Tipler cylinder

A Tipler cylinder is a cylinder of dense matter of infinite length, rotating about its longitudinal axis. This hypothetical object is theorized to allow time travel and is also called a Tipler time machine. While references to infinite length cylinders can be found in literature back to 1936, it was Frank Tipler in 1974 who recognized it would allow closed timelike curves and thus allow time travel. Tipler's solution was for a cylinder of infinite length. He suggested that a finite cylinder might produce closed timelike curves if the rotation rate were fast enough but he did not prove this. Stephen Hawking in his 1992 paper on the chronology protection conjecture posited that closed timelike curves cannot be created, and thus cannot be used for time travel. == Tipler cylinders in fiction == * John DeChancie's Starrigger series uses vertically-aligned Tipler cylinders (officially called Kerr-Tipler objects) to create spacetime gateways along an intergalactic highway.* Larry Niven wrote a short story, Rotating Cylinders and the Possibility of Global Causality Violation that borrowed its title from Tipler's paper. * Poul Anderson in The Avatar novel. * Vernor Vinge in the novel Marooned in Realtime, p. 174 (although the object is described as being a naked black hole).* Kris Straub's Starslip comic includes a Tipler cylinder created as a work of art (comic 569). *Ian Douglas in "Star Carrier Singularity" has a Tipler cylinder created by aliens of unknown origin == References == * Frank Jennings Tipler, Causality Violation in General Relativity, Ph.D. thesis at the University of Maryland, College Park (1976). Source: Dissertation Abstracts International, Vol. 37-06, Section B, pg. 2923. Also available as Dissertation 76-29,018 from Xerox University Microfilms, Ann Arbor, MI.* Penrose, Roger. "The Question of Cosmic Censorship." Journal of Astrophysics and Astronomy Vol. 20 (September, 1999): 233.* Wald, Robert (ed). Black Holes and Relativistic Stars. University of Chicago Press, 1998. ISBN 0-226-87034-0  Cilindru TiplerЦилиндр Типлера