APOD: 2016 August 7 - Io: Moon over Jupiter (original) (raw)

Astronomy Picture of the Day

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2016 August 7

Io: Moon over Jupiter
Image Credit: Cassini Imaging Team,SSI,JPL,ESA,NASA

Explanation: How big is Jupiter's moon Io? The most volcanic body in the Solar System, Io (usually pronounced "EYE-oh") is 3,600 kilometers in diameter, about the size of planet Earth's single largenatural satellite. Glidingpast Jupiterat the turn of the millennium, the Cassini spacecraft captured thisawe inspiring view of active Iowith thelargest gas giant as a backdrop, offering a stunning demonstration of the ruling planet'srelative size. Although in the featured picture Io appears to be located just in front of the swirling Jovian clouds,Io hurtles around its orbit once every 42 hours at a distance of 420,000 kilometers or so from the centerof Jupiter. That puts Ionearly 350,000 kilometers aboveJupiter's cloud tops, roughly equivalent to the distance betweenEarth and Moon. In July, NASA's Junosatellite began orbiting Jupiterand will sometimes swoop to within 5,000 kilometers of Jupiter's cloud tops.

Tomorrow's picture: perseid rain

Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)
NASA Official: Phillip NewmanSpecific rights apply.
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