The polarization of skylight: An example from nature

A simple analytical model is presented for calculating the major features of the polarization of skylight over a hemisphere centered on an earthbound observer. The model brings together material from different topics in optics: polarization of plane waves, natural (unpolarized) light, and dipole scattering. Results calculated with the simple model are compared with experimental data. A brief description of the ability of insects to sense the polarization of skylight and their use of it for navigation is given.