Astronomy is the study of everything in the universe beyond Earth's atmosphere. That includes objects we can see with our naked eyes, like the Sun , the Moon , the planets, and the stars . It also includes objects we can only see with telescopes or other instruments, like faraway galaxies and tiny particles.

An oscillation is quite simply a motion that predictably plays out over and over (think swinging pendulum); a wave is just an oscillation that's going somewhere (pendulum that always pays attention in class, asks thoughtful questions, and gets straight A's).