Jump to content

Tipler cylinder: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Removing some out-of-date templates
re-incorporating "in fiction" stuff added after the main article was massively trimmed, since I had reverted to a version before the trim
Line 10: Line 10:


* [[John DeChancie]]'s ''Starrigger'' series uses vertically-aligned Tipler cylinders (officially called [[Roy Kerr|Kerr]]-Tipler objects) to create spacetime gateways along an intergalactic highway.
* [[John DeChancie]]'s ''Starrigger'' series uses vertically-aligned Tipler cylinders (officially called [[Roy Kerr|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 (short story)|Rotating Cylinders and the Possibility of Global Causality Violation]] that borrowed its title from Tipler's paper.<ref>http://news.larryniven.org/biblio/display.asp?key=124</ref>
* [[Larry Niven]] wrote a [[short story]], "Rotating Cylinders and the Possibility of Global Causality Violation", that borrowed its title from Tipler's paper.<ref>{{cite web|url=http://news.larryniven.net/biblio/display.asp?key=124 |title=Larry Niven Bibliography |publisher=News.larryniven.net |date= |accessdate=2013-04-22}}</ref>
* [[Poul Anderson]] in ''The Avatar'' novel.<ref>Time Machines By Paul J. Nahin, page 95 [http://books.google.co.uk/books?pg=PA95&id=39KQY1FnSfkC]</ref>
* [[Poul Anderson]] in ''The Avatar'' novel.<ref>[http://books.google.co.uk/books?pg=PA95&id=39KQY1FnSfkC Time Machines By Paul J. Nahin, page 95]</ref>
* [[Vernor Vinge]] in the novel ''Marooned in Realtime'', [http://books.google.com/books?id=H1NOwjENGOkC&lpg=PP1&pg=PA174#v=onepage&q&f=false p. 174] (although the object is described as being a [[naked black hole]]).
* [[Vernor Vinge]] in the novel ''Marooned in Realtime'', [http://books.google.com/books?id=H1NOwjENGOkC&lpg=PP1&pg=PA174#v=onepage&q&f=false 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).<ref>{{cite web|url=http://starslip.com/2007/07/23/starslip-number-569/ |title=by Kris Straub - Starslip (number 569) |publisher=Starslip |date=2007-07-23 |accessdate=2013-04-22}}</ref>
*[[William H. Keith, Jr.|Ian Douglas]] in "Star Carrier Singularity" has a Tipler cylinder created by aliens of unknown origin
*[[Star Trek Online]] uses a device by the same name which gives the player the ability to reverse time several seconds within a localised field.[http://www.stowiki.org/Universal_Consoles#Tipler_Cylinder [4<nowiki>]</nowiki>] (The specificity of thirteen seconds of time reversal, along with the device having a beryllium core, are references to the science fiction comedy ''[[Galaxy Quest]]''.)


== References ==
== References ==
;Notes
{{Reflist}}
{{Reflist}}


;Bibliography
{{refbegin}}
{{refbegin}}
* Frank Jennings Tipler, [http://adsabs.harvard.edu/abs/1976PhDT........61T ''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.
# Frank Jennings Tipler, [http://adsabs.harvard.edu/abs/1976PhDT........61T ''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.
* [[Roger Penrose|Penrose, Roger]]. "The Question of Cosmic Censorship." ''Journal of Astrophysics and Astronomy'' Vol. 20 (September, 1999): 233.
# [[Roger Penrose|Penrose, Roger]]. "The Question of Cosmic Censorship." ''Journal of Astrophysics and Astronomy'' Vol. 20 (September, 1999): 233.
* [[Robert Wald|Wald, Robert]] (ed). ''Black Holes and Relativistic Stars''. [[University of Chicago]] Press, 1998. ISBN 0-226-87034-0
# [[Robert Wald|Wald, Robert]] (ed). ''Black Holes and Relativistic Stars''. [[University of Chicago]] Press, 1998. ISBN 0-226-87034-0
{{refend}}
{{refend}}


Line 28: Line 33:
[[Category:Physics in fiction]]
[[Category:Physics in fiction]]
[[Category:Time travel devices]]
[[Category:Time travel devices]]

[[ro:Cilindru Tipler]]
[[ru:Цилиндр Типлера]]

Revision as of 01:13, 10 January 2014

A Tipler cylinder, also called a Tipler time machine, was a hypothetical object theorized to be a potential mode of time travel— although later results have shown that a Tipler cylinder could only allow time travel if its length were infinite or with the existence of negative energy (see the discussion of Hawking's proof below).

