Review Questions
How are distant (young) galaxies different from the galaxies that we see in the universe today?
What is the evidence that star formation began when the universe was only a few hundred million years old?
Describe the evolution of an elliptical galaxy. How does the evolution of a spiral galaxy differ from that of an elliptical?
Explain what we mean when we call the universe homogeneous and isotropic. Would you say that the distribution of elephants on Earth is homogeneous and isotropic? Why?
Describe the organization of galaxies into groupings, from the Local Group to superclusters.
What is the evidence that a large fraction of the matter in the universe is invisible?
When astronomers make maps of the structure of the universe on the largest scales, how do they find the superclusters of galaxies to be arranged?
How does the presence of an active galactic nucleus in a starburst galaxy affect the starburst process?