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L8 Atmosphere
Material from lecture 8
24
Astronomy
Undergraduate 2
04/22/2011

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Cards

Term
Primary atmosphere
Definition
All of the planets in our solar system had primary atmospheres of hydrogen and helium from early accretion.
Term
Why do the inner planets no longer have their primary atmospheres of hydrogen and helium?
Definition
The gasses move too fast and the planets are too small to hold onto them.
Term
Secondary atmospheres
Definition
Form from the outgassing (release of gas) of melted rocks and volcanoes.
Term
What are the two main gasses released during outgassing?
Definition
H2O (water) CO2 (carbon dioxide)
Term
Why is Venus 400 degrees hotter then it should be?
Definition
The dense atmosphere contains a lot of greenhouse gasses that trap infrared radiation within the atmosphere heating up the planet.
Term
Greenhouse effect
Definition
Greenhouse gasses in the atmosphere allow some radiation from the sun to get to the surface of the planet but then trap the radiation between the surface and the atmosphere heating up the planet.
Term
Greenhouse gasses
Definition
Absorb and scatter infrared radiation
Term
What happened to the water in venus' atmosphere?
Definition
When Ultra Violet radiation from the sun impacts water molecules it breaks the hydrogen from the oxygen.
The hydrogen escapes from the atmosphere.
The oxygen bonds with other elements.
Term
Why does Venus not have plate tectonics?
Definition
Water on earth acts as a lubricant so that the plates can move past each other. Venus does not have any water on it's surface so it cannot have plate tectonics
Term
What is/are the main gas/es in Venus' atmosphere?
Definition
Mostly carbon dioxide with a little nitrogen.
Term
Why is there so little carbon dioxide in earth's atmosphere?
Definition
1. Rocks and weathering take CO2 from the atmosphere and replace it with oxygen
2. Life- animals in the ocean take CO2 from the atmosphere and store the carbon and release oxygen.
Term
How does the weathering of rocks remove CO2 from earth's atmosphere?
Definition
In the atmosphere, Water+CO2=carbonic acid.
This is acid rain and it weathers rocks. The process turns carbon from the CO2 into the weathered rock.
Term
How does life effect carbon dioxide And oxygen levels in our atmosphere?
Definition
Plankton in the ocean breaths in CO2.
It uses the carbon to make it's shells and breathes out oxygen.
When the animal dies the shell sinks to the bottom of the ocean and becomes a rock.
Term
Why has the amount of CO2 in earth's atmosphere been skyrocketing since the 1800's?
Definition
Since the industrial revolution we have been burning fossil fuels and pumping CO2 back into the atmosphere.
Term
What would the earth be like without greenhouse gasses?
Definition
The temperature on earth would be about zero degrees celsius.
Term
What don't the UV rays from the sun destroy all of the water in our atmosphere like they do on Venus?
Definition
The oxygen that makes up our ozone absorbs UV rays and protects the water in our atmosphere.
Term
What is earth's atmosphere made out of?
Definition
Mostly nitrogen and oxygen with a little water.
Most of the water from outgassing has gone into our oceans.
Term
Why does mars have such a thin atmosphere?
Definition
The polar ice caps on mars are made out of CO2 and water so much of it's atmosphere is frozen in it's ice caps
Term
Why does the atmospheric pressure on mars very with the seasons?
Definition
During winter the icecap is large so the atmosphere is very thin. During the summer the icecap is small and the atmosphere is thick
Term
Why does the temperature vary so much on the surface of mars between shade and sun?
Definition
The atmosphere is so thin, it takes very little energy to change the temperature.
Term
What happens during the transition of summer to winter on mars?
Definition
Global dust storms.
Term
Dust devils
Definition
Small, harmless tornadoes on the surface of Earth.
They are very large on mars but still harmless. They clean off the solar panels on the rovers.
Term
Why does all of the soil on mars have the same chemical composition?
Definition
The global dust storm mix all of the soils together.
Term
What are the three main reasons that mars does not have a thicker atmosphere?
Definition
1. Mars is just barely large enough to hold onto water vapor so it is very easy for it to loose water from it's atmosphere.
2. Earths magnetic field protects it's atmosphere from solar winds. Mars has no magnetic field and the solar winds blow off it's atmosphere.
1. Mars is very close to the astroid belt and is more often hit by large asteroids then the other inner planets
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