Atmospheric Evolution of Earth, Venus and Mars Mars Moons

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Atmospheric Evolution of Earth, Venus and
MarsMars Moons Life on Mars

• Leonard Garcia
• Linda Phan, Dennis Huynh
• Group 16

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Atmospheric Evolution of the Earth
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Primary AtmosphereGas, Poison, and a Whole lot
of Heat

• Most likely resembled that of Jupiter's
  atmosphere
• Contained hydrogen, helium, methane, ammonia,
  water vapor
• Poisonous to humans

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OutgassingGassing it Out

• Volcanic activity
• Released water vapor, carbon dioxide, sulfur
  dioxide, and compounds containing nitrogen into
  atmosphere

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Secondary AtmosphereFinally beginning to cool
down

• Surface Temperature dropped
• Carbon dioxide and sulfur dioxide dissolved into
  oceans or combined with surface rocks
• Water vapor condensed oceans
• BUT still no oxygen

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ITS ALIVE!!Life and oxygen

• Life developed in the oceans
• Organisms began producing oxygen
• Ozone layer formed, life moved to land

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TO REVIEW
N2 CO2 H2O
O2
O2 reaches current levels life invades continents
oceans form
CO2 dissolves
Life forms in oceans
Onset of photosynthesis
Outgassing
4 Gy B.P.
0.4 Gy B.P.
3.5 Gy B.P.
4.5 Gy B.P
present
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Runaway Greenhouse EffectWhy is Venus so Hot?

• 730 K Surface Temperature

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Greenhouse GasesThe second blanket

• Greenhouse gases stop the escape of infrared
  radiation emitted by a planets surface
• Carbon dioxide and water vapor are Greenhouse
  Gases
• Venus atmosphere consists of nearly 96 percent
  Carbon dioxide

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The Runaway Greenhouse EffectGetting a bit out
of hand

• In the past, Venus water vapors made the surface
  temperature twice as hot as it is today
• Water vapor reached the upper atmosphere at these
  temperatures and was broken up into oxygen and
  hydrogen by solar UV radiation
• Hydrogen escaped into space
• No more water on Venus

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Evolution of the Martian Atmosphere

• Believed to have started off much like earth,
  with a primary and a secondary atmosphere
• Greenhouse effect would have kept Mars warm

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Why did the Martian Atmosphere Disappear?

• Possibly because of large impacts early in the
  solar systems development
• Gases could have leaked into space because of
  Mars weak gravitational pull

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Reverse Runaway Greenhouse Effect

• Carbon dioxide combined with surface rocks and
  dissolved into water
• Decrease of carbon dioxide caused Mars to cool
  down, freezing any water it had

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The Moons of MarsFear and Panic
Deimos (Panic) is 16 km long 10 km wide.
Phobos (Fear) is 28 km long 20 km wide.

• Discovered in 1877 by Asaph Hall.

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Asteroids from the belt

• These moons are asteroids that were captured by
  Mars atmosphere.
• It is possible that the two moons are remnants of
  a single object that split during capture.

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Life on Mars?

• Lack of liquid water and oxygen dims the chances
  that there might be life on Mars
• Water in Mars history might have provided an
  environment suitable for life at one time, though

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A Machine on MarsViking sent to do the dirty work

• Viking missions reached Mars in 1976
• Viking performed various biological experiments
  on the soil on mars
• The tests initially suggested life on Mars, but
  scientists pointed out that the tests could have
  been the result of inorganic chemical reactions
• Official NASA Statement said there is no life on
  Mars

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Ok, no life on Mars, but what about a billion
years ago?

• Scientists want to launch more missions to test
  ice caps for fossils
• Meteoroids from Mars found on Earth have been
  tested for fossilized remains
• There are remains, but scientists suggest these
  may be Earth bacteria fossils
• The question of Life on Mars remains inconclusive