Announcements Don’t forget to take the test! (today, tomorrow, Friday before class) Don’t...
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20-Dec-2015 -
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Transcript of Announcements Don’t forget to take the test! (today, tomorrow, Friday before class) Don’t...
Announcements
• Don’t forget to take the test! (today, tomorrow, Friday before class)
• Don’t discuss the test with classmates until class on Friday.
• Pick up graded homework.
• First project due in 9 days!
Course Outline
• Naked-eye astronomy
• Crash course in physics
• Our solar system
• The stars
• Structure and history of the universe
Course Outline
• Naked-eye astronomy
• Crash course in physics
• Our solar system
• The stars
• Structure and history of the universe
You are
here
Earth
• My favorite planet• Largest known rock• Very geologically active• Atmosphere of nitrogen
and oxygen• 3/4 covered with water• Nice, comfortable surface
temperature• Only known home of life
Earth
• Made of rock (why?)• Hot inside (why?)• Atmosphere of nitrogen
and oxygen (why?)• 3/4 covered with water
(why?)• Nice, comfortable surface
temperature (why?)
Some partial answers• Made of rock because heavy atoms (Si, O, C, Ca, Na,
K, Fe, Mg) tend to form rocks, and light atoms (esp. H, He) are uncommon on earth (why?)
• Hot inside because of radioactive decay of rare atoms (U, Th, K, Rb), plus some residual heat from earth’s formation; heat builds up and escapes slowly due to earth’s size
• Atmosphere of nitrogen (N2) and oxygen (O2) because plant life has removed most carbon dioxide (CO2) and produced oxygen
• 3/4 covered with water because of size and surface temperature
• Nice, comfortable surface temperature because of our distance from the sun