Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Orbiting Earth once every 1.5 hours, the Hubble Space Telescope watched as Io accompanied by its shadow crossed the face of the reigning gas giant planet in 1997. In October and November of this year, the Galileo spacecraft currently operating in the Jovian system is scheduled to make two daring close approaches to Io , possibly flying through a volcanic plume .
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