Mars

1
Mars

• Kristen Bockenstedt and Emily DeLong

2
General Characteristics

• Distance from the Sun 1.5 AU
• Diameter 53 of Earths
• Mass 6.41851023 kg (0.107 Earths)
• Volume 1.63181011 km³ (0.151 Earths)
• Density 3.94 g/cm³ (0.1075 Earths)
• Orbital period 687 Earth days
• Rotational period 24 hours 37 minutes
• Escape velocity 5 km/s (about half of Earths)
• Temperature ranges between -220 to 68 F

3
Atmosphere

• Composed of 95 carbon dioxide, 3 nitrogen, and
  2 argon
• Similar to that of Venus
• No greenhouse effect due to thin atmosphere and
  low escape velocity
• Very thin (less than 1 than that of the
  Earths), but was once thicker
• But because of Mars lack of an ozone layer,
  ultraviolet radiation has broken up larger
  molecules
• Gravity and escape velocity are very low,
  allowing high velocity gases to escape
• Low air pressure

4
Seasons

• Very similar to that of Earth because of similar
  axial tilt
• Tilt of 25.19
• Length of seasons are almost twice that of
  Earths due to the farther distance from the Sun
• Opposed seasons in the hemispheres
• Dust storms occur when closest to the sun
• Raised global temperature

5
Orbital Bodies Phobos and Deimos

• Believed to be captured asteroids
• Irregular in shape too small to pull themselves
  into spheres
• Discovered in 1877 by Asaph Hall at the U.S.
  Naval Observatory
• Phobos
• Large crater with deep grooves (supposed
  fractures from impact) running to opposite side
  of satellite
• Dust on surface about 1 m thick
• Deimos
• Also has grooves, supposed fracture under dust
• Looks smoother, thicker layer of dust

6
Surface Features

• Highland region in southern hemisphere heavily
  marked by craters
• Believed to be 2-3 billion years old
• Lowland region in northern hemisphere
• Believed to be filled with major ocean
• 2.5-3.5 billion years ago

7
Volcanism on Mars

• Two main volcanic regions
• Tharsis and Elysium
• All volcanoes are shield volacanoes
• Tharsis region contains largest volcanoes
• Olympus Mons
• 370 mi in diameter
• 13 mi high
• Thick Martian crust can support its weight
• Mauna Loa by contrast is sunk into a moat because
  of its weight (6 mi high)
• Reason for size due to lack of plate tectonics

8
Valleys on Mars

• Near Tharsis region is Valles Marineris
• Block of crust dropped downward along parallel
  faults
• Faults indicate former plate tectonics, but have
  stopped
• 2,500 miles long, spanning 19 of Mars
• 4 mi deep
• As wide as 120 mi

9
Polar Regions

• Ice cap composed of carbon dioxide
• In summer, carbon dioxide changes from solid to
  vapor the opposite occurs in winter

10
Water on Mars?

• Outflow channels and valley networks observed by
  Viking spacecraft
• Craters show they were formed 1 to 3 billion
  years ago
• Shores on edge of northern lowlands?
• Ocean 2.5 to 3.5 billion years ago
• Blueberries found by Opportunity

11
Interior Structure

• Core
• Metallic core, composed of iron
• Makes up 21 of total mass and 49 total radius
• Around 3000 K
• Mantle and Crust
• Silicate mantle
• Around 1900 K
• Very thick crust
• 50-100 km thick

12
Interior Structure

• No plate tectonics or magnetic field
• Core is either solidified or moving very slowly
• Most is still unknown
• Compared to Earth
• Core is composed of nickel and iron at 6000 K
• High pressure keeps core solid and liquid farther
  out
• Mantle is plastic
• Crust made of low density rock with floats on
  heavier mantle
• Plate Tectonics

13
History of Exploration

• First probe to Mars was Mariner 4 in 1965
• Few photographs and poor resolution
• Mariner 9 in 1969 was the most successful
• 7,239 pictures total
• Photographed polar caps, volcanoes, etc.
• Revealed many surface features of Mars

14
Viking

• Viking missions sent in 1976 to discover possible
  life
• Highly detailed pictures of Mars surface
• Took measurements of temperature, composition of
  atmosphere

15
Mars Global Surveyor

• Launched in 1996
• Has taken pictures showing
• Gullies believed to indicate evidence of past
  water
• Revealed the face on Mars was nothing more than
  natural landscape
• Recently celebrated 10th anniversary of launch
• Lost transmission recently

16
The Face on Mars
1976 Viking Photograph
2001 Mars Global Surveyor Photograph
17
Rovers

• Rovers include
• Pathfinder (1997)
• Spirit (2004 to present)
• Opportunity (2004 to present)
• Are still gathering information, even two years
  after launch, and much past original mission
  parameters