today's picture

a montage of jupiter and it's moon lo. Jupiter is represented by false colours corresponding to the different infrared radiation wavelengths. The colour blue (representing the wavelength 1.85um) denotes high altitude clouds of above 300 millibars pressure level while the colour red (representing the wavelength 1.59um) represent clouds below the pressure level of several bars.

The red dot on lo is a volcano, captured during a major eruption. The volcanic plumes appears to be blue due to Rayleigh scattering by small particles.

source: http://www.nasa.gov/centers/goddard/news/topstory/2007/new_horizons_jupiter.html