Von Kármán Vortex

Lifted straight out of Wired

The crazy-looking swirls in the image above may be one of the weirdest cloud formations that can be seen from space. The pattern is known as a von Kármán vortex street, named after Theodore von Kármán. First noticed in the laboratory by fluid dynamicists, it occurs when a more-viscous fluid flows through water and encounters a cylindrical object, which creates vortices in the flow.

Alejandro Selkirk Island, off the Chilean coast, is acting like the cylinder in the image above, taken by the Landsat 7 satellite in September 1999. A beautiful vortex street disrupts a layer of stratocumulus clouds low enough to be affected by the island, which rises a mile above sea level.

More strange and wonderful vortex streets formed by islands can be seen in the images below . Below is Guadalupe Island, 21 miles off the coast of Mexico’s Baja California, shot in 2000 by Landsat 7; Rishiri Island in the northern Sea of Japan, photographed by space shuttle astronauts in 2001; and Wrangel Island, above the Arctic Circle northeast of Siberia, flanked by a vortex street created by the smaller Gerald Island, imaged by NASA’s Aqua satellite in August 2008.

Images: 1) Bob Cahalan/NASA, USGS. 2) NASA. 3) NASA. 4) NASA (STS100-710-182).