Jupiter and Io
This montage of images of Jupiter and its volcanic moon Io, was taken by the New Horizons spacecraft's flyby in early 2007. The Jupiter image is an infrared color composite taken by the spacecraft's near-infrared imaging spectrometer on Feb. 28, 2007. The infrared wavelengths used highlight variations in the altitude of the Jovian cloud tops, with blue denoting high-altitude clouds and hazes, and red indicating deeper clouds. The prominent bluish-white oval is the Great Red Spot.
The Io image, taken on March 1, 2007, is a nearly true-color composite. The image shows a major eruption in progress on Io's night side, at the northern volcano Tvashtar. Incandescent lava glows red beneath a high volcanic plume, whose uppermost portions are illuminated by sunlight. The plume appears blue due to scattering of light by small particles in the plume.
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Goddard Space Flight Center