Newton’s law of universal gravitation: Newton’s law of universal gravitation states that everybody in the universe attracts every other body with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

It is assumed that a gravitational field exists all around the Earth due to the gravitational force of attraction on Earth.

In the gravitational field of the Earth, the gravitational force per unit mass is called the gravitational field strength of the Earth. It is 10 N kg^-1 near the surface of the Earth.

An object that revolves around the planet is called a satellite.

The scientist has sent many objects into space. Some of these objects revolve around the Earth. These are called artificial satellites.