The concept of the fourth dimension is quite a hard subject to wrap your head around.
Our universe is only visible in three directions, but theoretical physicists believe that other dimensions may exist outside the range of our perception, one of which being the fourth dimension. In addition to the dimensions that determine length, area, and volume, it is a theorized spatial dimension.
Researchers have attempted to explain time travel using the fourth dimension, but it still seems fictitious since we already know that we cannot see or perceive it. What good is knowing about the fourth dimension if we can’t use it to go through time and if we can’t even see it? Mathematicians and physicists value this knowledge because it aids in their understanding of the universe.
String theory, for example, relies upon at least 10 dimensions to remain viable [source: Groleau]. For these researchers, the answers to complex problems in the 3-D world may be found in the next dimension — and beyond.
Although it is a quite a hard subject and tough to wrap your head around, this incredible High-School student does a wonderful job of explaining the fourth dimension.
Soucre: fancy4work.com