Saturn
DISTANCE FROM SUN: 887 million miles (1.427 million kilometers).
REVOLUTION AROUND SUN: 29.5 years.
ROTATION: 10 hours, 14 minutes.
DIAMETER: 74,600 miles (120,000 kilometers).
DENSITY: 0.7 x that of water.
MASS: 95 x that of Earth.
SURFACE TEMPERATURE: -288°F (-178°C) at cloud tops.

Satellites (closest to most distant):
Pan
Atlas
Prometheus
Pandora
Janus
Epimetheus
Mimas
Enceladus
Tethys
Telesto
Calypso
Dione
Helene
Rhea
Titan
Hyperion
Iapetus
Phoebe

Gliding across the night sky like a ballerina in a tutu, Saturn is among the most graceful sights in the solar system. The earliest telescope observers were dazzled by its ring system—once thought to be the only such structure among the planets, now known to be common to all the gas giants.
Saturn is the second-largest planet but it spins very rapidly: Its day is just over 10.5 hours long.
If you dropped a slice of Saturn in a lake, it would float like a styrofoam raft. It is the only planet with less density than that of water.
Like Jupiter, Saturn is marked by horizontal stripes created by violent wind currents. Near the equator, winds reach 1,100 miles (1,600 kilometers) per hour, primarily in an eastward direction. Nearer the poles, wind speeds drop considerably, and even alternate their direction between east and west.

FAMILIAR RINGS Visible even with a small telescope, Saturn’s rings are divided into distinct sections. The earliest observers divided them into two bright rings called A and B, and a fainter C ring. Not until the Voyager probes of the 1970s, however, was it discovered that the larger rings are actually made up of numerous much smaller ringlets. The A and B rings are separated by a gap, discovered in 1675 by Giovanni Cassini, and thus named the Cassini division. More than a century and a half later, astronomer Johann Encke observed that the A ring is split into two by a gap now called the Encke division.
Scientists are still not certain what created Saturn’s rings, which are probably made up largely of ice chunks measuring up to several yards wide. It is possible that they are the remains of moons or interloping bodies, shattered by collisions or disrupted by tidal forces.
The narrow rings of Saturn show unusual shapes, and at times seem to intertwine. The gravitational effect of nearby moons create the effect. The F ring, in particular, is clearly misshapen due to two small shepherd moons that trace its outline.

SATURN’S STORMS Observed from above, storms on Saturn’s surface appear white due to chunks of ammonia ice being tossed around. A Saturn storm may equal or even exceed the Earth’s diameter. The largest observed storm, seen by the Hubble Space Telescope, was stretched out by the wind until its clouds reached clear around Saturn—just under 75,000 miles (120,600 kilometers). As on Earth, the planet’s most ferocious storms seem to occur near the equator.
Aurora sometimes glow at Saturn’s poles (shown here), reaching as high as 1,200 miles (2,000 kilometers) above the cloud tops. They can change radically in appearance within just a few hours. Saturn’s aurora may be produced when electrified particles trapped in the planet’s strong magnetic field collide with atmospheric gases.

A FAMILY OF MOONS Like Jupiter, Saturn resembles a miniature solar system, with 18 named satellites and four other possible moons. Sighting undiscovered moons around Saturn can be tricky, because virtually all of them orbit directly on the same plane as the planet’s bright rings.
Titan, the orange-colored moon, was long thought to be the largest satellite in the solar system, but recent observations show that Titan’s thick atmosphere hides a solid surface that’s slightly smaller than Jupiter’s moon Ganymede. Titan is also a bit smaller than Mars, and may be the only body in the solar system besides Earth that may have oceans and rainfall on its surface. It must be noted, though, that those oceans would be of ethane-methane. Haze obscures the moon, but Hubble Space Telescope observers detected what may be large surface markings, including a region about the size of Australia.
Titan is the only satellite in the solar system with a significant atmosphere. It is four times thicker than Earth’s, an orange haze of hydrocarbons. The haze obscures the surface, but Hubble Space Telescope observers used various wavelengths to map much of its surface, including a prominent elevated surface area about the size of the United States.