This mission will spend several years studying the icy Galilean moons Europa, Callisto, and Ganymede in an attempt to better understand their formation, structure, and evolution.

This gas giant has some really unique features that make it stand out. If you’re curious about space, learning a few things ...

Both moons, as well as the two largest Galilean moons, Ganymede and Callisto, are tidally locked – they rotate once around their own axis during one complete orbit of the planet. This means one side ...

Most of us know four moons of Jupiter, called the Galilean moons because they were first discovered by Galileo in 1610. Named for figures closely associated with Jupiter from Greek mythology, Io ...

The two Galilean moons of Io and Europa (left to right) can also be seen. (CORBIS/Corbis via Getty Images) On Jan. 7, 1610, Galileo discovered four moons revolving around Jupiter — a discovery ...

Jupiter's four best-known moons are the Galilean moons, discovered by Galileo Galilei in 1610. They are named Ganymede, Callisto, Io and Europa, after figures in Greek mythology associated with ...

Unlike the four large "Galilean" moons, which have some dramatic features like volcanoes and subsurface oceans, the ones that Sheppard finds are tiny and orbit far out.

The moons’ extremely thin atmospheres make their red auroras shine far more intensely than their green ones do. Io, the oddest Galilean satellite, has a streetlamp-like yellow-orange radiance.

Jupiter's Galilean moons are also visible this evening, but spotting them may be challenging with the planet so low. If you want to try, note that your location - which will affect the time you're ...

Jupiter's four Galilean moons were discovered by Italian astronomer Galileo Galilei in 1610. NASA's Juno spacecraft launched from Earth in 2011 and entered Jupiter's orbit in 2016.