Let us note immediately that the preceding considerations
do not assimilate the visible Universe to a black
hole. Whereas in the case of a black hole, the observer
is on the exterior of the black hole, protected by the
horizon from the singularity, in the case of our visible
Universe, we are at the centre of our causal region: the
early periods of the evolution of our Universe (such as
the last scattering surface discussed in the context of the
Cosmic Microwave Background) are thin layers close to
the causal horizon, the initial singularity being rejected
beyond.