| 1960: |
| Fritz Zwicky proposes |
| space travel |
| by changing the |
| nuclear burning |
| in the sun. |
| The "spaceship" is |
| the solar system. |
| 2048: |
| routine sky surveys |
| show strong evidence |
| that one of the minor |
| planets will collide with |
| the earth in 2098 |
| The world science foundation |
| looks for a solution. |
| Zwicky's idea |
| is reconsidered. |
