Two New Saturnian Moons

Mixel writes "NASA's Cassini spacecraft, which has been orbiting saturn since the 30th of June has uncovered two previously unknown bodies. 'The moons are approximately 3 kilometers (2 miles) and 4 kilometers (2.5 miles) across -- smaller than the city of Boulder, Colorado.' The Huygens probe will be deployed to the large (bigger than Mercury!) yet mysterious moon, Titan, in December."

Comments

hurm

[ErikZ]

I'd say it's a moon when it's big enough to exert enough gravity to walk on, without worrying about being flung out into space.

Re:hurm

[Capt'n Hector]

You might, but then you're being human-centric. Our definition of moon shouldn't depend on our size/weight. I'd say that if two or more bodies are obriting around each other, which in turn are orbiting around a stellar body, then the largest one is a planet, and the smaller one(s) is/are a moon.

All of these objects must have a spherical shape, ie enough mass to have collapsed into a planetoid configuration.

Using this defintion, I would call mars's "moons" "captured astroids" or "natural satellites", since they fail a spherical test. Similarly, I would call Pluto/Charon a planet/moon system, because both a spherical, even though they don't really lie in the stellar plane.

Re:Are they really moons?

[servognome]

Moons orbit planets, asteroids orbit the sun.
There does need to be some cutoff at where something is considered a moon and where its just a rock going around a planet, otherwise all the stuff in Saturn's ring could be considered moons... hmm maybe I could name one "Servognome" and request a goverment grant of $50,000 to study the rock^H^H^H^H moon.
I think all this classification stuff probably has to do with how scientists can get more grant money. Kinda how there are 6 great lakes

What are 'moonies' composed of though?

[Joe 'Nova']

I know Io, Jupiters moon, gets tugged until molten. So, what are the rings/dust/moonies made of? If they are the same materials as Io, what keeps Io from becoming a ring?
I don't think gravity tugs would do it alone. An impact with a comet into a good sized moon, now pulverized, would do it. So, the rings would be a mix of the comet/moon, probably very different. It would be neat to get more info. If ring could be sampled, bringing back two types of chunks, would argue strongly for impact. It would be a cheap way of sampling a comet?
Also, the density of the rings would make ideal for mining? I know asteroid belt is out there, but would it be worth processing one rock instead of attacting alot of iron fragments with a magnet, with the plus of having a methane atmosphere for fuel a short trip away. Atmosphere skip/collect methane+oxides=rocket fuel. Maybe. Trying to think on a planetary scale here.