The Tipler cylinder was discovered as a solution to the equations of general relativity by Willem Jacob van Stockum[1] in 1936 and Kornel Lanczos[2] in 1924, but not recognized as allowing closed timelike curves[3] until an analysis by Frank Tipler[4] in 1974. Tipler showed in his 1974 paper, "Rotating Cylinders and the Possibility of Global Causality Violation" that in a spacetime containing a massive, infinitely long cylinder which was spinning along its longitudinal axis, the cylinder should create a frame-dragging effect. This frame-dragging effect warps spacetime in such a way that the light cones of objects in the cylinder's proximity become tilted, so that part of the light cone then points backwards along the time axis on a space time diagram. Therefore a spacecraft accelerating sufficiently in the appropriate direction can travel backwards through time along a closed timelike curve or CTC.[4]

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 and potentially shooting your own grandfather, although paradoxes might be avoided using some constraint such as the Novikov self-consistency principle. They have an unnerving habit of appearing in some of the most important exact solutions in general relativity, including the Kerr vacuum (which models a rotating black hole) and the van Stockum dust (which models a cylindrically symmetrical configuration of rotating pressureless fluid or dust).

An objection to the practicality of building a Tipler cylinder was discovered by Stephen Hawking, who posited a conjecture showing that according to general relativity 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. The Tipler cylinder, on the other hand, does not involve any negative energy. Tipler's original solution involved a cylinder of infinite length, which is easier to analyze mathematically, and although Tipler suggested that a finite cylinder might produce closed timelike curves if the rotation rate were fast enough,[5] he did not prove this. But Hawking argues that because of his conjecture, "it can't be done with positive energy density everywhere! I can prove that to build a finite time machine, you need negative energy."[6] Hawking's proof appears in his 1992 paper on the chronology protection conjecture, where he examines "the case that the causality violations appear in a finite region of spacetime without curvature singularities" and proves that "[t]here will be a Cauchy horizon that is compactly generated and that in general contains one or more closed null geodesics which will be incomplete. One can define geometrical quantities that measure the Lorentz boost and area increase on going round these closed null geodesics. If the causality violation developed from a noncompact initial surface, the averaged weak energy condition must be violated on the Cauchy horizon."[7]

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.[8]
  • Poul Anderson in The Avatar novel.[9]
  • 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).[10]
  • Ian Douglas in "Star Carrier Singularity" has a Tipler cylinder created by aliens of unknown origin
  • Star Trek Online uses a device by the same name which gives the player the ability to reverse time several seconds within a localised field.[4] (The specificity of thirteen seconds of time reversal, along with the device having a beryllium core, are references to the science fiction comedy Galaxy Quest.)

References

Notes
  1. ^ van Stockum, Willem Jacob (1936). "The Gravitational Field of a Distribution of Particles Rotating about an Axis of Symmetry". Proceedings of the Royal Society of Edinburgh.
  2. ^ Lanczos, Kornel (1924, republished in 1997). "On a Stationary Cosmology in the Sense of Einsteins Theory of Gravitation". General Relativity and Gravitation. 29 (3). Springland Netherlands: 363–399. doi:10.1023/A:1010277120072. {{cite journal}}: Check date values in: |year= (help)CS1 maint: year (link)
  3. ^ Earman, John (1995). Bangs, Crunches, Whimpers, and Shrieks: Singularities and Acausalities in Relativistic Spacetimes. Oxford University Press. p. 21. ISBN 0-19-509591-X.
  4. ^ a b Tipler, Frank (1974). "Rotating Cylinders and the Possibility of Global Causality Violation". Physical Review D. 9 (8): 2203–2206. Bibcode:1974PhRvD...9.2203T. doi:10.1103/PhysRevD.9.2203. Archived from the original (PDF) on 2009-10-26. Available in GIF format here: pages 1, 2, 3 and 4. See also here.
  5. ^ Earman, John (1995). Bangs, Crunches, Whimpers, and Shrieks: Singularities and Acausalities in Relativistic Spacetimes. Oxford University Press. p. 169. ISBN 0-19-509591-X.
  6. ^ Hawking, Stephen (2002). The Future of Spacetime. W. W. Norton. p. 96. ISBN 0-393-02022-3.
  7. ^ Hawking, Stephen (1992). "Chronology protection conjecture". Physical Review D. 46 (2): 603–611. Bibcode:1992PhRvD..46..603H. doi:10.1103/PhysRevD.46.603.
  8. ^ "Larry Niven Bibliography". News.larryniven.net. Retrieved 2013-04-22.
  9. ^ Time Machines By Paul J. Nahin, page 95
  10. ^ "by Kris Straub - Starslip (number 569)". Starslip. 2007-07-23. Retrieved 2013-04-22.
Bibliography
  1. 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.
  2. Penrose, Roger. "The Question of Cosmic Censorship." Journal of Astrophysics and Astronomy Vol. 20 (September, 1999): 233.
  3. Wald, Robert (ed). Black Holes and Relativistic Stars. University of Chicago Press, 1998. ISBN 0-226-87034-0
Retrieved from "https://en.wikipedia.org/w/index.php?title=Tipler_cylinder&oldid=590007962"