Astr 150 – Midterm Review Fall 2006

Astr 150 – Midterm Review Fall 2006
Chelsea MacLeod
Best way to study: Read through your notes while going through the lecture slides/notes online,
practice old midterm questions and email me if you have a question, and study past labs. Also
might be a good idea to make sure you know how to answer each question(s) of the day.
Topics to study:
I. General solar system info:
 The six numbers
Most abundant elements in solar system
Density (and compressed vs. uncompressed), albedo, moment of inertia
Five stages of planetary evolution
Geological activity scales with size
Gravity (study homework assignment!) and Kepler’s Laws (online tutorial)
What two factors determine whether a planet has an atmosphere
II. The inner solar system:
Land features: Impacts, volcanism, tectonics
o Tectonics (endogenetic):
Straight Rilles (faults), wrinkle ridges
plate tectonics
o Volcanism (endogenetic):
duration scales with size of planet
Sinuous Rilles (lava channels/tubes), lava flows (mare)
o Impacts (exogenetic):
three types: simple, complex, impact basins
ground folding out; rocks closest to rim are deepest and oldest
use to age surface (crater counting  crater density plots)
R plots: use to characterize population of craters; shows fraction of total
area covered by craters of different sizes
Crater density plots and R plots are similar among small worlds (moon,
Mercury, and Mars) and similar among larger worlds (Earth and Venus)
The Moon:
o negligible atmosphere, uniform density
o characteristics of lunar mare and lunar highlands
age, albedo, types of rocks found in each (study Moon Rocks lab)
o Moon origin: 4 theories
o why we love the moon (it stabilizes our tilt)
o negligible atmosphere
o large iron core => scarps
o Caloris Basin; hilly and lineated terrain on opposite side of Caloris Basin
o Thin cold CO2 atmosphere => low thermal inertia
o splash craters
o Tharsis range: huge volcanoes due to low gravity and lack of plate tectonics
o Evidence for water in Mars’ past: hematite spheres, layered sedimentary rock, and
weathered rock
=> thicker past atmosphere
o Thick hot CO2 atmosphere => high thermal inertia
o young surface; use radar to image
o Coronae (blobs): result from mantel plumes. There are also antiplumes
o Distribution of craters uniform over entire surface => all same age
o has been hit most in solar system
o craters get worn away in many ways
o KT event
Evidence: Iridium, shock lines in minerals
Global impact
Terrestrial atmospheres:
o can be blown away by huge impacts
o secondary atmosphere: Earth, Venus, and Mars
o How did Venus lose H2O, and Earth lose CO2?
o Greenhouse effect