Problem
1) How does the amount of dark matter influence the velocity of stars near the center of the galaxy? (Figure this out by adjusting the dark matter sliders and observing the how the velocity changes.)
2) How does the amount of dark matter influence the speed of stars near the outer edge of the galaxy?
3) Remove all dark matter from the galaxy. Describe what you see.
4) Based on the behavior of the orbiting stars for different amounts and distributions of dark matter, do you believe that there is enough of a difference to allow astronomers to infer the presence of dark matter?