Space-Time Engineering

But this was supposed to be a conservative implementation, utilizing nothing more exotic than directed ultrarelativistic neutron stars.
Mitch Porter

This section deals with technology and science which uses the properties of space-time in novel ways, or actually changes the properties (like wormholes and basement universes ). These technologies are naturally very speculative at present, but the scientific results below give an inkling of what may be possible.

WORMHOLE: A postulated topological structure in general relativity, where a space-time "tunnel" links two distant points with a shortcut. Whether they can be physically realized is not known, and they seem to require exotic matter to be stable. If they can exist, and can be built, they could provide a possible way to travel faster than light (in a global sense, since locally the travellers would move slower than light). For more information, see Traversable Wormholes by Michael Clive Price.

Artificial gravity. A short description of the torus method of Robert Forward of creating (a rather weak) gravity field.

The gravitational wave rocket by W. B. Bonnor and M. S. Piper. In principle it ought to be possible to move a rocket using gravitational waves.

FTL - Faster Than Light Travel

Travelling faster than light is an old dream, complicated due to relativity and causality (FTL travel can cause causal loops in relativity). One way of achiving extreme speeds in general relativity is to employ suitable warps of spacetime, but the principal difficulties are severe. Another kind of solution is wormholes.

The Warp Drive: Hyper-Fast Travel Within General Relativity by Miguel Alcubierre (Class. Quantum Grav. 11 (1994), L73-L77). Demonstrates that by manipulating spacetime locally, a spaceship can move faster than light as measured by the rest of the universe.

Miguel Alcubierre
Department of Physics and Astronomy, University of Wales, College of Cardiff, PO Box 913, Cardiff CF1 3YB, UK

Abstract. It is shown how, within the framework of general relativity and without the introduction of wormholes, it is possible to modify a spacetime in a way that allows a spaceship to travel with an arbitrarily large speed. By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it, motion faster than the speed of light as seen by observers outside the disturbed region is possible. The resulting distortion is reminiscent of the `warp drive' of science fiction. However, just as happens with wormholes, exotic matter will be needed in order to generate a distortion of spacetime like the one discussed here.

"Class Quant Grav 11 (1994) 73-77 ISSN 0264-9381"

The Warp Drive: Hyper-Fast Travel Within General Relativity

Miguel Alcubierre
Class. Quantum Grav. 11 (1994), L73-L77.

Abstract:
It is shown how, within the framework of general relativity and without the introduction of wormholes, it is
possible to modify a spacetime in a way that allows a spaceship to travel with an arbitrarily large speed. By a
purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it, motion faster than the speed of light as seen by observers outside the disturbed region is possible. The resulting distortion is reminiscent of the ``warp drive'' of science fiction. However, just as it happens with wormholes, exotic matter will be needed in order to generate a distortion of spacetime like the one discussed here.

When we study special relativity we learn that nothing can travel faster than the speed of light. This fact is still true in general relativity, though in this case one must be somewhat more precise: in general relativity, nothing can travel faster than the speed of light. Since our everyday experience is based on an Euclidean space, it is natural to believe that if nothing can travel locally faster than light then given two places that are separated by a spatial proper distance, it is impossible to make a round trip between them in a time less than ..., (where ...., is the speed of light), as measured by an observer that remains always at the place of departure. Of course, from our knowledge of special relativity we know that the time measured by the person making the round trip can be made arbitrarily small if his (or her) speed approaches that of light. However, the fact that within the framework of general relativity and without the need to introduce non-trivial topologies (wormholes), one can actually make such a round trip in an arbitrarily short time as measured by an observer that remained at rest will probably come as a surprise to many people.

Hyper-fast interstellar travel in general relativity by S. V. Krasnikov. A paper that demonstrates some limitations on FTL travel.
Quantum effects in the Alcubierre warp drive spacetime by William A. Hiscock. Quantum effects seems to prevent the use of the Alcubierre drive due to divergence of the stress-energy tensor as lightspeed is approached.
The unphysical nature of "Warp Drive" by Michael J. Pfenning and L.H. Ford. Another major problem with the Alcubierre drive.
Superluminal travel requires negative energies by Ken D. Olum. Superluminal travel violates the weak energy condition (like most other stuff on this page).

