  The scale of quantum mechanical effects in matter is set by Planck's
constant, $\hbar$. This represents the quantisation scale for material objects.
In this article, we present a simple argument why the quantisation scale for
space, and hence for gravity, may not be equal to $\hbar$. Indeed, assuming a
single quantisation scale for both matter and geometry leads to the `worst
prediction in physics', namely, the huge difference between the observed and
predicted vacuum energies. Conversely, assuming a different quantum of action
for geometry, $\beta \ll \hbar$, allows us to recover the observed density of
the Universe. Thus, by measuring its present-day expansion, we may in principle
determine, empirically, the scale at which the geometric degrees of freedom
should be quantised.
