Sparkles are a magnificent manifestation of optics in nature, and nowhere are they as abundant as on freshly fallen snow. Because they evade our depth-perception mechanism, sparkles have an otherworldly quality that makes them seem to float indeterminately rather than appearing on any surface or at any altitude.
© 2013 Optical Society of America
Vol. 8, Iss. 2 Virtual Journal for Biomedical Optics
Alfred Cann, "All about Sparkles," Optics & Photonics News 24(1), 42-45 (2013)