Problem in Light: Scientists have declared that time travel to the past is impossible

Light is a fundamental phenomenon that we encounter in our daily lives, and despite its triviality, it constantly leads to unexpected discoveries when investigated more deeply.

One such surprise was a phenomenon related to the interaction between light and matter, namely what happens when light passes through matter such as glass or water. This phenomenon has already been studied, but the latest research, published in the journal Optica, found something unusual, writes IFLScience.

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When light interacts with matter, its speed changes and appears to slow down. Such a phenomenon can be explained by the standard wave equation. However, the wave equation does not explain what is happening exactly at the interface between light and matter, where the wave of light should be accelerating.

In the new study, the scientists proposed a new equation that describes the behavior of light in a universe with one spatial dimension and one time dimension. They hypothesized that the speed of light can vary with time and derived an accelerating wave equation. This solution may seem obscure at first glance, but it has important scientific content. The scientists used the known constant speed of light in a vacuum to get the correct results. Thus, they obtained correct solutions both at the boundary of the interaction between matter and light and on both sides of it. An important feature of this equation is that it assumes motion in one direction - forward.

According to the study, in terms of accelerating waves, there is a well-defined direction of time that is always only forward and never backward. This direction of time is determined by thermodynamics because in all isolated systems, entropy increases with time. Thus, the new equation confirms that the arrow of time always moves in one direction, forward, and this property is common to nature and obeys even light.

This study has important implications for the resolution of an ancient scientific dispute related to light, which is known as the Abraham-Minkowski controversy. That dispute is that scientists could not reach a single conclusion about how the electromagnetic pulse changes when light hits matter. The new study indicates that both statements - an increase and decrease in momentum - can be true, depending on the observer's point of view.

Thus, scientists have concluded that light waves may have their own time, similar to the general theory of relativity. This research goes beyond optics and may be important for understanding fundamental aspects of the universe. If the arrow of time is always pointing in the same direction, it could indicate that traveling back in time is impossible.

Earlier, scientists learned that cavemen could have fallen into hibernation.

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