there are 4 basic kinds of field.
1. gravitational field
2. electromagnetic field - U(1) group symmettry
3. nuclear weak field - SU(2) group symmetry
4. nuclear strong (color) field - SU(3) group symmetry
to describe motions in the field, a quantum of the field has been established respectively
1. gravitons
2. photons
3. W+, W-, and Z0
4. gluons
the distance range of motion are infinite for quanta 1 and 2, but less than
centimeters for quanta 3 and 4.
the field as a continuum is infinite in its dimension, but all quanta are finite dimensional. It can be said that different dimensions must be used to describe different level of existence (LOE). Motion is detectable if and only if the particle quantum is found. this is a catch-22, no motion no quantum, no quantum no motion.
it is quite obvious what is moving in a gravitational field: the falling apple, the planets, the stars, the galaxies, but all these are simply macroscopic objects. The quantum of this field is really the graviton, to which identity still cannot be determined by any experiment. The empirical failure implies that the graviton moves in a much higher dimensional plane (LOE), higher than the 3D, 4D we are accustomed to, but maybe it moves in 5D (Kaluza-Klein dimension). But how do we perform a 5D motion experiment in 4D or 3D environment? This seems hopeless until we hypothesize that the speed of the graviton is greater than the speed of the photon in a 4D spacetime coordinate system. In superstring theory, the existence or motion of the graviton can be found, by 10 space and 1 time dimension and its speed is numerically equal to light speed. But at lower dimensions, the speed of the graviton must be superluminal.
finding the graviton is tantamount to detecting higher dimensional supercurrent of space or spacetime (when a space point moves as a quantum, time is inadvertently created).