Orbital period

Definition

The orbital period is the time it takes for a celestial object to complete one full orbit around another object. It is commonly measured in Earth days, months, or years depending on the context of the objects involved.

5 Must Know Facts For Your Next Test

1. The orbital period of an object depends on the mass of both the orbiting body and the central body as well as their distance from each other.
2. Kepler's Third Law states that the square of the orbital period is proportional to the cube of the semi-major axis of its orbit.
3. Astronomers use observational data and mathematical formulas to determine the orbital periods of planets, moons, and other celestial objects.
4. Orbital periods can help scientists understand the age and stability of planetary systems.
5. Comets often have highly variable orbital periods due to their elongated orbits and interactions with other celestial bodies.

Review Questions

• What factors influence an object's orbital period?
• How does Kepler's Third Law relate to orbital periods?
• Why are accurate measurements of orbital periods important in astronomy?

Related terms

Kepler's Third Law: This law relates the orbital period of a planet to its distance from the sun, stating that P² ∝ a³.

Semi-Major Axis: The longest diameter of an elliptical orbit, which directly influences an object's orbital period.

Celestial Mechanics: The branch of astronomy that deals with calculating motions such as orbits using principles like gravity and inertia.