  Gravitational anomalies such as the mine/borehole g anomaly, the
near-flatness of the spiral galaxy rotation-velocity curves, currently
interpreted as a `dark matter' effect, the absence of that effect in ordinary
elliptical galaxies, and the ongoing problems in accurately determining
Newton's gravitational constant G_N are explained by a generalisation of the
Newtonian theory of gravity to a fluid-flow formalism with one new
dimensionless constant. By analysing the borehole data this constant is shown
to be the fine structure constant alpha=1/137. The spiral galaxy `dark matter'
effect and the globular cluster `black hole' masses are then correctly
predicted. This formalism also explains the cause of the long-standing
uncertainties in G_N and leads to the introduction of a fundamental
gravitational constant G not = G_N with value G=(6.6526 +/- 0.013)x 10^-11
m^3s^{-2}kg^{-1}. The occurrence of alpha implies that space has a quantum
structure, and we have the first evidence of quantum gravity effects.
