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Introduction to Astronomy

Enrollment in this course is by invitation only

About This Course

In this class, we will be studying, quite literally, everything in the universe. We will start with "classical" astronomy, describing the night sky and organizing what we see as was done in ancient times. We will then embark on a journey, starting here on Earth and progressing outward, to study the Solar system, the Milky Way galaxy, and the wonderful and strange objects we observe in deep space, such as black holes, quasars, and supernovae. We will end with some discussion of what scientists know today about the universe as a whole. Along the way we will introduce some of the methods, theoretical and experimental, that have been used to understand all of this, from Newton's laws, through our understanding of light and matter, to Einstein's theory of relativity, and from Galileo's telescope to WMAP and LIGO.


Week 1: Positional Astronomy (naked-eye Astronomy)
We will spend our first week familiarizing ourselves with descriptions of the positions and motions of celestial objects.

Weeks 2-3: Newton’s Universe
Newtonian physics revolutionized the way we understand our Universe. We will discuss Newton’s laws of mechanics, the conservation laws that follow from them, his theory of gravity and some applications to Astronomy, as well as some properties of radiation. The last clip will be a quick look at the features of quantum mechanics relevant to our course. This will be a particularly busy and challenging unit, but hard work here will pay off later.

Week 4: Planets
We will not have time in this course to do justice to the broad and exciting field of planetary science. We will spend the week on a general review of the properties and structure of our Solar System and our understanding of its origins and history. We will end with some discussion of the exciting discoveries over the past decade of many hundreds of extrasolar planets.

Week 5: Stars
What we know about stars and a bit about how we found out. We will begin with a quick review of the best-studied star of all, our Sun. We will then talk about classifications; H-R diagrams and main sequence stars; distance, mass, and size measurements; binaries; clusters; and stellar evolution through the main sequence.

Week 6: Post-Main-Sequence Stars
Final stages of stellar evolution and stellar remnants. Giants, white dwarfs, novae, variable stars, supernovae, neutron stars and pulsars.

Week 7: Relativity and Black Holes
We will spend most of this week acquiring an understanding of the special theory of relativity. We will then discuss the general theory in a qualitative way, and discuss its application to black holes, gravitational lensing, gravitational radiation, and other phenomena of interest.

Week 8: Galaxies
Galactic structure and classification. Active galactic nuclei, quasars and blazars. Galactic rotation curves and dark matter. Galaxy clusters and large-scale structure.

Weeks 9-10: Cosmology
What we can say about the universe as a whole. Hubble Expansion. Big bang cosmology. The cosmic microwave background. Recent determination of cosmological parameters. Early universe physics.

Recommended Background

  1. An interest in learning something about the universe we live in and a willingness to invest some thought and some work in this.
  2. The ability to calculate with large and small numbers, e.g. to compute the product of and .
  3. A familiarity with the rudiments of high-school algebra, the ability to solve an equation like to get and comfortably use this to obtain numerical values for in appropriate units given values of , , and , and to draw and use graphs to describe the properties of functions.
  4. A basic background in science at a high school level. What elements, atoms, nuclei, magnetic fields, gravity, etc. are will be assumed familiar. The details of their physics or its mathematical description will not.

Suggested Readings

There are a lot of important and interesting facts to learn about astronomy, and lectures are a very inefficient way to learn facts. It would be extremely helpful, but not absolutely necessary, to read any of the many fine textbooks on introductory astronomy that are out there as you take this class and to have it handy as a reference. One example is "Universe" by Freedman, Geller, and Kaufmann - but there are many other comparable texts and I will not adhere strictly to any of them. The general astronomy Wikibook and Wikipedia entries for topics mentioned in class would be quite sufficient for this purpose, as would the notes by Nick Strobel generously available for free at In addition, I recommend (but do not require!) downloading and installing a planetarium application for your computer. Examples of free downloads sufficient for our purposes include (Windows only) or The specific software I will use in lecture, can also help to understand the material.

Course Staff

Course Staff Image #1

Course Instructor

Ronen Plesser is a professor of physics and mathematics at Duke University. He received his PhD in physics from Harvard University in 1991, and held positions at Yale University, the Institute for Advanced Studies, and the Weizmann Institute of Science before joining the Duke faculty in 1997. His research interests center on the interplay of geometry and physics in the context of string theory and particle physics. He has been teaching introductory astronomy at Duke since 2002.

Frequently Asked Questions

What web browser should I use?

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See our list of supported browsers for the most up-to-date information.

Will I get a certificate after completing this course?

No, this course does not offer any certificates. However we are sure you will be very proud of the skills and knowledge you will have gained if you complete the course!

Do I need to have had college physics or calculus to take this course?

No. If you have had any of these, you will find them helpful, but it is definitely possible to do this class and enjoy it without them. Supplementary notes reviewing the technical aspects of the physical principles we use will be posted to help keep the class as self-contained as possible.

Is this a hard course?

It should be. If done right you will have learned in a few short weeks a lot of truly exciting science, and this will require putting in some time to work on it, and some hard thinking. It should also be a lot of fun.

Do I need a telescope to take this course?

No. I will suggest some observing projects for naked-eye observing and some for telescope observing. If you can find a darkish place to look up at the night sky this will be both rewarding and instructive, and a telescope can amplify both effects if you know how to use it. But not all of us have access to such locations or equipment, and installing one of the planetarium software options allows you to make “observations" on your monitor.

Will this help me improve my skills as an observer?

Not directly. We will not spend much time on details of observational astronomy. We will focus more on the physical nature of astronomical objects. So the class might improve your knowledge of the object you observe, if not your observational technique.

  1. Course Number

  2. Classes Start

  3. Classes End

  4. Estimated Effort

    6-12 hours per week