Cosmological singularities and initial data on the big bang

The talk will begin with an overview of past results concerning cosmological singularities. This will be followed by a brief description of a framework for studying anisotropic big bangs. Finally, a notion of initial data on big bang singularities will be introduced, and it will be illustrated how this notion can be used to give a unified perspective on past results, how it can be used to predict asymptotic behaviour, and how it might be useful for future studies.