1. Solar System Chapter

2. Planet Groupings Terrestrial Planets – Inner Mercury Venus – Earth – Outer Mars Gas Giants – Naked Eye Jupiter Saturn – Discovered with Telescopes Uranus Neptune

3. Terrestrial Planets

5. Mercury Page 135-141

6. Mercury Visible Only a few hours before sunrise or after sunset. Sometimes the brightest object in the sky – Dark surface – Close to sun Temperature Extremes – Thin, Transient atmosphere (H 2, He, Na,K,O 2 ) – Solar day is 176 earth days long

9. Mercury Surface Like Lunar landscape – Many impact craters No maria – Plains Scarps – Long Cliffs – Cooled, contracted, collapsed nonuniformily

13. Caloris Basin Caloris = “heat” Closest area to the sun – Near Terminator Huge impact area – Twice Size of Texas Small craters filled with lava Opposite side jumbled hilly surface – Energy focused by the planet like a lens

14. By the Numbers StatisticMercuryEarth Avg Distance from Sun.387 AU1.0 AU Eccentricity.21.017 Orbital Speed47.9 km/s29.79 km/s Period of Revolution (Yr)88.0 Earth Days365.26 Days Rotation (Day)176 Earth Days24 hours Inclination to orbit.5 o 23.5 o Radius.382 Earth radii 1 Mass.0553 Earth mass 1 Density5430 kg/m 3 5520 kg/m 3 Gravity.38 Earth 1 Albedo.12.37 Avg Temperature350 O C, -170 O C60 O C, -90 O C AtmosphereThin, Transient, H, He,Na,K,ON 2,O 2, CO 2, H 2 O (vapor)

15. Crust

16. Interior Structure Average density similar to earth – Dense interiors – 5430 kg/m 3 versus 5520 kg/m 3 High Iron content – Low iron on surface – High percent from core (Earth 17%, Mercury 42%) Rocky Mantle Thin crust Earth’s Greater Volume compresses interior

19. Venus Page 141-147 Bright Morning or Evening Star Goddess of Love Earth’s Sister Planet

21. Comparisons Mercury and Venus – Not much in common – Neither has a moon – Venus twice distance from sun Venus and Earth – Same mass – Same size – ergo: same density – Venus is 30% closer to sun than earth

23. Appearance One of the brightest objects in sky – Sun and moon brighter Evening or Morning Star – Higher in sky than Mercury Often mistaken for a UFO – Light is refracted by atmosphere – Changes color and position Very bright – Light colored reflective clouds

24. 1960’s Probes US and Soviets sent probes – US light weight orbiters – Russians heavy landers Soviets – Venera 1970- 1983 – Transmitted for 23 minutes in 1970 – Surface Temperature 750k (900 F) – Atmospheric Pressure 90 atm (90x earth), 2700ft underwater (1/2 mile)

26. Atmosphere Content – 96% Carbon Dioxide – 4% mostly Nitrogen – Vented from inside the planet Clouds – Layer between 48 to 68 km – Haze 20 km above and 20 km below – Appear yellow due to presence of sulfur – Droplets of concentrated sulfuric acid

27. Volcanoes Sulfur compounds – breakdown easily, must be replenished – likely from volcanoes Lightening – Indicate volcanoes – Cause short lived magnetic field

28. Intense Greenhouse Effect Carbon dioxide is transparent to visible light. Most of sunlight that strikes Venus is reflected Some strikes the surface-heats the surface Heat energy is reflected as infrared Carbon dioxide absorbs this infrared radiation Atmosphere heats Some returns to surface, some radiated to space. Equilibrium is reached but very hot 750 K

30. Surface Features No water – Venusian rock quite similar to lava rock on earth – basalt see page 144 Surface mapped by radar from orbiting probes – Flat – Volcanic plains (filled smooth with lava) – Gentle rolling hills – 2 large highland areas (continents?)

33. Venus surface (continued) Northern highland – Ishtar Terra – Babylonia goddess of love – size of Australia – highest mountain – Maxwell Montes 11km versus 9km for Mt Everest Largest highland area – Aphrodite Terra – Roman goddess of love – Straddles the equator – ½ size of Africa No plate tectonics

35. Craters on Venus 1600 Volcano craters Fewer than 1000 impact craters Thick atmosphere vaporizes infalling objects

37. Composite of Infrared Images

39. Retrograde Rotation Rotation is clockwise while revolution around sun is counterclockwise. Tilt to the axis is 177 o Monumental Impact flipped the planet over Earth 23 o Venus 177 o

40. By the Numbers StatisticVenusEarth Avg Distance from Sun.723 AU1.0 AU Eccentricity.007.017 Orbital Speed35.0 km/s29.79 km/s Period of Revolution (Yr)224.7 Earth Days365.26 Days Solar Rotation (Day)116.8 Earth Days24 hours Inclination to orbit177.4 o 23.5 o Radius.949 Earth radii1 Mass.815 Earth mass1 Density5240 kg/m 3 5520 kg/m 3 Gravity.91 Earth1 Albedo.59.37 Avg Temperature460 O C60 O C, -90 O C Atmosphere96.5% CO 2, 3.5% N 2,.003 H 2 O N 2,O 2, CO 2, H 2 O (vapor)

