GEOL 125: Earth History

 Study Guide #3 (F05)

Draw a Hertzsprung-Russell diagram and indicate the positions of main sequence stars, red giants, white dwarfs, and our sun. How does a star of solar mass evolve on this diagram? What are the energy sources for stars in different parts or this diagram? Why is a mass of at least 0.1 solar masses necessary for a star to form?

What are the stages in the life of a massive star? Why does the lifetime a star depend on mass? How long will the sun exist in its present form? What will be the fate of our sun? How would the lifetime of a star of 10 solar masses compare to the lifetime of our sun? What is the likely fate of a star of 10 solar masses?

What evidence exists that earth material was once part of another star? How and in what setting were the following elements primarily produced: H, He, C, O, Si, Fe, Pb, U?

Describe the forces interacting between two protons as they approach and undergo fusion.

What factors influence density of earth materials? Why does heating change density? What are the densities of the inner and outer planets? Why do they differ?

What are important characteristics of our solar system that must be explained by a model for its formation? Describe the steps involved in formation of a solar system with planets. About when did our system form, and how long did it take? How do we know?

Why are some atoms radioactive? Why is radioactivity important to earth scientists?

Draw a graph that shows the amount of radioactive element that is present as a function of time after production of this element has ceased (i.e. plot radioactivity vs. time). If the element has a half-life of 1000 years, how much will remain after 3000 years?

How can we use radioisotopes to estimate the age of a rock? What assumptions are made?

Terms to know

 critical density  main sequence  angular momentum
 white dwarf  supernova  red giant
 density  isostasy  neutrino
 half-life  decay constant  alpha decay
 beta decay  fission  isotope
 parent  daughter  26Al
 fusion  Crab Nebula  Andromeda
 dust cloud  planetesimal  T Tauri
 shock wave  prograde  retrograde
 ecliptic  black hole  U/Pb dating
 super giant  population I star  population II star