Abstract

Extensions to General Relativity abound in the literature. However, rigorous testing of these theories against observational data is time-consuming, and in a very disjointed state. This leads us to seek an efficient, general way to test gravity which is independent of the specifics of individual theories.

I will present two strands of work related to this gravitationally agnostic approach. First, I will introduce a system for unifying tests of gravity on all scales in the universe, from laboratory experiments to cosmology. This hints at an untested regime of gravitational fields which deserves further investigation.

Secondly, I will show how a parameterisation of alternative gravity theories — written down at the level of the field equations — propagates through to `real-world’ effects on cosmological observables. Turning this around, I will indicate the strength of model-independent constraints on gravity we can expect in the near future.