   QUOTE (JRehling @ Feb 10 2006, 10:50 AM)http:...   Feb 10 2006, 05:54 PM
||- - Katie   QUOTE (JRehling @ Feb 10 2006, 10:50 AM)http:...   Feb 11 2006, 08:30 AM
||- - ljk4-1   I like the idea that when you die you get to evolv...   Feb 11 2006, 07:12 PM
||- - ljk4-1   Looks a lot like Europa! UB 313: Larger t...   Feb 11 2006, 09:53 PM
|||- - David   QUOTE (ljk4-1 @ Feb 11 2006, 09:53 P...   Feb 12 2006, 03:48 PM
||- - tty   QUOTE (ljk4-1 @ Feb 11 2006, 08:12 P...   Feb 12 2006, 07:31 PM
|- - Katie   QUOTE (Big_Gazza @ Feb 3 2006, 03:01 AM) ...   Feb 13 2006, 04:06 AM
|- - ljk4-1   QUOTE (Katie @ Feb 12 2006, 11:06 PM) Bei...   Feb 13 2006, 04:55 AM
|- - Bob Shaw   QUOTE (ljk4-1 @ Feb 13 2006, 04:55 A...   Feb 13 2006, 12:05 PM
- - BruceMoomaw   QUOTE (Big_Gazza @ Feb 3 2006, 11:01 AM)I hav...   Feb 11 2006, 08:56 AM
- - BruceMoomaw   If they declare Pluto a planet but 2003 UB313 a no...   Feb 12 2006, 06:08 AM
- - BruceMoomaw   Actually, it's kind of flattering that the Gre...   Feb 13 2006, 11:37 PM
|- - Bob Shaw   QUOTE (BruceMoomaw @ Feb 13 2006, 11:37 P...   Feb 14 2006, 08:57 AM
- - edstrick   "I can't believe I ate the ***WHOLE*** TH...   Feb 14 2006, 10:41 AM
- - dvandorn   Personally, I'd be more worried about your stu...   Feb 14 2006, 03:34 PM
- - BruceMoomaw   QUOTE (Bob Shaw @ Feb 14 2006, 08:57 AM) ...   Feb 14 2006, 10:07 PM
|- - SFJCody   Brown to discuss 'Xena' discovery http://...   Feb 19 2006, 12:34 PM
|- - SFJCody   Amateurs spot 10th planet http://www.spaceflightno...   Feb 21 2006, 10:22 AM
|- - SFJCody   The IAU will publish beginning of September 2006 t...   Mar 4 2006, 10:27 AM
- - BruceMoomaw   Dear God, I hope they don't decide that Pluto ...   Mar 4 2006, 10:48 PM
|- - Bob Shaw   QUOTE (BruceMoomaw @ Mar 4 2006, 10:48 PM...   Mar 4 2006, 10:58 PM
|- - SFJCody   No news for a while, which is kind of a shame. I h...   Mar 19 2006, 10:42 PM
- - Rob Pinnegar   Well, it's only been a month or so since the l...   Mar 20 2006, 05:09 PM
|- - SFJCody   UPDATE! http://www.gps.caltech.edu/~mbrown/pl...   Apr 11 2006, 05:45 PM
- - ljk4-1   FOR RELEASE: 1:00 pm (EDT) April 11, 2006 Erica ...   Apr 11 2006, 06:08 PM
- - BruceMoomaw   Robert Roy Britt, in his blog on this subject ( ht...   Apr 12 2006, 12:09 AM
|- - Bob Shaw   QUOTE (BruceMoomaw @ Apr 12 2006, 01:09 A...   Apr 12 2006, 12:31 AM
|- - David   QUOTE (BruceMoomaw @ Apr 12 2006, 12:09 A...   Apr 12 2006, 01:22 AM
|- - Stephen   QUOTE (BruceMoomaw @ Apr 12 2006, 12:09 A...   Apr 12 2006, 03:37 AM
- - nprev   The IAU & everyone else has to face up to one ...   Apr 12 2006, 03:41 AM
|- - Stephen   QUOTE (nprev @ Apr 12 2006, 03:41 AM) Wel...   Apr 12 2006, 04:45 AM
|- - David   QUOTE (nprev @ Apr 12 2006, 03:41 AM) The...   Apr 12 2006, 08:28 AM
|- - AndyG   QUOTE (nprev @ Apr 12 2006, 04:41 AM) Def...   Apr 12 2006, 01:46 PM
- - BruceMoomaw   I remain convinced of what I said in 1999: if you ...   Apr 12 2006, 04:51 AM
