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Mars
Schiaparelli’s “Canals”
Schiaparelli’s “Canals”

Schiaparelli:
More little green men…
Still more little green men…
Invading Earth?
The broadcast
The movies
The book…
The image…
… in higher resoluion!
More illusions:
Pyramids
Happy Faces!
Even More illusions:
Mars vs. Earth

50% Earth’s radius, 10% Earth’s mass

1.5 AU from the Sun

Thin CO2 atmosphere

Little greenhouse effect
=>Main difference: Mars is SMALLER
Mars is “Earthlike”

Axis tilt about the same as Earth

Similar rotation period (25 hours/”day”)

Sunrise & Sunsets!

Weather!
=> Could we survive?
Martian Year (686 Earth days)
Seasons on Mars

Seasons on Mars are more extreme in the
southern hemisphere because of its elliptical orbit.
A Martian Sunset…
Storms on Mars

Seasonal winds on Mars can drive huge dust storms.
Mars’ Moons: Fear & Death
Exploring Mars
Exploring Mars
Exploring Mars
Mars 1969A (USSR) March 27, 1969. The Mars orbiter did not reach Earth orbit.
Mars 1969B (USSR) April 2, 1969. The Mars orbiter failed during launch.
Mariner 8 (U.S.) May 8, 1971. The Mars orbiter failed during launch.
Kosmos 419 (USSR) May 10, 1971. The orbiter achieved Earth orbit only.
•Mars 5 launched July 25, 1973. The Mars orbiter arrived but lasted only a few days.
•Mars 6 launched Aug. 5, 1973., but the lander failed due to a fast impact.
•Mars 7 launched Aug. 9, 1973., but the lander missed the planet.
Exploring Mars
Viking (1976)
Exploring Mars
Sojourner (NASA) – 1997
Bounced to a safe landing
Exploring Mars
Spirit & Opportunity
(NASA) – 2004+
Exploring Mars
Mars Science Lab (NASA) – 2013 +
“Curiosity”
Looking for Capability
of Life
Exploring Mars

Opportunity (2004 – 16 and still going…)
Exploring Mars

MAVEN (2013)
Exploring Mars
ExoMars (ESA) – Crashed last month…
Water on Mars
Water on Mars?
Water on Mars
What geological features tell us
water once flowed on Mars?
What geological features tell us
water once flowed on Mars?
The surface of Mars appears to have ancient riverbeds.
Eroded
crater
The condition of craters indicates surface history.
Close-up of eroded crater
The Martian Surface Map
Volcanoes…as recent as 180 million years ago…
Past tectonic activity…
A *even bigger* volcano
A *really* GRAND canyon…
Differences in Hemispheres
Low-lying regions may once have had oceans.
Low-lying regions may once have had oceans.
Opportunity
Spirit
NASA’s SPIRIT & OPPORTUNITY Rovers…still sending data!
2004 Opportunity rover provided strong
evidence for abundant liquid water on
Mars in the distant past.
 How could Mars have been warmer and
wetter in the past?

© 2015 Pearson Education, Inc.
Clumps of
rounded
pebbles
discovered by
the Curiosity
rover compared
with similar
formations in
Earth
streambeds
Today, most water lies frozen
underground (blue regions).
Some scientists
believe accumulated
snowpack melts
carve gullies even
today.
Why did Mars change?
Climate Change on Mars
No widespread
surface water for
3 billion years.
 Greenhouse
effect probably
kept surface
warmer before.
 Somehow Mars
lost most of its
atmosphere.

Climate Change on Mars


Magnetic field may have preserved early
Martian atmosphere.
Solar wind may have stripped atmosphere after
field decreased because of interior cooling.
Polar Climate Change
Exploring Mars
Winds on Mars
Wind trails
from “dust
devils”
Rivers on Mars
… & Earth!
… More
evidence
of water
Carbon Dioxide Cycle
•
How do
atmospheres of
Venus & Mars
differ in their
ability to cycle
CO2 from
atmosphere to
crust and
back??
Carbon Dioxide Cycle
•
Assume all 3 planets
had similar compositions
and conditions “early” in
the solar system’s
history…
•
Assume all 3 had liquid
water, active volcanoes,
and CO2 in atmosphere
Carbon Dioxide Cycle
Step 1: Evaporation/Rain
1
•
Liquid water evaporates
•
Condenses into clouds
in lower atmosphere
•
Rain falls through
atmosphere forming
Carbonic Acid (H2CO3)
 CO2 gas is absorbed
Carbon Dioxide Cycle
Step 2: Mineral Erosion by Acid Rain
•
Carbonic Acid (H2CO3)
in rivers erodes rocks
•
Carbonate (CO32-) ion
picked up in minerals
washed to ocean
•
Calcium easily absorbed
2
 CO2 is carried to oceans
Carbon Dioxide Cycle
Step 3: Tying Carbon into Rocks &
Life!
3
•
Calcium from rocks
forms CaCO3 (Calcium
Carbonate)
•
CaCO3 = Limestone
•
CaCO3 = Coral, Mollusk
shells!
 CO2 accumulates on
seafloor
Carbon Dioxide Cycle
Step 4: Tectonics & Subduction!
4
•
Tectonics gradually pulls
seafloor down
•
CaCO3 broken back into
CO2 & other minerals
 CO2 now inside crust
Carbon Dioxide Cycle
Step 5: Volcanic Outgassing!
•
5
Eventual Volcanic
Activity pushes CO2
back into atmosphere
 CO2 now in
atmosphere again!
Carbon Dioxide Cycle
Mars Feedback Loop Failure
Evaporation
•
Rain
•
CO2 gas flushed out
But…
•
Interior cools off
•
Volcanoes Stop!
•
1
5
Carbon Dioxide Cycle
Mars Feedback Loop Failure
•
Atmosphere CO2
decreases
•
Planet freezes
1
5
Carbon Dioxide Cycle
Venus Feedback Loop Failure

1
5
Too Hot for
clouds to form
low enough
But…
 Volcanoes
don’t stop!
Carbon Dioxide Cycle
Venus Feedback Loop Failure
•
1
•
•
•
No Rain
NO CO2 gas
absorbed
More CO2 added!
Runaway
Greenhouse Effect!