Saturn

1. Saturn Presentation by: Heather DeRoy

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

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

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

5. Unlucky Saturn • In Astrology, Saturn is blamed for all things sad, unfortunate, and terrible

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

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

8. Saturn’s Orbit • Aphelion ~ 10.1 AU ; Perihelion ~ 9.0 AU • Period of Orbit – 29.46 Earth years • Axis tilt of 27 degrees • Eccentricity of .056 • Rotation is 2nd fastest of known planets • Saturn rotates ~ 10 hours 39 minutes

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

10. Saturn’s Rings • Discovered by Galileo (1600s) • Rings tilt at same angle as equator • ~20m 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

11. 2 Main Ring Theories • Theory 1 • Remnants of destroyed moon of Saturn • Theory 2 • Rings left over from original nebular material that formed Saturn • Some ice comes from the moon Enceladus’ ice volcanoes

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

13. Saturn’s Atmosphere • 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

14. Temperature • Tilt of axis causes seasons on Saturn • Each season = 7.5 Earth years (Saturn takes 29x longer than Earth to revolve) • Top of clouds is -175 degrees C (-285 F) • Below clouds is hot – planet gives off 2.5x the heat it receives from the Sun

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

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

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

18. Pioneer 11 Photos (1970s)

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

20. Photos from Voyager 1 • Saturn • Haze over Titan • F Ring

21. Photos from Voyager 2 • Saturn • Iapetus • Enceladus • Titan

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

23. Cassini Probe • New Moons Daphnis and Phoebe • Titan • Eclipse

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

25. References • Spinrad, Hyron. "Saturn." World Book Online Reference Center. 2004. World Book, Inc. http://www.worldbookonline.com/wb/Article?id=ar492440. • http://en.wikipedia.org/wiki/Saturn#Planetary_rings