Callisto may not make headlines like Io or Europa, but its beauty is unmatched. See this mysterious moon as you’ve never seen it before with these stunning high-resolution images. Dive into the ...

There are currently 92 moons known to orbit Jupiter. The four largest – Io, Europa, Ganymede and Callisto – were discovered by Galileo Galilei in 1610 when he pointed the first astronomical telescope ...