Faster Than Light ? by J. E. Maiorino and W. A. Rodrigues Jr. Discusses some electromagnetic field configurations that appear to move faster than light, and how they relate to the principle of relativity.
A `warp drive' with more reasonable total energy requirements by Chris Van Den Broeck A way of making the Alcubierre warp more "physical" by exploiting a movable basement universe. He has another paper, On the (im)possibility of warp bubbles, that discusses some of the objections.

Warp factor one (Robert Matthews, New Scientist 12 June 1999). Popular explanation of Chris Van Den Broecks trick to enable low-energy warp spacetimes.

Dosya Biçimi: PDF/Adobe Acrobat - The model this whole positive energy warp drive is based upon is an assumption ... Walker Spacetimes, by Michael J. Pfenning and LH Ford, Physical Review D, ... [PDF] A Realistic Solution To Warp Drive Without Exotic Energy By: Paul ...

The Alcubierre Warp Drive in Higher Dimensional Spacetime

The Alcubierre Warp Drive in Higher Dimensional. Spacetime. H. G. White. 1. and E. W. Davis. 2. 1. 5231 Pilgrim Oaks Lane, League City, TX 77573, USA. 2. Inst. for Advanced Studies at Austi...

Time Travel

Time travel may appear even more outrageous than FTL, but both phenomena are closely linked to each other. Causal loops (Closed Timelike Curves, CTCs) exist in some solutions to general relativity. The question is whether they can occur in physically relevant spacetimes and how paradoxes are avoided.

Dosya Biçimi: PDF/Adobe Acrobat - So all we need for time travel, is a space ship that will go faster than light. Unfortunately, in ... might be able to warp it enough, to allow time travel. ...[PDF] Space and Time Warps This lecture is the intellectual property of ...

Dosya Biçimi: PDF/Adobe Acrobat - [PDF] Time travel: separating science fact from science fiction

While many physicists regard the subject of time travel as having no place in ... know time travel to be possible, but that it has been ...

Dosya Biçimi: PDF/Adobe Acrobat - [PDF] Wormholes and Time Travel? Not Likely
Wormholes and Time Travel? Not Likely. L. Susskind. Department of Physics. Stanford University. Stanford, CA 94305-4060. Abstract ...

Time Travel for Beginners by John Gribbin.

Çetin BAL: Time Travel Theory... IS TIME TRAVEL POSSIBLE?

Theory of Time Machine

Dosya Biçimi: PDF/Adobe Acrobat - [PDF] Zero Point Energy Gravity Physics

Of UFOs, Star Gates, Time Travel and Parallel Brane Worlds. A Pedagogical Introduction ... MUFON paper http://198.63.56.18/pdf/davis_mufon2001.pdf ...

Zeitreisen - wozu? - Eine Reise durch die Zeit unternimmt jeder von uns: in jedem Augenblick machen wir einen Schritt in die Zukunft. Doch sind wir fest an den stetigen Fluss der Zeit gebunden, wir können weder schneller vor geschweige denn zurück. Wer von uns hat nicht schon davon geträumt, einmal in die Zukunft zu reisen, um mit den Lottozahlen der nächsten Ziehungen zurück zu kehren und damit seinem Glück ein wenig nachzuhelfen?

Time Travel Physics : In this series of articles we will show a solution using a rotating cylinder model that demonstrates how time travel is possible within the context of general relativity.

Wormholes

Wormholes are shortcuts through spacetime, connecting two distant locations through a short "tunnel". They can exist in general relativity, but the main issue is whether they are traversable and possible to create.

Traversable Wormholes: Some Implications by Michael Clive Price. A very good introduction to the possibilities of wormholes.
Wormhole Warfare by Robin Hanson. A comment to the above text about the military implications of wormholes.
Wormholes in "The Alternate View" columns of John G. Cramer (Analog).

Technical Papers

Inflating Lorenzian Wormholes by Thomas A. Roman. A technical paper about the possibility of using inflation to turn a quantum wormhole macroscopic.
Can wormholes exist? by V.Khatsymovsky. Technical paper about the renormalized vacuum expectation values of electromagnetic stress-energy tensor in wormhole spacetimes. Apparently they can be stable.

The null energy condition in dynamic wormholes Authors: Hochberg, David; Visser, Matt

We extend previous proofs that violations of the null energy condition (NEC) are a generic and universal feature of traversable wormholes to completely non-symmetric time-dependent wormholes. We show that the analysis can be phrased purely in terms of local geometry at and near the wormhole throat, and do not have to make any technical assumptions about asymptotic flatness or other global properties. A key aspect of the analysis is the demonstration that time-dependent wormholes have two throats, one for each direction through the wormhole, and that the two throats coalesce only for the case of a static wormhole.

