• • • A wormhole is a concept that represents a: a non-trivial structure linking separate points in. A wormhole can be visualized as a tunnel with two ends, each at separate points in spacetime (i.e. Different locations or different points of time), or by a transcendental bijection of the spacetime continuum. Wormholes are consistent with the, but whether wormholes actually exist is not known.

A wormhole could connect extremely long distances such as a billion or more, short distances such as a few, different, or different points of time. Contents • • • • • • • • • • • • • • • • • • • Terminology [ ] In 1921, proposed a wormhole theory of matter in connection with mass analysis of energy; however, he did not use the term 'wormhole' (he spoke of 'one-dimensional tubes' instead). American (inspired by Weyl's work) coined the term 'wormhole' in a 1957 paper co-authored by: This analysis forces one to consider situations. Where there is a net flux of lines of force, through what would call 'a ' of the multiply-connected space, and what physicists might perhaps be excused for more vividly terming a 'wormhole'. — Charles Misner and John Wheeler in Modern definitions [ ] Wormholes have been defined both, [ ] Topological [ ] An intra-universe wormhole (a wormhole between two points in the same universe) is a region of spacetime whose boundary is topologically trivial, but whose interior is not. Formalizing this idea leads to definitions such as the following, taken from 's Lorentzian Wormholes (1996).

If a contains a compact region Ω, and if the topology of Ω is of the form Ω ~ R × Σ, where Σ is a three-manifold of the nontrivial topology, whose boundary has topology of the form ∂Σ ~ S 2, and if, furthermore, the Σ are all spacelike, then the region Ω contains a quasipermanent intrauniverse wormhole. Geometric [ ] Geometrically, wormholes can be described as regions of spacetime that constrain the incremental deformation of closed surfaces. For example, in Enrico Rodrigo's The Physics of Stargates, a wormhole is defined informally as: a region of spacetime containing a ' (the time evolution of a closed surface) that cannot be continuously deformed (shrunk) to a (the time evolution of a point). Development [ ].

'Embedding diagram' of a Schwarzschild wormholes [ ] The equations of the theory of have valid solutions that contain wormholes. The first type of wormhole solution discovered was the Schwarzschild wormhole, which would be present in the describing an eternal black hole, but it was found that it would collapse too quickly for anything to cross from one end to the other. Wormholes that could be crossed in both directions, known as, would only be possible if with negative could be used to stabilize them.

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An artist's impression of a wormhole from an observer's perspective, crossing the of a Schwarzschild wormhole that bridges two different universes. The observer originates from the right, and another universe becomes visible in the center of the wormhole's shadow once the horizon is crossed, the observer seeing light that has fallen into the interior region from the other universe; however, this other universe is unreachable in the case of a Schwarzschild wormhole, as the bridge always collapses before the observer has time to cross it, and everything that has fallen through the event horizon of either universe is inevitably crushed in the. Schwarzschild wormholes, also known as Einstein–Rosen bridges (named after and ), are connections between areas of space that can be modeled as to the, and that are now understood to be intrinsic parts of the version of the describing an eternal black hole with no charge and no rotation. Here, 'maximally extended' refers to the idea that the space-time should not have any 'edges': it should be possible to continue this path arbitrarily far into the particle's future or past for any possible trajectory of a free-falling particle (following a in the spacetime). In order to satisfy this requirement, it turns out that in addition to the black hole interior region that particles enter when they fall through the from the outside, there must be a separate interior region that allows us to extrapolate the trajectories of particles that an outside observer sees rising up away from the event horizon. And just as there are two separate interior regions of the maximally extended spacetime, there are also two separate exterior regions, sometimes called two different 'universes', with the second universe allowing us to extrapolate some possible particle trajectories in the two interior regions. This means that the interior black hole region can contain a mix of particles that fell in from either universe (and thus an observer who fell in from one universe might be able to see light that fell in from the other one), and likewise particles from the interior white hole region can escape into either universe.

All four regions can be seen in a spacetime diagram that uses. In this spacetime, it is possible to come up with such that if you pick a of constant time (a set of points that all have the same time coordinate, such that every point on the surface has a separation, giving what is called a 'space-like surface') and draw an 'embedding diagram' depicting the curvature of space at that time, the embedding diagram will look like a tube connecting the two exterior regions, known as an 'Einstein–Rosen bridge'. Note that the Schwarzschild metric describes an idealized black hole that exists eternally from the perspective of external observers; a more realistic black hole that forms at some particular time from a collapsing star would require a different metric. When the infalling stellar matter is added to a diagram of a black hole's history, it removes the part of the diagram corresponding to the white hole interior region, along with the part of the diagram corresponding to the other universe.

