Preflight 4

Post your response on the course Compass site

Due Friday, April 4, 12noon

Readings

Peacock

Chapter 11

Questions

1. Discussion Question. Please go on Compass and answer this week's discussion question.
2. Inflation: Motivation
   1. What are the main cosmic puzzles which inflation addresses?
   2. In the absence of inflation, what is one possible solution of the horizon problem? Note: just becuase it is possible does not mean you necessarily have to find it satisfying!


3. Inflation in the Abstract.
   1. Inflation means more than just cosmic expansion. Indeed, for much of cosmic history the expansion is not inflationary. What is special about expansion during inflation? How is that different from (or similar to) expansion during other epochs (e.g., BBN, recombination, the present)?
   2. How does inflation solve the problems you mentioned in question 1?


4. Inflation and Dark Energy. Our current theoretical ideas about Inflation and Dark Energy are closely related but also have important differences.
   1. What are similarities between inflation and our current theoretical ideas about dark energy?
   2. In what way(s) do inflation and dark energy differ?
   
   
5. Predictions of Inflation.
   1. What are testable predictions of inflation? Which if any might be regarded as "postdictions"--i.e., inflation was designed from the start to give such a result? Which if any cannot be fairly regarded as postdictions--i.e., which predictions would you say are bona fide tests which could rule out (or rule in!) inflation?
   2. Which pre/postdictions of inflation have been tested observationally? Broadly speaking, what observations test them, and what grade would you give inflation on these exams?
   3. What is a prediction of inflation which has not yet been tested but could/will be in the forseeable future?


6. Other questions or comments?