Asthadi Setyawan in Malang, East Java, Indonesia posted this photo at EarthSky Photo on G+. What you see here is the shadow of a cloud. The great sky optics expert Les Cowley – of the website Atmospheric Optics – calls them the inverse of crepuscular rays and notes they can produce dramatic effects.
We asked Les why it appears that this shadow is on the wrong side of the cloud. It looks from the photo as if the sun and the shadow are both behind the cloud. He told EarthSky:
It only looks that way. The shadow is closer to the camera than the cloud. Rays from the sun 93 million miles [150 million km] away are (nearly) parallel and always downward pointing. The shadows can be through misty or hazy air, or, sometimes, they’re cast on a lower thin layer of cloud that is otherwise invisible.
Thank you, Asthadi, and thank you, Les!
Deborah Byrd created the EarthSky radio series in 1991 and EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.