Bombarded by charged particles and exposed to large magnetic fields, the Galileo spacecraft recently braved several passes through Jupiter's radiation belts to get a closer look at the planet's volcanically active moon Io. As it neared Io, the craft also captured portraits of Metis, Amalthea, and Thebe, three of Jupiter's small, innermost moons.
The new images, released April 24, resolve features as small as 2 kilometers, half the size of the tiniest structures previously visible.
The pictures show that a bright feature on Amalthea, which had appeared to be round in older images taken at other viewing angles, is in fact a 50-km-long streak. Known as Ida, the streak could be material thrown upward when an impactor gouged a nearby crater,