With no solid land to obstruct their progress, dark vortices often roll through Saturn's atmosphere for months or years, before merging with other vortices. On Earth, the continents usually halt the progress of large storms, like hurricanes.
Vortices like these are part of the general circulation pattern of east-west flowing cloud bands, called jets, on Saturn.
The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 939 nanometers. The image was obtained with the Cassini spacecraft wide-angle camera on Aug. 16, 2006 at a distance of approximately 259,000 kilometers (161,000 miles) from Saturn. Image scale is 12 kilometers (7 miles) per pixel.