Physicist Ron Mallett has been working on theories about time travel for decades. The professor of university of Connecticut recently said that he's written a theory that could serve as the foundation for an actual time machine.
He has even built a prototype device to illustrate his theory. The theory depends on Albert Einstein's theory of special relativity, which states that time accelerates or decelerates depending on the speed at which an object is moving.
Based on that theory, if a person was in a spaceship traveling near the speed of light, time would pass more slowly for them than it would for someone who remained on Earth. For the astronaut it will be like they had time traveled to the future. This theory is known for long. But time traveling to the past is a whole other issue and Mallett thinks he could solve using lasers. He said,
If you can bend space, there's a possibility of you twisting space. In Einstein's theory, what we call space also involves time - that is why it's called space time, whatever it is you do to space also happens to time.
According to his theory it is possible to twist time into a loop that would allow for time travel into the past. He's even built a prototype showing how lasers might help achieve this goal. Mallett added,
You can send information back. But you can only send it back to the point at which you turn the machine on.
But his peers remain unconvinced that his time machine will ever come to reality. Another astrophysicist Paul Sutter said,
I don't think his work is necessarily going to be fruitful, because I do think that there are deep flaws in his mathematics and his theory, and so a practical device seems unattainable.