If you know how long an object takes to orbit a central mass, you can work backward using Kepler's Third Law to find how far away it must be orbiting — the reverse of the standard orbital period calculation..
If you know how long an object takes to orbit a central mass, you can work backward using Kepler's Third Law to find how far away it must be orbiting — the reverse of the standard orbital period calculation.
An object orbits the Sun (M = 1.989×10³⁰ kg) with a period of 3.156×10⁷ s (about 1 year). a = ∛(6.674×10⁻¹¹ × 1.989×10³⁰ × (3.156×10⁷)² / 4π²) ≈ 1.496×10¹¹ m — matching 1 AU, as expected for a 1-year orbit around the Sun.
Using Kepler's Third Law, solving for the semi-major axis from a known orbital period and central body mass.
It helps characterize a planet's position in its system, including whether it falls within a habitable zone.
Only for a perfectly circular orbit — elliptical orbits have varying distance from the central body.