People have often thought about going back in time due to regrets or mistakes they want to correct in the past. The only way to return to the past is to time travel there. Time travel is known as science fiction, but scientists now believe that time travel is possible based on the laws of physics. If time travel is possible, then will it be useful for humans to start returning to the past? Time travel may not be worth it because if you change something in the past, it will greatly affect your future. The people you thought you knew may not be the same people in the future because something changes in the past. There are several theories that state that parallel universes and other versions of us could exist. There are philosophical opinions about the nature of time in time travel, if that's possible. One view is called eternalism, which means that beliefs about the past, present, and future already exist. Eternalism is the description of space-time as an unchanging four-dimensional block. Another philosophical view of the nature of time is presentism, which means that a past exists but the future is not yet established. As the present passes, it becomes like the past and the future like the new present. This means that time is moving into the future and leaving the past behind. The scientist came to the conclusion that time travel could be possible thanks to the new laws of modern physics. One theory is that wormholes are a short passage through space-time for long journeys. In 1935, Albert Einstein and Nathan Rosen developed the theory of general relativity in which they discovered bridges or wormholes across space-time. In one article it says: “A wormhole would allow a ship, for example, to travel from one point to another faster than the speed of light – sort of… middle of paper……h results from the fact that that person is not never born. This means that the person will disappear. In another example we see what happens if someone kills the grandfather after the birth of the mother. There are many chances that the traveler is not born or ends up in a different universe. After the death of the grandfather, the mother could move away or change her route and not meet the father, which causes the traveler not to be born. Another scenario is that when the traveler returns to his present, the mother may have a different personality than he was used to. Before the traveler killed his grandfather, the mother could have always been kind and sweet for receiving love from her father. No, after what the traveler did, mom couldn't show loving affection because her dad wasn't around. Changing something in the past could lead to different types of parallel universes in the future.