One of the big surprises: Despite the moon's cooled crust, the data shows Io maintains liquid hot lava just below the ground.

Recent flybys of the fiery world refute a leading theory of its inner structure — and reveal how little is understood about ...

Simply look to the western sky after sunset. The delicate form of the crescent moon is set to draw close to the planet Jupiter in the post-sunset sky on April 29, before later making its closest ...