";s:4:"text";s:1331:" It was discovered in 1979 when the Voyager 2 probe photographed it during a flyby. The Moons of Jupiter Paperback – May 7, 1991 by Alice Munro (Author) Jupiter has the second largest number of moons with reasonably stable orbits of any planet in the Solar System.. From top to bottom the moons are Io, Europa, Ganymede, Callisto. We have 5 answers for this clue. Find answers for the crossword clue: Moon of Jupiter. Composite image of Jupiter and its 4 Galilean moons. Combined, scientists now think Jupiter has 79 moons . The most massive of the moons are the four Galilean moons, which were independently discovered in 1610 by Galileo Galilei and Simon Marius.They were the first objects found to orbit a body that was neither Earth nor the Sun. The Galileo spacecraft obtained the images to make this composite in 1996. There are many interesting moons orbiting the planet, but the ones of most scientific interest are the first four moons discovered beyond Earth—the Galilean satellites. There are 79 known moons of Jupiter. The moons of Jupiter have orbital periods ranging from seven hours to almost three Earth years.