41. Solar System

42. Mars Page 147-162 God of War Alien Lair

44. Favorite Hangout for Aliens Christian Huygens telescopic observations – 1659 – Dark surface feature – 24 hour rotation Giovanni Schiaparelli – 1877 – 40 dark lines – Canali = channels, translated as Canals

46. Aliens continued Percival Lowell – Wealthy – Built major observatory (late 19 th century) – “Observed” 160 Martian canals – Speculated canals used to bring water from polar ice caps to dry equatorial area War of the Worlds – Orson Welles radio broadcast – Martian invasion – Listen Listen

50. Spacecraft to Mars Beginning in the 1970’s Mariner Missions Currently 3 Rovers on Mars (2 active) Surveys Pictures Chemical Sampling Planned manned missions to Mars ???

51. Mars Surface Red – rocks and dust indicating high iron oxide Dry- dusty (dust storms and dust devils) Broad plains Shallow craters Enormous inactive volcanoes Vast canyons

56. Mars Surface continued Vastitas Borealis – Northern Vastness or Northern Lowlands Southern Highlands – 5km higher than north – Heavily cratered – hilly plains Difference may be due to Plate Tectonics Valles Marineris – Parallel to equator – 4000 km (1/5 of circumference) – 4 miles deep and 120 miles wide – Large crack that formed as planet cooled. – Like a Grand Canyon from Los Angeles to New York

58. Olympus Mons Largest Volcano in the solar system Size of Missouri 16 miles (26 km) high – 3x Mt Everest – Mauna Loa (highest on earth) 17 km above ocean floor

59. Olympus Mons and Hawaiian Islands

60. Cluster of Cones Near Olympus Mons Cone shaped craters Similar cones in Iceland on Earth Believe they were formed by water under the surface vaporized by lava from the volcano and burst through the surface Compare to the holes in pancakes-

62. Other Evidence for water on Mars Polar Ice Caps – Frozen carbon dioxide on surface – Perhaps frozen water under surface Dried up river beds River deltas Sedimentation laid down by water Water formed hematite Recent evidence of flow

70. Evidence for water on Mars “Bubble” Cones Polar Ice Caps – Frozen carbon dioxide on surface – Perhaps frozen water under surface Dried up river beds River deltas Sedimentation laid down by water Water formed hematite Recent evidence of flow

71. Search for Life on Mars No canals or cities No structures Viking spacecraft in 1975 – Compact biological laboratory – No evidence of life – Methane – produced by life forms (cow burps) Meteorites from Mars on Earth – Possible bacterial life

73. Martian Atmosphere Very thin – 0.6% of earth atmospheric pressure 95% Carbon Dioxide – Nitrogen, Argon, trace Oxygen – Little water vapor because of low gravity

74. Martian Interior Lots of questions waiting for seismic detectors Crust 40km thick in north/70km in south Molten core – Less molten than earth – Once more molten No magnetic field, but once had magnetic field No tectonic plate motion now

75. Martian Moons Two tiny moons close to surface – Discovered in 1877 – Phobos = fear – Deimos = panic Phobos – Larger – Potato shaped – Heavily cratered Deimos – Football shaped Captured planetesimals (rock fragments)

76. By the Numbers StatisticMercuryVenusEarthMars From Sun.387 AU.723 AU1.0 AU1.52 Eccentricity.21.007.017.093 Orbit Speed47.9 km/s35.0 km/s29.79 km/s24.1 km/s Revolution88.0 Earth Days224.7 Earth Days365.26 Days687 earth days Solar Day176 Earth Days116.8 Earth Days24 hours24 hr 39m 35s Inclination.5 o 177.4 o 23.5 o 25.19 o Radius.382 Earth radii.949 Earth radii1.53 earth radii Mass.0553 Earth mass.815 Earth mass1.107 earth mass Density5430 kg/m 3 5240 kg/m 3 5520 kg/m 3 3950 kg/m 3 Gravity.38 Earth.91 Earth1.38 earth Albedo.12.59.37.16 Avg Temp350 O C, -170 O C460 O C60 O C, -90 O C20 O C, -140 O C AtmosphereThin, Transient, H, He,Na,K,O 96.5% CO 2, 3.5% N 2,.003 H 2 O N 2,O 2, CO 2, H 2 O (vapor) 95.3% CO 2 2.7% N 2,.03% H 2 O

77. Comparison of Planetary Features Page 160-162 Table 5-1

79. Planet Project Graphic Display – Photos and information Written Report (+500 words) Oral Presentation 3 Sources – Astronomy magazine – Text book – One other- “not wiki” Physical description – Size, orbit, rotation, orbit – Moons – Unusual feature Space probes that have visited – Names, dates, what was discovered