A brief introduction to time dilation.

This is another phenomenon related to relativity . Newton believed that time is constant or absolute but it’s not actually, When the speed of objects is nearer to light speed , time behaves differently

The time that is measured along world line of a particle is called proper time in simple terms it is the time measured by the frame of reference which is moving relative to another frame with some velocity nearer to the light speed.

This famous equation is called spacetime equation with this equation many problems in special relativity are solved .

Here ds is the spacetime interval, dx dy dz are the space intervals dt is the time interval .

The best example for the time dilation is the twin paradox , in this case two identical twins are considered, one is placed on the earth and the other twin is sent to a space trip, so the twin went on a space trip is considered to be travelling at a speed nearer to the light . He is traveling very fast in space but very slow in time (according to Einstein's special relativity )

After some years say 10 years, the twin went to a space trip returns back to earth to meet his another twin ,

Surprisingly both their ages are not the same , twin went on a space trip was younger than the twin stayed back . So from this phenomenon we can infer that light which travels very slow in time is almost the same light which was born during big bang.