Mars Lecture 13 Post Midterm No copyright infringement is intended by the creation or use of these notes Physical Qualities o Reddish appearance b c iron oxides rust on surface o Mars does not have plate tectonics to recycle and ride of iron oxide o Very thin atmosphere 1 150 of earth s 95 3 CO2 atmosphere to thing for greenhouse effect Not good protection from radiation Low pressure No clouds no H2O o Surface temperature 73 to 27 C o Avg temp about 50K C lower than Earth o Low pressure and low temperature on Mars water only as gas or solid Think about pressure and temp equilibrium graph o Has volcanoes and canyons o Geothermal Gradient rate of increasing temperature per increased depth into planet s interior Higher near volcano Exploration o Mars exploration dates back to Egyptians 1500 B C o Since 1965 satellites and rovers explored Mars Curiosity in 2012 o Curiosity to explore climate geology role of water habitability for future o Several geological features today provide evidence for previous liquid human exploration Water Life on Mars water on Mars Gullies Valley Networks Outflow Channels Ridges Riverbeds etc o Toady surface water is frozen in soil permafrost but there may be liquid water in the subsurface where geothermal heat can melt the permafrost o Salts lower the freezing temperature of water allowing it to stay liquid at night cold temps on Mars Perchlorate salts absorb water vapor and form brines that remain liquid during freezing night water cycle Temperature and water activity too low to support terrestrial life History of Mars o Noachian Cold arid and icy Clay formation is wetter and warmer subsurface environment o Hesperian clays near surface o Amazonian Volcanism surface water and near surface weathering to form Cold and dry stopped clay formation o Old Mars probably had a thick atmosphere higher pressure b c dist from sun hasn t changed much therefor temp remain the same o Major geological processes influence water availability on Mars Impact cratering Magnetic filed Volcanism Changing nature of environment Evidence of Liquid Water Life on Surface of Mars Today o Unlikely b c Biosignature sign of life No Liquid Water either vapor or ice Harmful UV Mars atmosphere has no ozone Hydrogen peroxide production in atmosphere kills organic material on Mars surface o Any substance element isotope molecule or phenomenon that provides scientific evidence of past or present life o Viker Lander biological experiment on Martial soil samples Radioactive CO2 added to see if C would assimilate into Carbon assimilation biomass NEGATIVE Labeled released Radioactive carbon organics food added to see if respired to CO2 POSITIVE but unsure if soil oxidants were responsible non biological reaction Gas Exchange Mix Martian soil with Earth organics test for gas production NEGATIVE o Methane on Mars o ALH84001 Satellite and Curiosity measurements report methane spikes in Mars atmosphere Source unknown but could be both biological microbes on earth or geological weathering of rocks Mars Metroid has potential biosignatures Microscopic fossils of Martian bacteria based on carbonate globules