Solar System Constraints on Gauss-Bonnet Dark Energy

Quadratic curvature Gauss-Bonnet gravity may be the solution to the dark energy problem, but a large coupling strength is required. This can lead to conflict with laboratory and planetary tests of Newton’s law, as well as light bending. The corresponding constraints are derived. If applied directly to cosmological scales, the resulting bound on the density fraction is |Omega_GB| < 3.6 x 10^-32.