A Brief History of Time Travel
- Traveling very fast allows you to go forward in time. Traveling backward in time is much harder, but mathematics says it is possible through geometric structures called closed timelike curves.
- A wormhole is one such curve. You would enter it through a spherical opening. Once inside, everything you observed in space would be normal and so would the passage of time.
- Closed timelike curves are useful for testing theories about the cosmos. For example, if one were present at the start of our universe, it could have allowed the universe to create itself.
- Quantum mechanics—and indeed, the nature of the universe itself—might forbid wormholes and therefore prevent backward time travel. Physicists just do not know yet if this is the case.
- read more at http://www.nature.com/scientificamerican/journal/v313/n3/full/scientificamerican0915-68.html?foxtrotcallback=true