免费轨道周期计算器
计算天体环绕运动的轨道周期。
轨道周期
31,554,223.24 s
Orbital Period vs Semi-Major Axis
公式
How the Orbital Period Is Calculated
The orbital period is the time a body takes to complete one full orbit around a central mass.
Kepler's Third Law (Generalized)
T = 2π √(a³ / (G M))
This assumes the orbiting body's mass is negligible compared to the central body.
计算示例
Find the orbital period of Earth around the Sun (a = 1.496e11 m, M = 1.989e30 kg).
- 01T = 2π √(a³ / (G M))
- 02a³ = (1.496e11)³ = 3.348e33 m³
- 03G M = 6.674e-11 × 1.989e30 = 1.327e20
- 04a³ / (G M) = 2.524e13
- 05T = 2π × √(2.524e13) ≈ 3.156e7 s ≈ 365.25 days
常见问题
Does the orbiting body's mass affect the period?
For most situations the orbiting body is far less massive than the central body, so its contribution is negligible. For a binary of comparable masses, replace M with (M1 + M2).
What shape of orbit does this assume?
The formula applies to any Keplerian elliptical orbit. The semi-major axis alone determines the period regardless of eccentricity.
How accurate is this for real solar-system bodies?
Accurate to better than 0.01% for planets, with tiny deviations from perturbations and relativistic effects.