- - Betelgeuze   QUOTE The problem is that it's easy to say tha...   Apr 12 2006, 05:15 AM
|- - Jyril   PSR 1257+12 B and C are a few times more massive t...   Apr 12 2006, 05:45 AM
|- - Stephen   QUOTE (Jyril @ Apr 12 2006, 05:45 AM) PSR...   Apr 12 2006, 06:05 AM
|- - Jyril   It's the mass that dominates. Even the least m...   Apr 12 2006, 08:16 AM
|- - tedstryk   QUOTE (Stephen @ Apr 12 2006, 06:05 AM) I...   Apr 14 2006, 04:28 AM
|- - BruceMoomaw   QUOTE (tedstryk @ Apr 14 2006, 04:28 AM) ...   Apr 14 2006, 07:21 PM
|- - David   QUOTE (BruceMoomaw @ Apr 14 2006, 07:21 P...   Apr 14 2006, 08:18 PM
|- - BruceMoomaw   QUOTE (David @ Apr 14 2006, 08:18 PM) But...   Apr 17 2006, 06:45 PM
|- - David   QUOTE (BruceMoomaw @ Apr 17 2006, 06:45 P...   Apr 17 2006, 07:17 PM
|- - JRehling   As if this issue hadn't already been faced on ...   Apr 17 2006, 07:59 PM
|- - The Messenger   QUOTE (JRehling @ Apr 17 2006, 01:59 PM) ...   Apr 17 2006, 08:45 PM
- - edstrick   ....it was good enough for Zaljyx, and it's go...   Apr 12 2006, 09:31 AM
|- - David   QUOTE (edstrick @ Apr 12 2006, 09:31 AM) ...   Apr 13 2006, 07:46 PM
- - Decepticon   Here is a image comparison... http://www.nasa.gov/...   Apr 12 2006, 01:24 PM
- - JamesFox   When I read that blog by Robert Roy Britt, I notic...   Apr 12 2006, 01:37 PM
- - ljk4-1   Astrophysics, abstract astro-ph/0604245 From: Mi...   Apr 12 2006, 06:08 PM
- - ljk4-1   Tenth planet as bright as fresh snow It is only s...   Apr 12 2006, 09:37 PM
- - edstrick   "Don't care what the latest rage is...Gim...   Apr 14 2006, 09:50 AM
|- - Bob Shaw   QUOTE (edstrick @ Apr 14 2006, 10:50 AM) ...   Apr 14 2006, 11:51 AM
- - Planet X   I came up with a unique definition according to ma...   Apr 14 2006, 09:08 PM
- - SigurRosFan   Interesting comment: - Comment on the recent Hubb...   Apr 17 2006, 04:52 PM
|- - SFJCody   Brown et al make more measurements with Keck. http...   Apr 17 2006, 06:17 PM
- - dvandorn   Well -- for scientific purposes, it would be far m...   Apr 17 2006, 08:47 PM
- - BruceMoomaw   Size makes more sense than discovery date, by any ...   Apr 17 2006, 09:59 PM
|- - Stephen   QUOTE (BruceMoomaw @ Apr 17 2006, 09:59 P...   Apr 18 2006, 04:15 AM
- - JamesFox   When it comes to 2003 EL61, it's odd shape is ...   Apr 18 2006, 01:56 AM
- - BruceMoomaw   Well, you've got to set the goalposts at SOME ...   Apr 18 2006, 06:40 AM
|- - AndyG   QUOTE (BruceMoomaw @ Apr 18 2006, 07:40 A...   Apr 18 2006, 09:08 AM
|- - ugordan   QUOTE (AndyG @ Apr 18 2006, 10:08 AM) ...   Apr 18 2006, 09:21 AM
|- - David   QUOTE (AndyG @ Apr 18 2006, 09:08 AM) Why...   Apr 19 2006, 08:31 PM
- - edstrick   Also... at all 4 giant planets, there is a clear d...   Apr 18 2006, 10:23 AM
- - edstrick   The arm-waving idea I've posted here before is...   Apr 20 2006, 09:36 AM
- - ljk4-1   Though it is not online, the July 24, 2006 issue o...   Jul 21 2006, 02:40 PM


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