Implications of cosmic repulsion for gravitational theory

We present a general, model independent analysis of a recently detected apparent cosmic repulsion, and discuss its potential implications for gravitational theories, both standard and non-standard. In particular, we show that a negatively spatially curved universe acts like a diverging refractive medium to thus naturally cause galaxies to accelerate away from each other. Additionally, we show that it is possible for a cosmic acceleration to only be temporary, with some accelerating universes actually being able to subsequently recontract.