Cosmic Time Machines: the Causality Issue
1 Dipartimento di Fisica e Astronomia, Università di Padova, I–35131 Padova, Italy
2 I.N.F.N. Istituto Nazionale di Fisica Nucleare, Sezione di Padova
a e-mail: email@example.com
Published online: 5 September 2013
Continued gravitational collapse gives rise to curvature singularities. If a curvature singularity is globally naked then the space-time may be causally future illbehaved admitting closed time-like or null curves which extend to asymptotic distances and generate a Cosmic Time Machine (de Felice (1995) Lecture Notes in Physics 455, 99 ). The existence of Cosmic Time Machines makes it plausible the violation of causality. I conjecture that this circumstance is prevented by some, yet unknown, physical process and show that such a mechanism indeed exists in the Kerr spacetime.
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