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Mars

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….

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Mars

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  1. Mars Now: ~ opposition (rises when?) magnitude -2.2

  2. Popular Interest

  3. Past and present… • 1938: Radio broadcast of War of the Worlds panics US • 2000: “Red Planet” • 2005 (and 1953) “War of the Worlds”

  4. First Observations • First observed by Dutch physicist Christian Huygens, 1659 • He noted…

  5. Rotation Motion of the feature Syrtis Major and concluded P=24h

  6. Giovanni Cassini • Determined to be 24:37 who also saw the polar caps…

  7. Polar Ice Caps • Ice cap seen in this ground based photo • Similar to view in scope

  8. 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

  9. Eccentricity and Oppositions • Causes some oppositions to be “favorable” • September 2003’s was especially favorable • Note angular size of Mars

  10. Giovanni Schiaparelli • First proposed that the caps made of ice • Became famous when he drew his sketch of Mars in 1877 …

  11. “Canali” (channels/canals)

  12. Percival Lowell • Wealth “Boston Brahman” (social and cultural elite) • Became interested in the Mars canals and established an observatory in Flagstaff, AZ

  13. Lowell at the scope • Drew on 6-inch globes to accommodate perspective

  14. Edward Barnard • In 1894 Edward Barnard and others could not convince himself the canals existed

  15. Mariner probes would resolve • dust storm here frustrated first photos in 1971 Mariner 9

  16. When cleared… • Many features but none lined up with canals drawn by Schiaparelli or Lowell

  17. 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

  18. Craters discovered • Not evenly distributed…

  19. Mostly in southern hemisphere • Dust has eroded rays and ejecta

  20. Volcanoes found • Volcanoes such as Arsia Mons shown above and...

  21. .. In perspective 3D

  22. 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.

  23. 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

  24. Valley Marineris • 4000 km long • Would span USA as shown • It is a huge crust fracture • not formed by water, but…

  25. These channels were formed by massive water flow But where is the water now?...

  26. Some water locked up in polar ice caps • South pole shown here • During summer CO2 portion sublimates, leaving H2O. (Temperature rises above sublimation point)

  27. color view of cap • shows ice melted off of sun-facing slopes, revealing strange terraced slopes

  28. North pole • this is almost all residual water ice shown here

  29. 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

  30. Some water seen in fog Early morning fog in canyons

  31. 1975-6: Two Viking Landers

  32. Approaching Mars • dawn view reveals clouds along volcano Olympus Mons, Valley Marineris • CO2 snow in Argyre Basin

  33. 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 ...

  34. …appear pocked (vesicular) Suggests outgassing during igneous formation

  35. Weather Report from mars

  36. 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

  37. Scoop Delivered Soil to Experiments

  38. Geological Results • surface rich in iron (magnet) --> rust red! • silicon --> 2/3 of Mars.. • little interior info since one seismometer failed... • Biological…

  39. gas-exchange Sensed respiration of samples (used gas-chromatograph/mass spectrometer)

  40. labeled release Used radioactive carbon nutrients -- checked for metabolism...

  41. pyrolytic-release Checked for photosynthesis with radioactive CO2 and artificial sunlight

  42. Biological Results • no life found • active chemical reactions believed due to release of peroxides & superoxides • surface is literally antiseptic!

  43. Magnetosphere • almost no magnetic field • Thus, core, if iron, not liquid, since Prot ~ PEarth • Thus solar wind and cosmic rays hit surface

  44. July 1997: Pathfinder

  45. Mars Global Surveyor • Imaging Mars from an orbit around it • Recent image of delta-like fans

  46. Other probes… • Mars Exploration Rover Spirit and Opportunity landed in January, 2004 Mars Odyssey continues to map Mars in infrared

  47. 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)

  48. Asaph Hall Discovered two moons in 1877 favorable opposition using the 26-inch refractor at the USNO, in Washington, DC

  49. 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. “

  50. Phobos Phobos is nearer and larger, P = 7:39! – rise to set in 5h! Not spherical – why not?

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