... STScI-PRC99-13 HUBBLE CLICKS IMAGES OF IO SWEEPING ACROSS JUPITER While hunting for volcanic plumes on Io, NASA's Hubble Space Telescope captured these images of the volatile moon sweeping across the giant face of Jupiter. Only a few weeks before these dramatic images were taken, the orbiting telescope snapped a portrait of one of Io's volcanoes spewing sulfur dioxide "snow." ... Astronomers increased the color contrast and added false colors to the image to make the faint plume visible. ...