Announcements Archive
|
|
: |
Course grades have been submitted. Note that in some cases these may differ from the ones on Canvas, which does not correctly calculate the total score according to the formula for this class. In general the actual course grades are better than the ones on Canvas! We will soon remove access to the detailed course materials through the Spring 2016 portal, so if you missed a class or a file and would like to keep it, this is a good time to download it. The top-level pages and indexes of materials will remain visible, but the username/password will be changed. I hope you heard some interesting things this semester and have a better understanding of where all those atoms in your body came from. We are all truly part of the cosmos, the children of the stars. Have a nice summer! |
|
|
||
|
|
: |
There are no more lectures in this class as of May 4, but office hours and a help session will be available that day. All remaining Star Party slips must be turned in no later than Thursday, May 5 at Exam 5. Remember that Exam 5 will begin at 12:30 PM, the start of the class period, and you must arrive on time or else risk not receiving credit for the exam. Prof. Dinerstein will hold her office hour on Wednesday, but will not be present on May 5; the exam will be proctored by the TAs and Prof. Sneden. Exam 5 scores will be posted early in the week of May 9, and course grades will be submitted by the end of the week (probably by May 12). Upcoming Sky Event: There will be a transit of Mercury on Monday, May 9. This is when Mercury moves between the Sun and the Earth, so that we will see a small, dark image against the bright Sun. Do not try staring at the Sun to see it! This is dangerous and can permanently damage your eyesight, and Mercury is too small to see it well this way, in any case. The Astronomy Department will be hosting special viewing opportunities of the event, weather permitting, in RLM. Details are available on the Out of Class Activities page. We mention this for your own interest; it will not count as extra credit for this course. |
|
|
||
|
|
: |
As of April 27, we have only two full class meetings left, since May 5 will be fully devoted to Exam 5. As usual, a Study Guide will be posted by the previous Friday, and there will be office hours and a help session the week of May 2. Reminder: Either Exam 4 or Exam 5 (or both) will count towards your semester grade. We are in the process of providing a quick look-up for your course grade on Canvas. The semester grade will consist of the sum of the eligible exam scores, the total quiz points up to a maximum of 15, total participation points up to a maximum of 10, plus the total of any extra credit points. The letter grade for a given numerical score will be taken from the Table on the Exams page. We will continue to post Class Slides, Quiz feedback, in-class activity feedback, and some video transcripts, up through May 3's class meeting. There will be a Quiz 7 and a Course-Instructor Survey before the end of the semester. The Star Party (weather permitting) on Wednesday, May 4, is the last one that can count as extra credit, and all slips must be turned in on May 5 in class. Upcoming Sky Event: There will a transit of Mercury on Monday, May 9. This is when Mercury moves between the Sun and the Earth, so that we will see a small, dark image against the bright Sun. Do not try staring at the Sun to see it! This is dangerous and can permanently damage your eyesight, and Mercury is too small to see it well this way, in any case. The Astronomy Department will have viewing of the event by projection of the Sun's image, on the 13th Floor of RLM. Check the Public Viewing links on the Astronomy home page, www.as.utexas.edu, for more information, closer to the day of the event. It will be happening in the morning of a UT "dead day." We mention this for your own interest; it will not count as extra credit because the course will be finished by then. |
|
|
||
|
|
: |
Prof. Dinerstein will not be responding to email from Thursday (4/21) through Sunday (4/24) due to travel. If you have questions, please direct them to the TAs. Some class materials from the 21st may not be posted until Monday, 4/25. We are now literally on "the home stretch." We have learned how the universe evolved from the first appearance of matter in the early universe to the chemical richness that filled the entire Periodic Table of elements. Now are connecting the final link: how interstellar gas, containing all these elements, is partly converted into molecules, solids, and finally into planets of various chemical compositions including the Earth. Exam 5 will be on Thursday, May 5. A Study Guide will be posted by the previous Friday, and there will be office hours and a help session the week of May 2. Either Exam 4 or Exam 5 will be one of the three exams counted towards your semester grade, a fact you should keep in mind when estimating your course grade as described in the announcement posted on April 19. (See the entry for that date in the Announcements Archive.) Unlike the previous exams, Exam 5 will be given at the beginning of the class period, and you must arrive within the first 15 minutes of class in order to be allowed to take it for credit. |
