Based on the idea of emergent spacetime, we consider the possibility that the
material underlying our spacetime is modelled by a fluid. We are particularly
interested in possible connections between the geometrical properties of the
emergent spacetime and the properties of the underlying fluid. We find some
partial results that support this possibility. By using the Kerr spacetime as
an example, we construct from the Riemann curvature tensor a vector field,
which behaves just like the speculated fluid flow.Comment: A mistake corrected, results improved, paper fully revised to account
for the change. 12 page
