Ganymede

Ganymede is the largest moon in our whole solar system. It is even bigger than the planet Mercury. Ganymede orbits around Jupiter, the biggest planet. It has ice on the outside and rock and metal inside.

A Giant Moon

Ganymede is so big that if it went around the Sun by itself, it would be called a planet. It has light and dark areas on its surface. The dark areas are very old and full of craters. The lighter areas have long grooves that look like scratches. Ice covers most of the moon.

Its Own Magnetic Field

Ganymede is the only moon known to have its own magnetic field. A magnetic field is like a giant invisible force around it. Earth has one too, and it protects us from space weather. Scientists think Ganymede also has an ocean of salty water below its icy shell. That ocean might have more water than all of Earth's seas.

Fun Facts

• Ganymede was found by Galileo in 1610.
• It takes about 7 days to go all the way around Jupiter.
• Ganymede is about 3,270 miles wide.

Did You Know?

A spacecraft called JUICE is on its way to study Ganymede and should arrive at Jupiter in 2031.