Observer stages:

 
 
 
 
 

Before beginning, get this activity's HAL (PDF, 269 KB) or get the full HAL (PDF, 355 KB) for the whole HDF lesson.

The final task

Congratulations on your progress! Now we'll embark on the last challenge — using what we've learned to make some predictions about a mystery object.

First, we'll review what was learned. On the next page, you will be asked seven review questions. Find the answers to the questions by clicking the galaxy diagram on that page. Click on the arms and the center of the galaxy.