Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important...
-
Upload
egbert-benson -
Category
Documents
-
view
213 -
download
1
Transcript of Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important...
![Page 1: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/1.jpg)
Lecture 6
6/11/07
Ast 1001
![Page 2: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/2.jpg)
Earth’s Atmosphere
• The Earth’s atmosphere has several very important properties:– Just enough warmth– Just enough pressure– Water can exist in three phases– Protects us from solar radiation– Allows for weather
![Page 3: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/3.jpg)
The Big Questions
• Why did Earth retain most of its outgassed water?
• Why does Earth have so little carbon dioxide compared to Venus?
• Why does Earth have so much Nitrogen and Oxygen?
• Why does Earth have a UV absorbing stratosphere?
![Page 4: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/4.jpg)
Water and Carbon Dioxide
• Temps were low enough for water vapor to condense– Earth had oceans 4.3 billion years ago
• Ocean’s explain why there is so little carbon dioxide in atmosphere– Most of the carbon dioxide dissolved into the
oceans
![Page 5: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/5.jpg)
Nitrogen and Oxygen
• We have so much nitrogen because it isn’t absorbed as much as carbon dioxide
• Life is key to explaining why we have so much oxygen– Oxygen breaks down after several millions of
years– Also explains why we have an ozone layer
![Page 6: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/6.jpg)
Earth’s Stable Climate
• Earth has a relatively stable climate• Earth self regulates via the carbon dioxide cycle
– Atmospheric carbon dioxide dissolve into rainwater
– Rain erodes the rocks, bringing minerals to the oceans
– Calcium combines with carbon dioxide and makes rocks like limestone
– Plate tectonics carry the rocks to the subduction zone
– Rock melts and releases its carbon dioxide back into the atmosphere through volcanoes
![Page 7: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/7.jpg)
Feedback• What if Earth warms up?
– More evaporation and rainfall
– More carbon dioxide out of the atmosphere
– Weaker greenhouse effect
• What if Earth cools down?– Less rainfall– More carbon dioxide in the
atmosphere– Stronger greenhouse effect
![Page 8: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/8.jpg)
Long Term Change• It takes the carbon dioxide
cycle time to stabilize the temps– We can have ice ages or hot
spells
– Geologists have discovered a snowball Earth phase
• Eventually the gradually brightening Sun will cause major climate issues
![Page 9: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/9.jpg)
Humans and Climate
• It is undeniable that humans affect climate and our planet– Ozone layer hole– Mass extinctions
![Page 10: Lecture 6 6/11/07 Ast 1001. Earth’s Atmosphere The Earth’s atmosphere has several very important properties: –Just enough warmth –Just enough pressure.](https://reader036.fdocuments.us/reader036/viewer/2022072015/56649ec15503460f94bcd3d5/html5/thumbnails/10.jpg)
Global Warming• There is controversy about how
serious the problem is, but the following facts are clear:– Measurements show that the Earth
has warmed over the past 50 years
– The burning of fossil fuels and other human activity dumps greenhouse gasses into the atmosphere
– Eventually, a continually rising concentration of greenhouse gasses would make our planet warm up