"Ask any kid how many planets are in our solar system, and you'll get a firm answer: nine. But knock on a few doors in Berkeley's astronomy department, and you'll hear, amid the hemming and hawing, a whole range of numbers." http://www.spacedaily.com/news/outerplanets-03e.html
Personally I believe a planet should be defined as: “Any natural non-nuclear fusing body orbiting a star and is over 2000km in diameter.” This way we can keep our nine and not (hopefully) add any more to are solar system.
In truth, the Sun's gravitational pull on the Moon is twice that of the Earth's, As a result, the Moon's heliocentric path is concave towards the Sun at all points. This is a situation that is unique to the Earth-moon system and is not duplicated elsewhere in the Solar system for any of the Major moons. As a result, it more accurate to say the the Earth and Moon individually orbit the Sun and mutually perturb each other's path. (Again this is not something that can be said for just any planet and moon. With all the others it is the planet that has the stronger gravitational grip on the moon)
No the moon spins around the earth hence a orbit... it may spin around a star as well but so does any body with multiple gravitational vectors on it. A moon: any natural body orbiting a planet... critieria for "a planet" above I think moon of a astroid is called a moonlit, so: A Moonlit: Any natural body orbiting a natural non-nuclear fusing body that is to small to be classify as a planet. hum I wonder what to call moons that obit moons?] Dam I should become a astronomical taxometist this is easy!
The question is, what is the primary body another body orbits; Which body has the greatest influence on its path. If you actually trace out the moon's path, you see that it simply follows a slighty wavy circle around the Sun, at at no time does that path curve away from the sun. Again this is unique to the Moon. Mars for instance, actually orbits around the Sun, Mercury, Venus and Earth, to be technical. Each body contributes to the center of mass around which Mars orbits. We say that Mars orbits the Sun because it is the Primary body of the Group and has the most influence. With the Earth-sun-moon system it is the Sun that has the primary influence on the Moon. (again, unilike any other system in the Solar system, where it is the planet that is the primary influence.)
Yes and you can do that with all the other moons as well! If it spins around a planet its a moon regardless of how you perceive the star influence. As for the case of mars it does not make full circles around a planet but has a orbit that goes around other planet's orbits. Its orbits center is closest to the sun.
