What are Jupiter's dark atmospheric bands called?

Jupiter’s dark atmospheric bands are called belts. They alternate with lighter bands known as zones, creating the striped appearance visible through telescopes and spacecraft images.

The belts and zones are broad east–west regions organized roughly parallel to Jupiter’s equator. Powerful jet streams separate them, and winds in neighboring bands can move in opposite directions. In the upper atmosphere, zones generally contain brighter, higher ammonia-ice clouds, while belts tend to have darker, thinner clouds at lower altitudes.

The pattern is more than a surface marking: it reflects deep atmospheric circulation. Gas often rises in the zones and descends in the belts in the upper layers, although Juno’s microwave observations show that Jupiter’s weather extends far below the visible clouds. The exact chemistry responsible for the belts’ darker colors remains uncertain; sulfur-, phosphorus-, and carbon-bearing compounds may contribute.

A frequent mix-up is reversing the terms. Belts are darker, while zones are lighter. Faculae are bright patches associated with some planetary surfaces, and rilles are channels on the Moon or other rocky bodies—not names for Jupiter’s cloud bands.