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Originally posted by mika
No offense, but I felt like answering a challenging Trivial Pursuit question only to find out that the company who made that question didn't know the correct answer themselves.
http://www.astro.queensu.ca/~wiegert/3753/faq.html
The question itself (about that asteroid) was interesting, though 
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Dude, you're criticizing me, and patting me on the back at the same time.
When I made the post, I read that this moon was categorized as a moon. Is it now? According to your article... no. Take a look at this:
http://www.space.com/scienceastronom...on_991029.html
To quote a bit of this:
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"Eventually these same channels provide the moons with escape routes. So the main difference between the moon (we?ve always known) and ?the new moons? is that the latter are temporary -- they come and go, but they stay for a very long time before they leave."
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Quote:
"A moon typically is defined as an object whose orbit encompasses a planet, say, the Earth, rather than the sun, said Carl Murray, who worked with Namouni and Christou on the research.
But it?s hard to say what a "true" moon is, he said.
In his view, there are three classes of moons ? large moons in near-circular orbits around a planet, having formed soon after the planet; smaller fragments that are the products of collisions; and outer, irregular moons in odd orbits, or captured asteroids like Cruithne. In the past year, astronomers have reported finding such objects around Uranus."
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Quote:
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"At some stage you have to consider the definition of ?moon,?" he said. "Is a dust particle orbiting the Earth a ?moon? of the Earth?"
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- very interesting because, as I said before, there is no minimal size of a satellite.
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"As for Cruithne, Namouni said it?s not really a "moon" because it moves around the Earth at this time but may not forever. Earth is causing Cruithne?s present trajectory, but it could eventually escape.
So it?s not a moon of Earth, but it might become one."
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It appears that they have to define "moon" more precisely than just "a natural satellite that orbits the earth. I guess this is ok; what they really have to define is "orbit"... if he object does not appear to "orbit" the planet, then it cannot be a moon. This object does not appear to, so it is not a moon. The Moon appears to, so it is a moon. The problem lies in that the gravity of all objects effect all others, so when does a 3 mass system (such as the Sun, Earth, and Moon) make a planet-moon system going around the sun, and when does it be just 2 objects orbiting the Sun (which appears to be the case with the Sun, Moon, and Cruithne.
And dude... I could not possibly know the "correct answer" if the party who defines the answer changes their mind.
Nevertheless, this is an interesting thing that not many people knew about... so I thought I'd bring it up. There is nothing wrong with enlightening some people with some information that they knew nothing about which is so close to home (astronomically, anyway).
Btw, isn't this cool:
Showing a camera view in which the Earth and Sun remain fixed, it shows the moon. Notice that it flies around the Lagrange points of the Sun-Earth system... it would be impossible to categorize this 'moon' as a simple orbit around the Sun by itself when it is so tied to Earth's orbit (just as the many Trojan Asteroids orbit in the Lagrange points around Jupiter).
Definition:
Lagrange points: Lagrange Points mark positions where the gravitational pull of the two large masses precisely cancels the centripetal acceleration required to rotate with them.
http://www.physics.montana.edu/facul.../lagrange.html