16 Atmospheric Evolution

Atmospheric Evolution of Earth, Venus and MarsMar’s Moons & Life on Mars : Atmospheric Evolution of Earth, Venus and Mars Mar’s Moons & Life on Mars Leonard Garcia Linda Phan, Dennis Huynh Group 16


Atmospheric Evolution of the Earth : Atmospheric Evolution of the Earth


Primary AtmosphereGas, Poison, and a Whole lot of Heat : Primary Atmosphere Gas, 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


OutgassingGassing it Out : Outgassing Gassing it Out Volcanic activity Released water vapor, carbon dioxide, sulfur dioxide, and compounds containing nitrogen into atmosphere


Secondary AtmosphereFinally beginning to cool down : Secondary Atmosphere Finally 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


IT’S ALIVE!!Life and oxygen : IT’S ALIVE!! Life and oxygen Life developed in the oceans Organisms began producing oxygen Ozone layer formed, life moved to land


TO REVIEW : TO REVIEW Outgassing N2 CO2 H2O oceans form CO2 dissolves Life forms in oceans Onset of photosynthesis O2 O2 reaches current levels; life invades continents 4.5 Gy B.P 4 Gy B.P. 3.5 Gy B.P. 0.4 Gy B.P. present


Runaway Greenhouse EffectWhy is Venus so Hot? : Runaway Greenhouse Effect Why is Venus so Hot? 730 K Surface Temperature


Greenhouse GasesThe second blanket : Greenhouse Gases The second blanket Greenhouse gases stop the escape of infrared radiation emitted by a planet’s surface Carbon dioxide and water vapor are Greenhouse Gases Venus’ atmosphere consists of nearly 96 percent Carbon dioxide


The Runaway Greenhouse EffectGetting a bit out of hand… : The Runaway Greenhouse Effect Getting 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


Evolution of the Martian Atmosphere : 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


Why did the Martian Atmosphere Disappear? : Why did the Martian Atmosphere Disappear? Possibly because of large impacts early in the solar system’s development Gases could have leaked into space because of Mar’s weak gravitational pull


Reverse Runaway Greenhouse Effect : 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


The Moons of MarsFear and Panic : The Moons of Mars Fear and Panic Discovered in 1877 by Asaph Hall. Deimos (Panic) is 16 km long & 10 km wide. Phobos (Fear) is 28 km long & 20 km wide.


Asteroids from the belt : 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.


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


A Machine on MarsViking sent to do the dirty work : A Machine on Mars Viking 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


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