Crepuscular Rays Over Lake Michigan

Explanation: What could cause such rays of dark? Dark sky rays were caught in spectacular fashion earlier last month from Pentwater , Michigan , USA , looking west over Lake Michigan . The cause is something surprisingly familiar: shadows . Clouds near the horizon can block sunlight from reflecting off air, making columns outward from the Sun appear unusually dark . Cloud shadow s can be thought of as the complement of the more commonly highlighted crepuscular rays , also visible above, where sunlight pours though cloud holes . Sometimes, on the opposite side of the sky, anticrepuscular rays can also be seen.