| Discovery | The expanding and contracting universe |
| Phenomena | Expansion • Contraction (The Collapse) |
| Discovered | Late 20th-early 21st century |
| Key concept | Cosmic cycles |
| Debated implications | Impact on cosmology • Ethics of manipulating new universes |
| Origin of child universes | From parent universe • During Collapse phase |
| Description of child universe | Newly formed, self-contained universe |
