Hyperspace theory (also called Superstring or Supergravity theory) begins with Einstein's General Relativity. In 1919, Theodr Kaluza, building upon relativity, made an astounding discovery: light and gravity can be unified and expressed with identical mathematics. This was the beginning of the unification of all physical laws, which is the ultimate goal of physics. There was only one catch. He needed an extra dimension. This fifth dimension, long recognized as mathematically plausible, had never before been seriously proposed as an actual component of reality. The usefulness of his theory was hard to deny; in five dimensions, there is "enough room" to accomplish the unification of gravity and light, which simply cannot be accomplished when trapped in four dimensional spacetime.

There is an obvious question to be asked at this point. "Where is the fifth dimension?" Kaluza's answer is clever, though suspiciously hard to test. He said that the fifth dimension is too small to see. The fifth dimension is contiguous with our four, but it is curled up, while the others are extended. To understand curled-up dimensions, imagine an ant living on a string (or a Linelander). click to see the ant For all its life, it is only aware of two directions: forward and backward. It lives in a one-dimensional universe. However, if you examine the string very closely, you find that it has a circumference; an extra dimension, curled up and wrapped back onto itself into a circle. If you could stretch this dimension, that is, make the circumference very large, the ant would be living on the two-dimensional surface of a cylinder. But when it's curled up, it effectively is undetectable by the ant, though it may surve as a medium for vibrations or other physical effects.