What is time travel?
Time travel refers to traveling to the past or the future by escaping the general flow of time. Time travel is a familiar word to people because it is used as a main subject in movies, novels, and dramas. A similar concept to time travel in everyday life is the stars that we can see in the sky every night. Stars far from Earth appear to have only one shiny spot. It takes a tremendous amount of time for the light emitted by the stars to reach Earth. For example, suppose that the brightest star in the night sky is 100 light years away. The light from that star we see now is the light emitted by the star 100 years ago because it takes 100 years to reach Earth.
Then, how is time travel possible, which is often seen in movies or science fiction novels? The answer to this can be found in Albert Einstein’s theory of relativity. The theory states that time and space are connected together, and explains that nothing in this universe can be faster than the speed of light. Furthermore, according to the theory of relativity, Einstein argued that time flows slower as it travels at a speed close to the speed of light. Many scientists have conducted several experiments to prove it. Using two clocks set at exactly the same time, one clock stayed on the ground and the other clock traveled around the world by plane. As a result, the clock in the airplane moved slightly slower than the clock that stayed on the ground. It proves that fast-paced movement has a slightly slower flow of time (NASA, 2020).
Ways to enable time travel
How is it possible to time travel to a particular future or past that can only be seen in movies and novels? In theory, several ways to enable time travel have been suggested.
- Time travel at a speed that is close to the speed of light – It is the most practical way compared to other methods. As described above, fast-paced movements can affect the flow of time. According to Einstein’s theory of relativity, as the speed of movement approaches the speed of light, time becomes significantly slower than that of the outside world. For airliners, the time difference is really small because it is less than 1 percent of the speed of light. If you travel to a flying object that is close to the speed of light, the time will travel about three times slower than the one on the ground. However, the fastest human-invented flying objects now travel at less than 1% of the speed of light. It is true that with modern technology, it is still difficult to make time travel happen even in the distant future.
- Gravity – According to Einstein’s theory of relativity, gravity distorts time and space. In other words, the greater the influence of gravity, the slower time goes. This has also been proven by experiments, not assumptions. Using this principle, time travel is possible by creating a time machine, but it is difficult because the Earth’s gravity is not strong enough to travel through time into the past. It is possible in a black hole with enormous gravity, but our human bodies cannot withstand the enormous gravity of the black hole. The experience of time travel under the influence of the strong gravity of the black hole can be seen in the movie “Interstellar”.
- Wormholes – Wormholes mean shortcuts between outer space. In other words, it’s a channel that connects distant space. In fact, no wormholes have been found, but Stephen Hawking and many physicists have suggested the existence of wormholes. A wormhole is a passage through a space formed by fluctuations in energy in the positive and negative directions. Physicists argue that it is theoretically possible for particles to pass through a wormhole if the wormhole lasts long enough. If the existence of a wormhole is confirmed, mankind will be able to take a step closer to understanding it.
Is time travel possible in the near future?
As explained above, many scientists argue that time travel is theoretically possible. However, some physicists are skeptical of the idea. This is because the level of technology required for time travel is too high for now. The most fundamental limit is speed. Skeptical physicists believe that it is impossible to build an airplane or a spacecraft with near-light speed based on human technology. Time travel using gravity and wormholes is also impossible to even try if speed-related technologies are not developed. For this reason, time travel seems impossible in the near future.
Conclusion
In addition to the ways of time travel explained above, there are some other ways. For example, one way to travel to the future may be by slowing one’s perception of time. By slowing down or stopping the bodily processes and then restarting them later, traveling into the future may be possible. Unlike the usual ways of skipping time and twisting space into the distant future or past, this is a creative way to travel through time by stopping the subject without breaking away from the usual passage of time. It is true that time travel is impossible with modern technology, but scientists have solved many problems that once seemed impossible. It may be fun to think about what to do if time travel becomes possible.
References
NASA (2020). Is Time Travel Possible? | NASA Space Place – NASA Science for Kids. [online] spaceplace.nasa.gov. Available at: https://spaceplace.nasa.gov/time-travel/en/ [Accessed 14 August 2022].
O’Connell, C. (2016). Five Ways to Travel through Time. [online] Cosmos Magazine. Available at: https://cosmosmagazine.com/science/physics/five-ways-to-travel-through-time/ [Accessed 14 August 2022].
Stein, V. and Harvey, A. (2021). Time Travel: Theories, Paradoxes & Possibilities. [online] Space.com. Available at: https://www.space.com/21675-time-travel.html#section-time-travel-in-science-fiction [Accessed 15 August 2022].
