Next: 2. The Sky Around Us |

The first week of this course is an introduction to some of the things we find in the Universe -- atoms, light, planets, stars, and galaxies. These lectures also describe a useful way of comparing the sizes, ages, and masses of different astronomical objects.

**Topics:**

- Linear & logarithmic scales
- Scientific notation
- The relative sizes of things
- Cosmic time
- Light & radiation
- Atomic structure

**Reading:**

Ch. 1-3 | Powers of ten notation |

Ch. 1-4 | Astronomical distances |

Ch. 2-2 | The complex nature of light became apparent only in the twentieth century |

Ch. 2-4 | Light is only one type of electromagnetic radiation |

Ch. 2-20 | An atom consists of a small, dense nucleus surrounded by electrons |

**Video:** *Powers of Ten*

**Web Resources:**

- Scientific Notation
A brief primer on scientific notation, and an on-line test you can take to check your understanding.

- Working With Units
A brief primer on units of measurement, how to use them in calculations, and how to convert between them.

- Just What is a Logarithm, Anyway?
A simple explanation of linear and logarithmic scales as well as an introduction to logarithms. (Note: available as a PDF file only.)

- Excerpt from
*Old Woodrat's Stinky House*An excerpt from a poem by Gary Snyder which conveys a sense of cosmic time.

- Length, Time & Mass Scales

**Homework 1:** *The Sun &
You*, due 9/04. The pages on Scientific
Notation and Working With Units may be
helpful in doing this assignment.

**Quiz 1:** *Sizes of
Objects*, given 8/30.

Joshua E. Barnes (barnes@ifa.hawaii.edu)

Last modified: August 30, 2001

`http://www.ifa.hawaii.edu/~barnes/ast110/stme.html`