Saturn Basic Facts 6 th Planet from the

Saturn

Basic Facts 6 th Planet from the Sun l 2 nd Largest Planet in the Solar System l 7 thin, flat rings l 62 Moons l

Ancient Observations Farthest planet prehistoric astronomers knew l Used in mythology l Planet can be seen by Earth with the naked eye, but the rings cannot l

Saturn the Name Roman god of agriculture and harvest l Father of Ceres, Jupiter, Pluto, and Neptune l Ruled during the Golden Age of Men l Saturn represents limits of control as it was thought to be the limit of the Solar System l

Unlucky Saturn l In Astrology, Saturn is blamed for all things sad, unfortunate, and terrible

But that doesn’t matter l l l l Because astrology is bollocks. Don’t believe in astrology. Look at me. Don’t. Believe. In. Astrology. It just makes scary things easier to deal with. Also its bollocks. Look. “Today you will feel a longing to reconnect with an old friend” There. Give me money. I’m magic.

Size of Saturn 2 nd largest planet in the Solar System l 95 Earth masses l “Gas Giant” along with Jupiter, Uranus and Neptune l Diameter 120, 540 km (10 x Earth) l

Density Lowest of all the planets l 1/10 the density of Earth l 2/3 dense as water l Saturn would float in water! l

Saturn’s Orbit Aphelion ~ 10. 1 AU ; Perihelion ~ 9. 0 AU l Period of Orbit – 29. 46 Earth years l Axis tilt of 27 degrees l Eccentricity of. 056 l Rotation is 2 nd fastest of known planets l Saturn rotates ~ 10 hours 39 minutes l

Shape of Saturn Rapid rotation causes the planet to bulge l Oblate spheroid – flattened at poles and bulges at equator l Rings l

Saturn’s Rings l l l Discovered by Galileo (1600 s) Rings tilt at same angle as equator ~20 m thick 93% water ice composition, 7% amorphous carbon 7 rings made up of thousands of ringlets, made up of billions of ice particles Particles range in size from dust to a car

2 Main Ring Theories l Theory 1 l Remnants l of destroyed moon of Saturn Theory 2 l Rings left over from original nebular material that formed Saturn l Some ice comes from the moon Enceladus’ ice volcanoes

Saturn’s Surface Saturn is a giant ball of gas l Believed to have no solid surface l Inner core of iron and rocky material l Outer core of ammonia, methane, and water l Liquid metallic hydrogen surrounds outer core l Hydrogen and helium in a viscous form l

Saturn’s Atmosphere l l The surface and atmosphere merge (hydrogen and helium) Dense clouds cover Saturn Difference in temperature and altitude cause patterns and color differences in cloud tops Hexagon clouds at North Pole

Temperature Tilt of axis causes seasons on Saturn l Each season = 7. 5 Earth years (Saturn takes 29 x longer than Earth to revolve) l Top of clouds is -175 degrees C (-285 F) l Below clouds is hot – planet gives off 2. 5 x the heat it receives from the Sun l

Moons 62 Moons l Largest, Titan (diameter 5, 150 km) is larger than Mercury and Pluto and contains an atmosphere l

Discovery Galileo discovered rings 1610, though believed they were moons on either side l Christian Huygens first coined “Rings” 1665 l

Exploration l 1973, Pioneer-Saturn launched by U. S. l Flew within 20, 900 km of Saturn l Sent close-up pictures l Discovery of 2 outer rings l Found a magnetic field 1000 times stronger than the Earth’s

Pioneer 11 Photos (1970 s)

Exploration l 1977, Voyager 1 and Voyager 2 l Confirmed existence of 7 th ring l Discovered planet’s rings are made of ringlets l Discovery of 9 satellites l Atmosphere of Titan is nitrogen

Photos from Voyager 1 Saturn l Haze over Titan l F Ring l

Photos from Voyager 2 Saturn l Iapetus l Enceladus l Titan l

Exploration l 1997 Cassini probe l Began orbiting Saturn in 2004 l Studying Saturn, its rings, and its satellites l First spacecraft to orbit Saturn (between F and G rings)

Cassini Probe New Moons Daphnis and Phoebe l Titan l Eclipse l

Saturn Mysteries? l Much to learn about the rings l Strange features l Clean ice suggests only few hundred million years old? Hexagon clouds at North Pole l Rotation impossible to pinpoint (approximate day calculated) l

References Spinrad, Hyron. "Saturn. " World Book Online Reference Center. 2004. World Book, Inc. http: //www. worldbookonline. com/wb/Article ? id=ar 492440. l http: //en. wikipedia. org/wiki/Saturn#Planeta ry_rings l