Properties and evolution of the Universe and of large systems within it. We will study qualitative aspects of general relativity (including Black Holes) and of mathematical models for the geometry of the Universe. We will then track the history of the Universe from its early exponential expansion to the formation of galaxies. The role of observations in refining our modern scientific understanding of the structure and evolution of the Universe will be stressed. The approach will be quantitative but any mathematics beyond straightforward algebra will be taught as we proceed.

Astronomy 101 is useful, but not a prerequisite.

Astro 112 will treat cosmology, defined as the study of the large-scale structure and the history of the Universe.

To understand the structure of the Universe, we will need first to study modern views of the geometry of space-time (based on Einstein's theories of special and general relativity). You will have to abandon your old, Newtonian, notions of absolute distance and time. Once we have established the properties of space-time, we will look at the three possible geometries for the Universeand at ways to determine which is the actual "correct" geometry. We will see that geometry and the long-term future of the Universe are directly connected.

We will also detour briefly to study the odd geometry around a Black Hole: Why is there no escape from a Black Hole?

The second half of the course will be devoted to the history of the expanding Universe. The dynamics of the Universe are dominated by gravity, so we will begin our study by treating gravitational effects in a uniform Universe. Once the basic equations are set up, we will look at possible futures for the Universe, then probe its distant past. As we look back over the 1020 billion year history of the Universe since the Big Bang, we will focus on four interesting epochs: the time when galaxies form; the time when the matter broke free from the heat radiation of the Universe (the earliest time we can "see" directly); the epoch of element formation about 3 minutes after the Big Bang; and the epoch of inflation when the Universe we know "blew up" by a factor of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000 in volume.

Almost all the reading in the course will be from books and articles addressed to intelligent lay persons (many of the articles will be from Scientific American). However, from time to time we will read slightly more technical articles from professional journalsI will provide notes or glosses when necessary. Cosmology as a science is moving so rapidly that many of the newest developments have not had time to reach books for the non-technical reader.

J. Silk, *The Big Bang*

S. Weinberg, *The First Three Minutes*

(optional) P. Bergmann, *The Riddle of Gravitation*, and J.
Hawley and K. Holcomb, *Foundations of Modern Cosmology*.

There will be roughly ten homework sets or projects (one or two of them involving computer programs, which I set up, to do the arithmetic). About 40% of your grade will depend on the homework. The other 60% will be determined by three tests, equally weighted. I am considering giving you the choice of replacing one of the tests with a 10 page paperwe will talk about that option later.

You do not need to have Astro 101 to take (and do well in) Astro 112. For those who haven't had 101, I'll teach an extra 1-2 hour session early in the semester to introduce some astronomical jargon and lore. No background in calculus is required, but we will make frequent use of algebra. I will teach some math as we go, and any difficult "number crunching" will be done by prepared computer programs. But you will earn your "Q" point.

Astro 112 is consciously designed to work you hard in the beginning, then relax a bit in the last few weeks (when you will be busy with other work). For instance, there will be no cumulative final exam, just a third test given in the exam period.

If you have questions about the nature of the course, see me soon. I am generally available Monday and Thursday afternoons and Monday and Wednesday mornings before 11:20.

Bruce Partridge

Observatory

Phone: 896-1144