Physics 101 - Astronomy  -  Spring 2009

Class notes for day 13, March 10, 2009

Ch. 5 the Earth and Moon

Here are links to some current events items that relate to Ch. 5 on the Earth and Moon

NEOs

A new NEO was observed last week, and passed relatively close to Earth.

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009+DD45&orb=1 

shows the orbit in a simulation based on 4 days of observations.

http://planetary.org/news/2009/0302_Space_Rock_Swoops_by_Earth.html 

has a overlay photo of what the telescope images looked like.

Close approach table:
http://neo.jpl.nasa.gov/ca/ 


Search for Earth-like planets (exoplanets)

Article on Kepler mission:

http://www.nytimes.com/2009/03/03/science/03kepl.html?_r=2 

Pictures on NASA web site:

http://mediaarchive.ksc.nasa.gov/search.cfm?cat=194 

Kepler home page at NASA:

http://www.nasa.gov/mission_pages/kepler/main/index.html 

The discussion for this chapter was mostly out of the book.  I pointed that most of the details about the interior of the Earth are due to seismic studies. Seismic waves pass through the entire Earth whenever there is an earthquake. These waves are really like sound waves traveling through the interior of the Earth. Some of them are not heard on the other side because part of the core of the Earth is liquid and transverse sound waves cannot travel through liquid.
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The Greenhouse effect is due to several factors, but the increase of carbon dioxide in the Earth's atmosphere is the most important, since we could do something about it by burning less fossil fuels. Global Warming is definitely occurring, but this may be due to several reasons. The influence of carbon dioxide is a topic of some debate, however. Other factors that influence the Greenhouse Effect include:

Clouds
Water vapor
Agriculture
City “heat islands”
Carbon dioxide
Methane
CFC gases
Dust and pollution
Snow cover
Desertification
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The mantle of the Earth is about 80% of the volume of the Earth. The Earth's core is believed to be mostly iron and nickel, but could have many of the heavier elements. There is certainly some Uranium and other radioactive elements which produce heat that keeps the core hot and molten. We will compare this structure with other planet’s structures.

We finished Ch. 5 by reviewing a few facts about the Moon. Most of my discussion is straight from the book. I showed a couple extra slides to emphasize the main features on the Moon: the Maria, the Lunar Highlands, craters, and a big impact basin on the far side. I stressed the idea that the maria were created quite a while after the highlands, due to lava flows. We know this since they have fewer craters.

I will discuss some of these current events on Thursday, but leave this material here. 

Moon exploration

Lunar Reconnaissance Orbiter

http://www.nasa.gov/mission_pages/LRO/main/index.html 

Japanese Lunar mission:

http://www.jaxa.jp/projects/sat/selene/index_e.html 

http://www.jaxa.jp/countdown/f13/index_e.html

http://www.jaxa.jp/countdown/f13/live/index_e.html  (pre-class?)

Chinese exploration:

http://www.chinadaily.com.cn/china/china_moon_page.html 

http://www.space.com/missionlaunches/090302-china-change1-crash.html  (has videos)



Greenhouse gas monitoring

Failure of OCO:

http://www.nasa.gov/mission_pages/oco/main/index.html 

Success of Japanese IBUKI launch (greenhouse gas observer)

http://www.jaxa.jp/countdown/f15/index_e.html 

also see my PowerPoint on greenhouse gases