ASTRO 120: Fall 2003
The Sky and the Solar System

Astronomy is the oldest of sciences. Yet it remains as important today as when humans first began to understand the motions of the Sun, Moon, planets and stars. Modern planetary astronomy provides us with a glimpse of the diversity of other worlds, from the runaway greenhouse effect on Venus and the changing climate of Mars to the shifting ice flows on the moons of Jupiter and Saturn. Knowledge of the similarities and differences between "worlds" in our solar system, and the factors which forged and continue to change them, may be crucial to our long-term survival on Earth. With the recent discoveries of planetary systems around other stars, we can ask (with hopes for an answer) that most profound of questions - are we alone in the Universe?

Astronomy places human development in context. The planets in our solar system began to form about 5 billion years ago as a result of violent collisions between chunks of debris left over from the formation of the Sun. This time period is more than 500 times farther back in prehistory than the appearance of the first human-like beings on Earth. Although astronomy cannot hope to solve our problems on Earth, it can provide us with a perspective of our surroundings which may positively influence future decisions we make about our fragile world, and the millions of life forms that exist on its surface and in its oceans.

Perhaps the best reason to study astronomy is the simple beauty of the night sky. As Prof. George Bowen of ISU has said:
    Above all, the sky is a thing of great wonder and beauty, giving rise to profound questions
    about the nature of our universe and our place within it.

We hope to try to capture some of the spirit of this statement in Astro 120. Keep in mind the words of Walt Whitman.

Lectures: The lectures are the core of this course, and define its content. Regular attendance in lecture will be a key component to your success in Astro 120. You can expect frequent, brief, in-lecture exercises and quizzes. In addition to helping you master the material discussed in lecture, these will be graded and recorded for each student. As attendence in lecture is expected, and each individual "lecture challenge" is lecture-specific, no makeup opportunities will be available for the in-lecture events.

Reading assignments provided in the Course Outline will assist your mastery of the material. Most things shown in lecture will also be posted at the Astro 120 WWW site.

Course assignnments, notices and other news items will also be posted on the and WWW site. We will also provide lecture summaries to help aid your review for exams. Grades for the course will be available through the ISU WebCT system.

Recitation Sections: These meet once per week in B57 Physics (in the planetarium). In recitation, topics presented in lecture will be discussed at length in smaller peer groups. The TAs who lead the recitations are all experienced astronomers. The planetarium will also be used to demonstrate some of the essential aspects of the sky and the motions of the Sun and moon. You will also learn to recognize a number of stars and constellations. This is mainly for fun and hopefully will ease your terror when standing within the inky blackness of space at night.

Recitation sections provide an opportunity to work individually and in small groups on course material and assignments. You are required to attend all meetings of your recitation section. Some course material will be covered only in the sections, and you will be responsible for that material on the exams. If you do not attend your recitation section regularly, you will not pass this course.

Help Room: The instructors in this course will be available for individual help during Help Room hours. The location of the Help Room, and the specific hours when Astro 120 instructors will be there, will be announced in lecture and recitation, and will be posted on the A120 bulletin board. Feel free to attend the hours of instructors other than your recitation TA. All instructors will also be available to help you at other times by appointment. Our offices, phone numbers, and e-mail addresses are listed above.

    The Solar System: The Cosmic Perspective, Volume 1
        by Bennett, Donahue, Schneider, and Voit, (Pearson / Addison Wesley, Third Edition - 2003)
Readings will be assigned in this text for almost all course topics. We will use this text to supplement lecture material: use the book as a resource to help understand the material presented in class. Feel free to dig deeper into this nicely illustrated text. Because astronomy is changing so rapidly, the book is already out-of-date in some areas. Special note:The text above is the first part of a more complete book, The Cosmic Perspective; a Volume 2 covers material about stars, galaxies, and cosmology. If you are taking Astro 150 at the same time as Astro 120, buy the complete text - it has both volumes and sells for much less than buying each volume separately.

Star Wheel: You should purchase a "star wheel", which will be available at the bookstore near the primary text. Your TA will discuss this with you in recitation. This clever and inexpensive device will be a big help as you learn the constellations. It shows the stars visible in the sky over Ames at any given date and time in a realistic way, allowing you to find your way across the skies.

Lecture Notes: Lecture notes will be posted on the course web site (see below). A warning: These notes are not a complete text, nor do they cover all the material that we expect the students to learn in this course.

Summaries of Essential Exam Material: Along with the WWW postings of lecture materials, we will also distribute brief summaries of each lecture which contain the MOST ESSENTIAL material you will need for the exams. They are NOT a substitute for the lectures themselves, or even for your notes from lecture.

Web Pages: The WWW homepage for Astro 120 is at
The pages will be used for course announcements, recitation information, and other administrative purposes. However, the most important use of the Web pages will be as a way for you to access photographs and notes shown in lecture. You will be able to get a close look at some of the very exciting and new images that we will be studying. Links to some interesting and fun web sites will also be found there.


As a guide, in past semesters the grade breakdown has been approximately: where the number grade is a combination of all exams and recitation grades. Grades on individual exams will not necessarily be representative of the final distribution, so following each exam we will provide estimates of the letter-grade equivalents.

Outdoor Observing Sessions: We are planning one or two evening outdoor observing sessions to obtain a first hand view of the sky. These sessions will be announced in advance in lecture, but are tentatively planned for the weeks of September 22, October 27, and/or December 1. These sessions are open to all Astro 120 students and their friends and family; they don't call them "star parties" for nothing!

Course Outline