 |
| 1 | |
Why do astronomers believe the Universe is expanding? |
| | |
|
|
|
| 2 | |
What is meant by a cosmic horizon? |
| | |
|
|
|
| 3 | |
What is Olbers’ paradox? |
| | |
|
|
|
| 4 | |
What is the cosmic microwave background? What is its origin? |
| | |
|
|
|
| 5 | |
Why do astronomers believe the early Universe was hot and dense? |
| | |
|
|
|
| 6 | |
What is meant by the age of the Universe? How old is it? How is its age found? |
| | |
|
|
|
| 7 | |
How was helium formed from hydrogen in the early Universe? |
| | |
|
|
|
| 8 | |
What explanation do astronomers offer for why the relative abundance of hydrogen and helium is uniform? |
| | |
|
|
|
| 9 | |
Is our cosmic horizon the same as that of beings in another galaxy? Why? |
| | |
|
|
|
| 10 | |
What is meant by inflation in cosmology? |
| | |
|
|
|
| 11 | |
What is the Big Bang? What are some of its properties? |
| | |
|
|
|
| 12 | |
What problems of the Big Bang theory are resolved by inflationary models? |
| | |
|
|
|
| 13 | |
What is meant by open and closed universes? |
| | |
|
|
|
| 14 | |
How do the shapes of open, closed, and flat universes differ? How does their energy content differ? |
| | |
|
|
|
| 15 | |
What is “unified” in grand unified theories? |
| | |
|
|
|
| 16 | |
What is meant by dark matter? |
| | |
|
|
|
| 17 | |
What role does the cosmological constant play in cosmology? What evidence makes astronomers think it may exist? |
| | |
|
|