Cosmology Notes/draft
From Jon's Wiki
What is cosmology
The modern consensus on the nature and evolution of the Universe is based on a particular mathematical solution (called the Friedman Lemaître Robertson Walker metric) of Einstein's field equations in his theory of General Relativity. General Relativity describes the Universe in terms of masses interacting with and distorting spacetime, a four dimensional mathematical space (a Riemannian manifold) which has the three dimensions of normal "Euclidean" space, plus one of time. One of the results of considering the Universe in this way is that gravity becomes no more than the linear trajectories of the moving masses in this four dimensional space, rather than a separate, arbitrary force that needs to be separately considered.