The influence of anisotropy on gravitational theories of dark energy in the universe - Molla Mengesha Nigus - Bog

This thesis titled "Impact of anisotropy on dark energy cosmological
models in theories of gravitation" consists of nine chapters and deals
with the investigation of some spatially homogeneous and anisotropic
dark energy cosmological models in the framework of Einstein's general
theory of gravitation, and also in some other theories of gravitation like
Brans-Dicke (1961) and Saez-Ballester (1986) scalar-tensor theories of
gravitation, which are viable alternatives to Einstein theory of gravitation.
Cosmology is the study of the universe as a whole. It mainly deals with
the mechanism of the evolution of the universe and its components. It
seeks to answer the oldest questions of mankind: How did the universe
come into existence? What is the universe made of? What will happen to
us in the future? There are still many unanswered questions which remain
subject to further scientific investigation and philosophical debate.
According to the modern cosmology, the universe begins with a Big
Bang, and through the evolution of the universe, different fields split from
each other and the components (fluids) of the universe evolve. While the
universe expands, different structures (such as galaxies, black holes, stars
and planets) emerge. In order to study the universe we need to know
its space-time geometry, and the fluids as its components and how they
interact with each other and with space-time. This has been done using
Einstein's theory of gravitation by constructing cosmological models.