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Jul7-11, 06:31 AM
P: 612
Quote Quote by byron178 View Post
do they exist in reality or in nature?
Closed timelike curves are predicted to exist around the ring singularity in Kerr-Newman metric-

though this is technically a hypothesis (CTCs) within a hypothesis (Cauchy horizon) within a theory (black hole/event horizon).

The CTCs are also within a boundary called the turnaround radius which some predict is supposed to send an infalling object out through a (very hypothetical) white hole- (page 23)

so even at this level of prediction, there seems to be some level of protection from reaching the CTCs (though a white hole would be just as elusive as CTCs, it's normally best to say that the Cauchy horizon is the barrier of predictability).