How is travelling back in time possible?

There is a new concept that could possibly allow future generations to travel into the past. How? Well there are quite a few theories out there, all of them impractical. What’s different about this new concept? Well, it doesn’t require theoretical forms of matter to make it work. Nevertheless, the new concept requires a technology more advanced than ours so…it’s still impractical.So how is travelling back in time possible or rather, what’s the summary of the concept? Well, it is known that matter bends space and time. Therefore the idea would be to bend space/time (currently a seen as a line) so much that it will turn back on themeselves (forming a circle).For this though, the bending needs to be very strong and it would require a stronger force to do it.What I also find interesting about this concept is that if a time machine will be invented that will use the space/time bending theory, then no one from the future will be able to travel back to a time before the machine was invented. Why? Because when the time machine will first be operational, that is when the circle starts to form…get it?