1. Astronomy 04 The Solar System
Chapter 23: “Jupiter & Saturn”
Chapter 24: “Uranus, Neptune”
Reminder: Test 3 Review will be this Fri 6/13. Test 3 will be Mon 6/16.
Extra Credit Deadline is Mon 6/23 (Last Day of Classes)

2. A Comparison of Mercury Venus & Mars
Small Earth-sized Small
No atmosphere Thick CO2 atmosphere Thin CO2 atmosphere
No Clouds Sulfuric Acid Clouds Water Ice Clouds
Hot and Cold Hottest Planet (900F) Cold
Slow Rotation Slow Reverse Rotation 24-Hour Day
No Mag Field Weak Mag Field Weak Mag Field
Craters Large craters only Craters
Few Smooth Plains Lowland lava plains Lowland lava plains
Caloris Basin Dormant Volcanoes Extinct Volcanoes
Geo Dead Continental Areas Continental Areas
Geo Alive Vallis Marineris Canyon
Dry Riverbeds
Two Small Moons
Geo Dead

3. Jupiter is :
The largest of the planets in our Solar System.
Its radius is 11.3 Earth radii.
Its mass is 317 Earth masses.
It is composed mostly of hydrogen (90%) and helium (9%) and traces of everything else.
Jupiter's mean density is 1.3 gm/cc, close to that of water.

4. History of Exploration by Unmanned Spacecraft
Pioneers 10 & 11 - Launched in
Explored asteroid belt.
Flew past and photographed Jupiter and (Pioneer 11) Saturn.
Probed Jupiter’s intense radiation belts.

5. Voyager 1 & 2 - Launched in 1977
Photographed Jupiter, Saturn and (Voyager 2) Uranus and Neptune.
Made possible by rare, once in 175-year, alignment of planets.

8. Galileo Spacecraft:
Released probe into Jupiter’s atmosphere.
Impact Jupiter after successful orbital mission.
Photographed Jupiter and its Satellites.

9. Cassini Spacecraft:
The Cassini Spacecraft has been in orbit about Saturn for the past two years.

10. Basic Characteristics:
1) Large size but low density
Jupiter: 318X mass of Earth
Density 1.3 g/cm3.
Saturn: 95X mass of Earth
Density 0.7 g/cm3.
Uranus &
Neptune 15X mass of Earth
Density 1.6 g/cm3.

11. Basic Characteristics:
2) Composition & Chemistry
Hydrogen (H)
Helium (He)
Methane (CH4)
Sulfur
Ammonia (NH3)
Acetylene (C2H2)
Ethane (C2H6)

12. Basic Characteristics: 3) Equatorial cloud belts: Jupiter & Saturn:
Clouds of ammonia and sulfur compounds.
Uranus:
No visible clouds.
Neptune:
Clouds of methane crystals.
Jupiter

14. Basic Characteristics:
4) Fast rotation
Jupiter in 9 hours 56 minutes
Saturn in 10 hours 40 minutes.
Rapid rotation causes distention at the equator so that equatorial diameter is greater then polar diameter.

16. Chapter 24: “Jupiter & Saturn”
Ju[iter
Jupiter
Jupiter

17. Jupiter
Saturn

18. Uranus
Neptune

21. The equatorial belts are bands of clouds moving with velocities up to 400 miles/hr. Wind direction alternates from one band to another.
The light colored zones are regions of upward moving convective currents. The darker belts are made of downward sinking material. The two are therefore always found next to each other.
The boundaries between the bands display complex turbulence and vortex phenomenon.

22. Wind velocities in the atmospheres of the Gas Giant plants increase from Jupiter to Neptune.
Winds in the atmosphere of Neptune were recorded at over 1300 mph.

23. Jupiter has a giant, strong magnetic field and trapped radiation belts.
Jupiter is a strong emitter of synchrotron radiation (radio waves) caused by electrons accelerating along the planet’s magnetic lines of force.
Jupiter radiates more energy than it receives from the Sun. This heat is generated from slow contraction.

24. Jupiter’s Great Red Spot is almost 20,000 miles long
Jupiter’s Great Red Spot is almost 20,000 miles long. It is a massive high pressure system which rotates in 6 days.
Without surface friction to slow their speed, storms last for hundreds of years or longer.

