He aimed at understanding how this ‘gravitational field’ worked, and how it could be described with equations.
And it is at this point that an extraordinary idea occurred to him, a stroke of
pure genius: the gravitational field is not diffused through space; the gravitational field is that space itself. This is the idea of the theory of general
relativity. Newton’s ‘space’, through which things move, and the ‘gravitational
field’ are one and the same thing.