2003 EL61 has not roused your intellectual curiosity? What a shame.

You've never heard of 2003 VB12? Oh, dear, instead perhaps you know it as Sedna.

Surely 2003 UB313 has not slipped your attention? Oh!

You had better just tighten your Kuiper Belt and get on the program, then!


The International Astronomical Union's Minor Planet Center has been abuzz with the first two. However, it's been oddly silent about the latter: Conversely, NASA has announced it quite solidly.

Is light dawning?

These three sets of numbers and figures represent the descriptions of Minor Planets of our Sun (Sol). They join the 9 "major" planets in being known, significant satellites of the Sun. It's been said that Sedna and the last one mentioned are "the size of Pluto". Of course, if these lot are not a 'planet' then... is Pluto still considered a planet? And, yes, there has been that debate for a while.

You see, the "inner" 8 planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune) of the solar system are quite neatly aligned in the plane of the ecliptic; Pluto, though, "breaks the rules" of these other planets and: (1) has an orbit that crosses inside Neptune, and, (2) is on an orbital plane that is not aligned witht he ecliptic plane of the other planets.

I'd better explain another term, before I use it: AU. This is a distance... from the Earth to the Sun. The astronomical unit (AU or au or a.u.) is a unit of distance, approximately equal to the mean distance between Earth and Sun. The currently accepted value of the AU is 149,597,870,691 ± 30 metres (about 150 million kilometres or 93 million miles).

So, like many other Trans-Neptunian objects (TNOs), the recently discovered, highly-inclined orbit objects like 2003 EL61, 2003 VB12, and now 2003 UB313, that are not really part of what is described as the Kuiper Belt (an area of the solar system extending from within the orbit of Neptune (at 30 AU) to 50 AU from the sun, at inclinations consistent with the ecliptic.)

##NOTE: (X) There is an argument about the next bit.

Did you get that last bit. Kuiper Belt objects are (supposedly) in the plane of the ecliptic. (It's the place where asteroids come from.)

Yet, Pluto is not in that plane, and neither are 2003 EL61, 2003 VB12, and now 2003 UB313. So, are they planets (the 10th, 11th and 12th), minor planets (making Pluto a minor planet, too, even though it has a moon), or what.

Oh, I love cosmic controversy! It's so good for the mental juices. And, it makes such a change from working out strategies for ending things such as terrorism, the drought, and global warming.

(And, wasn't 2003 a good year for astronomers!)

[ From Note (X), by an amateur astronomer:

> Coalescence into planets results from collisions which not only increase the size of the body, bit also push the orbit into the ecliptic plane.

> The argument about the three newly discovered bodies, as well as Pluto, is that they are Kuiper Belt Objects, not planets. ]

So, you see, it's no wonder I'm at a loss as to whether there's a story, here.

_____
Peter