Due February 18th, 2008
Name: _________________________________________________
1. The Earth's seasons result from the 23.5o degree tilt of its spin axis versus the perpendicular angle to its orbital plane (see Fig 2.15 in the textbook). Imagine the following scenarios and describe what you think the seasons (especially winter and summer) would be like [Hint--maybe a little drawing would help]:
a) If the Earth's spin axis was oriented exactly perpendicular to its orbital plane (i.e., instead of a 23.5o tilt from perpendicular, the tilt would be 0o from perpendicular---straight up and down). Would there be strong seasons? What about the lengths of days and the concentration of sunlight? (5 pts)
b) What if the spin axis was in the same plane as the Earth's orbit (that is
a tilt of 90o, instead of 23.5o)? Describe the nature
of winter and summer in this arrangement (note that the planet Uranus has
this type of a tilt!). (5 pts)
2. Explain why we do not see a solar eclipse at every New Moon, and
why there is not a lunar eclipse at every Full Moon (it is the same reason for
both!). Make a drawing of this geometry. (10pts)
3. There are a large number of processes that reshape the Earth's surface.
Describe one of these processes. How does it work? What timescale does it
work on? What are its main effects? (5 pts)