|
|
||
|
|
: |
We have now surveyed all the main nuclear reactions that synthesized the elements in the Periodic Table, as reviewed in the In-Class Activity on April 19. Our last unit is on interstellar clouds and the formation of the Solar System, which is addressed somewhat in King, ch. 8. There will be two more quizzes, and more in-class activities for participation credit. The times and dates of these will not be announced in advance. However, we do have a fixed date for the last hour exam, Exam 5, which will be on Thursday, May 5 as previously announced and listed in the Syllabus. Unlike the previous exams, Exam 5 will be given at the beginning of the class period, and you must arrive within the first 15 minutes of class in order to be allowed to take it for credit. Important: Exam 5 is your last opportunity to take an exam which might be used to replace an earlier, lower score. There will NOT be a final exam during finals week. Regarding estimating your course grade: I previously directed students to the Announcement Archive entry for 3/30. However, at that time we had given only three exams and four quizzes, and fewer than 10 participation activities in class. This was the reason for multiplying by factors of 1.5; if you read the instructions carefully, you should have gotten a reasonable estimate (as in, "if the total is larger than 15 points, replace it by 15 points"). Now that the semester is almost over, use the following procedure: (a) Add your three highest exam scores. If you missed an exam, drop that one. A perfect score would be 75. (b) Add all of your quiz scores. If the total is greater than 15 points, replace it by 15 points. (c) Add all of your in-class participation credits. If greater than 10 points, replace it by 10. (d) Add any extra credit points from attending Public Lectures and Star Parties. (e) Combine (a) - (d) to get your numerical total. If greater than 100, replace it by 100. (f) Look up the letter grade corresponding to that numerical score (in Column 2) on the table on the Exams page. If you have further questions, please email the TAs. |
|
|
||
|
|
: |
We have now surveyed all the main processes by which stars synthesize the various chemical elements, as part of their life stories. We'll now move in a different direction and talk about chemistry in a way that would make sense to an actual chemist. This includes chemical reactions in interstellar clouds, conversions between different phases of matter (e.g. gases and solids), and formation of stars and planets. King discusses this topic in ch. 8. There will be two more quizzes, and more in-class activities for participation credit. The times and dates of these will not be announced in advance. However, we do have a fixed date for the last hour exam, Exam 5, which will be on Thursday, May 5 as previously announced and listed in the Syllabus. |
|
|
||
|
|
: |
We have now discussed the general properties of the three kinds of compact objects left over after a star finishes its life: white dwarfs, neutron stars, and black holes. Now we are discussing the evolution of stars in interacting binary systems, and will talk about things that can happen when one member of such a system is a compact object. These include the transfer of mass from one star to the other; novae; a new type of supernovae; and X-ray emitting binary systems. See ch. 6 of King. The next exam will be on Thursday, April 14. The Study Guide for Exam 4 is posted on the Exams page. We will hold office hours and the usual pre-exam Help Session on April 13. Either this exam, or the one on May 5, must be counted towards your course grade. |
|
|
||
|
|
: |
We are now in the arena of the exotic kinds of stars known as "compact objects." These include white dwarfs, neutron stars, and black holes, covered in chapters 5 and 6 of King's book. First we are discussing them as individual (isolated) objects, and then we will talk about what can happen to such objects when they are in close binary systems where mass can flow from one star to the other, with sometimes explosive results. There will be a quiz, Quiz 5, on Tuesday, April 5, which will dip back to the material covered just before Exam 3 and include the new material from last week. The next exam will be on Thursday, April 14, with a Study Guide posted by April 8 and a pre-exam Help Session on April 13. Either this exam, or the one on May 5, must be counted towards your course grade. There was much confusion about the properties of pulsars, as revealed by the in-class exercise on March 31. A detailed Feedback file for this exercise is now posted. We have also posted transcripts for the several short videos shown in class on March 29 and 31. Final Reminder: Monday, April 4, is the deadline for academic Q-drops or changing the grading basis of a course. See the Announcements Archive or slides from March 31 for information on how to roughly estimate your course grade as of this point in the semester. Address questions about your scores on Canvas to Yao-Lun or John. |
|
|
||
|
|
: |
