Astronomy 172: Stellar, Galactic, and Extragalactic Astronomy

Spring 2000

  • Go directly to the Syllabus


    Office Hours

    Course Info and Resources

      You will have to complete for this course 6 homeworks and a paper. There will be three in-class exams, and a final exam. The final grade of the course will be determined according to the following rule:
      • Homework: 24%
      • Paper: 10%
      • Midterm I (April 24): 12%
      • Midterm II (May 15): 12%
      • Midterm III (May 30): 12%
      • Final Exam (June 5): 30%

      There will be 46 lectures during the course, running from March 27 to June 2. The syllabus page will give you the information on the material to be covered at every lecture. Every lecture has a number of key questions, and key points. The key points provide you with a very brief summary of the most important things you need to have learned for this lecture. After you attend the lecture, you can look at the key points to see if you understand what they all mean. If you do not fully understand them, that means you have not learned the material sufficiently well to get a good grade in this course. You should then prepare questions that you can ask in class or during office hours.

      The key questions are questions that you should clearly know the answer to after you have attended lecture and read the assigned material from the textbook. If there are key questions that you do not know the answer to, it also means there was something in the lecture you did not understand properly. Make sure to ask me about that before the exam is upon you.

      You are strongly encouraged to ask questions, during class and in office hours, but I am afraid I will not be able to answer your questions during the exam... =:-)

  • Syllabus

  • Homework:

  • Paper Assignment: As part of this course, you will be writing a brief paper on a subject of your choice describing an idea or point of view of your own. This assignment will be due on May 31.
    Here is the detailed information on the Paper Assignment .


      The textbook we will use in Astronomy-172 is "Discovering the Cosmos", by Robert C. Bless. The syllabus specifies the chapters that are required reading. It is highly recommended that you read what is assigned in the syllabus before every lecture. The assigned reading will complement what will be taught in the lectures; it will also help you to prepare questions, which you can ask during class.

    Roof and Planetarium Nights

    The Hubble Deep Field

    The faintest sources of light ever detected by human beings are the galaxies in the Hubble Deep Field. Some of these galaxies are seen when the universe was only 10% or 20% of its present age. This is our view of the universe that is our home: we see galaxies into the past, being born and evolving to their present form.

    The Hubble Deep Field

    Click here to see a movie where you start with a wide-angle view of the sky toward the constellation of Ursa Major (the Big Dipper), then you zoom in and see a smaller and smaller region of the sky until you end up in the Hubble Deep Field. All the sky around you is filled with similar images of faint galaxies as they were forming and evolving throughout the history of the universe!
    COBE Picture of the Milky Way Our view of the Milky Way Galaxy is hindered in visual light by dust obscuration. Absorption by dust is greatly reduced in the wavelengths of the far-infrared (much longer wavelength than visual light). Observations in the far-infrared must be done from space, because the Earth atmosphere is opaque to light at these wavelengths. The COBE satellite has given to us the best unobscured pictures of the Galaxy we live in. The picture shows many individual stars, the dust lane in the disk, and the bulge. Notice the asymmetry of the bulge, appearing slightly larger on the left side; this is an indication of the presence of a small bar in the inner parts of the Milky Way.

    COBE Picture of the Milky Way

    Movie of Stars orbiting around Black Hole in the Center of the Milky Way


    VLA Radio image of the Virgo galaxy M87 Giant galaxies in the centers of clusters harbor massive black holes in their cores, which eject jets of matter at relativistic speeds. Over millions of years, these jets energize the halo of hot gas surrounding the galaxy. Relativistic electrons produced in the jet slowly lose their energy spiraling in the magnetic fields of the energized cloud, creating these beautiful images in the radio part of the electromagnetic spectrum.

    The Radio Image around the M87 Galaxy observed with the Very Large Array

    What is astronomy about? Since ancient times, astronomy has been about watching the sky. At present, precisely when scientists are rapidly advancing in the understanding of astronomy, most people are being deprived of the spectacle of the sky because of pollution and city lights. But thanks to the internet, we can watch pictures of celestial objects by using the resources in a multitude of websites. Explore the links provided here, which will bring you to images of star clusters (open and globular), gaseous nebulae, galaxies, etc. As part of learning astronomy, you simply need to have a good idea of what all these objects really look like.

    Among many other links below, you can try the Astronomy Picture of the Day, where every day a different picture of some interesting object in the sky is displayed. If you then go to the index, you can click on any class of objects you wish, to access the archive of all images that have been displayed in the past. You should try also the Messier and NGC catalogues, the Ohio State University Astronomical Picture Gallery, and the Hubble Space Telescope Image Archive.

    Cosmology in a Computer

    The NCSA has put together a fascinating exposition Cosmos in a Computer featuring some of the latest state-of-the-art simulations of our Universe. Be sure to try the exhibit map to navigate the site.

    Where to find me:

    Astronomy 172 Spring Quarter 2000
    MTWRF 9:30am-10:18am McPherson Room 1008

      Instructor: Jordi Miralda-Escudé

      Teaching Assistant: Zheng Zheng Jordi Miralda-Escudé

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