Credit: Credit: NASA, ESA, J. Spencer and K. Jessup, (Southwest Research Institute), and the Space Telescope Science Institute
Hubble is monitoring the volcanically active moon Io in support of the Feb. 28 New Horizons spacecraft flyby of Jupiter. These images were taken with Hubble's Wide Field Planetary Camera 2 on Feb. 14, 2007. The left image, taken in natural color, reveals orange oval deposits of sulfur around the Pele volcano, and other familiar surface features on Io, which is innermost of the Galilean satellites. The ultraviolet image on the right shows a big plume rising above the surface, not far from the north pole. Though Io is no bigger than Earth's geologically dead Moon, Io's interior is kept molten due to the gravitational tug of Jupiter and the other Galilean satellites.