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Who was Giovanni Schiaparelli?
1877: identified 79 canali, mistaken as man made canals
Who was Percival Lowell?
1894: wrongfully studied canals on mars
What robots visited Mars?
S195: Mariner 4, 6, 7 (flybys)
1971: Mariner 9 (orbiting)
1976: Twin Viking (landers)
established harsh surface conditions and lack of liquid water
1997: Mars Global Surveyor, Pathfinder, rover Soujourner
2015: 5 orbiters, 3 rovers, one lander
Current: 5 orbiters, 2 rovers
What is Mars’ atmosphere like today?
CO2 similar to Venus
10,000 times thinner
little greenhouse effect
causes water to sublimate (solid to gas)
What are Mars’ seasons?
25 degree title
elliptical orbit
northern mars is drastic
winters cold enough to freeze the atmosphere (enlarge white cap)
Winds that cycle carbon dioxide gas cause large storms “dust-devils”
What is Mars’ surface like?
northern lowlands, southern highlands
southern hemisphere more cratered
Northern hemisphere, less cratered, newer crust
What are Mars’ three ages?
Early: Noachian - 3.7 billion years, more craters
Middle: Hesperian, 0.7 billion years, moderate craters
Recent: Amazonian, past 3 billion, light craters
What is Olympus Mons?
Largest volcano in universe
26 km high
600 km across
result of magma plume
What is Valles Marineris?
large canyon
4x deeper than Grand Canyon
Sedimentary walls similar to grand canyon
might offer fossils of martian life
What evidence is there of ancient water on Mars?
orbital evidence: images of river beds
rover evidence: hydrated minerals of water based reactions
evidence of periodic heating events (impacts, volcanism)
Water ice
13x more water than earth removed by solar winds
dark streaks on crater walls implying salty water in summer
What is the climate history of Mars?
much warmer and wetter in past
atmospher 400x thinker than ours
global greenhouse effect
maybe global magnetic field protecting from solar wind stripping
enough pressure and heat for surface water
cool of core ends global magnetic field and decreases volcanism leading to today (no CO2 or water)
What four experiments did Viking missions for life on Mars?
Carbon assimilation experiment:
mixed soil with carbon dioxide and monoxide
found no life
Gas exchange experiment:
martian soil and “broth”
found no life
Labeled release experiment:
martion soil and radioactive “broth”
showed signs of life (other missions debate)
Gas chromatograph experiment:
measured no organic material in martian soil
What other evidence of life does Mars have?
methane varies with seasons, should diminish unless reproduced
three possibilities: comet impacts, geological activity, life
What evidence do martian meteorites provide of life?
Layers carbonate grains similar to biological activity on Earth
PAHs produced by living and non-living processes
Crystals within meteorite match similar crystals from earth bacteria
images of rod-shaped structures resemble fossilized bacteria
What are non-biological explanations for the material on martian metorites?
non-biological mechanisms produce layered carbonates
PAHs produced by both living and non-living reactions
Similarities between crystals may be a coincidence
structures may be too small for RNA/DNA
What issues are there with future missions to Mars
Contamination
can’t decontaminate humans
worried about hurting ecosystems of earth and mars
What is terraforming Mars?
release greenhouse gases to warm and increase pressure
would make habitable but not like earth
impractical
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