Astronomy Astronomy is the science that deals with the sun, moon, planets, stars and other heavenly bodies. Tools A B elliptical oval shaped model a representation of how something looks or works asteroid a rocky object that revolves around the sun meteorid a small piece of rock and metal that travels in space around the sun meteor a bright streak of light that passes through Earth's atmosphere comet a ball of ice, dust, and gases that travels through space and orbits the sun meteorite a piece of a meteor that land on Earth after passing through the atmosphere light year sidtance light travels in a year constellation stars that appear to be in groups when viewed from Earth galaxy a group of billions of stars, dust and gases in space held together by gravity