Meaning Of Dimension In Physics

The dimensions are also used for dimensional analysis, which is the process to analyse the different relationships among physical quantities by finding their base quantities such as length, time, electric current,  and other units of measurement. 

The dimensions and units of measurement of the base quantities are:- 

• • Length – The SI unit of length is Metres and is denoted as ‘m’, whereas the CGS unit of length is centimetres which is denoted as ‘cm’.
  • Time – The SI and CGS unit of time is seconds and it is denoted as ‘s’.

• Electric current – The SI unit of electric current is Ampere and is denoted as ‘A’. The CGS unit of electric current is biot and it is denoted ‘Bi’.

• Mass – The SI unit of mass is kilogram and it is denoted as ‘kg’. The CGS unit of mass is gram and is denoted as ‘gm’.

Dimensions In Physics 

Dimensions in physics are as follows:- 

Space

The dimensional references in space are referred to as spatial dimensions. There are some classical physical theories which consist of three physical dimensions. 

According to those theories, an object placed at a particular point in space can basically move in 3 possible ways:-

• Move up or down 
• Left or right 
• Forward or backward

Moving down is usually explained to be a similar movement to moving up just in a negative distance. These movements usually follow a linear combination while moving. 

Time 

The dimension of time is known as the time or temporal dimension. In some theories, time is regarded as the fourth dimension but it does not imply that it is a spatial dimension. The main reason for it is that it is different than the spatial dimensions as we can’t move according to our will in time and can only keep moving in a particular direction. 

Humans’ treatment of time and its treatment in physics usually alter as the model of reality of physics treats it differently. The classical mechanics and its equations related to quantum mechanics are symmetric with respect to time. Whereas, equations of quantum mechanics are symmetric in cases where time along with quantities such as charge and parity are reversed. Here time flowing in a single direction is a part of the law of Thermodynamics and time is perceived to flow in the direction of increasing entropy. 

Other Dimensions 

Physics has only three dimensions of space along with the dimension of time referred to in quantum mechanics. 

Relatively new theories have come up with an effort for unifying four dimensions through extra dimensions and hyperspace. The most famous theory is known as superstring theory. This theory needs 10 space-time dimensions and it originates from the 11-dimensional theory called M-theory. Other than that there is the supergravity theory which supports the 11-dimensional space-time concept consisting of 7-dimensional hyperspace and 4 usual dimensions. To date no proper evidence is found of the alleged extra dimensions. Speculations of them existing in tiny scales to be invisible for the current forms of experimentation are still there. 

The extra dimensions are supposed to have more than one spatial dimension and can be said to be universal in cases when the fields are equally free for propagation inside them. 

Conclusion 

There are many theories with endless possibilities regarding different dimensions but as of now there is clarity about the 3 dimensions and time. Some experiments claim 5 dimensions and some claim 7 dimensions but they somehow fail to gather enough evidence to back their theories up.