As the distance between two objects decreases, the gravitational force between them increases. Conversely, as the distance between them increases, the gravitational force decreases. Gravitational force is inversely proportional to the distance between two objects squared.
The closer an object is to Earth, the stronger the planet's gravitational pull is on it, and the farther away it is from Earth, the weaker the gravitational pull. This is shown in the equation for the force of gravity, which states that the force of gravity equals a gravitational constant times the masses of the two objects in question divided by the distance between the objects squared. When the distance is a smaller number, and its square is, therefore, a smaller number, the gravitational pull is a larger number.