A field has a magnitude and a direction at every point in space. The Earth's gravitational field is 9.8 m/s2 pointing toward the center of the Earth.
|Gravitational field: g||=||
where F is the force of gravity.
Near the Earth's surface, the field is uniform. The strength of a field is reflected by the density of field lines - a uniform field has equally-spaced field lines.
Further from the Earth, the field is non-uniform and radial. The field
lines separate as they get further from the Earth, reflecting the fact that g
decreases with distance. At any point, the field-line pattern shows the
direction of the gravitational force that would be experienced by a mass
placed at that point.