The Einstein–Rosen bridge was discovered by in 1916, a few months after Schwarzschild published his solution, and was rediscovered by Albert Einstein and his colleague Nathan Rosen, who published their result in 1935. However, in 1962, and published a paper showing that this type of wormhole is unstable if it connects two parts of the same universe, and that it will pinch off too quickly for light (or any particle moving slower than light) that falls in from one exterior region to make it to the other exterior region. According to general relativity, the of a sufficiently compact mass forms a singular Schwarzschild black hole. In the –Sciama–Kibble theory of gravity, however, it forms a regular Einstein–Rosen bridge.

This theory extends general relativity by removing a constraint of the symmetry of the and regarding its antisymmetric part, the, as a dynamical variable. Torsion naturally accounts for the quantum-mechanical, intrinsic angular momentum () of matter. The minimal coupling between torsion and generates a repulsive spin–spin interaction that is significant in fermionic matter at extremely high densities. Such an interaction prevents the formation of a gravitational singularity.

[ ] Instead, the collapsing matter reaches an enormous but finite density and rebounds, forming the other side of the bridge. Although Schwarzschild wormholes are not traversable in both directions, their existence inspired to imagine traversable wormholes created by holding the 'throat' of a Schwarzschild wormhole open with (material that has negative mass/energy). Other non-traversable wormholes include Lorentzian wormholes (first proposed by John Archibald Wheeler in 1957), wormholes creating a in a general relativistic spacetime manifold depicted by a, and Euclidean wormholes (named after, a structure of ). Traversable wormholes [ ] The shows that allows the energy density in certain regions of space to be negative relative to the ordinary, and it has been shown theoretically that quantum field theory allows states where energy can be arbitrarily at a given point. Many physicists, such as, and others, therefore argue that such effects might make it possible to stabilize a traversable wormhole. Physicists have not found any natural process that would be predicted to form a wormhole naturally in the context of general relativity, although the hypothesis is sometimes used to suggest that tiny wormholes might appear and disappear spontaneously at the, and stable versions of such wormholes have been suggested as candidates.

It has also been proposed that, if a tiny wormhole held open by a had appeared around the time of the, it could have been inflated to size. Further information: The impossibility of faster-than-light relative speed only applies locally. Wormholes might allow effective superluminal () travel by ensuring that the speed of light is not exceeded locally at any time. While traveling through a wormhole, subluminal (slower-than-light) speeds are used. If two points are connected by a wormhole whose length is shorter than the distance between them outside the wormhole, the time taken to traverse it could be less than the time it would take a light beam to make the journey if it took a path through the space outside the wormhole. However, a light beam traveling through the wormhole would of course beat the traveler. Time travel [ ].

Main article: The theory of general relativity predicts that if traversable wormholes exist, they can also alter the speed of time. They could allow. This would be accomplished by accelerating one end of the wormhole to a high velocity relative to the other, and then sometime later bringing it back; would result in the accelerated wormhole mouth aging less than the stationary one as seen by an external observer, similar to what is seen in the. However, time connects differently through the wormhole than outside it, so that at each mouth will remain synchronized to someone traveling through the wormhole itself, no matter how the mouths move around. This means that anything which entered the accelerated wormhole mouth would exit the stationary one at a point in time prior to its entry. For example, consider two clocks at both mouths both showing the date as 2000.

After being taken on a trip at relativistic velocities, the accelerated mouth is brought back to the same region as the stationary mouth with the accelerated mouth's clock reading 2004 while the stationary mouth's clock read 2012. A traveler who entered the accelerated mouth at this moment would exit the stationary mouth when its clock also read 2004, in the same region but now eight years in the past. Such a configuration of wormholes would allow for a particle's to form a closed loop in spacetime, known as a.

An object traveling through a wormhole could carry energy or charge from one time to another, but this would not violate conservation of energy or charge in each time, because the energy/charge of the wormhole mouth itself would change to compensate for the object that fell into it or emerged from it. It is thought that it may not be possible to convert a wormhole into a time machine in this manner; the predictions are made in the context of general relativity, but general relativity does not include quantum effects. Analyses using the approach to incorporating quantum effects into general relativity have sometimes indicated that a feedback loop of would circulate through the wormhole and pile up on themselves, driving the energy density in the region very high and possibly destroying it before any information could be passed through it, in keeping with the. The debate on this matter is described by in the book, and a more technical discussion can be found in The quantum physics of chronology protection.

There is also the, which is a configuration of more than one wormhole. This ring seems to allow a closed time loop with stable wormholes when analyzed using semiclassical gravity, although without a full theory of it is uncertain whether the semiclassical approach is reliable in this case.

