Physics Lab #4: Citizen Science - The Milky Way Project

Transcription

1 Physics Lab #4: Citizen Science - The Milky Way Project Introduction This lab is the first of several Citizen Science labs we will do together this semester as part of the zooniverse.org project family. The concept of Citizen Science is that some Astronomical databases are so large and the data so complex that computer algorithms cannot accurately or reliably sort through all of the data to find the kinds of interesting things that astronomers are looking for. In this lab, we will be exploring the structure and interesting features within our Milky Way galaxy. Part 1 Using a web browser, navigate to and from there, select About and read through the short introduction, answering the associated questions on your worksheet. Part 2 For helpful background information about what astronomers are hoping to learn by studying bubbles, star forming regions, clusters and other structures in the Milky Way, please read through the February 2010 Scientific American article, Cloudy with a Chance of Stars. In order to access this article 1) You will need to go to the TCU library s website at 2) Once there, click on the Library Catalog button directly beneath the tculibrary logo. 3) Next, type Scientific American into the search box, and also change the drop-down menu from Words Anywhere to Journal name begins with 4) Click on the Search button. 5) On the Search results page, click on the first linked entry that simply says Scientific American. 6) On the next results page, in the first record, click on the 2nd or 3rd entry in the list that reads Full text available to the TCU community from Nature Journals Online: 1993 to present.!27

2 7) This will open a new window that gives you access to the complete archive of Scientific American. In the search box there, type in the name of the article we are looking for: Cloudy with a Chance of Stars. 8) On the search results page, the first entry should be the article we are looking for. Click on the PDF link to open up a PDF copy of the article. Ask your TA if you need help with any of the steps in this process. Once you have the article loaded, read through it and answer the questions on your worksheet, which are arranged in the same order that they are covered within the article. Part 3 Next, sign in to the Zooniverse website if you haven t already. You may need to create an account. Be sure to use a username/password that you can remember since we will do more Citizen Science projects later. This will enable the site to keep a record of your work so that we know how many data sets you have completed. Now click on the Classify button to start the tutorial on how to classify objects. Read through the tutorial. Now proceed to classify 90 images. If you have some uncertainty after looking at a few images, go through the tutorial carefully again. Also, click the Need some help with this task? button for some examples of things commonly marked. Many frames (maybe half) have nothing obvious to mark, and that s fine. Just inspect the image for a few seconds to be sure, then move on to the next. Once you have completed your contribution to the project, show your TA your profile page (click your username on the top right, then select Home ). The little ring around the circular icon can be hovered over to indicate how many data sets you have completed for any given project.!28

3 Lab #4 Worksheet Name: Home TA: Part 1 From the About section under the first tab ( Research ), explain what Astronomers hope to learn by studying the dust located on the outer edges of interstellar bubbles. From the About section under the fourth tab ( FAQ ), explain why the project needs many people to classify the same image.!29

4 Part 2 From the article, Cloudy with a Chance of Stars, what four questions about star formation does the author seek to answer with his research? When collapsing interstellar clouds reach a density of about 1000 atoms per cubic centimeter, we call them molecular clouds. Why can molecules survive in these clouds and not in other parts of interstellar space?!30

5 Describe two leading ideas that may explain what upsets the balance of pressure and gravity in order to initiate the formation of a star from an interstellar cloud Explain the evidence from the W5 region (described in the photograph on page 39) that radiation pressure from massive stars has triggered the collapse of surrounding dust clouds and subsequent star formation at the rim of the bubble. Describe the competitive accretion model for the formation of star clusters.!31

6 Describe the evidence in the Christmas Tree cluster that seems to support competitive accretion as a major influence, at least for some stars. Explain how recent theoretical simulations solve the problem of super-massive star formation, allowing stars to form with masses larger than 20 solar masses despite the enormous radiation they emit (which should disperse surrounding gas and dust, limiting further growth). Part 3 Once you have classified 90 images, show your TA your profile for verification. Don t forget to explore what others have also done with the same images using the advice I ve given you in the lab instructions for this part. TA Initials:!32