On Tuesday, March 29, after looking at pictures of planetary nebulae, we discussed the synthesis of heavy elements including those above element 92, Uranium. We noted that the remaining gaps in the bottom row of the Periodic Table have been filled in as of December 2015, with the heaviest confirmed element (as yet unnamed) being number 118. We began our next unit, on the compact objects left over when a star dies; in chapter 5, King calls them "Stellar Corpses." After a few last words on white dwarfs, we moved on to neutron stars. Neutron stars were found through the pulsar phenomenon. A schematic diagram for pulsars is shown on p. 74 of King's book. Reading for the material to be covered through Thursday, March 31 includes pages 59 - 74 (there seem to be two page 74's in the Kindle version), but as we head into next week (Apr. 5, 7) you should read the rest of chapter 6 as well (pages 74 - 97). Note: April 4 (next Monday) is the deadline for Q-drops or to change the basis of your course grade between the letter grade and credit/no credit options. You can For questions about scores posted on Canvas, please email the T.A.s (see right-hand banner), not the professor. |
|
|
||
|
|
: | New Posting as of March 23, 2:30 PM. The results of the March 22 in-class activity showed that many students didn't have a clear understanding of brown dwarfs and white dwarfs. There is now a feedback file about this, on the In-Class Participation page. |
|
|
||
|
|
: |
The Study Guide for Exam 3 is now posted on the Exams page, and feedback on Quiz 4 on the Quizzes page. In addition, I have introduced a new resource and study tool: transcripts for some of the short video clips shown in class. The first set to be posted includes videos presented between March 1 and 22, which should be useful in studying for Exam 3. Transcripts of selected other videos may be added in the future. After finishing the life stories of lower mass stars, we first summarize the properties of their central dense remnants, known as compact objects. These are the white dwarfs, neutron stars, and black holes. Then we will move on to the fascinating subject of how stars in close binary systems evolve and give rise to a wide variety of unusual, often explosive phenomena. The reading for these subjects is Chapters 5 and 6 in the King book. |
|
|
||
|
|
: |
I hope everyone has a nice Spring Break! Quiz 4 is being graded; these scores and credit for the In-Class Activity from Mar. 8 will be uploaded to Canvas soon. Exam 3 is scheduled for Thurs., Mar. 24 and a Study Guide will be posted on the Exams page about a week in advance. Our next topics will be: finishing the story of the aging and "death" of lower-mass stars like the Sun; and discussing a new type of nuclear reaction in which heavier nuclei are created by adding neutrons instead of crashing lighter, charged nuclei together. These "neutron capture" reactions help fill out the lower rows of the Periodic Table. Recommended reading in the King book can be found on the slides from March 10. |
|
|
||
|
|
: |
Exam 2 has been graded. The scores are posted on Canvas, and a feedback (Frequently Missed Questions) file is posted on the Ex ams page. The letter grade to exam score correspondences are the same as for Exam 1. On Mar. 8 we are having a guest lecture by Prof. Chris Sneden on observing metal-poor stars that formed early in the history of the univ erse. We will start class on Thurs., Mar. 10 with Quiz 4. Then we will continue the story of stellar aging and death, this time focusing on lower-mass stars that do not die as supernovae. See the first slide from Mar. 8 for the pages to read in the King book on this topic. Reminder: Any write-ups from the Public Lecture on Mar. 2 must be turned in - hard copy, handwritten only - no later than in class on March 10. |
|
|
||
|
|
: |
Exam 2 will be given during the second half of class on Thurs., March 3. Format and policies will be the same as for Exam 1; these include the requirement that you are present in the classroom when the exam begins. A Study Guide for Exam 2 is posted on the Exams page. We will hold office hours and a Help Session this week, at the times and places listed below right. The Exam will cover material addressed through Tuesday's (March 1) class meeting. Some of it is discussed in the King book, in parts of various chapters. See the Study Guide for details. Although the timing is not ideal (and is not under our control), there will be another Public Lecture you may attend for extra credit, on Wednesday, March 2. The speaker will be the Director of McDonald Observatory, Dr. Taft Armandroff, and the topic will be the Giant Magellan Telescope, which is being constructed by a consortium of universities and institutes that includes the University of Texas at Austin. Information and a further link is posted on the Out of Class Activities page. The write-up for this lecture is due no later than Thursday, March 10, in class. |
|
|
||
|
|
: |