Interuniversal travel [ ] A possible resolution to the paradoxes resulting from wormhole-enabled time travel rests on the of. In 1991 showed that quantum theory is fully consistent (in the sense that the so-called can be made free of discontinuities) in spacetimes with closed timelike curves. However, later it was shown that such model of closed timelike curve can have internal inconsistencies as it will lead to strange phenomena like distinguishing non orthogonal quantum states and distinguishing proper and improper mixture. Accordingly, the destructive positive feedback loop of virtual particles circulating through a wormhole time machine, a result indicated by semi-classical calculations, is averted. A particle returning from the future does not return to its universe of origination but to a parallel universe. This suggests that a wormhole time machine with an exceedingly short time jump is a theoretical bridge between contemporaneous parallel universes.

Because a wormhole time-machine introduces a type of nonlinearity into quantum theory, this sort of communication between parallel universes is consistent with 's proposal of an Everett phone (named after ) in 's formulation of nonlinear quantum mechanics. The possibility of communication between parallel universes has been dubbed interuniversal travel. Visualization [ ].

Contents • • • • • • • • • Biography [ ] Milne was born in, England, the only child of John Milne of, and at first raised in and later moved to Richmond near London. He was educated at (AKC in Applied Science, 1870) and the. Early career [ ] In the summers of 1873 and 1874, following a recommendation by the, Milne was hired by as a mining engineer to explore in search of coal and mineral resources. During this time he also wrote papers on the interaction of ice and rock, and visited, writing another paper on the newly extinct.

In December, 1873 Milne accompanied Dr. On an expedition to determine the true location of in northwest Arabia. He took the opportunity to study the geology of the and passed on a collection of fossils to the. Career in Japan (1875–1895) [ ].

Milne horizontal pendulum. Exhibit in the,,.

Milne was hired by the of the as a and professor of mining and geology at the in Tokyo from 8 March 1876, where he worked under and with and. Partly from a sense of adventure and partly because he suffered from, he travelled overland across taking three months to reach Tokyo. In 1880, Sir, and John Milne, all British scientists working in Japan, began to study following a very large tremor which struck the Yokohama area that year. They founded the (SSJ).

The society funded the invention of seismographs to detect and measure the strength of earthquakes. Although all three men worked as a team on the invention and use of seismographs, John Milne is generally credited with the invention of the horizontal pendulum in 1880. Milne's instruments permitted him to detect different types of, and estimate velocities. In addition, the foreign professors trained Japanese students including who would become, at the Imperial University, the first professor of seismology at any university in the world and his successor, who refined Milne's instruments to detect and record finer vibrations. Order of the Rising Sun [ ] In June, 1895, Milne was commanded to attend a meeting with His Imperial Majesty Emperor Mutsuhito and following this, returned to England. Soon after his arrival he learned that the Emperor had conferred upon him a rare distinction, The Third Grade of the and a life pension of 1,000 yen.

This was in recognition of Professor Milne's contributions to seismology during his long residence in Japan. Contributions to anthropology [ ] From 1882, Milne contributed also to. He helped to develop theories on the origin of the of northern Japan and on the prehistoric racial background of Japan in general. He excavated for several years in the and introduced the concept of the Koropok-guru race, linked with the. Koropok-guru is from an Ainu word meaning 'the man under the,' i.e. A small person. An Ainu legend concerning their existence seems first to have been reported by Milne.

But he believed their prehistoric sites to be only in. For northeastern Japan proper, he supported the tradition which ascribed prehistoric sites to the Ainu, who lived in pits and made stone implements and. He considered the inhabitants of the, and southern to be of a different race, but possibly related to the Koropok-guru. He anticipated the work of scientists who recognised, in excavated materials, different prehistoric cultures for Hokkaidō and northeastern Japan. Design Expert 6 0 8 Portable Tv. His first cousin (related through his mother, Emma Twycross) was also an anthropologist.

With his wife, Routledge worked in the early twentieth century in East Africa with the and on (). Career in England (1895–1913) [ ] After a fire on 17 February 1895 destroyed his home,, library, and many of his instruments. Milne resigned his posts on 20 June 1895 and returned to England with his Japanese wife, settling at Shide Hill House,, on the, where he continued his seismographic studies.

He was made a professor emeritus of. He was elected a in 1887 and persuaded the Society to fund 20 earthquake observatories around the world, equipped with his horizontal pendulum.

