Mars: Earth’s little brothe r What are the similarities and differences you notice? Mars’s axis is tilted at 25 deg What are seasons on Mars like? Mars’s axis tilt changes dramatically What happens when the tilt is less/more? Artist’s depiction of an ‘icy Mars’ Do the Earth and Mars have similar interiors? Why? How we even know what’s inside a planet? Atmospheres: Are they similar? Why? Constituents: Nitrogen: 78% Carbon Doxide: 95.% Oxygen: 21 % Nitrogen: 3% Argon: 0.9% Argon: 2% Water: > 1% Oxygen: 0.1% Carbon Doxide: 0.002% Water: > 0.03% Is there water on Mars? Why or why not? Is there water on Mars? Why or why not? Mars’s south pole Is there water on Mars? Why or why not? Mars or Earth? Dubai, UAE Endurance Crater, Mars What is the evidence for past water on Mars? Mars or Earth? Mars or Earth? Djado Plateau, Niger Valles Marineris, Mars Mars or Earth? Mars or Earth? Holden Crater NE, Mars Lena Delta, Mars or Earth? Yeme n Mars or Earth? Mars Mars or Earth? Mars or Earth? Niger Mars Seven minutes of terror Curiosity descent http://www.youtube.com/watch?v=gZX5GRPnd4U Google Mars Mars: Take-away messages •Although smaller than Earth, Mars and Earth are similar in many ways •Mars and Earth have similar interiors, although Mars has no liquid outer core, and so no magnetic field •Mars geology is/was formed by cratering, volcanism, tectonics and erosion by wind AND WATER! •(Plate tectonics doesn’t seem to have been important) •Mars’s atmosphere is very different from Earth’s - lower mass, and full of CO2 •Mars’s small atmosphere and low temperature makes liquid water unstable at its surface (at least right now) Percival Lowell’s Mars Lowell’s Map of Mar published in 1895 Viking’s Mars 1976 Viking’s Mars 1976