The visible tops of clouds in a planet’s atmosphere. When we look at Jupiter in visible light (for example, with our eyes through a telescope), we are only able to see the tops of the clouds. The clouds are not flat, but towering, three-dimensional structures. In some places the tops of the visible clouds are at lower altitudes, allowing us to see deeper into the planet’s atmosphere. Juno will pass over Jupiter’s uppermost cloud tops at an altitude of only 3,100 miles (5000 kilometers) every 11 days.