1 THE RINGS OF SATURN You are cruising in the troposphere of Saturn under the most magnificent ring structure in the solar system. Few sights are more astounding. The white, icy rings soar 75,000 kilometers above your head. Ring shine illuminates everything around you. No fewer than six crescent moons rise in the sky. The light from the setting sun scatters against a mist of ammonia crystals, forming a sun dog. You are buffeted by ammonia clouds that stream by you at speeds greater than 1,500 kilometers an hour. These are some of the fastest winds in the solar system. More than 30,000 kilometers below you, with pressures no human-made thing could survive, is a global ocean of liquid metallic hydrogen. There will be no landing on this planet.