Astronomy 15 Reading Report. Research a topic of interest to you in contemporary astronomy;

Transcription

1 Astronomy 15 Reading Report Students often make the mistake of not reading this assignment, and hence missing important points. Here are the essential points for the impatient: Research a topic of interest to you in contemporary astronomy; Write an 8-page ( 2000 word) summary of the topic; Cite primary sources as much as possible; support the entire paper with references to the literature. Use the required format for the references, not some other format you may have been taught elsewhere. Organize your presentation and try to write well (accurately, economically, and gracefully). Having said that, it s still important to read the details, which follow. Why do this? Too often in introductory courses one gets the impression that the material is completely cut-and-dried; you just read the book, go to lectures, and spit back what you read and hear. You get no sense of the subject as an ongoing enterprise, and no clue as to how business is actually conducted. Practicing scientists keep informed about progress in their field largely by reading the literature the professional journals. In astronomy, this consists of publications such as The Astrophysical Journal, The Astronomical Journal, and others. Even if you end up in another subject, it is essential to get into the habit of looking at the journals; this exercise is designed to ease you into that habit. I think also that introductory science courses often tend to emphasize technical detail and the acquisition of knowledge a great deal, without paying enough attention to communication skills, which are important in all fields. Formal writing skills in particular tend to get the short shrift. What s required: Your assignment is to find a topic that interests you in contemporary astronomy or astrophysics, read up on it, and write a report summarizing in your own words what you find out in the literature. You can choose any topic you like, provided that it s an active area of research. Since there s a separate course now in extragalactic astronomy and cosmology, you may have an easier time of it if you stay within our Galaxy, but I won t hold you to it. The assignment is to delve into the primary literature in some depth that is, the actual technical publications in the journals written by and for professional astronomers and astrophysicists. You may use popular articles, but only as a starting point, not as your sole source. This idea may seem frightening, but it will be less so if you keep in mind that you re not expected to understand every word and all the technical deatil in the papers you read. Instead, all you need do is get the basic idea, and try to trace developments to their sources. In all scholarly work, primary sources are the gold standard the closest 1

2 you can get to the real story without going out and doing the work all over again. By contrast, secondary sources especially journalistic treatments are often distorted or incorrect. There s a party game in which a sentence is whispered from person to person around a circle and arrives back in hilariously distorted form; secondary sources (including textbooks!) often fall into just this trap. Your report must cite all the sources which you use. You must use the bibliographical format used in astronomy (described later). This is different from the footnote format used in some other subjects (notably many of the humanities). Furthermore, just about everything you say in a report such as this (save for very general common knowledge statements) must be referenced to a source. Your own paper need not be highly technical; I d rather you stick with what you think you understand of the material. (However, you don t have to explain astronomy from the ground up ; you can assume that your reader that s me is already conversant with a good deal of background information.) You certainly don t have to do any original scientific research. The report should be equivalent to about 8 typewritten pages in length (about 2000 words). It should be carefully organized and well-written; writing is important in the sciences, not just the humanities! You may assume your reader has considerable background in astronomy, but you should not assume detailed knowledge of the sub-specialty you are exploring. The Honor Principle comes into play here, of course, in that you re expected to conscientiously note your sources and take care to use them appropriately. Incidentally, the assignment is so unusual that I would think it essentially impossible to find anything helpful in one of those cheat sites, not that you d try. The booklet Sources, Their Use and Acknowledgment, distributed to all first-year students, gives the general background on this topic. I ve compiled a list of general topics (on another sheet) to help you get started, but you re free to work on anything in astronomy that interests you. Experience shows, however, that many students will take on subjects which are too abstract; evaporating black holes, inflationary cosmology, and other such fascinating subjects are fun, but it s very difficult to read the primary sources in these fields. My advice is to choose something reasonably concrete. Here are a couple of tips for organizing a report of this type. It is a good idea to include sub-headings of some sort in your report to guide the reader. For example, your first subheading might be Introduction, your next What the Observations Show, or some such. The end of your introductory section might include a brief road map for the reader, such as In section 2 I review the pertinent observations; section 3 discusses the major theories of rotating blippies; and in section 4 I confront the theories with the observations and include some speculations of my own. One purpose of including this is clearly to make the organization clearer in your own mind! Finally, please print page numbers on your final report so I can refer to passages by page. Since I ve given this assignment before, I can give you a list of common errors students make. 2

3 Not reading or understanding the assignment. You re reading this, so you re already halfway there. Working from secondary sources instead of digging deep enough to get to primary sources. As I say above, secondary sources should be used as background and to get you started. Selecting a highly abstract topic which in which they have no hope of understanding the primary sources. Not narrowing their topic sufficiently. By the time you re ready to write, you should probably be writing about a topic which would have appeared to be a narrow subspecialty when you started. Using too many extended direct quotations. The most charitable interpretation of this practice is that the student is too unsure of the meaning to trust themselves to paraphrase; the least charitable interpretation is that the student doesn t want to bother to put the thought in his or her own words. Remember, using big chunks of someone else s prose without indicating it clearly is a violation of the Honor Principle. You re supposed to be summarizing the ideas in your own words. Writing poorly. While most Dartmouth students write fairly well, many do not (and they sometimes seek refuge in science classes). Poor organization is common; your exposition should hang together logically, with each paragraph carrying the story forward, and each sentence supporting the paragraph. Aim to develop ideas in a logical, pedagogically sound order. Finally, try to be use the English language as a precision instrument for conveying meaning. Be aware that I am the offspring of not one, but two, English teachers, so try to write good. Insufficiently close attention to the references. Your literature citations should be so thorough and so closely bound to the text that every statement of fact that you make which is not common knowledge should be traceable to a source. A common mistake is to write a couple of pages of introductory material based on your background reading, with few or no references. Using the wrong reference format. Note that the reference format which is standard in the astronomical literature (which you are to follow) is different from the the more common footnoted, numbered references. In the astronomical format there are no footnotes, except to offer additional information or explanations which are out of the main line of the discussion. The references are instead done by a convention of embedding the authors names in the text; it is explained fully below. To keep you on target, I m staggering the due dates for various phases of the project. A: topic selection, due Wednesday, May 8 B: progress report with secondary-source bibliography due Wednesday, May 15 3

