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Searching for Life in Our Solar System Chapter 7 Day 16. ASTR-3040. Stuff. HW: Chapter 7: Due Wed. March 25 Give or take 2, 5, 8, 21, 22, 26, 31, 33, 36, 38, 41, 43, 45, 51. Environmental Reqriments. Atmosphere Liquid water Temperature Pressure Radiation
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Searching for Life in Our Solar System Chapter 7 Day 16 ASTR-3040
Stuff • HW: Chapter 7: • Due Wed. March 25 • Give or take • 2, 5, 8, 21, 22, 26, 31, • 33, 36, 38, 41, 43, 45, 51
Environmental Reqriments • Atmosphere • Liquid water • Temperature • Pressure • Radiation • But, that's for Earth-like life. • What about other forms of life?
Earth Life • Use 25 of 92 elements • O, C, H, N – 96% of mass of living organisms • 3, 4, 6, 1 – abundance in Universe • 2% mass of solar system, < 0.1% in old SSs • Temperature in protostellar nebula. • Energy density from Sun • Liquid water at Earth's distance • Stays liquid over large temperature range • Facilitates chemical reactions
Earth Life • Water: • Liquid over wide and higher temperature range • Solid water floats • Charge separation of water molecule • Environmental Rqrmnts for Habitability • Source of molecules for building living cells • Source of energy for metabolism • Liquid medium for transporting molecules
SS Tour • Mercury and Moon • No atmosphere • No tectonic or volcanic activity • No volatiles * • Lunar polar ice? • No magnetic field • Temperatures
SS Tour • Venus and Mars • Venus – similar in size to Earth • Temperature and Pressure (95F w/o greenhouse) • 880F in reality, 90 atm pressure • Atmospheric composition – CO2 (96%) • volcanism • Mars – smaller, but Earth-like landscape • Probably had liquid water (3 Gyr) • More in next chapter
Moons • Large moons • Europa, Ganymede, Callisto, and Titan • Lots of ices • Small moons • Phobos, Deimos – too small • KBOs – too cold
S/C Exploration • Flyby • Orbiter • Lander/Probe • Sample Return
Astrobiology Missions • Only those to Mars have been specifically designed to look for evidence of life. However, several s/c -flown and planned- look for evidence of water, organic molecules... • Mars has a major exploration program • First sample return scheduled in about 10 yrs