The necklace-like shape shown in this picture is the result of magnetic influence on ferrofluid (an oil-based magnetic fluid) on water. The darker bits are agglomerations of iron-containing nanoparticles; the lighter stretch is formed due to fluid instability. This image was a finalist for the 2005 Science & Engineering Visualization Challenge (SciVis) competition, sponsored by the NSF and the journal Science. (Ashok Sinha, Ranjan Ganguly and Ishwar K. Puri / Engineering Science and Mechanics Department, Virginia Polytechnic and State University / Image used courtesy of National Science Foundation)
Ferrofluids are nifty stuff. A fluid which can become strongly magnetized in the presence of a magnetic field, they create all sorts of odd phenomena given the right circumstances. This particular picture is one such instance of coolness, captured by Ashok Sinha, Ranjan Ganguly and Ishwar K. Puri, from the Engineering Science and Mechanics Department of Virginia Polytechnic and State University.
Read more on the NSF website, or see all winning entries on the SciVis website.