4 C: outline with portion of the bibliography (aim for at least 5 to 10 sources in the primary literature) due Wednesday, May 22 D: final paper: due Wednesday, May 29 (final day of classes). Getting started. The journals you need are all in Kresge Library, in Fairchild. Perhaps the easiest way of finding a topic is to look in the more popular literature, such as Scientific American or Sky and Telescope magazines. (Astronomy magazine is another possible source, but it is not as authoritative as the other two; their authors are generally journalists rather than scientists.) Something there may pique your interest. Kresge Library has these; it s a simple matter to look through the last few years worth with this in mind. Another way to begin is to plunk yourself down with a current issue of one of the journals and just look around in it; maybe some article will look interesting. This plan of attack is brave but a little scary. The articles tend to look forbidding; remember, they don t bite! For this phase, paper journals and magazines are better than on-line versions, because they re much more amenable to casual browsing. Another interesting tactic would be to look over recent articles on the revolutionary astro-ph website, where most astronomers post their latest results. It will be difficult for most of you to read the format they use, but you can look at the summaries of the articles (the abstracts) with any old browser. It s at http : //xxx.lanl.gov/archive/astro ph. Your topic should be large enough to find a fair amount to read, and small enough so that you re actually dealing with the real stuff in at least modest detail. Thus the topic of quasars on which perhaps 500 papers are published every year is way too big, while the topic of absorption lines in quasars, which might produce 50 a year worldwide, is much more reasonable. I ve also thought up a number of possible topics (on a separate list), and I m happy to brainstorm with you to come up with others. Before you start working in earnest on a topic, check with me to see if it s tractable and appropriate. You ve now completed step (A) above. Once you have a topic, a possible plan of attack is as follows: a) Read some popular articles (Scientific American or Sky and Telescope are good sources for these) on the subject to get hold of the main ideas. You may also want to read what Shu has to say on the topic, to get a somewhat more technical view. b) Find a professional review article, as recent as possible. These are articles which survey the state of some topic; they re extremely useful in that some professional expert has basically done all the work for you. This will give you a more sophisticated understanding of what s going on. It will also give you very valuable information about who in the field works on what topics. These can be found, among other places, in Annual Review of Astronomy and Astrophysics (though 4

5 these tend to be rather heavy going) and sometimes in Publications of the Astronomical Society of the Pacific. You now have your secondary-source bibliography; hand it in as part (B). c) Find a few recent journal articles in the subject. Read through them to get their gist and note especially any useful references they give. Now create your final outline and tentative bibliography to hand in (step (C) above). d) Look more carefully at a good set of papers in the area perhaps about a dozen papers in total keeping notes on what they say. e) Organize and write your report; that s obviously step (D). In recent years this has all become much easier because of a powerful bibliographic search engine available on the World Wide Web, the NASA Astrophysics Data System (ADS). Nearly all the actual professional literature is available on-line and linked through the ADS. It s available at http : //adswww.harvard.edu. You ll mostly want to search references in Astronomy and astrophysics. 5

6 The Required Bibliographic Form Astronomy uses a very convenient form of bibliographical reference; the name of the author and year of publication are inserted into the text itself; the bibliographical reference is then included in an alphabetical list at the end of the article. Some mythical examples follow. This example shows how to use the author s name in a sentence; the year of publication is then put in parentheses: Hawking (1999) recently showed that the universe is in fact made of green cheese If the syntax of your sentence does not include the author s name naturally, you put the name in parentheses together with the year; you can also chain together references this way: The universe is made of green cheese (Hawking 1999; Penrose 2000). If you have three authors or fewer, you mention them all in the text: Winken, Blinken, & Nodd (1999) showed that the cheese has holes in it. If there are more than three authors, you use the lead author s name with an et al. (which means and others in Latin) on it: Veeblefetzer et al. (2002) combined these observations and proposed that the universe is made of green Swiss cheese. If there are seven authors or fewer, you do have to mention them all in the reference list. Otherwise, you can use an et al. there too. Note that if you cite an article which appears in a collection of papers these often are reports from conferences on special topics you cite the paper under the name of the actual author of the paper, not the editor of the book. The editors should then be credited in the bibliographic description of the book in the reference list. There s an example of this cited below. The reference list itself looks like this: Hawking, S. 1999, ApJ, 302, 443 References Hawking, S., & Penrose, R. 2000, MNRAS, 304, 893 Veeblefetzer, J. R., Kromhunger, B. J., Zablonski, R. W., & Smith, L. M. 1999, in Structural Ramifications of Dairy-Product Cosmology, ed. J. L. Smith (Boston: Reidel), p

7 Winken, J. L., Blinken, W. S., & Nodd, R. T. 2001, PASP, 92, 838 Common abbreviations used for journals: ApJ = Astrophysical Journal ApJS = ApJ Supplement AJ = Astronomical journal A&A = Astronomy and Astrophysics A&AS = A&A Supplement MNRAS = Monthly Notices of the Royal Astronomical Society PASP = Publications of the Astronomical Society of the Pacific The number following the publication name is the volume number of the journal. You can find examples of the format at the end of any recent article in the journals. 7