Most people are aware that various objects in space are constantly moving, but what causes these routine movements? This informational text is for grade 8 students, it explains what orbits are and why objects in space circle one another. As you read, take notes on the different objects that can orbit in space and on the forces that allow an object to maintain its orbit. "What is an Orbit" from NASA Knows by David Hitt (2010) is in the public domain.