Are there extra dimensions of space?
The revolutionary concept of string theory is a bold realization of Einstein's dream of an ultimate explanation for everything from the tiniest quanta of particle physics to the cosmos itself. String theory unifies physics by producing all known forces and particles as
different vibrations of a single substance called superstrings. String theory brings quantum consistency to physics with an elegant mathematical construct that appears to be unique.
Do superstrings exist?
The strings themselves are probably too tiny to observe directly, but string theory makes a number of testable predictions. It implies supersymmetry and predicts seven undiscovered dimensions of space, dimensions that would give rise to much of the mysterious complexity of particle physics. Testing the validity of string theory requires searching for the extra dimensions and exploring their properties. How many are there? What are their shapes and sizes? How and why are they hidden? And what are the new particles associated with the extra dimensions?
to travel from one parallel universe to an adjacent one. A wormhole which connects (usually closed) universes is called a Schwarzschild wormhole. In string theory, a wormhole has been envisioned to
connect two D-branes, where the mouths are attached to the branes and are connected by a flux tube. If a brane is in fact a universe, this would make perfect sense. Also wormholes are believed to be a part of space-time foam. There are two main types of wormholes: Lorentzian wormholes and Euclidean wormholes.
..Lorentzian wormholes are a product of general relativity and semi-classical gravity, but Euclidean wormholes are studied in particle physics. Interestingly, traversable wormholes (a special kind of Lorentzian wormhole) could possibly allow a human to travel from one side of the wormhole to the other. It would certainly allow a cross transmission of EMF or other forms of pure energy.
..Lorentzian wormholes are not excluded within the framework of general relativity, but the physical plausibility of their existence has remained elusive. It is also unknown whether a theory of quantum gravity, merging general relativity with quantum mechanics, would still allow them, but I suspect they would. Most of the accepted solutions of general relativity which allow for traversable wormholes require the existence of exotic matter, a theoretical substance which would have to have a negative energy density. However, it has not been mathematically proven that this is an absolute requirement for traversable wormholes, nor has it been established that exotic matter cannot exist.
Exotic matter is a hypothetical concept of particle physics. It covers any material which violates one or more classical conditions or is not made of known baryonic particles. Such materials would possess qualities like negative mass or being repelled rather than attracted by gravity. The closest known real representative of exotic matter is a region of pseudo-negative pressure density produced by the Casimir effect. In physics, the Casimir effect and the Casimir-Polder force are physical forces arising from a quantized field. The typical example is of two uncharged metallic plates in a vacuum, placed a few micrometers apart, without any external electromagnetic field.
Scientists discuss what sort of life could be found in the eleventh dimension. With talk of world of lightning bolts, electricity, unstable atoms and more, this video from BBC show 'Parallel Universe' is full of mind-bending theories.