Planetary Society logo
  • “Exploration is in our nature.” - Carl Sagan

Spiraling in to Io

Spiraling in to Io
Spiraling in to Io It's beautiful; it changes every time we see it. It's Io, the most volcanically active object in human experience. This look is from Galileo's 10th orbit through the Jupiter system. On previous orbits, the red halo surrounding the volcano Pele was the most prominent feature in the southern hemisphere. On the 9th orbit, Galileo saw a gigantic plume, 120 kilometers (75 miles) high, from an eruption near Pele, from a volcanic center called Pillan Patera. On the next orbit, a large, dark feature, 400 kilometers (about 250 miles) in diameter, had broken Pele's red halo—one of the most dramatic changes seen on Io. Galileo took this image on September 19, 1997, from a distance of 500,000 kilometers (about 310,000 miles) JPL/NASA