[X] My Assistant

[Guest_Kevin Heider_*]

I had assumed that 1 Ceres was still considered an Asteroid since it orbits in the asteroid belt and has the same origin as the other asteroids.

But I noticed that on wikipedia they say: "Ceres is a 'dwarf planet', and may no longer be classified as an asteroid."

Wikipedia cites the IAU website at http://www.iau2006.org/mirror/www.iau.org/...u0603_Q_A2.html that states:
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Q: What is Ceres?

A: Ceres is (or now we can say it was) the largest asteroid, about 1000 km across, orbiting in the asteroid belt between Mars and Jupiter. Ceres now qualifies as a dwarf planet because it is now known to be large enough (massive enough) to have self-gravity pulling itself into a nearly round shape. [Published reference for shape of Ceres: P. Thomas et al. (2005), Nature 437, 224-227. Dr. Peter Thomas is at Cornell University.] Ceres orbits within the asteroid belt and is an example of a case of an object that does not orbit in a clear path. There are many other asteroids that can cross the orbital path of Ceres.

Q: Didn’t Ceres used to be called an asteroid or minor planet?

A: Historically, Ceres was called a “planet” when it was first discovered (in 1801) orbiting in what is known as the asteroid belt between Mars and Jupiter. Because 19 th century astronomers could not resolve the size and shape of Ceres, and because numerous other bodies were discovered in the same region, Ceres lost its planetary status. For more than a century, Ceres has been referred to as an asteroid or minor planet.
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Is Ceres still classified as an asteroid since it is located in the asteroid belt? Pluto is a Kuiper Belt Object (KBO) even though it is also a 'dwarf planet'.

Has Pallas become the 1st asteroid discovered? Has Vesta become the largest asteroid (at least until the IAU decides that since Vesta is a damaged, differentiated protoplanet that it was probably spherical in the past)? *IF* Ceres is truely no longer an asteroid, because it is spherical, then those two very basic questions have new answers!

How do we contact the IAU for an official statement on the classification of Ceres as an asteroid?

-- Kevin Heider

[Mariner9]

As an aside, I've found a useful comeback for the next time one of your friends or colleagues asks "Why can't those darn people define what a 'planet' is? I should think it should be clear by now!"

Just give them a terrestial example, like I did to a friend. "Well, a pebble, a boulder, and a mountain are all basically made out of the same thing... why do they have different words for them?"

If that doesn't stop them in their tracks, keep going with "And by the way, when does a pile of dirt and rock go from being a pile to a mound, and then into a hill? And exactly what is the difference between a hill and a mountain anyway? And don't try to tell me mountains have rocky tops, have you taken a good look in New England lately? And why is there a mountain range called the Blue Hills?"

So far I haven't had to go much past "pebble, boulder and mountain'

[Stephen]

If that doesn't stop them in their tracks, keep going with "And by the way, when does a pile of dirt and rock go from being a pile to a mound, and then into a hill? And exactly what is the difference between a hill and a mountain anyway? And don't try to tell me mountains have rocky tops, have you taken a good look in New England lately? And why is there a mountain range called the Blue Hills?"

When I did geography in high school--a discipline, BTW, which has apparently been abolished from school curricula, at least in Australia--the term "mountain" had a formal definition: it was a peak 3000 feet or over. Anything under that was a mere hill.

But that was the geographers' definition. Most other people knew nothing about such technicalities--or if they did (eg the cartographers responsible for drawing the maps with all those "Mount X's" sprinkled across them) they happily ignored them--and had been happily applying the words "mount"and "mountain" (not to mention combinations like "mountain range") to heights well under 3000 feet.

Frankly I intend to apply the same principle to "planet": I shall ignore the edicts of the IAU and continue to use the word "planet" rather than "dwarf planet" for Pluto. IAU members may feel themselves under some kind of obligation to adhere, but AFAIK the IAU does not have copyright or trademark control of the word so that means the rest of us are free to do as we see fit. If the Academie Francaise cannot stop the French public using Franglais I'd like to see the IAU stop English-speakers using the word "planet" for Pluto.

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Stephen