Lecture 6 Flashcards
Percival Lowell’s study of Mars
- good place to study earth
- light patches and dark patches on map that change shape during the year
- the poles also melt and come back throughout the year
- Lowell’s map is based on the detailed images he saw through a telescope (1908)
- looked very closely and could see lines on the planet that he denoted as canals
- concluded that these were signs of intelligence on mars that made these systems of water to transport things and that the dark patches were signs of plant growth
- pretty widely accepted view into the 20th century
H.G. Wells
- Used Lowell’s interpretation of the planet to write his book The War of the Worlds
- depicted the intelligent life as evil
- transformed into a radio show later that caused a panic because they took it more seriously than intended.
C.S. Lewis
- Out of the Silent Planet
- different view of Martians
- they’re the good ones and humans are evil but can possibly be redeemed.
- creates a Martian ecology in writing this novel
- makes up names for all the topography, zoology, and the botany.
Different constructs of martians due to our fears and desires
- Martian-invader: powerful and evil
- Kindly ones: higher purpose for us
- Ironic ones: Kurt Vonnegut’s Sirens of Titan–>turns out to have manipulated all of Earth’s history
- Unimaginably different ones: Stanislaw Lem’s Solaris–>Whole planet is alive that communicates with the scientists…?
NASA changed our view of Mars
- dark spots weren’t vegetation, but craters
- word was slow to get out–>Quote by Vice President Dan Quayle as Chairman of the National Space Council
Valles Marineris
- Canyon in mars is largest canyon in the solar system–>much bigger than the grand canyon probably made by some plate tectonic event
- most craters from meteors
Mars and Earth’s similar features
- Both rocky (close together)
- Active geologically
- Have atmospheres (Mars is thinner)
- Have water and surface effects of water
- Both have potential for life to have evolved
- Mars still has early Precambrian surface lost to erosion and geologic forces on Earth
- Mars is the closest possibility to see if life is unique to Earth
Dealing with mars is a little difficult
- small size and distance from Sun
- gravity is only 37% of Earth
- most of original atmospher-N2 and CO2 and Water have departed via solar wind (core has frozen…? ask about this)***
- dissociation of water by UV left lots of oxygen to oxidize the iron of the crust
- most remaining water is ice
- rovers and satellites seek (and find) geological evidence of surface water
- Phoenix Lander looked for subsoil ice directly-has remnants of glaciers
- rover being developed to look for life on planet
Mars isn’t very lively now but ask if life existed when planet was young
- How long did it have a dense atmosphere? Any free O2?
Was the temperature ever above freezing? - Did it have free flowing neutral water on the surface?
- Were organic compounds related to life available?
- Is there direct evidence of life?
Mars vs. Earth’s timelines
-Mars preserves a record from 4.5 byr to 3.7 byr lost on earth because of out planets active geology
Opportunity at Victoria Crater
- one of the most interesting places the rover visited
- finds that there was flowing water in the deep past because of hematite “blueberries” which need water to form and water deposited strata in Martina crate wall
Gale crater
- hump in the center is because of all the wind and erosion that it excavated out some of the sediment that had been deposited by flowing water and wind.
- reconstruction shows that it was a major body of water
- Clay/Shale layer important because it shows that it has an environment that can support life if this rock can be formed
Water on Mars
-There was flowing water in the deep past! Unfortunately,
the surface at the Opportunity site represents a late stage
of free water on Mars, when high sulfate levels made the
water a highly acidic brine
-Other sites with older geology from before the drying out
of the planet were sought.
-The Curiosity rover mission was aimed at a site in a
crater that has signs of surface water and rock
deposits from an earlier time. Curiosity landed in Gale
Crater in 2012 to inspect the older geology.
Life under Earth’s crust
- full of life under the crust some as much as 3 miles under the ground (diamond and gold mines in Africa)
- look into walls and they’re full of bacteria–>as could be the case on mars
Gale crater geological section
-We don’t have the rocks on Earth like those on Mars to make such a comparison. They existed at one point in time but we don’t have access to them now.
