Peacock (1999) came out just as the evidence for cosmic acceleration and dark energy was just starting to appear. Thus there is some mention of the first evidence, but the discussion is fairly brief.
This is a comprehensive but very readable overview of both observational and theoretical issues surrounding the cosmological constant or dark energy. It's longish, but you won't need to read the whole thing unless you want to.
The questions are really meant to help guide your thinking as you read. You may find it helpful to look at the questions first and bear them in mind as you read.
Post your answers on Compass. Your answers must be in your own words.
Note: Since you brave souls taking the course have very different backgrounds and interests, the Preflights are an obvious place to try to introduce some flexibility to pursue your particular interests more. So this Preflight will focus on Dark Energy in general, and you'll read some about both observational and theoretical issues. But you'll also have an opportunity to go in more depth in whatever aspect pleases you.
Be sure to read at least Sections 1, 3, and 10 of Frieman et al. You should read beyond that, following your interest and background, and then adjust your answers accordingly. Read to get the big picture.
Discussion Question 2
The anthropic principle. Posted on Compass; your reply will be visible to your classmates.
What are the main lines of observational evidence for cosmic acceleration? For dark energy? Which is the most direct? Which is the least direct? How many observations have to be wrong to make dark energy unnecessary?
Discuss possible problems and/or uncertainties with some or all of the evidence from part (a). What efforts have been made to address these problems? How might future work (already planned, or dreamed of) address these issues?
What is the connection between cosmic acceleration and a cosmological constant/dark energy?
Dark energy can be defined as any cosmogical component with equation of state parameter w < -1/3. Given this definition, how are dark energy and the cosmological constant related?
Dark energy presents many theoretical challenges. It could be that these are too great, and that dark energy does not exist. That is, it could be that the universe only contains matter and radiation, without any new substance with an exotic equation of state. In this case, what is needed to explain cosmic acceleration?
Why is a nonzero cosmological constant a surprise from a quantum point of view. What is the naive quantum prediction for the comological constant, and how wrong is it?
For the particle-physics inclined: how well does the (observed) cosmological constant fit into theories going beyond the Standard Model? If the cosmological constant (or dark energy) is indeed real, what is your best bet as to the explanation--i.e., what new physics do you think is likely to be involved?