  The spacetime inside the white hole is like an anisotropic cosmological
background with the past singularity playing the role of a big bang
singularity. The scale factor along the extended spatial direction is
contracting while the scale factor along the two-sphere is expanding. We
consider an eternal Schwarzschild manifold and study quantum cosmological
perturbations generated near the white hole singularity which propagate towards
the past event horizon and to exterior of the black hole. It is shown that an
observer deep inside the white hole and an observer far outside the black hole
both share the same vacuum. We calculate the Hawking radiation associated to
these quantum white hole perturbations as measured by an observer in the
exterior of the black hole. Furthermore, we also consider the Hawking radiation
for the general case where the initial cosmological perturbations deep inside
the white hole are in "non-vacuum" state yielding to a deviation from Planck
distribution. This analysis suggests that if the black hole is not entirely
black (due to Hawking radiation) then the white hole is not entirely white
either.
