New Theory in Physics Time Definition If we go to search everything about definition of time finally will be a disillusion because of confusing definitions. My theory will brink you clear vision about fog and confusion. Here the definition of time: Time is 4th dimension and is equal to radius of sphere where the space is defined. Compression or expansion of space will generate compression or expansion of time. All four dimensions are correlated and cannot be separated. More concise: space is surrounded by time or defined by time and part of time. This is way so far time cannot be seen because is hard to be seen from inside.