11c. Red Planet Mars

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11c. Red Planet Mars. Mars data Earth-based observations of Mars Early observations mistaken as evidence of life Spacecraft find craters, volcanoes & canyons Surface features indicate flowing water Earth & Mars began alike, evolved differently Rovers explored the Martian surface - PowerPoint PPT Presentation

Transcript of 11c. Red Planet Mars

Env 384/A: Remote Sensing (RS) and Geographic Information Systems (GIS)

11c. Red Planet MarsMars dataEarth-based observations of MarsEarly observations mistaken as evidence of lifeSpacecraft find craters, volcanoes & canyonsSurface features indicate flowing waterEarth & Mars began alike, evolved differentlyRovers explored the Martian surfaceThe Martian atmosphere changes seasonallyMartian moons resemble captured asteroidsMars Data (Table 13-1)

Mars Data: NumbersDiameter:6,794 km0.53 . EarthMass:6.4 . 1023 kg0.107 . EarthDensity:3.9 . water0.72 . EarthOrbit:2.3 . 108 km1.52 AUDay:24h.37m 23s1.02 . EarthYear:686.98 days1.88 . EarthMars Data: Special FeaturesMars is farthest terrestrial planet from the SunMars is the second smallest terrestrial planetMars has < 1% the Earths atmosphereMars atmosphere is ~ 95% CO2 & 3% N2Mars has rapidly changing polar ice capsMars has two very different hemispheresThe north is covered with volcanoes & lava flowsThe south is covered with numerous cratersMars holds some Solar System recordsOlympus Mons:The tallest mountain (a volcano)Valles Marineris:The longest canyonMars will be the first planet visited by humansEarth-Based Observations of MarsMars is the closest superior planet to EarthConjunctionAlways superior [far side of the Sun]Mars is overhead at local solar noonMars isfarthest fromEarth & appears smallestOppositionMars is overhead at local solar midnightMars isclosest toEarth & appears largestMars orbit is rather highly ellipticalMars oppositions vary in favorabilityAugustoppositions aremostfavorable28 August 2003 closest in nearly 60,000 yearsFebruaryoppositions areleastfavorableMars looks very small even at favorable oppositionsHubble Space Telescope cannot identify impact cratersFuture Mars OppositionsMay 22, 2016July 27, 2018October 13, 2020Orbits of Earth & Mars

Mars: Hubble Space Telescope

Old Mars Observations From EarthGiovanni Schiaparelli1877Reported seeing canali on MarsItalian Meanschannels&is ambiguousNatural stream channelsEnglish Translatedcanals&has implicationsArtificial shipping routesLong viewing sessions & poor seeing conditionsHe saw what was not actually thereHe incorrectly interpreted what he did not actually seeObservations As Evidence of LifeSeasonal color changes do occur on MarsWinterFine red dust settles on large lava flowsAreas look relatively lightField stubbleon EarthSummerWind removes thin cover of dustAreas look relatively darkVerdant fieldson EarthThe human eye plays tricksAstronomers stare at bright red areas on MarsMost of Mars has a distinct red colorAstronomers see cyan [blue-green] in dark areasTendency of retinal fatigue to see complementary colorMisinterpretationCanals + summer greening = Intelligent life

Martian Canali & Craters

Martian Global Topography

Spacecraft Find Craters & VolcanoesMariner 4, 5 & 7First close-up pictures of MarsTwo distinctly different hemispheres on MarsBoundary tilted ~ 30 to the Martian equatorNorthern hemisphereRelatively low & relatively smoothSouthern hemisphereRelatively high & heavily crateredUnusual featuresValles MarinerisFly-overLongest, widest & deepest canyon in the Solar SystemWould reach from San Francisco to New YorkMany side canyons are as large as the Grand CanyonMars shows no evidence of plate tectonicsAs on Venus, lack of oceans may be critical hereOlympus MonsFly-overSolar Systems largest volcanoClear evidence of hot-spot volcanism

Valles Marineris: Hemispheric View

Olympus Mons: Solar System Champ

Surface Features Indicate WaterEarth-like streamflowclearly existed on MarsDendriticstream channels flow downmountainsMost of these appear to berelatively oldParallelstream channels flow downslopesMany of these appear to beremarkably youngPermafrost may be just beneath the Martian surfaceCatastrophic floodsclearly existed on MarsTeardrop-shaped islands around crater rimsRemarkably similar to Glacial Lake Missoula floods 109 floods from ~ 15,500 to ~ 13,500 years agoBiggest floods ~ 500 cubic miles of water past PortlandEvidence for a Great Northern OceanStrandlines on northern hemisphere slopesNotches cut by wave action along shorelinesDendritic Stream Channels on Mars

