Aleutian Islands - Von Karman Vortices (background/logo fill image)
As air flows over and around objects in its path, spiraling eddies, known as Von Karman vortices, may form. The vortices in this image were created when prevailing winds sweeping east across the northern Pacific Ocean encountered Alaska's Aleutian Islands. [Image and caption courtesy of USGS National Center for EROS and NASA Landsat Project Science Office] Image taken 7/4/2002 by Landsat 7



Crab Nebula (center image)
The Crab Nebula is a six-light-year-wide expanding remnant of a star’s supernova explosion. Japanese and Chinese astronomers recorded their observations of this violent event nearly 1,000 years ago, in 1054. This composite image was assembled from 24 individual exposures taken with the NASA Hubble Space Telescope's Wide Field and Planetary Camera 2 in October 1999, January 2000, and December 2000. [Image and caption credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)]