Distribution of Galaxies
- What is the main purpose of the lecture?
- A. To explain the difficulty of classifying distant objects in the universe
- B. To introduce a classification system for galaxy clusters
- C. To present some recent discoveries about the shapes of galaxies
- D. To describe some differences between galaxies and clusters
- What did Shapley and Ames discover about the universe?
- A. Most galaxies are symmetrical.
- B. More galaxies exist in the universe than was once believed.
- C. Galaxies occur in clusters throughout the universe.
- D. Clusters are distributed uniformly throughout the universe.
- Why does the professor emphasize the number of clusters mapped by Abell?
- A. To help explain why Abell’s classification scheme was widely adopted
- B. To explain why Abell was the first astronomer to notice spiral-shaped galaxies
- C. To provide evidence that Abell’s method of surveying galaxies was superior to that used for previous surveys
- D. To show how much Abell relied on earlier research
- What aspects of clusters did Abell use to classify them?
[CHOOSE 2 ANSWERS]
- A. The density of the cluster
- B. The shape of the cluster
- C. The age of the cluster
- D. The type of galaxies in the cluster
- Why does the professor discuss the Coma and Virgo clusters?
- A. To indicate a limitation of Abell’s survey
- B. To distinguish between rich and non-rich clusters
- C. To demonstrate that clusters considered irregular in shape are basically spherical
- D. To illustrate that the shape of a cluster is independent of the shape of the galaxies within it
- What is the professor’s opinion of Abell’s assumption that all clusters are about the same size?
- A. He is surprised that it has been disproved.
- B. He believes that there is not enough data to support it.
- C. He is impressed that it has been proved correct.
- D. He thinks it is Abell’s most important contribution to astronomy.
B C A AB D C