Astronomy Practice Exam

What does revolution refer to in astronomy?

1. The motion of an object around another object

2. The spin of an object on its own axis

3. The constant motion of a satellite

4. The gravitational attraction between two bodies

The correct answer is: The motion of an object around another object

Revolution in astronomy specifically refers to the motion of an object moving around another object in an orbit. This is a fundamental concept, as it describes how celestial bodies, such as planets, moons, and artificial satellites, move in elliptical paths around larger bodies, like stars or planets. For instance, Earth revolves around the Sun, taking approximately one year to complete this motion. This term is distinct from other related motions; for example, the spin of an object on its own axis is known as rotation, while the gravitational attraction between two bodies pertains to the force that governs their movements rather than describing the motion itself. Similarly, the constant motion of a satellite could refer to both its revolution around a planet and its actual speed or trajectory, but it does not specifically define revolution. By understanding that revolution encompasses the orbital path and movement around another celestial body, one gains insight into the dynamics of our solar system and beyond.