Tipler Cylinder
Tipler's Original Paper: Rotating cylinders and the possibility of global causality violation - tipler1974 pg. 1
A Tipler Cylinder uses a massive and long cylinder spinning around its longitudinal axis. The rotation creates a frame-dragging effect and fields of closed time-like curves traversable in a way to achieve subluminal time travel to the past.
Tipler’s cylinder has to be infinitely long.
The Tipler cylinder was discovered as a solution to the equations of general relativity by Willem Jacob van Stockum in 1936 and Kornel Lanczos in 1924, but not recognized as allowing closed timelike curves until an analysis by Frank Tipler in
Tipler showed in his 1974 paper, "Rotating Cylinders and the Possibility of Global Causality Violation"
CTC's are associated, in Lorentzian manifolds which are interpreted physically as spacetimes, with the possibility of causal anomalies such as going back in time
An objection to the practicality of building a Tipler cylinder was discovered by Stephen Hawking
it is impossible to build a time machine in any finite region that satisfies the weak energy condition, meaning that the region contains no exotic matter with negative energy.
Hawking's proof appears in his 1992 paper on the chronology protection conjecture,
