Gravitational Constant
The empirical physical constant relating the gravitational force between two masses to their product and inverse-square separation.
Governing formula
G = 6.67430 × 10⁻¹¹ N·m²/kg²
SI unit
N·m²/kg²
In depth
First measured accurately by Henry Cavendish in 1798 using a torsion balance. G sets the strength of gravity in Newton's gravity law and Einstein's field equations of General Relativity.
Examples in the real world
Calculating the gravitational attraction between two 1000 kg satellites spaced 10 m apart: F = G (1000 × 1000)/10² ≈ 6.67 × 10⁻⁷ N.