The phenomenon of dark energy and its manifestations are studied in a
spherically symmetric universe considering the Brans-Dicke scalar tensor
theory. In the first model the dark energy behaves like a phantom type and in
such a universe the existence of negative time is validated with an indication
that our universe started its evolution before t=0. Dark energy prevalent in
this universe is found to be more active at times when other types of energies
remain passive. The second model universe begins with big bang. On the other
hand the dark energy prevalent in the third model is found to be of the
quintessence type. Here it is seen that the dark energy triggers the big bang
and after that much of the dark energy reduces to dark matter. One peculiarity
in such a model is that the scalar field is prevalent eternally, it never tends
to zero.Comment: 15 page