TPO42L2 Distribution of Galaxies (Astronomy)

音频

题目

1.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

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2.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.

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3.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

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4.What aspects of clusters did Abell use to classify them? [Click on 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

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5.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

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6.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.


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