Quiz 3 will be given at the beginning of class on Thursday, Feb. 25, covering the new material since the last quiz. If you did not pick up your graded quiz in class on Tuesday, you can do so at the Help Session on Wednesday afternoon, Feb. 24, at the usual time and place (see below right). We are now in the middle of discussing the basic properties of stars and will continue with an overview of their life histories, covered somewhat in ch. 4 of the King book. (This is a review of material you should have covered in your intro course.) After that we will jump back to the early generations of stars in the universe, their compositions, and how they affected the abundances of elements in the universe. Exam 2 will be given during the second half of class on Thurs., May 3. Format and policies will be the same as for Exam 1. A Study Guide will be posted by the end of Friday, Feb. 26. The week of Exam 2 we will hold office hours (note that Prof. Dinerstein's hours changed slightly) and have a Help Session at the regular time and place. If you attended either (or both) of the Public Lectures last week, these write-ups are due on class on Feb. 25. Please put them in the cardboard box at the front of the room. One additional public lecture is scheduled for Wed., Mar. 2 from 4-5 PM (yes, this is just before the Help Session), on the east side of campus, near the LBJ Presidential Library. Details will be announced later. |
|
|
||
|
|
: |
On Thursday, Feb. 18 we started talking about the formation of astronomical objects - stars, galaxies, galaxy clusters - in the early universe, which was primarily driven by the clumping of dark matter. Before moving on to discussing the first generations of stars, we will do a brief review of properties of stars in general, which is necessary in order to understand the issues. There are relevant readings in King's book for this subject, specifically: pages 6 - 13 (in ch. 1), 23 - 28 (in ch. 2), and 41 - 53 (all of ch. 4). The username/password interface is now set up and you must enter the data (which was written on the blackboard on both Tuesday and Thursday) in order to access the content materials such as Class Slides and feedback files for exams, quizzes, and in-class participation exercises. If you did not get this information in class, your next opportunity to obtain it will be Tuesday in class. We will not be emailing or posting this security data. Several students attended and enjoyed Friday's Public Lecture on Pluto. Be sure to turn in a short write-up that demonstrates that you attended and engaged with the material, by Thursday, Feb. 25. There will be another talk, on Molecules in Space, on Saturday, Feb. 20. See the details on the Out of Class Activities page. Also, it looks like there will be another special talk on March 2. Further information about that lecture will be made available soon. |
|
|
||
|
|
: |
Tuesday's (Feb. 16) class was devoted to discussing gravity and how scientists deduce mass from orbital motions and gravitational lensing. You can view the video on "Dark Matter: Seeing the Invisible," part of which we viewed in class, at www.tcc.utexas.edu. Scroll down to find this video, but feel free to watch other videos on this page as well. Quiz 2 will be given at the beginning of class on Thursday, Feb. 18, covering what we've said about gravity for the past few classes. Next we move on to the development of structures (galaxies, galaxy clusters) in the universe and formation of the first stars. Again this is not covered in the King book. As announced at the beginning of the semester, we will be instituting a password-enabled interface in order to access class materials. The required data will be announced in class ONLY and will not be emailed or posted. This will be put into effect after class on Thursday, Feb. 18. Reminder: There will be two Public Lectures at the end of this week, on NASA's recent Pluto mission and on molecules in space. Check out the details and instructions on the Out of Class Activities page. |
|
|
||
|
|
: |
As you heard at Thursday's (Feb. 11) class, a dramatic discovery has been made using LIGO, the Laser Interferometric Gravitational wave Observatory, a highly advanced instrument funded by the National Science Foundation (your tax dollars at work). First the first time, gravity waves, predicted a century ago by Albert Einstein, have been directly detected. We talked about this during the first half hour of class on Feb. 11, and some links are posted on the Current Events page, but you can easily find more information online. The waves came from two black holes that merged in a galaxy 1.3 billion light-years away. Exam 1 has been graded, and your scores are posted on Canvas. These include any points added based on explanations written in the "Argue Space" on the exam. Correspondences between numerical scores on the exam and the letter grade they would be assigned is summarized on the Exams page. It is expected that these correspondences will hold for the rest of the semester, including future exams and the overall semester grade. This coming week there will be two very interesting Public Lectures on campus, during daytime hours. They are happening because of a special conference organized by UT Astronomy. While the rest of the conference is private, these two lectures are of broad interest and should be at a level that is comfortable to non-scientists. If you attend either or both of these and turn in a write-up that satisfies the specified requirements, you can earn extra credit for this class. See the Out of Class Activities for more information. |
