A161 13

The Red Planet: 

The Red Planet

Robotic Missions to Mars: 

Robotic Missions to Mars

Viking Lander: 

Viking Lander

Martian landscape with frost: 

Martian landscape with frost

“Face” on Mars ?: 

“Face” on Mars ?

Mars – Vital Statistics: 

Mars – Vital Statistics Mass ~ 1/10 Earth’s Diameter = 4200 mi, ½ Earth’s Density = 3.9 x water Year = 1.9 Earth years Day = 24 hr 37 min Distance to Sun = 1.5 AU (227 million Kms) Surface gravity (g) = 0.38 Earth’s Tilt of rotation axis = 25 degrees (seasons!) Surface T: Max 70 F, but usually -100 to -220 F Large variations in T (thin atmosphere)

Martian Gravity : 

Martian Gravity Although Mars almost certainly had a primordial atmosphere similar to Earth’s, most of it was lost primarily because of low gravity Gravitational acceleration g(Mars) = 0.38 g(E) M (Mars) ~ 1/10 M(E); R(Mars) ~ ½ R(E) g(Mars) = G M(Mars) / R(Mars)^2  g(Mars) / g(E) = (1/10) / (1/4) = 0.4 Objects on Mars fall 2 ½ times slower

Mother of all canyons: Valles Marineris: 

Mother of all canyons: Valles Marineris 5000 Kms (coast-to-coast if in US)

Polar “dry ice” caps (CO2): 

Polar “dry ice” caps (CO2) Polar icecaps are dry ice on top and water ice underneath

Polar cap with dust lanes: 

Polar cap with dust lanes

Evidence of ancient water flows on Mars : 

Evidence of ancient water flows on Mars “Canal” type features (dried up riverbeds); Martian climate was warm and wet in the past. Why did it change to the barren environment today ? The atmosphere evaporated ! Anti-greenhouse Effect !! Opposite of Venus !!!

More evidence of water: 

More evidence of water

Ancient volcanic flows: 

Ancient volcanic flows Recent volcanic activity (~ 100 million yrs) with huge runny lava flows (why?) Low gravity !

Mother of all volcanoes: Olympus Mons: 

Mother of all volcanoes: Olympus Mons 24 Kms high (3 times Mt. Everest), 600 Kms across (as big as Missouri)

Volcanic Plains – Giagantic Shield Volcanoes: 

Volcanic Plains – Giagantic Shield Volcanoes Summits capped with “Calderas” – flat, broad, collapsed craters

“Mud-splash” crater: 

“Mud-splash” crater

Topography: Warmer, Volcanic Northern Hemisphere and colder, cratered Southern Hemisphere: 

Topography: Warmer, Volcanic Northern Hemisphere and colder, cratered Southern Hemisphere

Some Basic Features of Mars: 

Some Basic Features of Mars First superior planet, best seen at opposition Most like Earth (season like on Earth, but twice as long) Eccentricity = 0.09, 3 times that of Earth’s orbit; Mars is 20% closer to the Sun at perihelion; receives 44% more sunlight Perihelion occurs during southern summers, which are shorter but hotter than northern summers, but southern winters are much longer; large variations in southern polar ice caps (may extend halfway to equator) North is warmer than the south !

Recycling heavy compounds H2O and CO2 and the Greenhouse Effect: 

Recycling heavy compounds H2O and CO2 and the Greenhouse Effect H2O,N2 remain in the atmosphere; CO2 is recycled on earth via photosynthesis H2O breaks up from UV; H2,N2,O2 escape; CO2 freezes on Mars as permafrost, or on polar icecaps Martian atmosphere (0.007 bars) is 95% CO2 EARTH MARS

Oppositions of Mars (Best Viewing): 

Oppositions of Mars (Best Viewing) The best time to view a superior planet is at Opposition, whereas the best time to view an inferior planet is at maximum elongation

Opposition and Retrograde motion: 

Opposition and Retrograde motion

Steps to a Martian Dust Storm:: 

Steps to a Martian Dust Storm: Convection between night and day sides produces 50-200 MPH winds Dust blown into upper atmosphere (no rain to clear!) Sunlight blocked by dust  upper air gets warmer, surface cooler  “anti-greenhouse effect” Temperature difference makes convection worse, so more dust blown into atmosphere Nuclear Winter (nuclear war!) Extinction of Dinosaurs (asteroid impact!)

Life on Mars: 

Life on Mars Viking Landers, Pathfinder, Rover and Spirit robotic missions TV  Nothing big seen moving around (at least so far) No organic compounds (C,H,O molecules) found No micro-organisms found Biological tests by robotic experiments are sensitive enough to have detected life in Antarctica

Terra-forming: 

Terra-forming Altering a planet’s environment to create a climate simulating Earth’s Prescription for Mars: Melt polar CO2 to start greenhouse effect Raises the temperature so rest of ice melts Plant algae, etc. for photo-synthesis: CO2  O2 (Voila !) How does one start step 1?

Small Moons of Mars: 

Small Moons of Mars Moons of Mars are about the size of Columbus I-270 beltway