Mars Notes

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?

1. Layers carbonate grains similar to biological activity on Earth

2. PAHs produced by living and non-living processes

3. Crystals within meteorite match similar crystals from earth bacteria

4. images of rod-shaped structures resemble fossilized bacteria

What are non-biological explanations for the material on martian metorites?

1. non-biological mechanisms produce layered carbonates

2. PAHs produced by both living and non-living reactions

3. Similarities between crystals may be a coincidence

4. 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