The properties of universes are explored that are entirely in the interior of
black holes in another universe, a `mother universe’. It is argued that these
models offer a paradigm that may shed a new light on old cosmological problems.
The geometry of such a universe is discussed including how it would appear to
the observer. The Hubble parameter is direction dependent, but it is argued
that the interpretation of any such dependence will be hard to separate from
local inhomogeneities. The models do not originate from a big bang, but rather
from an initial collapse and subsequent infall, that started probably a very
long time ago, presumably much earlier than the accepted age of the universe.
The relation to the concordance model is discussed and it is shown that a lot
of the existing theory can be taken over into the proposed models. The universe
has an edge, which is an ordinary spherical surface in 3 dimensions. That
sphere acts as a gravitational mirror as seen from inside the universe, but it
does not mirror redshift. The same object can thus be seen in direct sight and
in reflection, although with different redshifts, different ages and different
aspect angles. The models do not need dark energy, but they need dark matter,
of course. Since the models are closed and neutrino’s are nowadays believed to
have mass, neutrino’s can be reconsidered as candidates for the dark matter. As
a bonus result from this paradigm, mass ejection from black holes is shown to
be possible, which links that process to the controversial anomalous galaxy
redshifts. Finally, we show that gravitational mass and inertial mass are
proportional, and that the inertial acceleration scales as $c^2/M$, with $M$ a
characteristic length scale of the universe.
