\begin{definition}[Definition:Gravitational Field]
Every body which has mass influences every other body which has mass, according to Newton's Law of Universal Gravitation.
Thus any body can be considered as being surrounded by a field given rise to by its mass, called a '''gravitational field'''.
Its value $\mathbf g$ at any point is given by:
:$\mathbf g = \dfrac {G M} {d^3} \mathbf d$
where:
:$G$ is the gravitational constant;
:$M$ is the mass of the body;
:$\mathbf d$ is the displacement vector from the point to the center of gravity of the body, whose magnitude is $d$.
\end{definition}