MarsMars
Now: ~ opposition (rises when?) magnitude -2.2
Popular InterestPopular Interest
Past Past and and
presentpresent…… 1938: Radio 1938: Radio
broadcast broadcast of War of of War of the Worlds the Worlds panics USpanics US
2000: “Red 2000: “Red Planet”Planet”
2005 (and 2005 (and 1953) “War 1953) “War of the of the Worlds”Worlds”
First First ObservationsObservations
First observed by Dutch physicist Christian Huygens, 1659
He noted…
RotationRotation
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 CapsPolar Ice Caps
Ice cap Ice cap seen in seen in this this ground ground based based photophoto
Similar to Similar to view in view in scopescope
Seasons and eccentricity 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 This is unlike Earth seasons, since Earth’s orbital eccentricity is smalleccentricity is small
Eccentricity and Eccentricity and OppositionsOppositions
Causes Causes some some oppositions oppositions to be to be “favorable”“favorable”
September September 2003’s was 2003’s was especially especially favorablefavorable
Note angular Note angular size of Marssize of Mars
Giovanni Schiaparelli First proposed that First proposed that
the caps made of the caps made of iceice
Became famous Became famous when he drew his when he drew his sketch of Mars in sketch of Mars in 1877 …1877 …
““Canali” (Canali” (channels/canals)
Percival LowellPercival Lowell
Wealth “Boston Wealth “Boston Brahman” (social Brahman” (social and cultural elite)and cultural elite)
Became Became interested in the interested in the Mars canals and Mars canals and established an established an observatory in observatory in Flagstaff, AZFlagstaff, AZ
Lowell at the scopeLowell at the scope Drew on 6-inch globes Drew on 6-inch globes
to accommodate to accommodate perspectiveperspective
Edward Barnard
In 1894 Edward Barnard and others could not convince himself the canals existed
Mariner probes would resolveMariner probes would resolve
dust storm here frustrated first photos in 1971 Mariner 9
When cleared…When cleared…
Many features Many features but none lined but none lined up with canals up with canals drawn by drawn by Schiaparelli or Schiaparelli or LowellLowell
Possible explanation Possible explanation based on Lowell’s Venus based on Lowell’s Venus
“spokes”“spokes” Doctors noted that Doctors noted that
Lowell had Lowell had stopped his scope stopped his scope down to a few down to a few inches, effectively inches, effectively creating a pinhole creating a pinhole camera at eye, camera at eye, which displays which displays veins in retinaveins in retina
Similar to Similar to ophthalmoscope, ophthalmoscope, an instrument an instrument used to used to examine the examine the interior of the eye interior of the eye
Craters discovered
Not evenly distributed…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 But where is the water now?...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 fogSome water seen in fog
Early morning fog in canyons
1975-6: Two Viking Landers1975-6: Two Viking Landers
Approaching MarsApproaching 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 marsWeather Report from mars
Other ResultsOther 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 Scoop Delivered Soil to ExperimentsExperiments
Geological ResultsGeological 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 ResultsBiological Results
no life found active chemical reactions believed
due to release of peroxides & superoxides
surface is literally antiseptic!
MagnetosphereMagnetosphere
almost no magnetic field Thus, core, if iron, not liquid, since Prot ~ PEarth Thus solar wind and cosmic rays hit surface
July 1997: PathfinderJuly 1997: Pathfinder
Mars Global Surveyor
Imaging Mars from an orbit around itImaging Mars from an orbit around it Recent image of delta-like fansRecent image of delta-like fans