Safely smoothing spacetime: backreaction in relativistic cosmological simulations

Understand

A persistent theme in the study of dark energy is the question of whether it really exists or not.

• It is often claimed hat we are mis-calculating the cosmological model by neglecting the effects associated with averaging over large-scale structures.
• In the Newtonian approximation this is clear: there is no effect.
• Within the full relativistic picture this remains an important open question however, owing to the complex mathematics involved.