Dynamic wormholes and energy conditions by Wang, A ; Letelier, P S. Non static wormholes can obey the weak and dominant energy conditions.
Bubbles and wormholes: analytic models, by Wang, A ; Letelier, P S. Discusses spacetime bubbles and how wormholes could link them.The first junction conditions of spherically symmetric bubbles are solved for some cases, and whereby analytic models to the Einstein field equations are constructed. The effects of bubbles on the spacetime structure are studied and it is found that in some cases bubbles can close the spatial sector of the spacetime and turn it into a compact one, while in other cases they can give rise to wormholes. One of the most remarkable features of these wormholes is that they do not necessarily violate the weak and dominant energy condition even at the classical level.

Wormholes, Warp Travel, Time Travel

Time Travel Possibilities: It still is, but there might be a trick of hitching a ride on something that doesn't quite follow spacetime rules. The answer to this is what scientists call a wormhole.

PDF Files:
Towards possibility of self-maintained vacuum traversible wormhole by V. Khatsymovsky
Traversable wormholes: the Roman ring by Matt Visser. Apparently chronology protection can be fooled by more complex arrangements of wormholes.
Rotating traversable wormholes by Edward Teo.
Toward a Traversable Wormhole by S. V. Krasnikov

Basement Universes

According to some theories, it is possible to spawn new universes (i.e. independent volumes of spacetime) through various means. This could be used for a variety of things, such as computation or escape from a unsuitable spacetime.

Possible Implications of the Quantum Theory of Gravity, An Introduction to the Meduso-Anthropic Principle by Louis Crane. Nontechnical paper about how the activities of technological civilizations could influence the evolution of baby universes.

Warp Drive Propulsion : The Warp Drive works by creating a contraction in front of a spaceship and an expansion behind it, this method of warp drive was proposed in 1994 by Miguel Alcubierre.

Anti-gravity Propulsion Engine Levitation ....

Wurmlöcher sind Abkürzungen durch den Raum, die es Raumschiffen ermöglichen, eigentlich sehr große Entfernungen in relativ kurzer Zeit zurückzulegen. Sie bewegen sich zwar nicht mit größerer Geschwindigkeit, aber die zurückzulgende Entfernung bis zum Ziel wird durch das Wurmloch entscheidend verkürzt.

Warp Drive: A subsection of the general theory of relativity, which utilizes spacetime as a form of propulsion; which to an outside observer appears to yield Faster Than Light (FTL) travel. This page discusses the theoretical physics behind the basic physics warp drive which may yield possible mechanisms for interstellar travel.

CREATE NEGATIVE ENERGY : If Kerr rings prove to be lethal or too unstable for use as cosmic portals, an advanced civilization might instead contemplate opening up a new wormhole by using negative matter or negative energy. (In principle, negative matter or energy should weigh less than nothing and fall up rather than down. This is different stuff from antimatter, which contains positive energy and falls down.) In 1988 Kip Thorne and his colleagues at Caltech showed that with sufficient negative matter or negative energy, one could create a wormhole through which a traveler could freely pass back and forth between, say, his laboratory and a distant point in space or time.

Relativitätstheorie...

Viajar en el tiempo ¿Fantasía o realidad?: La Teoría General de la Relatividad indica que los cuerpos con masa distorsionan la estructura geométrica del espacio-tiempo.

Einstein and the Universe II: Einstein knew that his Special Theory of Relativity should be expanded to include gravity and in 1907 started to work on what would be later called his General Theory of Relativity.

The (Alcubierre) Warp Drive Spacetime: In order to do so one will need to construct an arbitrary function f as to produce the contraction/expansion metric proposed by the Alcubierre Spacetime.

Theoretical Warp Drive: - Devise a Way To Manipulate It: Even if scientists could transform matter into negative energy, they would still have to find a way to focus it and create an infinitesimally thin, yet extraordinarily stable, bubble of the stuff around the spaceship.

Negative Mass Warp Drive - Devised by Robert Heckadon: The negative mass drive has an advantage over conventional warp drive. Though initially slower than warp drive, with the use of the ship’s impulse engines the negative mass drive can constantly accelerate the ship until its fuel supply is exhausted. Whereas conventional warp has a maximum warp limit.

