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Making a splash on MARS

Making a splash on MARS. Keith Piersol Geochemistry. Article. Article is “Making a splash on MARS” by Charles W. Petit. Published July 2005 in National Geographic, volume 208. Goes over the discoveries of the Spirit and Opportunity landers.

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Making a splash on MARS

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  1. Making a splash on MARS Keith Piersol Geochemistry

  2. Article • Article is “Making a splash on MARS” by Charles W. Petit. • Published July 2005 in National Geographic, volume 208. • Goes over the discoveries of the Spirit and Opportunity landers. • Does not go deep into science but is never in error. • Very little context as to Mars paleoclimateor why Mars may have had water in the past.

  3. Introduction • Paleoclimate of Mars • Major theory • Loss of atmosphere • Discoveries by Spirit and Opportunity • Hematite • Problems • Other proof of water • Conclusions

  4. Paleoclimate • Theorized to have had a much thicker atmosphere in the past 4 billion years ago, primarily CO2. • May have been as thick as Earth’s atmosphere, allowing for the existence of large bodies of surface water. • Possibility of an oxygen rich atmosphere as indicated by comparisons of Martian meteorites and Martian surface rocks by Spirit and Opportunity.

  5. Paleoclimate • Lost atmosphere over the last 4 billion years, current atmosphere is 1% of the pressure at earth sea level. • May have lost atmosphere and heat to: • Solar winds (gradual and plasmoids) • Large asteroid impact • Low gravity • High surface area relative to mass

  6. Mars Today • 95.9% CO2, pressure of only 7 millibars. • During winter 25% of atmospheric CO2freezes at the poles as dry ice. • Frost forms at night during summer, as well as earth-like cirrus clouds. • Subsurface water discovered at north pole by Phoenix Mars mission.

  7. Spirit and Opportunity

  8. Purpose • Finding evidence of past water on mars. • Equipped with: • Panoramic Camera • Miniature Thermal EmissionSpectrometer • Mossbauer spectrometer • Alpha particle X-ray spectrometer • Microscopic Imager • Rock Abrasion tool.

  9. Landings • Spirit was landed at Gusev Crater which had an apparent water channel flowing into it. Gusev Crater is 4 billion years old and 166 km in diameter. • Opportunity was landed on a flat equatorial plain called Meridiani Planum, where orbital satellites had detected infrared signatures of Gray Hematite.

  10. Discoveries • Found water-related minerals in thin surface deposits, including a large deposit at Meridiani Planum, and also at Gusev Crater after a few months. • Gray Hematite • Goethite • Magnesium sulfate, chlorides, bromides, other iron rich compounds.

  11. Gray Hematite • Fe2O3 • Variant of red iron-oxide with sand-sized crystals. • Generally form in the presence of water through precipitation. • On Mars it was discovered in the form of round spheres geologists called “blueberries”.

  12. Gray Hematite • Gray hematite is not always a marker for the presence of water. Arguments over how exactly was formed continue today. • The hematite could have formed through the following primary and secondary processes: • Precipitation from cool iron rich waters. • Precipitation from warm iron rich hydrothermal systems • Thermal oxidation of volcanic deposits (No presence of water). • Leaching from groundwater. • Hydrothermal modification to porous strata. • Hematite coatings caused by liquid and vaporous water.

  13. Sedimentary Strata • Crossbedding, festooning, and ripples have been found all across Meridiani Planum, particularly at the Burn’s Cliffs. • Because of festooning the ripples are believed to not be caused by wind. • Ripples are estimated to have been created by shallow water at least 5 cm deep flowing between 10 cm and 50 cm per second.

  14. Problems • Beyond Gray Hematite and Goethite, rather exotic evaporites minerals, there have been no common minerals to support a long-term presence of water. • No salts, gypsum, anhydrite, or carbonates have been detected. • Chemistry seems to have been a strongly acidic and weakly oxidizing and shallow body of water, either as individual bodies or one large body. Presence seems to have been ephemeral.

  15. Conclusions • Water seems to have been present on mars at one point, implying an atmosphere and temperature that could support liquid water as well. • Presence of water seems to have been ephemeral and does not seem to have been present long enough to make deep deposits. • Deposits are all 3.7-4 bya, so water has not existed on the surface for a long time. • Theoretically there could be more water evaporite deposits beneath the surface, but that is unknown at this time. • As a side note, Opportunity is still functioning 3423 Martian days past it’s expected lifetime, or 9.6 Earth years.

  16. Conclusions Questions?

  17. References • http://science1.nasa.gov/media/medialibrary/2001/03/22/ast28mar_1_resources/tes_hematite_sm.jpg • http://athena.cornell.edu/mars_facts/sb_hematite.html • http://paganpages.org/content/wp-content/uploads/2012/10/Goethite-171990.jpg • http://www.nasa.gov/vision/universe/solarsystem/mer-121304b.html • http://www.psrd.hawaii.edu/Mar03/Meridiani.html

  18. References • http://upload.wikimedia.org/wikipedia/commons/d/d8/NASA_Mars_Rover.jpg • http://science1.nasa.gov/science-news/science-at-nasa/2008/21nov_plasmoids/ • http://www.nasa.gov/vision/universe/solarsystem/Mars-more-water-clues.html • http://www.fas.org/irp/imint/docs/rst/Sect19/Sect19_13b.html

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