Frozzy said:
I'd have thought the names were grandfathered, in a way. We call it moon, and suddenly someone announces "Hey! I found another moon!" "Well, we can't call it moon II because that's stupid, and we can't call it Mars Moon because there's another. Let's just give it a name."
That's more or less it precisely. We didn't call it "moon" because we saw a moon & said, "hey it's a moon, we'll call it 'Moon' since it was first." We saw this thing in the sky & thought, "hmmm, it seems to show up brightest around once a month, it must be a month-thing.." Then we discover that other planets have these things too, but obviously we can't give them the same names..
The same logic goes for the Sun - it's only called the Sun because that's the name we created for it when we first named it. Once we discovered that the sparkly things we see at night-time were the same thing, the stars can't use the name Sun but have to get different names.
As for Earth, well that one's quite simple. Go outside, what are you standing on? Earth. Or, if you're in Spain, Terra; in Germany, Erde; France, Terre.. it's no co-incidence that in ALL languages, the word for our planet is also a word for dirt. I'll bet that Gaia means dirt in some language, too - although maybe not, since Gaia actually refers to the
spirit of the Earth (though I may have been watching too much Final Fantasy..
)
Finally, any planet-orbiting body is indeed a satellite. Thus all moons are satellites. Obviously though not all satellites are moons. Satellite is the global term for a planet-orbiting body & moons happen to be one type of satellite.
Any questions, children?