Time travel has been completely ruled out for good by scientists

The concept of time traveling is one that has been debated many a year and one that has been explored in countless movies and TV shows.

While the likes of Back to the Future make it look pretty simple, time travel in real life is very much a different story.

And it appears that the current story will forever remain the same as scientists have essentially ruled out traveling back in time for good.

The assumption has been made from a well-established phenomenon: what happens when light passes through an interface? This could be anything from glass or water.

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While the solution to this has been well known for a long while, scientists have now found something rather peculiar going on in the middle.

As light goes through the interface, we know that speed often changes - though that doesn't explain what actually happens at the interface itself.

An equation has now been put forward in the case of a universe with one space dimension and one time dimension.

Lead author of the study assistant professor Matias Koivurova, from the University of Eastern Finland, said: "Basically, I found a very neat way to derive the standard wave equation in 1+1 dimensions. The only assumption I needed was that the speed of the wave is constant. Then I thought to myself: what if it’s not always constant? This turned out to be a really good question."

The team working on the study, which has been published in full in the journal Optica, delivered the expected solution on either side of the interface.

But there was one crucial requirement to achieving this... it needs time to only move forward.

While the equation may just be one dimensional, it has solved a long-standing controversy that has stumped scientists for many a year.

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Study lead Professor Marco Ornigotti explained: "There is this very famous debate in physics, which is called the Abraham-Minkowski controversy. The controversy is that when light enters a medium, what happens to its momentum? Minkowski said that the momentum increases, while Abraham insisted that it decreases.

"We found that we can ascribe a ‘proper time’ to the wave, which is entirely analogous to the proper time in the general theory of relativity."

While the results may be a major breakthrough, we can pretty much say goodbye to he possibility of time travelling into the past.

This is because if the arrow of time is always going in one direction, it would be impossible to go back in time.