The Introduction of a Breakthrough in Advanced Interstellar Space Propulsion: In order to surmount the vast distance the entire method depends heavily on the relative relationship of electromagnetic fields to inertial frames of reference and the existance of a Unified Field throughout all Space/Time.

Teleportation as Interdimensional Travel: The 4^th dimension can also be used to help explain some of the more unusual phenomena that have been reported - that of teleportation.

Warp Drive FLASH-- Basic Sci-fi like interactive FLASH animation (for fun) of key Warp Drive principles with modern science [lcars show] (129 kb)

Warp Drive E-book [(742 Kb) PDF] Draft Manuscript by: Dr. Paul Hoiland and Edward Halerewicz, Jr. Hyperbolic Geometrodynamic Warp Drives & Beyond

WHAT IS THE UNIVERSE MADE OF? - ( PDF ) - JACK SARFATTI- The emergence of gravity and dark energy/matter from the cohering of zero point energy.Therefore, the original unrealistic Alcubierre toy model warp drive metric with a point-like unconventional flying object is too simplistic to be implemented by controlled partially coherent exotic vacuum zero point energy density. The zero-point energy powered warp drive metrics must be computed from scratch and this will be done in a future paper.

PROBLEMS WITH WARP DRIVE EXAMINED -Pdf -In a short examination of some of the major problems raised as objections to Doctor Alcubierres original proposal of warp drive within General Relativity(1) by many authors in both peer review publication and archive articles one discovers that solutions to these problems do exist if one is willing to consider a modified version of that original proposal. It is the findings of this Author that Warp Drive cannot be properly ruled out at this time at least as a possible future method of sub-light propulsion with the possible added benefit of working as a superluminal field propulsion drive.

Warp Drive Today: theory andlimitations - E. F. Halerewicz, Jr.[ Pdf ]

Engineering the Zero-Point Field and Polarizable Vacuum For Interstellar Flight -[ Pdf ] -H. E. Puthoff- A theme that has come to the fore in advanced planning for long-range space exploration is the concept of "propellantless propulsion" or "field propulsion." One version of this concept involves the projected possibility that empty space itself (the quantum vacuum, or space-time metric) might be manipulated so as to provide energy/thrust for future space vehicles.

Reduced total energy requirements for a modified Alcubierre warp drive spacetime -[ Pdf ]- E. Halerewicz, Jr - It can be shown that negative energy requirements within the Alcubierre spacetime can be greatly reduced when one introduces a lapse function into the Einstein tensor. Thereby reducing the negative energy requirements of the warp drive spacetime arbitrarily as a function of A(ct, ). With this function new quantum inequality restrictions are investigated in a general form. Finally a pseudo method for controlling a warp bubble at a velocity greater than that of light is presented.

An Assessment of Faster-Than-Light Spacetimes: Make or Break Issues -[ Pdf ] - Eric W. Davis - Implementation of faster-than-light (FTL) interstellar travel via traversable wormholes,warp drives, or other spacetime modification schemes generally requires the engineering of spacetime into very specialized local geometries. The analysis of these via Einstein’s General Theory of Relativity plus the resultant equations of state demonstrates that such geometries require the use of “exotic” matter. It has been claimed that since such matter violates the energy conditions FTL spacetimes are not plausible. However, it has been shown that this isa spurious issue. The identification, magnitude, and production of exotic matter is seen to be a key technical challenge, however. FTL spacetimes also possess features that challenge the notions of causality, and there are alleged constraints placed upon them by quantum effects.These issues are reviewed and summarized, and an assessment on the present state of their resolution is provided.

Der Warp-Antrieb: Nach dem Physiker Miguel Alcubierre kann der Raum zwischen dem Ziel und dem Objekt so zusammengezogen werden, dass man mit einem Schritt die Reise von ein paar Lichtjahren erledigen kann. Aber man muss auch den Raum vom Objekt zum Startpunkt entsprechend dehnen. Dies erfordert extrem viel Energie und wir wissen im Moment nicht, wie man das bewerkstelligen kann. Zusätzlich benötigt man exotische Materie.

Other Sites

Books

C W Misner, K S Throne, and J A Wheeler, Gravitation, (Freeman) UL QC 178.M57. The classic textbook.

Robert Forward, Indistinguishable from Magic, Pocket Books; ISBN: 0671876864 1995