Earth is perhaps the solar system’s most interesting planet. Atmospheric conditions allow for frequent movement of water in all three phases—solid, liquid, and gas. The planet’s 23 degree tilt produces seasonal changes and continents move over a somewhat liquid interior. Earth makes 365 ¼ rotations in one revolution around the Sun and has a rather large moon that revolves around the planet in 29 1/3 Earth days, so that one hemisphere always faces the Earth. The moon has no atmosphere.
