In this paper we discuss how information transferred optically through
a gravitational field is degraded as the quanta interact with the mad
ium (vacuum state). We quantify information by means of Shannon's entr
opy, and consider information carriers that are quanta of some field.
Next, we obtain the quantum noise ('quantum fog') produced by the grav
itational field and derive the appropriate 'channel capacity' formula,
which quantifies the maximum amount of information that can be transm
itted per pulse, in the face of this noise. We show that the channel c
apacity formula vanishes if the source of information is a space-time
singularity because a very intense noise is produced in the vicinity o
f the singularity. In other words, space-time singularities are hidden
behind a very intense 'quantum fog' and cannot be optically observed.
A second consequence is that information is degraded as anisotropies
(lumpiness) develop in the universe.