NASA scientists have sought to understand planet Jupiter, the gas giant whose mass is more than the rest of the planets in ...

But it hasn’t always been this way. Jupiter’s four largest moons – Io, Europa, Ganymede and Callisto – were the first ever discovered orbiting another planet. They were spotted by Galileo ...

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

Discover the planet that has the most moons. This planet is a ringed giant and the second largest in the solar system.

On the fiery Io, the innermost and third-largest of Jupiter’s four Galilean moons, Juno's observations have provided more insights about its incessant volcanic activity. It's a world home to ...