Characteristics and consequences of the closed curve of type time
Normally the causality implies that each event in spacetime must be produced by a cause, taking how frame of reference the rest. This is a principle based on determinism, according to general relativity, which States that from the knowledge of the universe on a surface of Cauchy type space, it is possible to determine any later state of spacetime.
However, in one closed curve of type timethe law of causality is not met because an event can be simultaneous with its cause, so that the event would become its own cause.
Based only on the knowledge of the past, it would be impossible to determine if something exists in the closed curve of type time that it can interfere with other objects in the spacetime. So a closed curve of type time It is called Cauchy horizon, and a region of space-time where can not be predicted from a past event.
The existence of the closed curve of type time It would impose restrictions on the States of matter-energy physics fields. Many scientists have used the approach that, if we propagásemos the settings of a field along a family of closed universe lines of type time, I should get a State identical to the original, so that it would rule out the existence of the closed curve of type time.