Bizarre Star-Shaped Gravity Waves Created

Star-shaped waves can form in vibrating tanks of liquid oil, researchers say.

Learning more about such bizarre waves could shed light on counterparts that may exist elsewhere in nature, researchers added.

Waves of all kinds often behave in an intuitively linear manner. For instance, a weight on a spring will bob up and down in a manner directly proportional to the force that the weight exerts on the spring.

However, a number of strange waves can also form. They come from what is called nonlinearity, in which a small or simple change results in a disproportionately large or complex effect. For instance, aspects of weather behave chaotically, in a nonlinear manner.

The waves seen on the surface of water also behave in a nonlinear manner, and bizarre phenomena can result, such as X- and Y-shaped ocean waves or monstrously large freak waves that seem to come out of nowhere. Scientists have spotted similar nonlinear effects elsewhere in nature, such as with super-cooled atoms or light traveling in fiber optics.

To uncover new, remarkable nonlinear waves, scientists experimented with circular and rectangular tanks containing about two-fifths of an inch (1 centimeter) of silicon oil. Researchers placed the tanks on shakers to vibrate the fluid. Scientists then observed that the liquid contained gravity waves — oscillations due to gravity pulling downward and vibrations pushing upward.

source @ http://www.livescience.com/27342-star-shaped-gravity-waves.html