ASTRO 735: ORDER OF MAGNITUDE ASTRONOMY

Meeting Times

The basic slot is THURSDAYS 10:30 - noon, through the whole semester, starting January 17. This will be augmented as necessary.

Need

Many graduate students (and many faculty, for that matter) have had little practice in making rough estimates or order of magnitude assessments of physical problems, and even less practice at "talking through" a problem with others. The reasons for this are no doubt many and varied, but a key problem is the tendency for rote memorization to take precedence over understanding, presumably because it seems "easier" in a narrow-minded way. All TAs and lecturers in Astro 110 know about this problem with undergraduates but, amazingly, the same thing extends all the way to graduate level classes and, perhaps, beyond. The problem with this is that it leaves you with a diminished capacity for understanding new things, or any things that have not already been presented in a pre-packaged, class format. I don't like that.

Aims

The objectives in teaching this seminar are

  • To emphasize the importance of physical understanding and approximation in science.
  • To encourage you to "think on your feet" and "talk on your feet".
  • To encourage you to take a broad perspective and to be scientifically judgemental of others, and of yourselves.

    Not coincidentally, the things we will do in Astro 735 will be of value in your general exam (especially the oral part), where basic understanding, simple calculations and broad knowledge are the main things tested. In fact, this seminar was suggested by distressed members of a recent oral exam committee after facing a number of nearly content-free students.

    Format

    I am making this up as I go along, so the format of the seminar will probably change as I see what works and what doesn't. Here are my initial ideas:

  • It is a 2-unit seminar because there is too much to do in only 1-unit.
  • It must be interactive to be effective (i.e. you will do things, not just listen to me)
  • You must take it for credit to be involved. Auditors will not have sufficient commitment.
  • The class size is limited by me in order to maintain reasonable interaction with each person. Acceptance is tilted in favor of 1st and 2nd year (i.e. pre-exam) students.

    This year, the class consists of Vivian U, Geoff Matthews, Tian-Tian Yuan, Brendan Bowler and Sarah Sonnett and Brian Stuart.

    What We Will Do

  • In one part of the seminar we will solve simple problems in an order-of-magnitude, physically-based way. We'll do this in-person, in-class, interactively.

    The purpose is to inculcate physically-based reasoning and also to promote effective on-your-feet communication.

  • In the second part I want to do the following. You are required to attend the IFA colloquium each week. After each colloquium, you should independently email me your "grades" for the speaker according to simple criteria to be discussed. I will combine your assessments and we will talk about them in the next seminar meeting. In addition, I will ask one of you, selected at random, to present a 5 or 10 minute off-the-cuff precis of the colloquium, which we will also discuss as a group.

    In this way, I hope to encourage your critical listening skills, as well as provoke your judgement about the speaker's style and content.

    Here is the grading guideline.

    In the third part, we will hold a simulated Time Allocation Committee meeting based on the Keck I proposals from 2007B. In this, you will read the submitted proposals and rank them according to criteria to be developed in class. Along the way, we will encourage OOM-style calculations to assess the science and discuss the presentation. At the end of the exercise, the simulated TAC will allocate time to the projects. Finally, we will compare those allocations with ones made by the "real" TAC.

    Here are the reviewer assigments.

    The purpose is to encourage critical reading skills and to develop an appreciation for what lies behind a successful proposal. This might help you write better proposals yourselves, in the coming years.

    Preparation

    OOM thinking won't work without a platform of basic numbers that you should carry in your head. Over the xmas vacation, you should have made sure that your brain carries the fundamental physical constants. I use MKS units (kg m s) for everything.


    David Jewitt. Last updated Jan 17 2008

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