Mars
Images
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)
Current Spacecraft at Mars
Mars Science
Laboratory
Mars
Odyssey
Mars Express
MAVEN
Mars Curiosity
Rover
Mars Reconnaissance
Orbiter
Mars Orbital Mission
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 (CO2)
•Too thin for appreciable greenhouse effect
Mars – Pictures from the Surface
Mars – Pictures from the Surface
•Rocks and sand
•Reddish color due to iron oxide – aka rust
Mars – Climate
Sun
Mars
Mild summer north
Severe winter south
•Colder than Earth (far from Sun)
•130 K – 290 K
•Pressure fluctuates seasonally
•Southern hemisphere is more
extreme
Mars
Mild winter north
Severe summer south
How does the northern
climate compare with the
southern climate?
A) Warmer C) More severe
B) Cooler D) Milder
Craters on Mars
•Many craters
•Closer to Asteroid belt
•No water erosion
•Older surface
•Cratering is not uniform
•More in southern
hemisphere
Southern Cratered Terrain
•Comparable to Lunar Highlands
•More worn down
Erosion of Craters
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, Southern D) Northern, Southern, Tharsis
B) Tharsis, Southern, Northern E) Northern, Tharsis, Southern
C) Southern, Northern, Tharsis F) Southern, Tharsis, Northern
The Tharsis Region
•Elevated region
•Volcanic outflows
•Volcanoes nearby
•Probably extinct
•So large they can be
seen easily from space
Olympus Mons
•Giant Volcano
•Largest Mountain in Solar System
•Top sticks out of atmosphere
Olympus Mons
•3 times taller than Mt. Everest
•Bigger than North Carolina
Olympus Mons
Mars Volcanoes
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
•Smaller planets cool more quickly
•Mars probably has no active volcanoes now
•But it did within past billion years or so
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
Valles Marineris
•Largest Valley in the Solar System
•As big across as USA
•Crack caused by weight of
Tharsis Bulge
Valles Marineris
Candor Chasma
The Polar Caps on Mars
•Carbon dioxide (dry ice) layer on top
•Water ice underneath
The Northern Polar Cap
•Size of cap
changes
seasonally
•Carbon dioxide
evaporating and
refreezing
•Causes large
change in
atmospheric
pressure (50%)
Global Dust Storms
•Atmosphere
flow causes huge
dust storms
•Can envelope
entire planet
Clouds on Mars
Dust Devils on Mars
•Mini-tornadoes
•Leave tracks across surface
Sand Dunes on Mars
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?
Past Evidence of Water
Craters and Evidence for Water
•Some craters look like
they were made in mud
•Teardrop shaped islands
look like terrestrial
islands in rivers
Dried up Lakes
Water-based Minerals
•“Blueberries” are hematite
•Mineral normally only forms in water
•Strong
evidence
of past
water
Civilization on Mars!
Cydonia Region
The Face
Natural Features
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
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
Mars Moons
•Two small moons
•Phobos
•Deimos
•Probably captured asteroids
•Phobos the size of Winston-Salem