astrtology homework 10 questions

Professor’s Questions Set 8

Provide comprehensive answers to the following questions. Remember to support your arguments where necessary by websites and pictures.

Chapter 12 Readings

1. Why is it difficult to specify the dimensions of the disk and halo?

2. Why didn’t astronomers before Shapley realize how large the galaxy is?

3. What is the evidence that the galaxy contains large amount of dark matter?

4. Why are all spiral tracers young?

5. What are some of hypotheses for mechanisms to trigger or sustain spiral density waves?

6. Why are metals less abundant in older stars than in younger stars?

7. Why do metal-poor stars have a wider range of orbital shapes than metal-rich stars like the sun?

8. What evidence contradicts the monolithic collapse hypothesis for the origin of our galaxy?

9. Why must astronomers use infrared telescopes to observe the motions of stars around Sgr A*.

10. What evidence can you cite that the nucleus of the galaxy contains supermassive black hole?