According to Albert Einstein’s theory of relativity, humans can potentially travel through time under certain conditions.
An American scientist has demonstrated that humans can indeed travel to the future if equipped with the necessary tools, as reported by Space on September 1.
Time travel is feasible according to Albert Einstein’s theory of relativity. (Photo: Daily Express).
According to Einstein’s special relativity, the three dimensions of space and the single dimension of time are closely interconnected, explains Paul Sutter, an astrophysicist at Ohio State University. They are not considered separate elements but rather a unified entity.
However, time seems to be somewhat different. While humans can move freely through space, we must always flow with the current of time. Time only moves in one direction, from the past to the future.
Although we cannot resist the flow of time, humans can control their speed of moving toward the future. This is also based on relativity, which states that time is not experienced the same everywhere. The speed at which one moves through space will determine the rate of movement through time.
If one were to construct a sufficiently large rocket that could continuously accelerate at 9.8 m/s² (the acceleration due to gravity on Earth), a person could reach the center of the Milky Way galaxy, located 20,000 light-years away, in just a few decades. This duration is how long the people on the spacecraft would perceive. However, upon returning to Earth, approximately 40,000 years would have passed.
Humans can control their speed of moving toward the future. (Photo: NBC News).
Time is relative but still moves in sync with everyone. Let’s analyze general relativity to assess the potential for time travel backward. General relativity explains gravity as well as the complete relationship between space-time and motion.
The question is whether there is an arrangement of matter and energy—those factors that bend space-time—that allows closed time loops to exist. “In a closed time loop, you will never move faster than the speed of light and time will loop back to the starting point, meaning returning to the past,” Sutter explains.
Some theories regarding space-time suggest that closed time loops could potentially exist. If the universe continuously rotates and expands at an ever-increasing rate, closed time loops could emerge, allowing individuals to return to the past, according to Kurt Gödel, a mathematician famous for his incompleteness theorem.
However, all observations thus far indicate that the universe is merely expanding and not rotating. Thus, his theory cannot be applied.
The second hypothesis is to create an infinitely long cylinder and rotate it along its axis at a speed close to the speed of light. This would pull space-time around it, and certain points on the cylinder would return to their original position, effectively allowing a return to the past. Of course, humans have not yet been able to create such a large and infinite cylinder, making this method unfeasible.
Wormholes are shortcuts connecting two distant points in space-time. (Photo: YouTube).
Another hypothesis is to create a wormhole—a shortcut connecting two distant points in space-time and move one point at a speed close to light before returning it to its original position. The time dilation effect would allow this point to reach the “future” of the other. Thus, humans could traverse through the wormhole to reach the past. However, creating a wormhole requires something that does not exist: “negative mass.”
While returning to the past is theoretically possible according to general relativity, there are currently no specific methods to achieve it. On the contrary, the research community has yet to establish any principle that negates time travel. Science has not found any particle interactions at the subatomic level that clearly prevent the formation of closed time loops.
The inevitable motion from past to future of time is akin to another natural law: Entropy. This is a law in thermodynamics that states that closed systems tend to change from order to disorder. There may be some relationship between time and entropy, Sutter predicts.
