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Lecture 35 – Other Galaxies and Cosmology
Summary / Checklist of the Main Concepts to Understand and Remember
| Other Galaxies | ||
| • | What is M31 (the Andromeda Galaxy), and how far is it from us? What are the Large and Small Magellanic Clouds? | |
| • | What are Cepheid variables? Why are they very useful in astronomy? How are distances to nearby galaxies measured? | |
| • | What is the Local Group? What is the Virgo Cluster? How far is it from us? | |
| • | How do we find distances to galaxies beyond 100 million ly? (Supernovas, Hubble's Law.) | |
| • | What are the three types of galaxies, in terms of their shapes? What do we think will happen to our galaxy and M31 over billions of years? | |
| • | How are galaxies distributed in space, at the largest scales? What is the Hubble Deep Field, and what is its significance? | |
| Hubble's Law and Universal Expansion | ||
| • | How is the radial velocity of a galaxy measured? Why is their sideways motion (proper motion) not observable? | |
| • | What did Edwin Hubble find out about galaxies in the 1920s? What is Hubble's Law? | |
| • | Why do we believe that the universe is expanding? What is cosmology? | |
| The Big-Bang Model | ||
| • | What was the Big Bang? Approximately how long ago did it happen? How do we know? Does the universe have a center, an edge? | |
| • | Has the universe always been expanding at the same rate? How can we find out, and what was discovered around 1997? | |
| • | What are dark matter and dark energy, and what are the main differences between them? Why do we believe they exist? | |
| • | What do we think is the most lilkely scenario for the future of the universe? (Continued expansion, contraction? Why?) | |
Topics from the lecture page and textbook not listed above [or between square brackets]
were not covered in class;
Underlined words indicate that I will expect students to remember a number or a name related to that topic.
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