What is the Gravitational Constant?

Gravitational force between two masses

Gravitational constant is a physical constant and determines how strongly masses attract each other. It therefore determines the strength of gravity. It is abbreviated with the letter \(G\) and has the following value:

Value of the gravitational constant
Formula anchor

The unit of the gravitational constant \(G\) is for example Newton square meter per kilogram squared or cubic meter per kilogram second squared:

Unit of gravitational constant
Formula anchor

The gravitational constant occurs in the Newton law of gravity and Einstein field equations, which describe the interaction between masses.

Gravitational Force Between Two Masses
Need this image? Download image Add copyright notice "Alexander Fufaev (fufaev.org)" ➡ Use image. [All images]
The gravitational force between two masses is determined in particular by the gravitational constant.

Because of the small value of the gravitational constant (see equation 1) gravity is one of the weakest fundamental forces of nature. The gravitational constant only plays a significant role when large masses are involved, such as the mass of the Earth.

The gravitational constant is difficult to measure accurately compared to other constants of nature. This is simply because any mass around the experiment will affect the measurement. The gravitational constant can be approximately determined, for example, with the Cavendish experiment.

+ Perfect for high school and undergraduate physics students
+ Contains over 500 illustrated formulas on just 140 pages
+ Contains tables with examples and measured constants
+ Easy for everyone because without vectors and integrals

Learn more