I know there are solutions with CTC, I know about: 1. Goedel Universe 2. Case with moving infinite sticks 3. Ring singularity inside the rotating BH However, in all 3 cases above CTC is "eternal" - the universe "always" contains CTC, and case 3 is a part of the "eternal" BH, We know "realistic" BH are quite different, for example, there is no corresponding "white hole" part of the solution. So my question is, can we create CTC from nothing - having initially Universe without CTC and without high curvature (so notion of "global time" can be used in some sense, and we can say "at some TIME there were no CTCs) but trajectories of ideal dust are adjusted in a way that CTC is created somewhere at SOMETIME? Or are CTC always "eternal" and can't be created in any realistic scenario? And related question, depending on the answer above, does *realistic* Kerr BH have ring singularities inside? P.S. I know that QFT diverges near the CTC and (probably) prevents their formation, but my question is about "pure" GR.