2. Mars Images

3. How We Know What We Know Current Spacecraft Mars Odyssey (’01-present) Mars Express (’03-present) Mars Exploration Rovers (’04-present) Mars Reconnaissance Orbiter (’06-present) Mars Science Laboratory (’12-present) MAVEN (’14 - present) Mars Orbital Mission (’14-present) Future Spacecraft ExoMars Trace Gas Orbiter (March 14, 2016) InSight (May 2018)

4. Current Spacecraft at Mars Mars Odyssey Mars Reconnaissance Orbiter Mars Express Mars Curiosity Rover Mars Science Laboratory MAVEN Mars Orbital Mission

5. Mars – Basic Facts Size – Half the size of Earth Mass – 1/10 of Earth’s Slightly less dense than Earth Orbit: 1.38 AU, fairly eccentric Mars year = 1.9 Earth years Rotation: Once every 24 hours 40 minutes Atmosphere – Thin – < 1% Earth pressure Mostly Carbon Dioxide (CO 2 ) Too thin for appreciable greenhouse effect

6. Mars – Pictures from the Surface

7. Rocks and sand Reddish color due to iron oxide – aka rust

8. Mars – Climate Sun Mars How does the northern climate compare with the southern climate? A) Warmer C) More severe B) Cooler D) Milder Mild summer north Severe winter south Mild winter north Severe summer south Colder than Earth (far from Sun) 130 K – 290 K Pressure fluctuates seasonally Southern hemisphere is more extreme

9. Craters on Mars Many craters Closer to Asteroid belt No water erosion Older surface Cratering is not uniform More in southern hemisphere

10. Southern Cratered Terrain Comparable to Lunar Highlands More worn down

11. Erosion of Craters

12. Regions on Mars Southern Hemisphere Heavily Cratered Northern Hemisphere Medium Craters Tharsis Region Fewest Craters Order the three parts of Mars from youngest to oldest. A) Tharsis, Northern, SouthernD) Northern, Southern, Tharsis B) Tharsis, Southern, NorthernE) Northern, Tharsis, Southern C) Southern, Northern, TharsisF) Southern, Tharsis, Northern

13. Elevated region Volcanic outflows Volcanoes nearby Probably extinct So large they can be seen easily from space The Tharsis Region

14. Olympus Mons Giant Volcano Largest Mountain in Solar System Top sticks out of atmosphere

15. Olympus Mons 3 times taller than Mt. Everest Bigger than North Carolina

16. Olympus Mons

17. Why does Mars have only inactive volcanoes, while Earth and Venus have active volcanoes? A) It is farther from the Sun, and therefore not as hot B) It is smaller and loses heat faster C) It doesn’t undergo tidal heating from a large moon D) It has little atmosphere, and volcanoes are caused by the atmosphere Mars Volcanoes Smaller planets cool more quickly Mars probably has no active volcanoes now But it did within past billion years or so

18. Mars Composition Mars has virtually no global magnetic field No protection for life from cosmic rays Internal Structure: Crust, thicker than Earth (?) Mantle, most of the volume Solid core near the center

19. Valles Marineris Largest Valley in the Solar System As big across as USA Crack caused by weight of Tharsis Bulge

20. Valles Marineris

21. Candor Chasma

22. The Polar Caps on Mars Carbon dioxide (dry ice) layer on top Water ice underneath

23. The Northern Polar Cap Size of cap changes seasonally Carbon dioxide evaporating and refreezing Causes large change in atmospheric pressure (50%)

24. Global Dust Storms Atmosphere flow causes huge dust storms Can envelope entire planet

25. Clouds on Mars

26. Dust Devils on Mars Mini-tornadoes Leave tracks across surface

27. Sand Dunes on Mars

28. Water on Mars Current pressure slightly too low for liquid water to form Mars Phoenix confirmed there is permafrost near poles We also have seen frost on the ground Was there liquid water on the surface in the past?

29. Past Evidence of Water

30. Craters and Evidence for Water Some craters look like they were made in mud Teardrop shaped islands look like terrestrial islands in rivers

31. Dried up Lakes

32. Water-based Minerals “Blueberries” are hematite Mineral normally only forms in water Strong evidence of past water

33. Civilization on Mars! The Face Cydonia Region Natural Features

34. Life on Mars! Mars has water – could it have life? A meteorite found in 1984 is one of several known to have come from Mars This meteorite contained what some thought were fossilized bacteria Scientists divided

35. Life on Mars? The conditions on Mars are rather different from Earth Mostly colder temperatures No oxygen, low air pressure No liquid water No large form of life on Earth survives these conditions But some bacteria on Earth live in similar conditions! What would life on Mars look like? Bacterial, too small to see without a microscope Probably live well below the surface (cosmic rays) Water-based

36. Mars Moons Two small moons Phobos Deimos Probably captured asteroids Phobos the size of Winston-Salem