Today I am going to tell you something that is very interesting. We all know what a time machine is but we at present do not know how to build one but that doesn't mean we don't know the theory behind it.

Many of you must have heard about time dilation and space contraction. If not don't worry. Today I am going to try my best to explain these phenomena. About a 100 years ago some scientists proved that the speed of light remains constant in all frames of reference. Take an example of a ball thrown horizontally with a velocity of 2 m/s from a car moving with a velocity of 10 m/s in the same direction. With respect to the observer in the car the velocity of the ball would be 2 m/s, but with the respect to the observer on ground the velocity of the ball would be 12 m/s (10 m/s + 2 m/s). This does not happen with light. The speed of light is constant.

In order to get a feel of this, let's look at this example. Imagine you are moving on a horizontal road only in the west-east direction with a velocity of 70 m/s. Now if you move in the north-eastern direction with the same velocity, your west-east velocity would be less than 70 m/s as some of this velocity would be in the northern direction. Now replace the west-east direction with time axis and and the north-south direction with space axis. All the matter in the universe move with the speed of light but in both these axes hence our velocity in any one of these axes is less than the speed of light. Hence if you increase your speed in space axis, time will run slow and if you increase your speed in time axis, space will contract.

Many of you must have heard about time dilation and space contraction. If not don't worry. Today I am going to try my best to explain these phenomena. About a 100 years ago some scientists proved that the speed of light remains constant in all frames of reference. Take an example of a ball thrown horizontally with a velocity of 2 m/s from a car moving with a velocity of 10 m/s in the same direction. With respect to the observer in the car the velocity of the ball would be 2 m/s, but with the respect to the observer on ground the velocity of the ball would be 12 m/s (10 m/s + 2 m/s). This does not happen with light. The speed of light is constant.

In order to get a feel of this, let's look at this example. Imagine you are moving on a horizontal road only in the west-east direction with a velocity of 70 m/s. Now if you move in the north-eastern direction with the same velocity, your west-east velocity would be less than 70 m/s as some of this velocity would be in the northern direction. Now replace the west-east direction with time axis and and the north-south direction with space axis. All the matter in the universe move with the speed of light but in both these axes hence our velocity in any one of these axes is less than the speed of light. Hence if you increase your speed in space axis, time will run slow and if you increase your speed in time axis, space will contract.