, but this is of no particular importance. This formula proves that the
’s have the following values when computed in a Cartesian space-time co-ordinate system:
all other
’s vanishing. Now, while leaving the time axis unaltered, we might also have split up space, no longer with parallel planes, but with concentric spheres and with lines radiating from their centre. We then obtain a polar co-ordinate system. In this case, neglecting one of the spatial dimensions for purposes of simplicity, and calling
the distance from the centre, and
