MARS

0.53 Diam(earth),    -140 oC to 20 oC

Atmosphere 95% CO2, 3% N2, 2% Ar              24 hr day, 25o axial tilt like Earth

1.  Small liquid core and magnetic field.  Much thicker solid

       mantle than Earth.  Thin basaltic crust (20 km).

2. Surface Features: Largest in solar system

A.  Two hemispheres separated by 1 km high scarp tilted 35o from equator:

               i.  To the North--sparsely cratered lowlands.

       ii. To the South--very cratered highlands.

B. Tharsis province--just North of scarp--a giant volcanic bulge 5,000 mi long, 4 mi high.

       i.  3 giant volcanos near crest--195-250 mi across,

     15 mi high.

       ii. Olympus Mons--NW flank 400 mi wide, 16 mi hi.

       iii. Clouds of ice near peaks of mtns.

C. Fractures radiating out from Tharsis:

       i.  Valles Marineris--to east---3,100 mi long. Water

      erosion.  Flooding onto lowlands-Chryse Planitia.

                      ii. Coprates Chasma--430 mi wide, 4 mi deep landslides.

       iii. Other canyons--blocks collapsed--chaotic terrain.

3. Dust storms--closer to sun by 20%, 45% hotter--dark spots.

4. Phobos--closest satellite--will take plunge in 100 mill. Yrs.

Stickney--big crater on Phobos.  Deimos--smaller satellite.

5. Visits: Mariners 4, 6, 7, 9 orbit, Viking 1, 2 landers.

      Pathfinder landed lakebed like Mono Lake, satellite photos.

6. Life?  Viking--Amino Acid-like. Antarctic meteorite-bacteria?