The Time travel !!

           The concept of time travel is an unsolved mystery in the field of Physics and here is an attempt to gain knowledge about some popular theories and facts on time travel.

Time travel is a phenomenon of moving an object or sending information between different moments in time. And any device which is used to travel through time is known as time machine.

There are many theories about time travel, the famous ones are general and special theories of relativity explained by Albert Einstien. They suggest that if one were to move away from the earth at relativistic velocities and return,more time would have passed on earth than for the traveller. So we can accept that he has travelled into the future.

Then according to the special theory of relativity, if a signal or an object travels faster than speed of light, then it can move backwards in time. Scientists say that in some cases different reference frames will not synchronise, whether tow events at different locations happened at the same time or not. In that, one frame represents the sending of a signal and the other frame, the reception. In these type of cases, if the signal is sent faster than light, then the signal is received before it was sent. Hence it can be said that it came from the future and travelled back in time.

The other way for a possible time travel is through wormholes. Wormholes are tunnels connecting tow different locations and perhaps even two different times. Large wormholes may exit naturally in deep space or even artificial ones can also be created by partical acceleration, but they are enlarged to usefull sizes using energy fields.

But some paradox like grandfather paradox oppose the possibilites of time travel and even creates some doubts. According to this, if one goes back in time and kills one’s grandfather before one’s father was even conceived, then will the traveller still exist or perish?… These types of question and paradoxes start arising in the mind of scientists  who pursue the notion of time travel. Thus in a concept called branching of parallel universes, which says that when the traveller kills his own grandfather, then the future of that time branches from actual traveller’s time and a pair of parallel universes are formed with different instances taking place at the same time side by side.

Untill now, time travell has not been practically proved and currently we don’t even know wheather the laws of nature allow time travel or not. Thus time travel remains as an unrevealed part of physics where more discoveries are needed.

Reference :
1. Wikipedia.
2. Magazine – scientific American {Sept. 2002}.