“The picture of two ballet dancers soaring across a simulated lunar crater comes from the set of Destination Moon, a 1950 space adventure film. But the dance is not in the film. The context of the photograph is unknown, and the identity of the dancers a mystery — one that William Higgins, a radiation safety physicist at Fermi National Accelerator Laboratory in Illinois, has been trying to solve since he first stumbled across the photo seven years ago.”