Abstract:
In this short review, we discuss how Earth’s climatological and geological history and also
how the shadows of galactic black holes might reveal our Universe’s past evolution. Specifically
we point out that a pressure singularity that occurred in our Universe’s past might have left its
imprint on Earth’s geological and climatological history and on the shadows of cosmological black
holes. Our approach is based on the fact that the H0 tension problem may be resolved if some sort
of abrupt physics change occurred in our Universe 70–150 Myrs ago, an abrupt change that deeply
affected the Cepheid parameters. We review how such an abrupt physics change might have been
caused in our Universe by a smooth passage of it through a pressure finite-time singularity. Such
finite-time singularities might occur in modified gravity and specifically in F(R) gravity, so we show
how modified gravity might drive this type of evolution, without resorting to peculiar cosmic fluids
or scalar fields. The presence of such a pressure singularity can distort the elliptic trajectories of
bound objects in the Universe, causing possible geological and climatological changes on Earth, if
its elliptic trajectory around the Sun might have changed. Also, such a pressure singularity affects
directly the circular photon orbits around supermassive galactic black holes existing at cosmological
redshift distances, thus the shadows of some cosmological black holes at redshifts z ≤ 0.01, might
look different in shape, compared with the SgrA* and M87* supermassive black holes. This feature
however can be checked experimentally in the very far future.
