ocr: Penguin Dictionary of Hstronomy Lontents Index Back History << >> Io One of the four Galilean moons of Jupiter number I), the nearest to the planet and arguably the most remarkable. Its surface is brightly coloured, 1n shades of red, orange and white. Eight active eruptive centres were dentilied in the images returned during the encounter of the * Voyager 1 spacecrart, six of which were still active when o Voyager 2 flew by: four months later. The eruptive centres appear as dark spots. mMany are surrounded by: roughly circular halos', presumably of ejected material, and lava flows are also vis ...
