Saturn: Sixth Planet from the Sun

Saturn - Ringed Planet - Saturn is the 6th From Sun
Saturn - Ringed Planet - Saturn is the 6th From Sun. NASA

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 km
  • MASS: 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 au
  • ECCENTRICITY OF ORBIT: 0.056

Satellites of Saturn

Saturn has dozens of moons. Here is a list of the largest known ones.

  • Pan
    Distance (000km) 134 - Radius (km) 10 - Mass (kg) ? - Discovered By & Year Showalter 1990
  • Atlas
    Distance (000km) 138 - Radius (km) 14 - Mass (kg) ? - Discovered By & Year Terrile 1980
  • Prometheus
    Distance (000km) 139 - Radius (km) 46 - Mass (kg) 2.70e17 - Discovered By & Year Collins 1980
  • Pandora
    Distance (000km) 142 - Radius (km) 46 - Mass (kg) 2.20e17 - Discovered By & Year Collins 1980
  • Epimetheus
    Distance (000km) 151 - Radius (km) 57 - Mass (kg) 5.60e17 - Discovered By & Year Walker 1980
  • Janus
    Distance (000km) 151 - Radius (km) 89 - Mass (kg) 2.01e18 - Discovered By & Year Dollfus 1966
  • Mimas
    Distance (000km) 186 - Radius (km) 196 - Mass (kg) 3.80e19 - Discovered By & Year Herschel 1789
  • Enceladus
    Distance (000km) 238 - Radius (km) 260 - Mass (kg) 8.40e19 - Discovered By & Year Herschel 1789
  • Tethys
    Distance (000km) 295 - Radius (km) 530 - Mass (kg) 7.55e20 - Discovered By & Year Cassini 1684
  • Telesto
    Distance (000km) 295 - Radius (km) 15 - Mass (kg) ? Reitsema - Discovered By & Year 1980
  • Calypso
    Distance (000km) 295 - Radius (km) 13 - Mass (kg) ? Pascu - Discovered By & Year 1980
  • Dione
    Distance (000km) 377 - Radius (km) 560 - Mass (kg) 1.05e21 - Discovered By & Year Cassini 1684
  • Helene
    Distance (000km) 377 - Radius (km) 16 - Mass (kg) ? - Discovered By & Year Laques 1980
  • Rhea
    Distance (000km) 527 - Radius (km) 765 - Mass (kg) 2.49e21 Cassini 1672
  • Titan
    Distance (000km) 1222 - Radius (km) 2575 - Mass (kg) 1.35e23 - Discovered By & Year Huygens 1655
  • Hyperion
    Distance (000km) 1481 - Radius (km) 143 - Mass (kg) 1.77e19 - Discovered By & Year Bond 1848
  • Iapetus
    Distance (000km) 3561 - Radius (km) 730 - Mass (kg) 1.88e21 - Discovered By & Year Cassini 1671
  • Phoebe
    Distance (000km) 12952 - Radius (km) 110 - Mass (kg) 4.00e18 - Discovered By & Year Pickering 1898

Updated by Carolyn Collins Petersen.