Study Guide for the Final Test in ISP 205, Section 2, Spring 2003


IMPORTANT CAUTIONARY NOTE: This study guide is a general outline of the material that will be covered on the exam. It may be useful in helping you to spend your time studying the most relevant material. However, it is only an outline, and is NOT a replacement for studying your notes, the appropriate sections of the book, and the homework.

Expansion of the Universe (Ch 25.5, 27.1, and 28.1-3) How do we know the universe is expanding? How fast is it expanding? How do we measure this (redshifts and distances)? How do we estimate the age of the universe from the expansion rate? Was it always expanding this fast? How can we tell? Will it expand forever? What are the ways we try to determine this?

Even though this part of the review is short, the above material is important for this exam (don't judge the relative importance of each of these sections by the length of the section).

General Relativity and Black Holes (Ch 23, 26.4) General idea of general relativity - gravity distorts space, distortion of space is gravity. Similar version- mass curves space, space is curved because of mass. Everything takes shortest path in spacetime (this tells you how things move).

A black hole is an object with such a high density (mass/volume) that light can not escape. Another way to say this is the space is so curved by the mass that it is closed.
Examples of black holes - a few seen in binary star systemd. Most galaxies have massive ones at their centers. Black holes identified through their gravitational effects - velocities (motions), Newton's version of Kepler's law to get required mass, and upper limit on size to show likely black hole (lots of mass in a very small space).
Other examples of general relativity - light bent a little by the Sun. More dramatic examples in the universe in objects known as gravitational lenses.

Fate of the Universe (Ch 28, but not all in book) More on determining the history and predicting the future of the universe. The observable consequences of the different possibilities for our universe. How adding up the matter in the universe can help us determine this. What that result is. How looking at galaxies and other objects (like supernovae) far in the past can help us determine this, and what those data suggest for the history of the universe. Understand how redshift is a time machine when used to look at very distant galaxies from the early universe. The start of the discussion on the physical properties of the universe at early times. General idea of how the universe was different physically in the past. How the "cosmic microwave background photons'' originate from the early universe (about 300,000 years) - when the universe changed from being opaque because photons kept bouncing off free electrons to being transparent because electrons joined up with the protons. How the current temperature of these photons tells us about the conditions in the early universe.

The Very Early Universe (Ch 28.4-6)- a review of the ``cosmic microwave background''. Stepping backward in time to when the universe was even hotter and denser, how protons and neutrons came together at even earlier times (about 3 minutes since start of Big Bang) to make Helium, but not enough time to make heavier elements. What the horizon and flatness problems are, and how a very early, super-inflationary period in the universe solves them.

isp205-2@pa.msu.edu