Parallel Stream Channels on Mars

Evidence of Sheet Flow on Mars

Water Flow DirectionTeardrop-Shaped IslandMars Orbiter: Dao Valley

Mars Orbiter: Reull Channels

A Possible Water History on Mars

Ancient

Modern

Earth & Mars Evolved DifferentlyHistoric observations1800sAstronomers saw Martian clouds1965Mariner 4 measured very high CO2 levelsMartian cirrus clouds contain both H2O & CO2 ice crystalsAtmospheric warming effectsCO2 on Earth raises temperature ~ 36CMuch terrestrial CO2 is locked in carbonate rocksSubduction recycles CO2 back into Earths atmosphereCO2 on Mars raises temperature ~5CMars quickly cooled & solidified because it is so smallNo subduction recycling of CO2 back into Mars atmosphereRainfall dissolved CO2 & removed it from the atmosphereRunaway icehouse effect on MarsStabilized at present levelsThe Martian AtmosphereEarlyatmosphereProbably very similar for Venus, Earth & MarsAbundant volcanic activity during Mars early historyAbundant H2O, CO2 & SO2Being very small, Mars ran out of heat & magmaOnce outgassing decreased, the oceans disappearedWater dissociated into H & O, which escaped Mars weak gravityRemaining volcanic gases entered the atmospherePresentatmosphereChemicallyRemarkablysimilar toVenus~ 95.3% CO2 & ~ 2.7% N2Expected due to little remaining volcanic outgassingPhysicallyRemarkablydifferent fromEarth~ 0.63% as much atmospheric gas as EarthExpected due to weak gravity & little replenishmentAtmospheres of Earth & Mars

Viking & Pathfinder Explored MarsViking spacecraft1976Experiments looking for signs of lifeWaterPeroxides & superperoxides released O2NutrientsNo obvious organic waste productsHeatedMass spectrometer analyzes gasesC14 addedNone taken up by possible organismsMars Pathfinder spacecraft4 July 1997Sojourner was the small rover on Mars PathfinderControlled from Earth with some autonomous functionsDiscovered an abundance of andesiteVolcanic rockmoderately richin quartzRock type first described in South Americas Andes MountainsSurprisingly different from Mars southern basaltVolcanic rockvery poorin quartzCommon in Earths ocean basins & the Moons mariaMars Viking Landerhttp://en.wikipedia.org/wiki/File:Sagan_Viking.jpg

Mars Pathfinder & Sojourner Rover

Mars Exploration RoversOverall missionSearch for clues to ancient water2 rovers on opposite sides of MarsExpected operating lifetime of 3 monthsUltimately a search for lifeMars Exploration Rover ASpiritLanded 4 January 2004Crater GusevAppears to have been affected by waterFirst intentional grinding of a rock on MarsOperated until 22 March 2010Mars Exploration Rover BOpportunityLanded 25 January 2004Landed in Meridiani PlanumCame to rest in Eagle Crater, a small impact craterStill operating as of 22 February 2013Mars Opportunity Before Launchhttp://en.wikipedia.org/wiki/File:Opportunity_Lander_Petals_PIA04848.jpg

Mars Spirit & Opportunity Rovershttp://en.wikipedia.org/wiki/File:NASA_Mars_Rover.jpg

Mars Opportunity Blueberries

Mars Opportunity Meridiani Meteorite

93% iron & 7% nickel6 inchesMars Opportunity Escher Rock

Mars Opportunity at Endurance Crater

Mars Curiosity RoverMars Science Laboratory (MSL) missionSpacecraft componentsEarthMars fueled cruise stageSkycraneEntrydescent-landing (EDL) systemCuriosity rover with instrument packageSoft-landed in Gale Crater on 6 August 2012Unique sky crane landing strategyGeneral mission objectivesAssess Martian climate & geologyAssess favorability of conditions for microbial lifeAssess habitability for future human explorationSpecific Curiosity objectivesBiologicalGeological & geochemicalPlanetary processSurface radiationMSL Cruise Stage Before Launchhttp://en.wikipedia.org/wiki/File:MSL-Cruise_Stage_Test.jpg

Opportunity, Sojourner & Curiosityhttp://en.wikipedia.org/wiki/File:Mars_Science_Laboratory_mockup_comparison_.jpg

Mars Atmosphere Is Very DynamicDiurnal changesMars Pathfinder76C to 10CDaytime heating generates dust devilsWeak clear-air tornadoesPressure dropped as dust devils passed PathfinderSeasonal changesBasic patterns~ 20% seasonal pressure changesWinterFrigid temperatures freeze out much CO2SpringWarm temperatures thaw out much CO2SummerFrigid temperatures freeze out much CO2FallWarm temperatures thaw out much CO2Hemispheric differencesNorthern summerMars is at aphelionClear skies warm northern summer much more than expectedSouthern summerMars is at perihelionDust storms cool southern summer much less than expectedMartian Dust Devil From Above

http://lightsinthedark.files.wordpress.com/2012/03/dustdevil.jpgMars Global Dust Stormhttp://science.nasa.gov/media/medialibrary/2001/10/11/ast11oct_2_resources/0131w.jpg

Cloud Caps on Martian Volcanoes

Cloud Cap On Mount Hoodhttp://fox12weather.files.wordpress.com/2010/09/lenticular-cropped1.jpg

Mars Craters & Mounds at Sunset

Mars Odyssey (Themis scanner)Mars Moons Resemble AsteroidsDiscoveryAsaph HallFavorable opposition of 1877Named after chariot horses of the Greek god of warMight be captured asteroidsDetailsPhobosFearClosest toMars &largestin sizeOrbital period of ~ 7 hours 39 minutesRaces from West to East from horizon to horizon in ~ 5.5 hoursComparable to artificial satellites in low Earth orbitSeveral times brighter than Venus appears from EarthDeimosPanicFarthest from Mars & smallest in sizeOrbital period of ~ 6 daysCreeps from East to West from horizon to horizon in ~ 3.0 daysAb