Crepuscular means like twilight or dim. That’s a clue that this effect is often seen around sunrise or sunset, when the sky is somewhat dark. Crepuscular rays may appear to fan across the sky, but the rays are really parallel to each other. They appear to diverge, much as a road that looks narrow in the distance appears wide beneath your feet. Airborne dust, droplets of water and the air molecules themselves are what make the sunrays visible. Next time you see them, remember to turn around. You might be in luck and see fainter and less noticeable anticrepuscular rays.
Most of these photos came from friends at EarthSky Facebook. Thank you so much for sharing your photos with us!
Bottom line: Beams of light shooting out from horizon, or from the clouds, are called crepuscular rays, or sunrays. These columns of sunlit air are beautiful, mysterious and very noticeable. Photo gallery here.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.