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we are not alone
2011-Oct-09, 08:51 AM
UT Scientist Searches for Moons Around Asteroids (http://www.spacedaily.com/reports/UT_Scientist_Searches_for_Moons_Around_Asteroids_9 99.html)

According to Josh Emery about 20% of asteroids have moons. Ironic really as many planetary moons are captured asteroids.

Paul Beardsley
2011-Oct-09, 10:39 AM
Interesting, but not ironic.

we are not alone
2011-Oct-11, 01:26 AM
Its hard to know what any celestial bodies are nowadays the way they keep renaming them. Pluto is no longer a planet so what do we call its moons? Still moons I guess if asteroids have them too. If I recall the definition correctly. A moon is a body that orbits another body orbiting a sun right.

Cobra1597
2011-Oct-11, 05:29 AM
Its hard to know what any celestial bodies are nowadays the way they keep renaming them. Pluto is no longer a planet so what do we call its moons? Still moons I guess if asteroids have them too. If I recall the definition correctly. A moon is a body that orbits another body orbiting a sun right.
First, get rid of the notion that what we call something in any way changes that something. It is not hard to know what a celestial body is "nowadays" because what we call them has no change at all on what they are. The physical properties of the object "Pluto" did not in any way change when we stopped calling it a planet. Pluto, as an object in the Kuiper Belt, doesn't care whether we call it a planet or a dwarf or a comet or an ice cream sunday. Its orbit doesn't change when we call it something else, its mass doesn't change, its albedo doesn't change. To quote Shakespeare, "A rose by any other name would smell as sweet."

Second, the term you are looking for when you say "moon" is "natural satellite," and its definition doesn't care what it is orbiting. There's nothing in the definition preventing the moons (or natural satellites) around other planets from having their own natural satellites, and there is nothing preventing an asteroid from having natural satellites.

Gsquare
2011-Oct-11, 12:24 PM
UT Scientist Searches for Moons Around Asteroids (http://www.spacedaily.com/reports/UT_Scientist_Searches_for_Moons_Around_Asteroids_9 99.html)

According to Josh Emery about 20% of asteroids have moons. Ironic really as many planetary moons are captured asteroids.

I don't think the article mentioned it, but the good thing about moons is that it allows us to determine the mass of the asteroid (or planet).

G^2