Mars

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Mars
Now opposition (rises when?) magnitude -2.2
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Popular Interest
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Past and present

• 1938 Radio broadcast of War of the Worlds panics
  US
• 2000 Red Planet
• 2005 (and 1953) War of the Worlds

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First Observations

• First observed by Dutch physicist Christian
  Huygens, 1659
• He noted

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Rotation

• Motion of the feature Syrtis Major and
  concluded P24h

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Giovanni Cassini

• Determined to be 2437 who also saw the polar
  caps

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Polar Ice Caps

• Ice cap seen in this ground based photo
• Similar to view in scope

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Seasons and eccentricity

• Seasons are affected (made more extreme) because
  perihelion occurs at Southern Hemisphere summer
• This is unlike Earth seasons, since Earths
  orbital eccentricity is small

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Eccentricity and Oppositions

• Causes some oppositions to be favorable
• September 2003s was especially favorable
• Note angular size of Mars

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Giovanni Schiaparelli

• First proposed that the caps made of ice
• Became famous when he drew his sketch of Mars in
  1877

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Canali (channels/canals)
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Percival Lowell

• Wealth Boston Brahman (social and cultural
  elite)
• Became interested in the Mars canals and
  established an observatory in Flagstaff, AZ

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Lowell at the scope

• Drew on 6-inch globes to accommodate perspective

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Edward Barnard

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

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Mariner probes would resolve

• dust storm here frustrated first photos in 1971
  Mariner 9

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When cleared

• Many features but none lined up with canals drawn
  by Schiaparelli or Lowell

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Possible explanation based on Lowells 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

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Craters discovered

• Not evenly distributed

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Mostly in southern hemisphere

• Dust has eroded rays and ejecta

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Volcanoes found

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

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.. In perspective 3D
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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.

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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

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Valley Marineris

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

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These channels were formed by massive water flow
But where is the water now?...
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Some water locked up in polar ice caps

• South pole shown here
• During summer CO2 portion sublimates, leaving
  H2O. (Temperature rises above sublimation point)

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color view of cap

• shows ice melted off of sun-facing slopes,
  revealing strange terraced slopes

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North pole

• this is almost all residual water ice shown here

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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

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Some water seen in fog

• Early morning fog in canyons

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1975-6 Two Viking Landers
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Approaching Mars

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

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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 ...

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appear pocked (vesicular)

• Suggests outgassing during igneous formation

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Weather Report from mars
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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

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Scoop Delivered Soil to Experiments
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Geological Results

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

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gas-exchange

• Sensed respiration of samples (used
  gas-chromatograph/mass spectrometer)

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labeled release

• Used radioactive carbon nutrients -- checked
  for metabolism...

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pyrolytic-release

• Checked for photosynthesis with radioactive CO2
  and artificial sunlight

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Biological Results

• no life found
• active chemical reactions believed due to release
  of peroxides superoxides
• surface is literally antiseptic!

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Magnetosphere

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

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July 1997 Pathfinder
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Mars Global Surveyor

• Imaging Mars from an orbit around it
• Recent image of delta-like fans

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Other probes

• Mars Exploration Rover Spirit and Opportunity
  landed in January, 2004

Mars Odyssey continues to map Mars in infrared
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Rover Assignment

• Write up, in lt 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)

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Asaph Hall

• Discovered two moons in 1877 favorable
  opposition using the 26-inch refractor at the
  USNO, in Washington, DC

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150 years before the were predicted in
Gullivers 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.

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Phobos

• Phobos is nearer and larger, P 739! rise
  to set in 5h!
• Not spherical why not?

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Deimos

• Almost Marsynchronous -- appears to take 3 days
  horizon to horizon.