  We investigate the dynamics of a Yang-Mills cosmology (YMC, the FRW type
spacetime) bubble in the Bartnik-McKinnon (BK) spacetimes. Because a BK
spacetime can be identified to a YMC spacetime with a finite scale factor in
the neighborhood of the origin, we can give a natural initial condition for the
YMC bubble. The YMC bubble can smoothly emerge from the origin without an
initial singularity. Under a certain condition, the bubble develops
continuously and finally replaces the entire BK spacetime, the metric of which
is the same as the one of the radiation dominated universe. We also discuss why
an initial singularity can be avoided in the present case in spite of the
singularity theorems by Hawking and Penrose.
