Is Time Trouble Really Possible?

General relativity permits some act solutions that allow for time trouble. Some of these exact solutions describe universes that contain what's known as closed time like curves. These are world lines that lead back to the same point in space time. In this you can travel backwards in time, but not forwards. This is called a causal loop. But does it work that way? We still don't have the actual answers. So there is something about time travel. It's not entirely verboton. There are many unanswered s about causality and entrope.