A

David

Darling

curvature constant

The curvature constant is a constant (k) appearing in the Robertson-Walker metric which determines the curvature of the spatial geometry of the universe. The three standard Friedmann models have: k > 0 for positive curvature (spherical geometry), k < 0 for negative curvature (hyperbolic geometry), and k = 0 for zero curvature (flat geometry).