This image was taken Dec. 13, 2000, by NASA's Cassini spacecraft. It shows how the banding of Jupiter gives way to a more mottled appearance as the clouds reach higher altitudes. This tapestry effect is the result of atmospheric changes, according to NASA. Most visible clouds are composed of ammonia. The planet's "stripes" are dark belts and light zones created by strong east-west winds in Jupiter's upper atmosphere. Experts also believe Jupiter emits almost as much heat as it absorbs from the sun, and it does so more at its poles.