Strange phenomenon of shadow bands captivates scientists as a total solar eclipse nears | CNN

Racing water. Phantom serpents. Rippling patterns of light and dark. Solar eclipse watchers have for centuries vividly described an eerie phenomenon known as shadow bands that appears just before and after totality — the period when the moon completely blocks the sun’s light and the sky goes dark. Long dark lines, separated by white spaces, race across the ground or sides of buildings. David Turnshek, a professor of physics and astronomy at the University of Pittsburgh, first witnessed shadow bands as a teenager. “I guess I would have been 14 years old. I went to see a total eclipse near Virginia Beach. It was 1970, and I had made my own telescope, and I went down there to try to photograph the eclipse,” said Turnshek, who is also the director of the Allegheny Observatory in Pittsburgh. “And while I was down there, I noticed right before the total eclipse, these bands of light were sweeping across the ground.” The human eye can easily detect shadow bands, but they are difficult to photograph and capture on video because of the subtle contrast. Turnshek’s research as an astronomer has primarily focused on galaxy formation and quasars, the luminous cores of distant, anc