QueXtion for Kol...

[Billyman]

What makes a moon....a moon?

This is the reason for my question. (http://robots.cnn.com/2001/TECH/space/12/29/nixed.moon.ap/index.html)

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"I am enough of an artist to draw freely upon my imagination. Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world."
--Albert Einstein

[skalie]

<IMG SRC="http://www.keith-moon.com/keithmoon.jpg" border=0>

[Koliedrus]

Good quextion. In this case, it seems to be a matter of confirming that the observed object is still in orbit (or ever was). Might it be possible that the object in question just happened to be passing through during those observations?

A moon, in my opinion, is a celestial body of natural origin and significant mass which primarily orbits a planet. Defining a "planet" has also proven to be more difficult than it once was. Brown dwarfs are larger than Jupiter but too small to be classified as true stars. What do you call the objects orbitting them? Are they moons or planets?

Recently it's also come to light that planet-sized objects travel through the galaxy without a parent star. Perhaps they've been ejected from a stellar system because of some cataclysmic gravitational event. No matter their origin, a companion body with a regular orbit around them and significantly smaller mass could be considered a "moon". It's highly unlikely that these orphan planets would take their original moons with them as they are thrown headlong out of their parent systems so any moons that they might have would most likely have fallen into orbit as the planet passed through a field of interstellar debris.

I've been known to be wrong, though.

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May fortune favor the foolish.

[Smug Git]

Charon is not that much smaller than Pluto, and is called a moon of Pluto.

I think that it is just a word of convenience.

Sometimes people talk of 'moonlets' too.

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If you find out what happened yesterday
While you were away in this land of Cain
We were upstairs in the bedroom, dancing, disgusting
And flushing our babies down the drain