This may be the most common question that may come to many of your mind that will we be able to travel in time some day or not. According to one the theory given by Albert Einstein states that an object could travel in time if we are able to provide it with speed more than that of speed of light. But then are we capable of producing such large speeds? Answer to this question is obviously not as we all know.
According to physics there are several theories which states that time travel is possible, special and general theory of relativity says that one could travel in time by specific motion in space. According to general theory of relativity there are certain geometries which allow a particle to travel with a speed greater than the speed of light such as wormholes and cosmic string but again this is just a theoretical concept and practically not possible yet but could be possible in future. There are other theories which says that it is possible to travel in time such as the Spinning dense cylinder theory proposed by Stephen Hawking one of the greatest physicist ever known , but again it is just a theory based upon certain mathematical calculations and does not seems to be a practical idea.
There is one more theory which question the possibility of time travel or I should say paradox which is popularly known as Grandfather paradox,According to which one could travel back in time and kill his grandfather so that his father is not able to come into existence, but this in term question’s his own existence. Then it must mean that he himself would automatically disappear and also all the differences he made to world would also disappear along with him. Hence this event is not possible and therefore question’s the possibility of time travel.
After all this do think it is possible to travel in time? Now let’s think about another interesting question which often arise in my mind. Is there any particle or object or something that is capable of traveling with speed greater than or equal to the speed of light? Yes, there is the light itself i.e. the light particle photon, travels with a speed equal to the speed of light.
There is one more concept known as Time Dilation which states that for any object moving at a speed time moves slowly for that object. So now photon is to traveling with a speed of light and hence for a photon also the time is moving slower that normal hence every photon is traveling in time which means that every photon entering our eyes is carrying the information of some other time, which means that we are not seeing present, but we are seeing the future or the past.So, does this mean that we are always traveling in time? And the answer to the above question is no, because according to Einstein’s theory of relativity all the laws of relativity are not applicable to light.