  We study the dynamics of false vacuum bubbles. A nonminimally coupled scalar
field gives rise to the effect of negative tension. The mass of a false vacuum
bubble from outside observer's point of view can be positive, zero, or
negative. The interior false vacuum has de Sitter geometry, while the exterior
true vacuum background can have geometry depending on the vacuum energy. We
show that there exist expanding false vacuum bubbles without the initial
singularity in the past.
