  We describe radiative processes in Quantum Cosmology, from the solutions of
the Wheeler De Witt equation. By virtue of this constraint equation, the
quantum propagation of gravity is modified by the matter interaction
hamiltonian at the level of amplitudes. In this we generalize previous works
where gravity was coupled only to expectation values of matter operators. By a
``reduction formula'' we show how to obtain transition amplitudes from the
entangled gravity+matter system. Then we show how ``each'' transition among
matter constituents of the universe determines dynamically ``its'' background
from which a time parameter is defined. Finally, we leave the mini-superspace
context by introducing an extended formalism in which the momenta of the
exchanged quanta no longer vanish. Then, the concept of spatial displacement
emerges from radiative processes like the time parametrization did, thereby
unifying the way by which space and time intervals are recovered in quantum
cosmology.
