Spatial dimensions

Although modern physicists usually consider space in association with time to be part of a boundless four-dimensional continuum known as space-time, physical space is often conceived in three linear dimensions. Currently, the standard spatial interval, called a meter, is defined as the distance traveled by light in vacuum during a time interval of exactly 1/299,792,458 of a second. Use of circular logic to define time is usually ignored. In order to relate one object to another (or a point in a body to another point) or locations of a body at different intervals, we use spatial dimensions. They indicate (quantify) extent of real space (universal medium) between two points. Although there are different systems of spatial-dimensions, the most convenient and widely used spatial dimensional system is that of ‘three-dimensional’. For this, we divide space about a reference point into eight parts by three mutually perpendicular planes and relate location of a point in space with each of these planes (length, breadth and depth). In order to have spatial dimensional systems with more than three, we should be able to divide space into more parts by mutually perpendicular planes through a reference point. This is quite impossible. Three-dimensional spatial system includes both, two-dimensional and single-dimensional systems, as its integral parts. See description of ‘space’.