AST101
Lecture 17
Barsoom
There are 4 Terrestrial Planets
• Mercury
• Venus
• Earth
• Mars
Mercury
From the
Messenger
Orbiter,
March 2011.
Rayed crater:
Debussy
Venus
From the Venus
Express, 2007.
H2SO4 clouds
Earth
(Terra)
Apollo 17
Mars
Hubble
Space
Telescope
Barsoom
A world like our own?
Populated by aliens?
Telescopic Observations
Mars is dynamic
• Polar caps wax and wane
• Surface features change shape regularly
• Clouds obscure the surface
Giovanni Schiaparelli
Published a map of Mars in 1877
Identified surface features he called “canali”
Schiaparelli’s Mars
Percival Lowell
Mistranslated “canali” (channels) as canals
Established Lowell Observatory on Mars Hill, Flagstaff AZ
Lowell’s map of Mars (excerpt)
Lowell’s Mars
Canals imply
• intelligent life, and
• deliberate construction
Lowell created a Mars that is
• a dying planet,
• whose intelligent denizens built canals
– to collect the melting polar ice, and
– to distribute the water among the oases
Camille Flammarion (1884)
Chesley Bonestell: Surface of Mars © Bonestell Space Art
No one would have believed in the last years of
the nineteenth century that this world was being
watched keenly and closely by intelligences
greater than man's and yet as mortal as his
own; that as men busied themselves about their
various concerns they were scrutinised and
studied, perhaps almost as narrowly as a man
with a microscope might scrutinise the transient
creatures that swarm and multiply in a drop of
water.
H. G. WELLS
THE WAR OF THE WORLDS
Illusions of Mars. I.
This mythos arose from two optical illusions.
1. The human brain tends to connect the dots, which
results in apparent linear features.
2. Dark grey, when viewed next to red, appears green.
Mars is not a red planet with green vegetation outlining
water canals.
Mars is a red planet with dark grey regions.
The Dream is Smashed
Mariner 4, 1965
Mariner 6, 1967
Meridiani Sinus and
Deucalionis Regio
Mariner 9, 1969
Rilles in Mare
Sirenum
Mars
Today
Valles
Marineris
and the
Tharsis
Ridge
Schiaparelli
Hemisphere
Hellas Basin
Northern
Polar
Cap in
Spring
Olympus Mons
Weather
Severe Weather
A Dust Devil
A Frosty Morning
In Utopia Planitia
July 1976
Viking 2
Roaming on the Surface
Dried Riverbeds
Snow on
Mars
Phoenix
May 25 2008: Landing on a patch of ice.
Sedimentation?
Sedimentary
Rocks
Endurance
Crater
Hematite Concretions
Fossil Icebergs?
Curiosity on Mars
Gale Crater
Wall of Gale Crater
Science Highlights
• NASA Rover Finds Conditions Once Suited for Ancient Life on Mars
• NASA Rover Finds Old Streambed on Martian Surface
• NASA Rover Finds Clues to Changes in Mars' Atmosphere
Illusions of Mars. II.
A Face on Mars?
The Face on Mars
More recent images with better cameras (MGO)
More Illusions of
Mars
Life on Mars today?
• There is no macroscopic life
• There is no permanently running water
• The atmosphere is about 0.001 bar
• Mars today is old, cold, and dry
Methane on Mars
Methane on Mars
Meteorites from Mars
Are We the Martians?
• Mars was more hospitable to life early on
• Mars had a significant atmosphere and surface water
• Earth took longer to develop a solid surface
• How did microbial life evolve on Earth a mere 200
million years after the Earth's surface solidified?
• Perhaps life evolved on Mars, and was carried to
Earth on meteorites