Time travel is a genre that has been popular in science fiction for years. This topic is indeed a favorite of many people because of its extraordinary ability if it can come true.
If time travel occurs, we can go back in time, change past events to prevent mass extinctions, for example. Or we can go to the future, to see what it would be like if humans managed to live on other planets.
Time travel sometimes sounds like a fairy tale or a lie that is far from reality. But time travel has a lot to do with science. This topic can be explained scientifically so that maybe in the future, humans can make it happen.
The scientific side of the concept of time
To understand how time travels from a scientific perspective, we must first understand how the concept of time is generally accepted.
Many say that time is constant, or not moving. But a well-known figure in the field of science, Albert Einstein, considered time an illusion, something relative. According to him, time can be different for each observer, depending on how fast the travel is in space.
For Einstein’s scientists, time has four dimensions. He explained that space is described as a three-dimensional area that has coordinates such as length, width and weight and can indicate location. Meanwhile, time has other coordinates, namely the direction that only moves forward.
His theory of special relativity says that time slows down or becomes faster depending on how fast we are moving relative to something.
If a person on a spaceship moves near the speed of light, he will age more slowly than his twin on Earth. This phenomenon is one of several phenomena that can occur in the human body in outer space.
Not only that, Einstein’s theory of general relativity also explains that gravity can change time.
Imagine a four-dimensional cloth called space-time. When something with mass inhabits the cloth, a space-time curve will occur. This is what causes objects to move along the curved path. This curvature is what we understand as gravity.
Through the Wormhole media
NASA once explained that the general theory of relativity also gave rise to scenarios that allow humans to travel back in time. But the equation may be very difficult to physically compute.
A person might be able to move faster than light, which is 299,792 km per second in a vacuum. However, Einstein’s equations show that an object moving at the speed of light will have an infinite mass and a length of Zero. This is physically impossible even though some scientists think otherwise.
And continued NASA also said that this possibility could create a wormhole between several points in space and time. But while Einstein’s equations allow it, it can only happen to very small particles. Scientists also haven’t really observed these wormholes because the technology required has to be very sophisticated.
Some Time Travel Theories
From Einstein’s advanced theory, we can in a sense conclude that closer time travel in extremely difficult directions becomes nearly impossible. However, there are several alternative theories that have emerged for humans to time travel.
- Tipler’s Cylinder
Frank Tipler, an astronomer, proposed a mechanism by which a person would have matter ten times the mass of the sun. Then it is rolled into a very long and dense cylinder.
After rotating it several billion times per minute, a spaceship that rotates around this cylinder will enter into a closed curve that resembles time. However, this method has many limitations, one of which is that the cylinder must have an infinite length.
There are other possibilities that time travel occurs. The trick is to quickly move the plane around the black hole. Or it could be creating similar conditions by using a very large rotating structure, resembling a black hole.
I once read of planes that would keep turning and passing only half the time that other people who were far from the black hole had traveled. Imagine if the plane circled the black hole for five years inside the black hole.
Out there time has passed for ten years. So when the plane returns, everyone will be five years older than those on the plane.
However, he also added that the crew on the plane must travel at the speed of light for this theory to work.
This means that if the theory of time travel uses a machine, for example a time machine, the machine will first destroy before it can spin fast.
The latter is a theory that has the potential for the realization of time travel, namely the cosmic string, a narrow, thread-like, thread-filled object that extends throughout the universe. This narrow section is believed to have formed in the early generations of the universe. It is thought that these threads had such a large mass that they could bend space-time around them.
Cosmic string theory is also believed by scientists to be in the form of an infinity or in the form of an endless circle. The meeting of two threads that are parallel to each other will change the spacetime into a certain configuration that can realize time travel.
All of this, of course, is only theoretical because until now there is no technology that can accommodate it. Scientists only partially agree with these theories.
Although it can be explained scientifically, not all scientists think time travel is possible. Some experts argue that the experiment itself could harm humans.
With the physics used by humans today, the topic of time travel is very likely to change over time.
Theories will continue to evolve so that one day humans can finally understand how time travel can be done.