EVOLUTION OF:

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EVOLUTION OF THE EARTHS ATMOSPHERE and THE
CHEMISTRY OF EARTHS OCEANS
PART 1
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Greenhouse effect occurs when certain gases,
particularly carbon dioxide, methane and water
vapor warm the surface of the planet. Light
enters easily but the gases intercept the
infrared rays that the planet reflects and
reradiates much of this energy toward the
surface. This raises the temperature 35C above
what it would be if they were absent
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On Earth, water in the troposphere is blocked
from entering the stratosphere by a cold trap-
i.e. cold T relatively high ambient pressure
minimize the concentration of water vapor (it
condenses out)
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On Earth, water in the troposphere is blocked
from entering the stratosphere by a cold trap-
i.e. cold T relatively high ambient pressure
minimize the concentration of water vapor (it
condenses out). On Venus the early sea
vaporizes, gradually pushing the cold trap
upwards. The vapor at the top of the atmosphere
disassociates, losing its constituent hydrogen.
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THE FAINT YOUNG SUN PROBLEM
THE EARLY SUN WAS 30 LESS BRIGHT WHEN IT
FIRST STARTED SHINING
SO THE EARTH RECEIVED LESS ENERGY IN ITS EARLY
HISTORY
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MAGNITUDE OF GREENHOUSE EFFECT
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ONCE OUR SUN BEGAN TO OPERATE AT FULL
CAPACITY WHAT ELSE CONTROLED INCOMING ENERGY?
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ONCE OUR SUN BEGAN TO OPERATE AT FULL
CAPACITY WHAT ELSE CONTROLS INCOMING ENERGY?
Milankovitch cycles
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400,000 YEARS
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