  In the groupoid approach to noncommutative quantization of gravity,
gravitational field is quantized in terms of a C*-algebra A of complex valued
funcions on a groupoid G (with convolution as multiplication). In the
noncommutative quantum gravitational regime the concepts of space and time are
meaningless. We study the "emergence of time" in the transition process from
the noncommutative regime to the standard space-time geometry. Precise
conditions are specified under which modular groups of the von Neumann algebra
generated by A can be defined. These groups are interpreted as a state
depending time flow. If the above conditions are further refined one obtains a
state independent time flow. We show that quantum gravitational dynamics can be
expressed in terms of modular groups.
