Of Jupiter’s 63 moons, four can be viewed from Earth through binoculars. These moons were first discovered by Galileo Galilei, looking through a newly refined telescope around 1610. And they still are called the Galilean moons.
Galileo was astonished to find that these four moons –Ganymede, lo, Europa , and Callisto- from a perfect line with the planet. Each has its own distinctive features.

With more than 150 volcanoes, lo is the most geologically active moon in the solar system. Europa has an icy surface that may cover liquid water , offering the possibility that we may one day discover some kind of life-from there. Ganymede is the largest moon in the solar system, larger even than the Earth’s moon. Callisto, heavily pockmarked, is that most cratered object in the solar system.