25. Moons of Jupiter
61+ Moons and a Faint Ring
Galilean Satellites:
Ganymede & Callisto – Larger than Mercury
Io & Europa are about the size of our Moon
Many of other Moons may be captured Asteroids

27. Callisto is the outermost of Galilean moons at a distance of 1
Callisto is the outermost of Galilean moons at a distance of 1.2 million miles.
It is in synchronous revolution around Jupiter every 17 days.
The moon has a heavily cratered surface that has seen little change over the last 4.4 billion years.
CALLISTO

28. Callisto froze solid before the process of differentiation occurred
Callisto froze solid before the process of differentiation occurred. It is a geologically dead world.
CALLISTO

29. Closeup of Callisto

30. Ganymede is the largest moon in the Solar System.
Parts of its surface are very old like Callisto but others are relatively young, perhaps a billion years old.
Ganymede may have a rocky, metallic core.
Tidal forces may occasionally heat the interior and cause water to erupt and resurface portions of the moon.
GANYMEDE

31. Closeup of Ganymede

32. Europa is predominantly a rocky world with an ice-covered surface that is crisscrossed with cracks and low ridges.
Few craters are evident.
The ice appears to be the frozen surface of a great water ocean that has broken up and refrozen many times.
EUROPA

33. Tidal forces may generate enough heat to keep water in the liquid state not too far beneath the surface layer of ice.
EUROPA

34. Closeup of Europa

35. Io is a close twin our Moon with about the same size and density.
Io has active volcanoes on its surface. Volcanoes emit hot rocky lava, sulfur and sulfur dioxide.
The sulfur and sulfur dioxide recondense in the cold and snow down upon Io’s surface. IO

36. Io is constantly resurfacing itself.

37. Closeup of Io

38. Today we will see the Sky Skan Full Dome Presentation
… “Saturn: Jewel of the Heavens”
Reminders: Extra Credit Deadline is this Fri 6/22
Your final exam is Wed 6/27 at 7:00 a.m.

39. Cloud belts of Saturn as viewed by Cassini spacecraft

40. Photograph of “dragon storm” in Saturn’s
atmosphere (Cassini spacecraft)

41. All four giant planets have rings.
Saturn’s Rings are ice particles spread out into several vast flat rings.
Uranus and Neptune’s rings are composed of dark particles confined to a few narrow rings.
Jupiter’s ring is composed of dust particles. Io

42. Saturn’s Rings as viewed by the Cassini spacecraft

43. The Sun seen through Saturn’s rings as photographed by Cassini spacecraft.

44. Electrically charged clouds of dust particles floating above Saturn rings (Cassini spacecraft)

46. Moons of Saturn
31+ Moons and Massive Ring System
Titan is most significant satellite and the only moon with a significant atmosphere
Ring material size of ping-pong, tennis and basketballs.

47. Saturn’s Titan is about the size of Jupiter’s Ganymede and is about half ice and half rock.
It is the only moon to have a substantial atmosphere.
The atmospheric surface pressure is 1.6 times that of Earth. Io

48. Titan’s atmosphere is composed mostly of methane
Titan’s atmosphere is composed mostly of methane. Nitrogen and hydrocarbon compounds are also present.
Methane clouds composed of shroud the surface. The surface is probably covered with methane ice and perhaps methane oceans. Io

49. False color image of Titan by Cassini revealing surface features

50. Surface of Titan in color as viewed by
the Huygens probe

51. Clouds over Titan’s south pole

52. Uranus

53. Rings
of Uranus

54. Neptune has a storm similar to the great Red Spot called the Great Dark Spot.

56. Moons of Uranus
26+ Moons and 11 Dark Rings
Miranda – A Moon that may have broken up and then reassembled.
Moons of Neptune
13+ Moons
Triton – A large satellite in retrograde orbit

57. Miranda

58. Triton is the largest moon of Neptune.
It has the coldest temperature of any object unmanned spacecraft have visited – degrees above Absolute Zero.
Triton is so cold that N and CH4 are frozen on its surface.
The moon is 75% rock and 25% water ice. Io