Is Time Travel Possible? Exploring the Feasibility of Traversing the Past and Future

The concept of time travel, a favorite subject in many science fiction stories, has long captured the imagination of people around the world. However, is time travel feasible in reality? Specifically, can we travel to the past and come back to the time we left, or travel to the future and then return?

The Entropic Arrow of Time

In our universe, everything with substantial degrees of freedom, such as rocks, amoebas, people, and galaxy superclusters, is bound to its own unique “entropic arrow of time,” which advances with increasing entropy. This means that an object can only be affected by its past and not influence its past or travel into it. This concept was first articulated by astronomer and physicist Arthur Eddington in 1927.

Effects on Entropic Clocks

Hypothermia can slow our entropic clock, making us age slower compared to our friends for a while. Moving into a stronger gravitational field or even moving can slow down our entropic clock by a microsecond in a decade. However, this is not considered a form of time travel. To truly travel through time, one would need to travel at a significant fraction of the speed of light (c) for a considerable period. This would allow you to accumulate a significant amount of retarded time relative to your Earth-bound friends. However, this is a one-way trip, and you cannot travel back.

Impediments to Time Travel

We, as entropic beings, are essentially stuck moving with our entropic clock. Fundamental particles are non-entropic and are ubiquitous in terms of their timespan. However, practical limitations make it nearly impossible for us to reset these particles to an earlier time. To actually put ourselves into a different time in our universe, we would need to reset the entropic clocks of each entropic entity in our universe to their values at a different time. This would mean knowing and resetting every degree of freedom in our universe to its value at a specific time.

Science Fiction vs. Reality

Based on scientific understanding, time travel is considered impossible in both the forward and backward direction. Time can only move forward, and one cannot travel to an event that has not yet happened.

Practical Examples and Debates

One might wonder, “Of course we can, just watch “Back To The Future” 1, 2, and 3!” While these movies do showcase time travel, the reality is that it is extremely difficult to achieve. The logistics of finding and modifying a DeLorean, a car used in the films as a time machine, have made it a near impossible task.

On the other hand, some argue that time travel is not only possible, but it is unavoidable. We all travel forward in time at the same speed, and this is part of the very fabric of existence. If you were to travel in time, say, one hour into the past or the future, your body would essentially be left behind due to the Earth’s rotation and movement through space. Similar examples of what happens when you try to change the laws of physics are presented in the short story “The Billiard Ball” by Isaac Asimov.

Conclusion

While the concept of time travel continues to captivate us, scientific evidence and theoretical physics suggest that it remains an intriguing, albeit unattainable, idea. The reality of our universe is governed by the entropic arrow of time, and the practical obstacles to manipulating it are significant. Despite this, the possibility of time travel offers endless fascination and discussion in both science fiction and scientific discourse.