Gravitational fields and space-time are equivalent names for the same mathematical object in Einstein's theory of general relativity. A gravitational FORCE, is a change in the strength of the gravitational field and corresponds to the idea of 'curvature' in the geometry of space-time. But, gravitational fields can exist everywhere without producing a gravitational force, so long as the field does not change in strength from place to place. Electromagnetic fields are embedded within the framework of space-time and as such are in some way derivable from space-time and from the nature of the gravitational field, but presently, theoreticians do not exactly know what the proper mathematics are that describe this relationship, which we call the 'Theory of Everything'.