We will be experimenting with providing audio recordings of lectures from a previous semester, for students who are cannot attend an occasional lecture due to illness or to an excused activity. If you miss a lecture, listen to the recording, and then give us some clear feedback on how helpful it was in acquiring the material. If your feedback helps us to improve the course, we will excuse your absence.

You will need a high-speed internet link of some sort in order to acquire these recordings. The lectures are provided in both a low-resolution (2 to 6 MB per lecture) and a high-resolution (8 to 24 MB per lecture) MP3 format. Do not attempt to download either size file over a phone line! If you do not have a fast internet link at your home, you can download the files onto a USB memory stick, or into an IPod or music player, from a NMSU computer at the library or elsewhere on campus, and then copy them to your own computer.

The recordings can be played using RealPlayer, Windows Media Player, XMMS, or any other audio file player of your choice. If you have questions about music players, consult a friend who plays lots of music on their computer for advice.

These recordings are best played while looking at a HTML browser, so that you can follow along with the relevant lecture slides (listed under Contents for each lecture). We have edited them to remove intervals where students worked together in small discussion groups, or worked on in-class assignments, and so they are each less than 75 minutes in length.

We have also added audio clips directly to many lecture slides. However, by listening to the entire audio stream here you will have access to extra materials, including every diagram drawn on the board during the semester.

Lecture	Contents	Length	Lo-Res	Hi-Res
1	The Contents of the Universe	49 min.	5.8 MB	23.2 MB
2	Scientific Notation	43 min.	5.1 MB	20.4 MB
3	Timescales in the Universe	23 min.	2.7 MB	10.6 MB
4	The Phases of the Moon	31 min.	3.7 MB	14.7 MB
5	The Seasons on Earth	26 min.	3.1 MB	12.2 MB
6	The Origin of the Moon	24 min.	2.9 MB	11.4 MB
7	The Celestial Sphere	42 min.	4.9 MB	19.6 MB
8	Planetary Orbits	36 min.	4.2 MB	16.9 MB
9	The Scientific Method	46 min.	5.4 MB	21.7 MB
10	Geocentric and Heliocentric Models	47 min.	5.6 MB	22.2 MB
11	The Formation of the Planets	32 min.	3.8 MB	15.1 MB
12	The Terrestrial Planets	25 min.	3.0 MB	11.8 MB
13	The Jovian Planets	40 min.	4.7 MB	18.8 MB
14	Waves and Light	44 min.	5.1 MB	20.5 MB
15	Atomic Structure	48 min.	5.6 MB	22.5 MB
16	Absorption and Emission	37 min.	4.4 MB	17.4 MB
17	Stellar Temperatures	24 min.	2.8 MB	11.1 MB
18	Nuclear Reactions	35 min.	4.0 MB	16.2 MB
19	Binary Stars	23 min.	2.7 MB	10.9 MB
20	The Hertzsprung-Russell Diagram	38 min.	4.4 MB	17.7 MB
21	White Dwarfs	23 min.	2.7 MB	10.6 MB
22	Neutron Stars	33 min.	3.8 MB	15.4 MB
23	Black Holes	44 min.	5.2 MB	20.8 MB
24	The Milky Way	28 min.	3.3 MB	13.3 MB
25	The Expansion of the Universe	28 min.	3.3 MB	13.3 MB
26	A Universe of Galaxies	47 min.	5.5 MB	22.2 MB

This material is based upon work supported by the National Science Foundation under Grant No. 0349155. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).