In the previous lab we learned about the difference in the distribution of globular and open star clusters. This difference in distribution tells us something about the Milky Way Galaxy and its surroundings. The graphics (left) provide a bird's-eye-view of what our Galaxy would look like if we could step outside of it. We live in the disk, which has spiral structure.  Note the distribution of globular clusters. They are found outside the disk of the galaxy.

The open clusters are also in the disk, as you discovered in the last lab.

Purpose

In the previous lab we learned about the difference in the distribution of globular and open star clusters. In this lab we will travel beyond the Milky Way galaxy to some of our galaxy's nearest neighbors. We will first learn how to measure distances to other galaxies and then we will learn about some of their interesting properties.

Instructions

  1. Read the background material by clicking on the topics listed on the menu on the left side of this page. For a given topic there may be multiple pages each of which can be accessed using the navigation buttons arranged across the top of each page.
  2. Click on the menu item "Problems". A window should open at the bottom of your screen with the questions.
  3. Read the information about Cepheid variables and answer the corresponding questions.
  4. Read the information about the properties of galaxies and answer the corresponding questions. You will use the interactive image processor and the virtual observatory to answer some of the questions.
  5. Answer the questions by filling in the form fields on the computer.  Hit the button labeled "Submit" when you are done. A confirmation page will appear with all your answers imbedded. Be careful not to close the problems window until you are finished and want to submit or your answers may be lost and you will have to reenter your answers.
  6. Check over the confirmation page to make sure that you are happy with your answers. If you need to change your answers go back to step 5 and re-submit. We will only grade the last form you submit.


    Good Luck!