Theory of relativity

Theory of relativity was given by Albert Einstein. According to this theory time and space are connected with each other it means time do not flow with same speed it each place in the world.

for example:- In outer space time is relatively slower then time on any other place on Earth.

Suppose there are 2 twins one of them became an astronaut and went to space for some time when he will come age of both twins will be different because in outer space time is slower then Earth.