Viewed at radio wavelengths, the planet Saturn quite different than it does in visible light. It looks, in fact, remarkably like a hydrogen bomb explosion. Like Jupiter, Saturn is one of the monstrous “gas giants” of the solar system, made up mostly of gas with a relatively small rocky core. With radio observations astronomers can begin to understand Saturn’s dynamic and thick atmosphere. At its center, the planet appears quite bright and hot (red in this false color image) and gradually cools closer to the edges. This fading, known as “limb darkening,” results from Saturn’s increasing coldness at higher altitudes. The Earth does the same thing: there is a great deal of snow high in the Himalayas, but not much at sea level. Limb