Saturn
Saturn is the sixth planet from the Sun
the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus (the Titan father of Zeus), the Babylonian Ninurta and the Hindu Shani. Saturn's symbol represents the Roman god's sickle (Unicode: ♄).
Saturn, along with Jupiter, Uranus and Neptune, is classified as a gas giant. Together, these four planets are sometimes referred to as the Jovian, meaning "Jupiter-like", planets. Saturn has an average radius about 9 times larger than the Earth's. While only 1/8 the average density of Earth, due to its larger volume, Saturn's mass is just over 95 times greater than Earth's.
Because of Saturn's large mass and resulting gravitation, the conditions produced on Saturn are extreme if compared to Earth. The interior of Saturn is probably composed of a core of iron, nickel, silicon and oxygen compounds, surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium and finally, an outer gaseous layer. Electrical current within the metallic-hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is slightly weaker than Earth's magnetic field and approximately one-twentieth the strength of the field around Jupiter. The outer atmosphere is generally bland in appearance, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 km/h, significantly faster than those on Jupiter.
Saturn has nine rings, consisting mostly of ice particles with a smaller amount of rocky debris and dust. Sixty-two[16] known moons orbit the planet; fifty-three are officially named. This is not counting hundreds of "moonlets" within the rings. Titan, Saturn's largest and the Solar System's second largest moon (after Jupiter's Ganymede), is larger than the planet Mercury and is the only moon in the Solar System to possess a significant atmosphere.
Orbital characteristics
- Epoch J2000.0
Aphelion 1,513,325,783 km
10.115 958 04 AU
Perihelion 1,353,572,956 km
9.048 076 35 AU
Semi-major axis 1,433,449,370 km
9.582 017 20 AU
Eccentricity 0.055 723 219
Orbital period 10,759.22 days
29.4571 yr
24,491.07 Saturn solar days
Synodic period 378.09 days
Average orbital speed 9.69 km/s
Mean anomaly 320.346 750°
Inclination 2.485 240° to Ecliptic
5.51° to Sun’s equator
0.93° to Invariable plane
Longitude of ascending node 113.642 811°
Argument of perihelion 336.013 862°
Satellites ~ 200 observed (61 with secure orbits)