Vortex‐line photographs confirm helium‐II prediction

According to the work of Lars Onsager and Richard Feynman, when a container of $He−-$ II is rotated, discrete, quantized vortex lines appear. Many experiments have subsequently lent strong support to this prediction. However, if seeing is believing, then Gary A. Williams and Richard E. Packard of the University of California at Berkeley have produced irrefutable evidence; they have directly photographed these vortices using a technique suggested by Michael Sanders (University of Michigan) that is conceptually simple but technologically difficult.