gravitational constant

The gravitational constant (G) is an experimentally-determined value that relates gravitational force between any two objects to their masses and the distance between them. The force is proportional to the product of the masses and inversely proportional to the square of the distance between them, and the gravitational constant relates the masses and distances to the magnitude of the force:

F = -Gm1m2/r²

• F - the force on each object (toward the other).
• G - the gravitational constant.
• m₁ and m₂ - mass of the two objects.
• r - distance between the two objects.

The currently-determined value of the gravitational constant is 6.67430 × 10^-11 N·kg^-2m² (i.e., m³ kg^-1 s^-2), where:

• N - newtons (force units of 1 kg·m·s^-2).
• kg - kilograms.
• m - meters.
• s - seconds.

The Einstein gravitational constant (κ) is:

κ = 8πG/c4

This expresses gravity in a manner convenient to general relativity (GR) equations and according to GR, is perhaps "more basic". G is referred to as the Newtonian gravitational constant when there is a need to distinguish which one is intended.