Chapter 9MercurySurface of MercuryCaloris BasinChaotic TerrainTemperature and AtmosphereMercury’s InteriorMassive ImpactRotationSlide 10Slide 11Venus The Morning/Evening “Star”Atmosphere of VenusVortexes at PolesGreenhouse Gone WildSurface of VenusSurface of VenusSurface FeaturesInterior of VenusVenus’ RotationWhat kind of features dominate Venus’ landscape?Slide 22Why is Venus hotter than Mercury?Mars “The Red Planet”Notable FeaturesSurface of MarsValles MarinerisTharsis Bulge and Olympus MonsPolar CapsWater on MarsSlide 31Water on MarsWe found it!Martian AtmosphereMartian InteriorMartian MoonsLife on Mars?Slide 38What is the name of largest mountain in the solar system?Mars has no magnetic field. What does this imply?Why are the Terrestrial Planets so DifferentWhy are the Terrestrial Planets so DifferentWhy are the Terrestrial Planets so DifferentWhere did all the CO2 from Earth’s atmosphere go?Slide 45Slide 46Chapter 9The Terrestrial PlanetsMercury•1.4x Moon’s radius, 4.5x Moon’s mass•1/3 Earth’s radiusSurface of Mercury•Craters and rays like moon•New feature: Scarps•Formed as planet cooled and shrankCaloris Basin•Depression 1300 km across surrounded by a ring of mountains.•3.8 billion years old (around same time as Mare Orientale on moon)•Several interesting features: volcanoes, radial cracks, and…Chaotic Terrain•Opposite side of planet from Caloris Basin•Convergence of seismic wavesTemperature and Atmosphere•Slow rotation + lack of atmosphere = huge temperature swings•710K (820ºF) at noon at equator. 80K (-320ºF) at night.Mercury’s Interior•High average density (5.4 g/cc) and gravitational fields suggest large iron-rich core with thin silicate mantle?•How did the silicate mantle get so thin?•So close to sun that silicates had trouble condensing•MASSIVE IMPACT•Liquid core (weird) but small magnetic field (1% of Earth)Massive ImpactRotation•1 rotation = 59 days•1 orbit = 88 days•3 rotations per 2 orbits•Resonance and Tidal Forces!Which of the following is NOT responsible for Mercury’s wild temperature swings?A. Slow rotationB. Lack of atmosphereC. Close to the sunWhat is it called when rotation periods and orbital periods are a precise ratio?A. Ratio orbitsB. ResonanceC. Residual orbitsD. Retrograde motionVenusThe Morning/Evening “Star”gvenus = 8.87 m/s2Atmosphere of Venus•Thick (100x atmospheric pressure on Earth), lots of CO2.•HOT (>750ºF, 900 K)•Heat from Sun drives fast winds•Clear below the cloudsVortexes at PolesGreenhouse Gone Wild•Opposite problem of Mercury. Venus can’t get rid of it’s heat.•300,000x more CO2 than Earth.•Venus used to have more water. (be careful, Earth)Surface of Venus•Pictures from Russian “Venera” program from 70s and 80s•Clear below clouds, everything has an orange tintSurface of Venus•Flatter than Earth. Mostly rolling plains of lava fields.•Highlands are a granite-like material, which needs HOH to form!Surface Features•Most surface features are volcanic•Most of the surface is <0.5 billion years old, may be current activity•Lava plumes everywhere?Interior of Venus•Same-ish size as Earth, but very different•Thicker crust than Earth•Results from less water content in the rocks. (makes them “runnier” and melt at lower temperatures on Earth)Venus’ Rotation•“Retrograde” rotation•1 Orbit = 243 days1 solar day = 117 days•“Solar day”•How did Venus get backwards?•Started normal, tidal forces slowly flipped it upside-down •MASSIVE IMPACTWhat kind of features dominate Venus’ landscape?A. Volcanic featuresB. Features formed by liquid waterC. Ice-capsD. CratersWhich of the following is NOT a possible explanation for Venus’ backwards rotation?A. Venus always rotated backwardsB. Gravitational interactions tilted the axis all the way aroundC. Massive impactWhy is Venus hotter than Mercury?A. Venus is closer to the SunB. Venus has a smaller atmosphere than MercuryC. Venus’ atmosphere retains most of its heatD. Venus rotates backwardsMars “The Red Planet”Notable Features•Surface gravity = 3.71 m/s2•Warm day at equator is 50ºF•Winds sweep clouds of dust and ice crystals through an otherwise clear sky•Sparkling white polar caps (north bigger than south)•Why is Mars red? Iron minerals in the dust (not rust)Surface of Mars•Valles Marineris (huge rift) Tharsis Bulge Olympus MonsValles Marineris•4000 km long, 100 km wide, 7 km deepTharsis Bulge and Olympus Mons•Probably caused by hot material rising underneath.•Less than 250 million years old, maybe active more recently•Are Tharsis Bulge and Valles Marineris related?•Olympus Mons: biggest mountain in Solar SystemPolar Caps•Sizes change with season•Surface layer is CO2 but rest is HOH.•Layers suggest cyclical changes with seasons.•Why is southern cap smaller?Water on Mars•Water crucial for life, so it’s of great scientific interest•Viking —> Pathfinder —> Spirit & Opportunity —> Curiosity•Evidence of past water is all over Marsxkcd’s take on Spirithttps://xkcd.com/695/Water on MarsMartian “blueberries”Likely iron depositsfrom standing waterWe found it!•Image credit: NASA•Streaks of mineral deposits with water in the crystal structures•Indicates slow trickle of salty water just underneath the surface.Martian Atmosphere•Very thin atmosphere. Used to be more dense.•95% CO2 with 3% N2. Trace O2 and water.•Average temperature is -67ºF.•Clouds of dry ice and water ice.•No rain. Too cold and dry.•Where did atmosphere go?•Low gravity allowed it to escape•MASSIVE IMPACTMartian Interior•Thick crust•Intermediate tectonic activity•Surface has been quiet for a while, for the most part.•No magnetic fieldMartian Moons•Phobos has cracks, suggesting some sort of MASSIVE IMPACT in its past.“Gravity wells”Life on Mars?•Not yet.•Little green microbes, not little green men.If Mars’ atmosphere is mostly CO2 why is there no greenhouse effect?A. Mars is too small to have a greenhouse effectB. Mars is too far from the Sun to have a greenhouse effectC. Mars has too thin an atmosphere to have a greenhouse effectD. There is TOO MUCH carbon dioxide, choking out the greenhouse effectWhat is the name of largest mountain in the solar system?A. Mount OlympusB. Olympus MonsC. Mount EverestD. K2Mars has no magnetic field. What does this imply?A. Mars has no atmosphereB.