|
|
||
|
|
: |
The first in-class Exam will be on Thurs., Feb. 11 during the second half of the class period. You must be present in the classroom when the exam begins in order to receive credit for it. Latecomers will not be allowed to take the exam. The format will be the same as for the Background Survey: 25 multiple-choice questions to be answered on a scantron sheet; closed-book; closed-notes. Half a dozen students failed to correctly fill in the header on the scantron sheet. This makes extra work for us. We tolerated it on the Survey, but will not do so on the exam. A Study Guide for the exam is posted on the Exams page. It lists the main topics we have discussed so far, and gives a set of Review Questions. These do not cover absolutely every question that might be on the exam, but should help you focus on most of the main points. The review questions are my answer to the question: "What will be on the exam?" Note: We should finish all of the material on the exam during Tuesday's (Feb. 9) class meeting. We may also cover some new material that will not be tested until Quiz 2 and Exam 2. |
|
|
||
|
|
: |
We will finish our review of the properties of light on Tues., Feb. 2, and start talking about the very early universe (Big Bang), from which the two simplest elements, hydrogen (H) and helium (He) emerged. If you have not already done so, read ch. 1 of King, especially the first few pages, which talk about light and spectra. Our book does not cover the Big Bang. If you have access to any introductory astronomy textbook (the one you used for your intro course, or any other), read the chapter on this topic. Our first Quiz will be given at the beginning of class on Thurs., Feb. 4. It will have two short-answer questions and cover the following topics: the Sun, and properties of light. We will have a credit-earning participation activity on Feb. 2. Office hours will be held this week, and a help session on Wednesday, Feb. 3. |
|
|
||
|
|
: |
On Tues., Jan. 26 we continued talking about the Sun: how it holds itself up against gravity; how energy moves through it; and the (now solved) mystery of the missing neutrinos. Students answered a "thought question" on index cards, which will count as one participation credit. A summary of student responses will be posted on the In-class Participation page within a week. We will review the basics of light and spectra on Thursday, including an in-class demonstration. Next week: the Big Bang, and the nuclear reactions that happened in it! This is the first full week of classes, so we will begin holding office hours and the weekly Help Session (see when and where, at right). Our first quiz will be given the week of Feb. 1 (date to be announced). It will consist of two short answer questions similar in style to the participation activity of Jan. 26. Star Parties also begin this week (see Out of Class Activities). |
|
|
||
|
|
: |
The class meeting on Thurs., Jan. 21 was unfortunately interrupted by an emergency evacuation of the classroom, which prevented us from doing the planned in-class participation activity. It is rescheduled for next Tuesday. When we were allowed to re-enter the building, I showed a few additional slides. We will briefly view those slides again on Tuesday; your assignment for this weekend is to review slides 19 - 24 in the Jan. 21 Class Slides. On Tues., Jan. 26, we will continue our discussion of the inner structure of the Sun, and how it creates and moves energy from the center to the surface. Part of this material is covered on pages 14 - 20 in the King book. The next topic after "The Sun" will be a review of the properties of light, covered in the first few pages of King, ch. 1. See the new Current Events pages for information on viewing the Solar System's brighter planets next week, and other items as they arise. |
|
|
||
|
|
: |
We held our first class meeting on Tues., Jan. 19. In addition to taking a Background Survey (worth 1 point of participation credit), we reviewed the syllabus and began talking about the structure of atoms. Some of the slides shown are posted on the Class Slides page. The first assigned readings in the book by Andrew King are pages 21 - 34 on atoms and fusion, and 14 - 20 on the Sun. Exciting things are happening in the sky in the next two weeks, but you have to be awake before dawn to see them. All five of the planets easily seen with the naked eye (Mercury, Venus, Mars, Jupiter, and Saturn) will be visible at the same time, but you'll need an obstructed view of the eastern horizon to see Mercury, which never gets very far from the Sun. You may notice that the planets line up roughly along an (imaginary) arc across the sky. This is the ecliptic (discussed in your introductory course), the projection onto the sky of the orbital plane of the planets around the Sun. Look up the details here. |
11 May 2016
CNS Help Request · web accessibility policy · web privacy policy