Science, Tech, Math › Science Saturn: Sixth Planet from the Sun Share Flipboard Email Print Saturn and its lovely rings, seen almost backlit. This is the second-largest gas giant planet. NASA Science Astronomy Stars, Planets, and Galaxies An Introduction to Astronomy Important Astronomers Solar System Space Exploration Chemistry Biology Physics Geology Weather & Climate By Nick Greene Astronomy Expert Nick Greene is a software engineer for the U.S. Navy Space and Naval Warfare Engineering Center. He is also the U.N. World Space Week Coordinator for Antarctica. our editorial process Nick Greene Updated May 04, 2019 The Beauty of Saturn Saturn is the sixth planet from the Sun and among the most beautiful in the solar system. It's named after the Roman god of agriculture. This world, which is the second largest planet, is most famous for its ring system, which is visible even from Earth. You can spot it with a pair of binoculars or a small telescope fairly easily. The first astronomer to spot those rings was Galileo Galilei. He saw them through his home-built telescope in the year 1610. From "Handles" to Rings Galileo's use of the telescope was a boon to the science of astronomy. Although he didn't realize the rings were separate from Saturn, he did describe them in his observing logs as handles, which piqued the interest of other astronomers. In 1655, Dutch astronomer Christiaan Huygens observed them and was the first to determine that these odd objects were actually rings of material circling the planet. Before that time, people were quite puzzled that a world could have such odd "attachments". Saturn, the Gas Giant The atmosphere of Saturn is made up of hydrogen (88 percent) and helium (11 percent) and traces of methane, ammonia, ammonia crystals. Trace amounts of ethane, acetylene, and phosphine are also present. Often confused with a star when viewed with the naked eye, Saturn can be clearly seen with a telescope or binoculars. Exploring Saturn Saturn has been explored "on location" by the Pioneer 11 and Voyager 1 and Voyager 2 spacecraft, as well as the Cassini Mission. The Cassini spacecraft also dropped a probe onto the surface of the largest moon, Titan. It returned images of a frozen world, encased in an icy water-ammonia mix. In addition, Cassini has found plumes of water ice blasting from Enceladus (another moon), with particles that end up in the planet's E ring. Planetary scientists have considered other missions to Saturn and its moons, and more may well fly in the future. Saturn Vital Statistics MEAN RADIUS: 58232 kmMASS: 95.2 (Earth=1)DENSITY: 0.69 (g/cm^3)GRAVITY: 1.16 (Earth=1)ORBIT PERIOD: 29.46 (Earth years)ROTATION PERIOD: 0.436 (Earth days)SEMIMAJOR AXIS OF ORBIT: 9.53 auECCENTRICITY OF ORBIT: 0.056 Satellites of Saturn Saturn has dozens of moons. Here is a list of the largest known ones. PanDistance (000km) 134 - Radius (km) 10 - Mass (kg) ? - Discovered By & Year Showalter 1990 AtlasDistance (000km) 138 - Radius (km) 14 - Mass (kg) ? - Discovered By & Year Terrile 1980 PrometheusDistance (000km) 139 - Radius (km) 46 - Mass (kg) 2.70e17 - Discovered By & Year Collins 1980 PandoraDistance (000km) 142 - Radius (km) 46 - Mass (kg) 2.20e17 - Discovered By & Year Collins 1980 EpimetheusDistance (000km) 151 - Radius (km) 57 - Mass (kg) 5.60e17 - Discovered By & Year Walker 1980 JanusDistance (000km) 151 - Radius (km) 89 - Mass (kg) 2.01e18 - Discovered By & Year Dollfus 1966 MimasDistance (000km) 186 - Radius (km) 196 - Mass (kg) 3.80e19 - Discovered By & Year Herschel 1789 EnceladusDistance (000km) 238 - Radius (km) 260 - Mass (kg) 8.40e19 - Discovered By & Year Herschel 1789 TethysDistance (000km) 295 - Radius (km) 530 - Mass (kg) 7.55e20 - Discovered By & Year Cassini 1684 TelestoDistance (000km) 295 - Radius (km) 15 - Mass (kg) ? Reitsema - Discovered By & Year 1980 CalypsoDistance (000km) 295 - Radius (km) 13 - Mass (kg) ? Pascu - Discovered By & Year 1980 DioneDistance (000km) 377 - Radius (km) 560 - Mass (kg) 1.05e21 - Discovered By & Year Cassini 1684 HeleneDistance (000km) 377 - Radius (km) 16 - Mass (kg) ? - Discovered By & Year Laques 1980 RheaDistance (000km) 527 - Radius (km) 765 - Mass (kg) 2.49e21 Cassini 1672 TitanDistance (000km) 1222 - Radius (km) 2575 - Mass (kg) 1.35e23 - Discovered By & Year Huygens 1655 HyperionDistance (000km) 1481 - Radius (km) 143 - Mass (kg) 1.77e19 - Discovered By & Year Bond 1848 IapetusDistance (000km) 3561 - Radius (km) 730 - Mass (kg) 1.88e21 - Discovered By & Year Cassini 1671 PhoebeDistance (000km) 12952 - Radius (km) 110 - Mass (kg) 4.00e18 - Discovered By & Year Pickering 1898 Updated by Carolyn Collins Petersen.