Geological Evidence for Water on Mars

Geological Evidence for Water on Mars - Transcript

Water on Mars
Geological Evidence for Water on Mars
gullies erosion channels layers sedimentary features

The Physics of Water on Mars
polar ice caps seasonal variation atmosphere history

Chemical Evidence for Water on Mars Theories for Water on Mars debates
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Water on Mars
One of the most natural human curiosities related to the ultimate question of LIFE on Mars

Viking 1 Orbiter

MGS

although many images suggest SIGNS of water 5NO2003 Sept LIQUID WATER orSystem C C Lang ever been observed 2 Solar RAIN has

Geological Evidence Outflow Channels

Ares Valles

MGS data

Outflow channels suggest that massive floods happened water discharge rates 10 000 times Mississippi River flood did these floods form into aC C Lang ocean massive 5 Sept 2003 Solar System

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Geological Evidence Martian Channels
Martian Gullies left Mars and right Earth

In the Earth picture rain water flowing under and seeping along the base of a recently deposited volcanic ash layer has created the gully

For Mars water is not actually seen but is inferred from the landforms and their similarity to examples on Earth
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Mars Global Surveyor Image June 2000

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Earth Mt St Helens

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Geological Evidence Sustained Water Flow

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MGS

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Geological Evidence
Possible Ancient Streambeds and Erosion Channels

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Summers in the Martian southern hemisphere are shorter than summers in the northern hemisphere
Why 1 The northern hemisphere is chilled by a larger polar cap 2 There are more volcanoes in the southern hemisphere 3 The southern hemisphere is at much lower elevation on average the Martian equatorial bulge makes the sun shine more directly on the Southern hemisphere 4 This is a consequence of Mars elliptical orbit

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The physics of finding water on Mars
When how does water H20 exist in its liquid state
LIQUID water exists over a very NARROW range in TEMPERATURE if T is too high gas if T is too low solid ice The TEMPERATURE of water will depend on the ATMOSPHERIC PRESSURE if Pressure is too low water will vaporize evaporate if Pressure is too high water will stay liquid

Mars atmospheric pressure is 1 of Earth s LOW pressure LOW temperature FROZEN WATER ice
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Mars Global Surveyor TES instrument 5 Sept 2003

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Mars Global Surveyor TES instrument 5 Sept 2003

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Martian Atmosphere
Carbon Dioxide CO2 95 32 Nitrogen N2 2 7 Argon Ar 1 6 Oxygen O2 0 13 Water H2O 0 03 Neon Ne 0 00025 1 1 000 as much water as our air only enough to cover the surface of the planet with 0 4 inches if melted out of the atmosphere Martian atmosphere does not regulate the surface temperature on the planet as Earth s
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Mars Global Surveyor TES instrument

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History of Mars atmosphere first like Earth s

Atmospheres of terrestrial planets created by out gassing of volcanoes 4 Billion years ago Mars Earth same atmosphere volcanic gasses nitrogen CO2 water vapor H2O in atmospheres condensed to create oceans on Earth CO2 cycles through our atmosphere volcanoes carbonate rocks
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What happened to the atmosphere on Mars

CO2 and H2O may have condensed out and onto the surface got so cold that the water froze into permafrost End of volcanic activity however would stop the cycle Strong UV light from the Sun will break up chemicals on surface 5 Sept 2003 Solar System C C Lang 15 and cause them to evaporate

Storage place for Water some in N Polar Cap
Caps are frozen carbon dioxide CO2 dry ice and some frozen water notes on frozen CO2
CO2 freezes at T 150 K 200 F block of dry ice T 110 F sublimes directly ice to gas

Southern residual cap is 300 km across T 150 K Northern cap is 1 000 km T 200K implies mostly water ice b c CO2 ice would be sublimating
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Chemical Evidence Looking for presence of minerals which suggest water
Small amounts of water vapor in the atmosphere indicated that much of the planet s water lost to space evaporated Recent Mars missions have looked for evidence of carbonates
large seafloor beds resulting from consumption of atmospheric CO 2 finding little or none this is problematic controversial

Recent Mars missions have found Hematite a signature of dried up lakes on a few places on the planet
from TES instrument on MGS

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Recent Chemical Evidence for water on Mars Detection of Hydrogen Mars Odyssey 2003

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Recent chemical Evidence for water on Mars Detection of Hydrogen Mars Odyssey 2003

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Theories for Water on Mars WET WARM MARS
early atmosphere was dense could support water in liquid form could rain out the CO2 onto the surface large beds of carbonate form in standing water like on Earth Oceans water would be plentiful on Mars could generate the observed features

Theories for Water on Mars COLD DESERT MARS
Never right conditions for water to condense and to create erosions Have to rely on other eroding agents wind dust liquid carbon dioxide
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Theories for Water on Mars Current Data Ideas
Mars probably did have a warmer wetter past but not extreme studies show water can exist in ice covered lakes as long as temperatures get above freezing for a few days clues from glacial regions on Earth have helped

Geological Evidence Use Ancient Lakebeds Glacial Lakes as analogy
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Geological Evidence Layered Sedimentary Features

141 km 88 miles

Holden Crater
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Theories for Water on Mars Current Data Ideas
Also can invoke CYCLES of warm wet climates volcanic activity generates atmosphere for short periods water starts flowing again unfreeze it create the observed layers of water erosion features water freezes into permafrost under Mars surface Also can invoke an active underground system of water water lower down may be able to be liquid warmer near Mars core volcanic soils megaregolith are incredibly porous The final word keep watching the skies NASA Monday review of current future Mars Exploration New results in every day
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Martian Meteorites
Martian data without going there

What are these meteorites Unusual rocks found in Antarctica How did they get to Earth
An impact on Mars crater size 10 100 km ejected part of the Martian surface Chemical composition does not match usual meteorites Only 1 3 billion yrs old most asteroid type meteorites MUCH older Higher content of volatile substances

How do we know these meteorites are from Mars

Why aren t they orange the color of Mars surface
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Has to do with how the rocks weathered 24

What DO they tell us

Physical processes on Mars Crust core developed early in Solar System Volcanism until 1 Billion Years ago Chemical composition Interaction with water Martian atmosphere composition Location of origin Enough about Mars water atmosphere Need to RETURN ROCKS from Mars

What DON T they tell us

Case Study Martian Rock ALH84001
Mass 1 9 kg Igneous Rock Discovered in Antarctica easier to find 1984 Formed on Mars 4 5 Billion yr ago Ejected 16 Million yr ago Landed 13 000 yr ago
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Controversial microbial presence in meteorites

Globules of carbonate minerals the yellow orange grains are scattered along cracks in this small chip of ALH 84001

The rims contain iron oxides including magnetite and iron sulfides incompatible minerals that on Earth would suggest microbial action

Close up views reveal structure similar to Earth microbes
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Mars has a very thin atmosphere and no magnetosphere If humans populated the Martian surface what environmental problems will they be concerned about

1 Global Warming 2 Solar flare particles and ultraviolet radiation 3 Nitrogen poisoning 4 Lead contamination from volcanoes 5 Magnetic anomalies in the interior causing brain disorders
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Monday Mars Surface Exploration

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Monday Mars Surface Exploration

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