What is Hubble's law? How was it discovered?
Why is it difficult to determine the value of the Hubble constant? What is the best value obtained for this constant?
What is the cosmological distance ladder? What are the steps in this ladder needed to calculate the Hubble constant?
List two ways to determine the mass of clusters of galaxies. How does the mass calculated in these methods compare with the number of stars observed in clusters?
What are clusters of galaxies? How many galaxies are in a typical cluster?
What are walls and voids? How were these features discovered?
What are peculiar galaxies? How are they different from irregular galaxies?
How are peculiar galaxies often formed?
What is Galactic Cannibalism?