# Gravitational field

Representation of the lines of force of the gravitational field

Newton’s theory of gravitation states that bodies attract each other because of their mass, even if they are not in direct contact. It was with this idea of ​​action at a distance that Newton was able to give an explanation for the “world system”.

In the 18th and 19th centuries, the study of electrical and magnetic phenomena established new concepts. Among them, the concept of field proved to be very useful for the analysis of the universe of phenomena, being, therefore, applied to gravitation. Let’s analyze gravitation from the point of view of the notion of field, taking the Earth as an example.

The Earth defines a region of space where any object is subject to an attractive force. We represent this property by means of a set of lines called lines of force of the gravitational field . See the figure above.

The arrows indicate the direction and direction of the force to which an object placed in this region will be subjected. According to this representation, the lines are semi-straight and point towards the center of the Earth, getting closer to each other as they approach the Earth. Thus, in addition to the direction of the force, this drawing indicates the dependence of force on distance: the closer the lines are to each other, the greater the magnitude of the force to which an object will be subjected. The above expression for the value of the gravitational field is valid for any distance from the center of the Earth. It allows the calculation of the gravitational field at any location on Earth and can be applied to planets, stars, satellites, etc., as long as we use their mass ( M ) in the calculation.