In about one year, Earth completes one orbit around the Sun. Which term describes this motion?

In about one year, Earth completes one orbit around the Sun. Which term describes this motion?

• A. Precession
• B. Rotation
• C. Orbit
• D. Revolution

Answer: (D)

This is about how a body moves around another body under gravity. Earth travels along a path around the Sun and completes one full cycle in about a year, which is described as a revolution. Rotation would be spinning on Earth’s own axis, like day and night, not the orbital motion around the Sun. Orbit refers to the path itself, the ellipse traced by Earth; the period of that path is the revolution. Precession is a slow wobble in the orientation of Earth’s axis over long timescales and isn’t about the yearly motion. So the motion described is a revolution.

This is about how a body moves around another body under gravity. Earth travels along a path around the Sun and completes one full cycle in about a year, which is described as a revolution. Rotation would be spinning on Earth’s own axis, like day and night, not the orbital motion around the Sun. Orbit refers to the path itself, the ellipse traced by Earth; the period of that path is the revolution. Precession is a slow wobble in the orientation of Earth’s axis over long timescales and isn’t about the yearly motion. So the motion described is a revolution.