Note: Ganymede is the largest moon of Jupiter and is the largest in our solar system. If Ganymede orbited around the Sun instead of Jupiter, it could be classified as a planet. Ganymede has no known atmosphere, but the Hubble Space Telescope detected ozone at its surface, however the amount is small as compared to that of Earth. It has a thin tenuous oxygen atmosphere like that detected on Europa. Ganymede has a varied terrain that includes mountains, valleys, craters and lava flows, and is mottled by both light and dark regions.