Courtesy of NASA/JPL/University of Colorado An ultraviolet view
of Saturn’s A ring, colored by NASA. The red Cassini Division
(left) is about the width of the United States. The Cassini
spacecraft is off to a blazing start. During its first day in
orbit around Saturn, the probe’s ultraviolet camera beamed back
colorful images that are already expanding our understanding of
the planet’s majestic rings. UV snapshots highlight fine
variations in the rings, explains Jeff Cuzzi, a planetary
scientist at NASA’s Ames Research Center and a member of the
Cassini science team. Because humans cannot perceive ultraviolet
radiation, NASA researchers use artificial colors to illustrate
what Cassini’s cameras saw. “The subtle shades of blue and green
will tell us about a combination of grain size and particle
composition,” Cuzzi says. Red indicates areas where the rings
are nearly empty or where ring particles are particularly
small—places where ultraviolet radiation from interstellar
hydrogen shines through. Turquoise deno