the capacity of man to go to past was never thought unless and untill Einstein gave the principle that the speed of light is contant and is not affected by any thing in space. earlier newton gave the principle that when the sun will get destroyed immdiately then as there is no force of attraction which keeps the planets in orbits, planets will go away from the orbits. later einstein's discovery made it clear that 8min time is required for the light to come on earth from sun.. a simple concept is used to describe the effect of stop of time. time is the fourth dimension of space. now the atomic clock is used to calculate the actual time. the time that is on the earth and the SECOND which we calculate is different in space. as the altitude increases and we begin to move in the outer space, the second hand of the atomic clock ticks faster. a light clock works on the principle of reflection of a photon between two mirrors perpendicular to each other. the photon appears to bounce between the mirrors. now that is a standard second. but if we accelerate towards the velocity of light, the photon will travel in a slant line rather than perpendicular distance. so time period for the photon to touch the mirrors increases. if one light clock is in space and is accelerated to the speed of light then it will be travelling such a distance that with refrence to us we will find that that photon is not touching the mirror. and hence TIME STOPS. this is proved by experiments. the only thing is to achieve the velocity of light. the time willl stop for the OBSERVER ONLY!!! but for the person with that clock it is going. so 1 hour for that person may equivalate to about many days of earth and this is applicable when we recieve the near the velocity of light.!! there are mysteries which are termed with this TIME DILATION CONCEpt. One of my cousin asked me why is it not possible to go in past. but we can. the only thing velocity of light has to be achieved. coming out of this imagination we now move to another concept. the name is TIME CHANGES--
suppose that i am having a car. i am moving on the road with the speed of 100km/hr. a train with speed of 200km/hr was behind me. it then came infront of me at the moment when we are in uniform motion, and train crosses me, then i find that the train is moving with the speed as it was before when i observed the train when i was at rest. the same is for train driver. for both of us the speed with respect to each other is same but something is changing and that is TIME as the train is with same speed for car and car relative to it..
this concept makes time the 4th dimension of space... and it is curved space time.!!!
