Giant Worlds March 2, 2011

Beyond Mercury, Venus, Earth and Mars are four colossal, gaseous planets that dwarf the inner, terrestrial planets. The Solar System's outer, giant planets - Jupiter, Saturn, Uranus, and Neptune - present some fascinating mysteries: enormous hurricanes that last for centuries; moons that harbor vast oceans below an icy surface; and magnetic environments that can generate massive storms of charged particles. As our knowledge of the giant planets has evolved, we've discovered that each one is a complete system that is more diverse and extraordinary than we previously understood. Since Galileo first glimpsed the rings of Saturn in 1610, the beauty of the outer Solar System's giant planets has captivated us. Now scientists are seeing beyond their beauty to gain a deeper understanding of their importance. Where do these fascinating worlds call home? What role does gravity play in planetary formation? What tools do we use to study them either from Earth's neighborhood or up close?