The discovery of Pluto's satellite Charon in 1978 enabled a determination of the mass of the Pluto–Charon system by application of Newton's formulation of Kepler's third law.
Penemuan satelit Pluto, Charon, tahun 1978 memungkinkan pengukuran massa sistem Pluto–Charon menggunakan rumus Newton dari hukum ketiga Kepler.