NASA mission solves volcanic mystery of Jupiter’s ‘tortured moon’ Io

Sign up for CNN’s Wonder Theory science newsletter. But the moon’s wild volcanic activity wasn’t detected until Voyager 1 flew by Jupiter and its moons in 1979, revealing Io’s dynamic surface that resembled a pepperoni pizza, Bolton said. We knew data from Juno’s two very close flybys could give us some insights on how this tortured moon actually worked.” This sequence of images taken by the New Horizons spacecraft in 2007 shows a giant plume from Io's Tvashtar volcano. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute Flyby revelations Io orbits around Jupiter, the largest planet in our solar system, which Bolton calls a “monster.” The moon’s orbit is imperfect, meaning that sometimes it comes closer to Jupiter during its orbit, and other times it is farther away. “Juno’s discovery that tidal forces do not always create global magma oceans does more than prompt us to rethink what we know about Io’s interior,” said lead study author Ryan Park, a Juno co-investigator and supervisor of the Solar System Dynamics Group at JPL, in a statement.