Phys 1053: Old News Items

Phys 1053: Old Breaking News

04/29/2008 Reading: You should now be able to read Ch2 in the Dark Side text. The last few pages will be a preview of upcoming lectures. After Thursday's lecture, you will also be able to read Ch3, and this opens up the rest of the book. Chapters 4, 5 & 7 will elaborate on topics in the Rotation Curves lecture. Chapters 8 and 9 (and the second half of Ch2) will elaborate on topics in the Cosmology lecture. (Ch9 also discusses using Type Ia supernovae as standard candles, so it should already make some sense. We've also already discussed parts of chapters 4 and 5; e.g. gravitational lensing, neutrinos.) See Reading Study Questions link for more details.

04/25/2008 Hubble Law exercise: If you missed Thursday's class (4/24) you will need to complete this before Tuesday's class, since we will start by discussing the results. The items you need to do this, as well as the worksheet and instructions, are hanging on my bulletin board.

04/24/2008 One Last Extra Credit Opportunity: Public lecture on the Aurora Borealis: Thursday, May 1 at 4:00 pm in SCI 1020 (by the post office). Sign in before it begins, turn in a brief worksheet as you leave (at the end!) and get 2 bonus exam points. (2 points added to your midterm comes out to 0.4 points added to your final course grade. If you complete all the extra credit events you would change your course grade by 2.4 points - that's a lot!) As explained in class, there are two more Tuesday evening study sessions with the tutor, worth 2 XC points each. They begin at 8:00 pm in the physics lounge at the north end of the 4th floor (basically right above our classroom) and last until observing starts.

04/24/2008 More on Notecard Question #18: What can we see by looking at infrared wavelengths? Cool stars, warm dust, star formation regions and really distant galaxies.

04/16/2008 Crazy Stuff: How do you get an 8-meter mirror from Milan to the top of a mountain in the Chilean Atacama desert? Photo sequence. What can we see by looking at infrared wavelengths?

04/15/2008 Notecard Question #17: "As you get closer to a black hole the escape velocity does what?" Originally I agreed that if your ship had a lot of mass and you threw it out of the window fast enough as you approached the black hole, option "d" was possible (escape velocity could decrease), but upon reflection I've changed my mind. Here's the thing: Changing the mass of your ship (m) affects the gravitational force you feel (through Fgrav = GMm/r^2), but it doesn't change the acceleration you feel - this depends only on the black hole's mass (M)! So you can do whatever you want to your own mass and it won't affect how fast you need to go to be able to just escape the gravitational well and arrive at an infinite distance away having just slowed to zero velocity. The force you feel depends on your mass, but how your motion responds to the force actually doesn't! Link

04/15/2008 Reading Assignments in Dark Side text : I've now added a link on the vocabulary page to a table showing the sections of Dark Side that you should read, along with the major topics covered. Some of these topics we have already discussed in class, so you might want to get started by reading the sections on neutrinos or microlensing right now!

04/15/2008 Last Essay: I've added two more topics to the list of essay topics. By the end of next week, I should be done grading your first two essays. When I return those, I will also give you a summary of your course grade to date.

04/15/2008 Tutoring: Tonight (Tuesday), Ben will be available from 8 pm to 9:30 in the 4th floor physics lounge for tutoring help. Katie from Academic Assistance is still recovering from bronchitis, so she expects to be there to talk about effective study tips not tonight but next tuesday night.

04/08/2008 Interesting Astro Blog: Recent posts on all kindza stuff we've covered or are about to.

04/08/2008 Stellar Evolution Simulation: Another movie I couldn't make work in class! There are a whole bunch of these simulations here, if you find them interesting.

04/07/2008 Helioseismology: Here's the animation I mentioned in lecture, showing the "bouncing" of a spherical surface as sound waves travel around the interior.03/10/2008 Midterm: I've posted important information about the midterm on the Reading Study & Essay page.

03/04/2008 Essay Topics: I've posted three more essay topics, for a total of five now available. There will probably be one more posted before the midterm. I've also converted the format of that page to "html" instead of "mht" so it should be readable by Firefox browsers.

02/14/2008 Lost Items: Did you leave your Stars text in the classroom two weeks ago, or your black spiral notebook in SCI 4550 today? They are now in my office - come n' get 'em!

01/30/2008 The text for the second half of the semester, Dark Side of the Universe, is now available at the campus bookstore. I'm just finishing the last chapters myself, and I'm really excited about this book. Its going to take us some time to work our way through Stars, which is necessary in order to understand the Dark Side, but if you want a preview you could read the first chapter which covers in 20 pages what Stars covers in the first three (or more) chapters. You should find that some parts are already familiar from lecture and your reading.

02/20/2008 Sun Dogs: They're not really 'astronomical' but they've been visible recently in the few hours after sunrise and again before sunset. Learn more about how they form (under "frequent halos") or see pictures and simulations.

02/14/2008 Diffraction: Here's a nice movie of the diffraction of a red laser beam passing between two razor blades.

02/14/2008 Lost Items: Did you leave your Stars text in the classroom two weeks ago, or your black spiral notebook in SCI 4550 today? They are now in my office - come n' get 'em!

02/11/2008 Webpage Issues: A student pointed out to me that the links to pages ending in ".mht" are not readable by the Firefox browser. Internet Explorer can handle them, so if you're having problems switch browsers. (Sorry about that!)

01/30/2008 The Disability Services office is looking for a note-taker for this class. More info....

02/05/2008 Observing Saturn: Saturn is rising in the East in the evening. Tonight it will have achieved an altitude of only 25 degrees by 9:30 pm, so we probably won't be able to see it (at least not well). You can check on the visibility of any target by going to the SCI 2530 computer lab and downloading the setup file (see Constellations assignment in the middle column below) - you will need to change the date and time, turn on planet labels and perhaps turn off "chart mode". (Saturn should be moving into perfect position within the next month or so.)

02/05/2008 If you haven't turned in the Celestial Sphere exercise, the Constellations exercise or the Distance Modulus homework, now is the time. I will be posting solutions Thursday (02/07) after class and will not accept work turned in after that.

01/29/2008 The weather report for tonight is for clouds, so it will likely be a planetarium night. (4th floor, roughly SCI 4560? The one with the open door!) There is now a planetarium-related assignment appearing under Assignments & Solutions. Also, I forgot to hand out a Magnitudes homework assignment today in class, so you will get that on Thursday.

01/26/2008 I've now posted the observing assignment (in the center column, below). You might want to glance at the instructions before Tuesday's class, because on Tuesday we will be using the software that you will also need for your observing preparation. (This software, The Sky, is available only in the SCI 2530 public computer lab.)

01/24/2008 Here is an interesting website that, among other things, includes a table of the satellites currently leaving the Solar System. (Notice that the Voyagers from 1977 are the only ones that can tell us about what they find there.)

01/22/2008 Welcome to Stars, Galaxies & Cosmology! In this space you will find information of immediate importance such as: impending assignment deadlines, updates of the impact of current weather on scheduled telescopic viewing nights, links relevant to recent lectures, responses to student questions and more, much more. When the information gets stale, it moves to the Old Breaking News Page where it is preserved for posterity for all time (or at least until the end of the course). Items of lasting value or general interest generally get permanent links in the table below.

01/22/2008 Yes, we will try to observe tonight... although the forecast is for continued clouds.... See the Telescope Schedule for more info.