Volcanoes on Jupiter's moon Io keep erupting. To investigate, NASA's robotic Juno spacecraft has begun a series of visits to this very strange moon. Io is about the size of Earth's moon, but because of gravitational flexing by Jupiter and other moons, Io's interior gets heated and its surface has become covered with volcanoes. The featured image is from last week's flyby, passing within 12,000 kilometers above the dangerously active world. The surface of Io is covered with sulfur and frozen sulfur dioxide, making it appear yellow, orange and brown. As hoped, Juno flew by just as a volcano was erupting -- with its faint plume visible near the top of the featured image.
Image Credit: NASA, JPL-Caltech, SwRI, MSSS; Processing: Ted Stryk & Fernando García Navarro
"A specal color reconstruction of the eruption of the volcano Loki pn the Iovian satellite Io. The picture was taken by the Voyager I from a range of about half a million kilometers." March 5, 1979.
Voyage to Jupiter. 1980. Scientific and Technical Information Branch NASA.