On the following page are pictures showing what an elliptical galaxy would look like if it were located in different galaxy clusters. The farther away from the cluster, the smaller the galaxy looks. There is an inverse relationship between apparent size and distance. Next to each galaxy, there is a spectrum of a bright star in the galaxy. The dark lines are “Balmer” hydrogen absorption lines. These lines are not always found at the same wavelength; they are “shifted.” However, the general pattern that the hydrogen lines form in each spectrum always stays the same. That is how we can tell if a certain line is a hydrogen line, even though it is not always found at the same wavelength. The “shift” of the pattern is the Doppler Effect, and it is caused by the motion (relative to us, the observers) of the star that is emitting the light as seen in Part 1 of this lab.