Science Education

Privacy and Security Notice

Light and Dark Swirls on Ganymede

It is thought that the light areas are younger than the dark areas. Scientists can tell how old something is by counting the number of craters on it. The more craters there are, the older the surface is.

Other photos of Ganymede

• Rills on Ganymede

Want to re-read about Ganymede?

• Return to Ganymede Fact Page

Click below to return to Jupiter

• Mission Briefing

Click below to go to another moon

• Io
• Europa
• Callisto