Fall 2000 ASTR 1120-001 Final Review

This is the seventh and last review sheet. The final exam will cover everything we have done during the semester.

1. Inflation. What is inflation? What dominates the energy density of the Universe during inflation? When is inflation thought to have happened? How does the Universe expand during inflation? What happens to the horizon during inflation?

2. Problems of the Universe. How does inflation solve the following problems:
   1. Why is the Universe expanding?
   2. Why is the Universe at large so smooth, as indicated by the tiny (few × 10^-5) fluctuations in the CMB?
   3. Why is the Universe so flat, as indicated by the Boomerang CMB observations?
   4. The Horizon Problem?
   5. What caused ripples in the smoothness, which later grew by gravity into galaxies, stars, and you?
   6. Where did vacuum come from?
3. Unification of Forces. The four forces of nature are:
   1. the strong, or nuclear, or color force, which keeps atomic nuclei bound;
   2. the electromagnetic force, which keeps electrons in orbit around nuclei;
   3. the weak force, which does not seem to have much direct effect on ordinary life, but which mediates radioactivity;
   4. the gravitational force, which keeps planets in orbit around the Sun.
   What does the Unification of Forces mean? Is there any evidence for it? What is the electroweak force? At what energy/temperature do the electromagnetic and weak forces unite? What has the (de)unification got to do with vacuum energy?