An Etymological Dictionary of Astronomy and Astrophysics

A fundamental constant that appears in → Newton’s law of gravitation. It is the force of attraction between two bodies of unit mass separated by unit distance:
G = 6.673 x 10^-8 dyn cm² g^-2 or 6.673 x 10^-8 cm³s^-2g^-1, or 6.673 x 10^-11 N m² kg^-2 or
6.673 x 10^-11 m³s^-2kg^-1. It was first measured in 1798 by Henry Cavendish (1731-1810), 71 years after Newton’s death. Same as the → Newtonian constant of gravitation.

See also: → gravitational; → constant.