Preflight 1

Post your response on the course Compass site

Due Friday, Jan. 29, 12noon

Reading

Course Text

Peacock

Chapter 1; Chapter 3

The first chapter is a discussion of General Relativity. After some nice conceptual discussion, the rest of the presentation becomes a bit dense and probably is hard to decipher for a neophyte to GR.

The third chapter is Peacock's opening discussion of cosmology, but comes after chapters on astrophysics and relativity. As such, it's rather direct, not a "chatty" or informal easing into the subject, and is focussed on establishing the basic concepts and their mathematical description. For a broader review with a wider focus, see..

Articles

Michael S. Turner

"Cosmology Solved? Quite Possibly!"
Publications of the Astronomical Society of the Pacific (1999) 111, 264-273
arXiv:astro-ph/9811364; Published article: PDF version

Athough somewhat dated, this is a very accessible and exuberant review which captures the spirit of excitement in cosmology. For more detail, see the Turner & Tyson review in the supplemental reading.

Suggested Supplemental Reading

John C. Baez and Emory F. Bunn

"The Meaning of Einstein's Equation"
Amer. Jour. Phys. 73 (2005), 644-652
arXiv:gr-qc/0103044

This is a brief but conceptual review of some of the essentails of General Relativity. The authors consciously try to avoid mathematical detail and to appeal to key physical and geometrical principles.

Michael S. Turner and Anthony J. Tyson

"Cosmology at the Millenium"
Reviews of Modern Physics (1999) 71, S145-S164
arXiv: astro-ph/9901113

Sean Caroll

"Lecture Notes on General Relativity"
online html version
arXiv: gr-qc/9712019
Book: Spacetime and Geometry: An Introduction to General Relativity

Questions

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.

1. Introductions.

   We'd like to know a little bit about you for our files. Briefly, what is your background in astronomy/astrophysics? In nuclear/particle physics? If you are already involved in research, what are you working on? If you are not, what area(s) interest you?

   Are there specific topics would you like see discussed in this course?

2. Cosmology solved?

   For inspiration and a view of the big picture (as of 10 years ago), read the Turner article.

   1. In the introduction, Turner quickly outlines the basic physics of big bang cosmology, and highlights the "three pillars" of evidence which provide the strongest support for the theory. what are they? What is strongest evidence for them?
   2. In your view, to what extent is cosmology solved?
   3. What questions/issues in cosmology remain unsolved--not only those Turner mentions, but others that occur to you? What would you add to Turner's checklist for this decade in cosmology?
   
   
3. Cosmology in an Evolving Universe.

   A fundamental aspect of cosmology is that we live in an evolving universe. This basic fact presents challenges for cosmologists trying to reconstruct the history of the universe from the vantage point of a single particular location (the Earth) at a single time (now).

   1. What are some conceptual ("in principle") difficulties with doing cosmology in an evolving universe? (For example, consider the problem of making independent tests of basic assumptions of the big bang model. But there are many other issues--please think of at least one other). Are there possible ways around these problems?
   2. What are some practical (e.g., observational) difficulties with doing cosmology in an evolving universe? What are possible ways around these problems?
   
   
4. General Relativity.

   Take look at either the Baez & Bunn article, and/or the initial discussion in Chapter 1 of Peacock, reading for concepts more than for the formalism. Clearly, this reading is not going to teach you General Relativity from scratch, but is only meant to give you a flavor of the philosophy and some of the results of this beautiful theory. To really understand GR, take Stu Shapiro's course!

   Given these limited goals with respect to GR, the questions here are just to help you think about the basics.

   1. What is the equivalence principle? Give an example of an experiment which verifies it.
   2. How could the equivalence principle be used to argue that gravity is not a force but rather has a geometrical explanation?
   3. What does it mean to say space is curved? What is an experiment you can do to determine if you live in a curved space (hint: the surface of the Earth is one)?
   4. Bonus for style points: What does it mean to say spacetime is curved? What is an experiment you can do to determine if you live in a curved spacetime (hint: the surface of the Earth is one)?
   
   
5. What material did you find difficult, confusing, or unclear? What material would you like to know more about?


6. Other questions or comments?