Parallel Universes ![Parallel Universes - 8 Interesting Theories About Time Travel [Plethrons.Com]](http://plethrons.com/wp-content/uploads/2013/09/Parallel-Universes-8-Interesting-Theories-About-Time-Travel-Plethrons.Com_.jpg)
Oxford scientists claim parallel universes exist. The universe splitting constantly is seen as a way to combat the problems of time-travel paradoxes.
Exotic Matter ![Exotic Matter - 8 Interesting Theories About Time Travel [Plethrons.Com]](http://plethrons.com/wp-content/uploads/2013/09/Exotic-Matter-8-Interesting-Theories-About-Time-Travel-Plethrons.Com_.jpg)
Theoretical matter with negative mass & energy density, that curves space – time in the opposite way to normal matter. Could be used to create wormholes.
Cosmic Strings ![Cosmic Strings - 8 Interesting Theories About Time Travel [Plethrons.Com]](http://plethrons.com/wp-content/uploads/2013/09/Cosmic-Strings-8-Interesting-Theories-About-Time-Travel-Plethrons.Com_.jpg)
A theory about narrow tubes of energy stretching across the universe. Containing huge mass, if two approached each other, it could bend space – time around them.
Plethrons What's Beyond the Obvious