VIEWS: 5 PAGES: 51 POSTED ON: 8/25/2012
Mars Now: ~ opposition (rises when?) magnitude -2.2 Popular Interest Past and present… 1938: Radio broadcast of War of the Worlds panics US 2000: “Red Planet” 2005 (and 1953) “War of the Worlds” First Observations First observed by Dutch physicist Christian Huygens, 1659 He noted… Rotation Motion of the feature Syrtis Major and concluded P=24h Giovanni Cassini Determined to be 24:37 who also saw the polar caps… Polar Ice Caps Ice cap seen in this ground based photo Similar to view in scope Seasons and eccentricity Seasons are affected (made more extreme) because perihelion occurs at Southern Hemisphere summer This is unlike Earth seasons, since Earth’s orbital eccentricity is small Eccentricity and Oppositions Causes some oppositions to be “favorable” September 2003’s was especially favorable Note angular size of Mars Giovanni Schiaparelli First proposed that the caps made of ice Became famous when he drew his sketch of Mars in 1877 … “Canali” (channels/canals) Percival Lowell Wealth “Boston Brahman” (social and cultural elite) Became interested in the Mars canals and established an observatory in Flagstaff, AZ Lowell at the scope Drew on 6-inch globes to accommodate perspective Edward Barnard In 1894 Edward Barnard and others could not convince himself the canals existed Mariner probes would resolve dust storm here frustrated first photos in 1971 Mariner 9 When cleared… Many features but none lined up with canals drawn by Schiaparelli or Lowell Possible explanation based on Lowell’s Venus “spokes” Doctors noted that Lowell had stopped his scope down to a few inches, effectively creating a pinhole camera at eye, which displays veins in retina Similar to ophthalmoscope, an instrument used to examine the interior of the eye Craters discovered Not evenly distributed… Mostly in southern hemisphere Dust has eroded rays and ejecta Volcanoes found Volcanoes such as Arsia Mons shown above and... .. In perspective 3D The volcano Olympus Mons rises 24 km (15 miles) above plains! (3x Mt Everest). Great size of volcanoes on both Venus and Mars suggests no current plate tectonics ... same surface sits above hot spot. Tharsis Rise Olympus Mons and other volcanos comprise the Tharsis Rise Shown compared to eastern US here Is an average of 5 - 6 km above most of surface Valley Marineris 4000 km long Would span USA as shown It is a huge crust fracture not formed by water, but… These channels were formed by massive water flow But where is the water now?... Some water locked up in polar ice caps South pole shown here During summer CO2 portion sublimates, leaving H2O. (Temperature rises above sublimation point) color view of cap shows ice melted off of sun-facing slopes, revealing strange terraced slopes North pole this is almost all residual water ice shown here Broken terrain from outflow in the Capri plateau, suggests water violently outgassed when heated by volcanic activity below Like similar event in eastern Washington state 14,000 years ago that created the Channeled Scablands Some water seen in fog Early morning fog in canyons 1975-6: Two Viking Landers Approaching Mars dawn view reveals clouds along volcano Olympus Mons, Valley Marineris CO2 snow in Argyre Basin Viking I Lander View Landed in Chryse Planitia (Golden Plains) Shows edge of crater on horizon, probably responsible for jagged rocks in scene. Foreground shows regolith covered with other rocks that under closer examination ... …appear pocked (vesicular) Suggests outgassing during igneous formation Weather Report from mars Other Results 95% CO2, 2% N2, 1.6% Argon 6-8 mBar pressure (Earth: 1000 mB) no ozone layer no magnetic field (therefore no iron core, also supported by low avg density 3.9) large temp swings ... -80OC to -20O C in warmer areas! seasonal pressure variationss as CO2 freezes out/sublimates Scoop Delivered Soil to Experiments Geological Results surface rich in iron (magnet) --> rust red! silicon --> 2/3 of Mars.. little interior info since one seismometer failed... Biological… gas-exchange Sensed respiration of samples (used gas- chromatograph/mass spectrometer) labeled release Used radioactive carbon nutrients -- checked for metabolism... pyrolytic-release Checked for photosynthesis with radioactive CO2 and artificial sunlight Biological Results no life found active chemical reactions believed due to release of peroxides & superoxides surface is literally antiseptic! Magnetosphere almost no magnetic field Thus, core, if iron, not liquid, since Prot ~ PEarth Thus solar wind and cosmic rays hit surface July 1997: Pathfinder Mars Global Surveyor Imaging Mars from an orbit around it Recent image of delta-like fans Other probes… Mars Exploration Rover Spirit and Opportunity landed in January, 2004 Mars Odyssey continues to map Mars in infrared Rover Assignment Write up, in < 1 typed page… Current mission status (a paragraph) 5 interesting things about the mission Use the link on our WebCT Class Links page Due next time (make a copy for yourself so we can discuss it) Asaph Hall Discovered two moons in 1877 favorable opposition using the 26-inch refractor at the USNO, in Washington, DC 150 years before the were “predicted” in Gulliver’s Travels “They have likewise discovered two lesser Stars, or Satellites, which revolve about Mars; whereof the innermost is distant from the Center of the primary Planet exactly three of his Diameters, and the outermost five; the former revolves in the space of ten Hours, and the latter in Twenty-one and an Half; so that the Squares of their periodical Times, are very near in the same Proportion with the Cubes of their Distance from the Center of Mars; which evidently shews them to be governed by the same Law of Gravitation, that influences the other heavenly Bodies. “ Phobos Phobos is nearer and larger, P = 7:39! – rise to set in 5h! Not spherical – why not? Deimos Almost Marsynchronous -- appears to take 3 days horizon to horizon.
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