Current status
How complete is the theory of relativity?
General relativity
General relativity has emerged as a highly successful model of gravitation and cosmology, which has so far passed many unambiguous observational and experimental tests. However, there are strong indications the theory is incomplete. The problem of quantum gravity and the question of the reality of spacetime singularities remain open. Observational data that is taken as evidence for dark energy and dark matter could indicate the need for new physics. Even taken as is, general relativity is rich with possibilities for further exploration. Mathematical relativists seek to understand the nature of singularities and the fundamental properties of Einstein's equations, and increasingly powerful computer simulations (such as those describing merging black holes) are run. The race for the first direct detection of gravitational waves continues, in the hope of creating opportunities to test the theory's validity for much stronger gravitational fields than has been possible to date. More than ninety years after its publication, general relativity remains a highly active area of research.