His network initially included seven in England, three in, two in (one in and one in Victoria ), three on the east coast of the United States, and one in, eventually growing to total 40 worldwide. These stations sent their 'station registers' to Milne, where the data formed the basis of Milne's researches. For the next 20 years, Milne’s seismological observatory was the world headquarters for earthquake seismology. In 1898, Milne (with ) published Earthquakes and Other Earth Movements, which came to be regarded as a classic textbook on earthquakes. The need for international exchange of readings was soon recognized by Milne in his annual 'Shide Circular Reports on Earthquakes' published from 1900 to 1912.

This work was destined to develop in the being set up immediately after the. He delivered the to the Royal Society in 1906 entitled Recent Advances in Seismology and was awarded their in 1908.

Milne died of on 31 July 1913 and is buried in. He had married Tone, daughter of Horikawa Noritsune, who returned in 1919 to Japan and died in 1926. To mark the one hundredth anniversary of Milne's death, a public artwork has been commissioned for Little London near the harbour at Newport. The local Parish Council is providing a detailed explanatory board at Shide. [ ] Notes [ ]. • Who's Who 1914, p.

Xxiii • • McKeegan, Alice (27 October 2007).. Retrieved 2008-04-22.

• John Milne: Considerations on the Flotation of Icebergs-Geological Magazine (Decade II) (1877), 4: 65–71 Cambridge University Press • Relics of the Great Auk on Funk Island, by John Milne. The Field, 27 March, 3, 10 April 1875. • Massachusetts Institute of Technology, • Gregory Clancey.

(Berkeley: University of California Press, 2006). • Otani, Shunsuke (2006).

'A Japanese View of the 1906 San Francisco Earthquake Disaster'. Earthquake Spectra, Earthquake Engineering Research Institute. 22: S183–S205. Herbert-Gustar and P.A.

Nott, biography of Milne John Milne, Father of Modern Seismology in 1980 pp 120 • Paul Kabrna ' John Milne – the Man who Mapped the Shaking Earth' Published by Craven & Pendle Geological Society in March 2007.pp68 • Nishioka •. Royal Society. Retrieved 2012-03-05. References [ ] • Clancy, Gregory. Earthquake Nation: The Cultural Politics of Japanese Seismicity, 1868–1930. Berkeley: University of California Press.; • Herbert-Gustar, A.

Leslie and Patrick A. John Milne, Father of Modern Seismology. Tenterden: Paul Norbury.; Japanese edition 1981 • Paul Kabrna ' John Milne – the Man who Mapped the Shaking Earth' Published by Craven & Pendle Geological Society in March 2007. • Nishioka, Hideo; W. Egbert Schenck. An Outline of Theories concerning the Prehistoric People of Japan. American Anthropologist © 1937 American Anthropological Association • Robert Stonely.

The History of the International Seismological Summary, Geophysical Journal Research (1970), 20, 343–349 • British Geological Survey:Scotland: A Catalogue of Archive Materials associated with John Milne.() • John Milne: The Miner's Handbook: A Handy Reference on the subjects of Mineral Deposits, Mining operations etc. 1894 () • John Milne: Earthquakes and other Earth Movements. - New York: D.

Appleton And Company, 1886. – 363 pages () • John Milne: Seismology 1898 – 348 pages () • John Milne: Considerations on the Flotation of Icebergs-Geological Magazine (Decade II) (1877), 4: 65–71 Cambridge University Press () • Prof. John Milne, F.G.S.of the Imperial College of Engineering,Tokio, Japan Quarterly Journal of the Geological Society; 1877; v. 33; issue.1–4; p. 929–931; On the Action of Coast-Ice on an Oscillating Area () • John Milne: Ice and Ice-work in Newfoundland:Geological Magazine, July, August, September, 1876.() • Seismological Journal of Japan, Volume 11, By John Milne, Nihon Jishin Gakkai (Japan).

Earthquake Effects, Emotional and Moral. () • Burton, W.K.; Ogawa, K; Milne, John (1894).. Yokohama, Japan: Lane, Crawford & Co.., with 30 Plates () • John Milne: The Prehistoric Remains of Japan, Notes on Stone Implements from Otaru and Hakodate, 1879 () • John Milne: The Stone Age in Japan; By John Milne, F.G.S.of the Imperial College of Engineering, Yedo, Japan.() • Yamashita,Shinji: Bosco,Joseph, Seymour Eades,Jeremy: The making of anthropology in East and Southeast Asia () • Seismological Journal of Japan, Jishin Gakkai. Articles by John Milne. Volumes 5, 8,12 (5 articles), 13,15,16(2 articles),17 (5 articles). Book digitized by Google and uploaded to the Internet Archive () • John Milne (1878). III.—Across Europe and Asia.—Travelling Notes.