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View Diary: Overnight News Digest: Drones And Such Edition (66 comments)

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  •  Tom Kibble (2+ / 0-)
    Recommended by:
    Larsstephens, maggiejean

    http://en.wikipedia.org/...

    EXCERPT

    Cosmic strings are hypothetical 1-dimensional (spatially) topological defects which may have formed during a symmetry breaking phase transition in the early universe when the topology of the vacuum manifold associated to this symmetry breaking was not simply connected. It is expected that at least one string per Hubble volume is formed. Their existence was first contemplated by the theoretical physicist Tom Kibble in the 1970s.

    The formation of cosmic strings is somewhat analogous to the imperfections that form between crystal grains in solidifying liquids, or the cracks that form when water freezes into ice. The phase transitions leading to the production of cosmic strings are likely to have occurred during the earliest moments of the universe's evolution, just after cosmological inflation, and are a fairly generic prediction in both Quantum field theory and String theory models of the Early universe.

    We're the first in the Constitution, the legislative branch, what we're supposed to do is legislate and not make up excuses as to why we don't. ~ Nancy Pelosi

    by anyname on Tue Feb 11, 2014 at 02:43:54 AM PST

    [ Parent ]

    •  stabilized with negative mass (2+ / 0-)
      Recommended by:
      Larsstephens, maggiejean

      http://www.crystalinks.com/...

      EXCERPT

      In physics and fiction, a wormhole is a hypothetical topological feature of spacetime that would be, fundamentally, a "shortcut" through spacetime. Although they are very popular in science fiction, there is no actual evidence that they exist. For a simple visual explanation of a wormhole, consider spacetime visualized as a two-dimensional (2-D) surface. If this surface is "folded" along a (non-existent) third dimension, it allows one to picture a wormhole "bridge". A wormhole is, in theory, much like a tunnel with two ends each in separate points in space-time.

      There is no observational evidence for wormholes, and, although wormholes are valid solutions in general relativity, this is only true if exotic matter can be used to stabilize them. Even if the wormhole is stabilized, the slightest fluctuation in space would collapse it. If such exotic matter (that is, matter with negative mass) does not exist, all wormhole-containing solutions to Einstein's field equations are vacuum solutions, which require an impossible vacuum, free of all matter and energy.

      There is no evidence or experimental suggestion that wormholes do exist, except as predictions of certain (exotic) physical models. Wormholes allowed by current physical theories might arise spontaneously, but would vanish nearly instantaneously, and would likely be undetectable.

      The American theoretical physicist John Archibald Wheeler coined the term wormhole in 1957; however, in 1921, the German mathematician Hermann Weyl already had proposed the wormhole theory, in connection with mass analysis of electromagnetic field energy.

      We're the first in the Constitution, the legislative branch, what we're supposed to do is legislate and not make up excuses as to why we don't. ~ Nancy Pelosi

      by anyname on Tue Feb 11, 2014 at 02:50:12 AM PST

      [ Parent ]

      •  J Richard Gott (2+ / 0-)
        Recommended by:
        Larsstephens, maggiejean
        Cosmic String

        We've blown through black holes and wormholes, but there's yet another possible means of time traveling via theoretic cosmic phenomena. For this scheme, we turn to physicist J. Richard Gott, who introduced the idea of cosmic string back in 1991. As the name suggests, these are stringlike objects that some scientists believe were formed in the early universe.

        These strings may weave throughout the entire universe, thinner than an atom and under immense pressure. Naturally, this means they'd pack quite a gravitational pull on anything that passes near them, enabling objects attached to a cosmic string to travel at incredible speeds and benefit from time dilation. By pulling two cosmic strings close together or stretching one string close to a black hole, it might be possible to warp space-time enough to create what's called a closed timelike curve.

        Using the gravity produced by the two cosmic strings (or the string and black hole), a spaceship theoretically could propel itself into the past. To do this, it would loop around the cosmic strings.

        Quantum strings are highly speculative, however. Gott himself said that in order to travel back in time even one year, it would take a loop of string that contained half the mass-energy of an entire galaxy. In other words, you'd have to split half the atoms in the galaxy to power your time machine. And, as with any time machine, you couldn't go back farther than the point at which the time machine was created.

        Oh yes, and then there are the time paradoxes.

        http://science.howstuffworks.com/...

        http://en.wikipedia.org/...

        J Richard Gott

        Exotic matter time travel theories

        http://www.dummies.com/...

        Cosmic strings are theoretical objects that predate string theory, but in recent years there’s been some speculation that they may actually be enlarged strings left over from the big bang, or possibly the result of branes colliding. There has also been speculation that they can be used to create a time machine.

        Regardless of their origin, if cosmic strings exist, they should have an immense amount of gravitational pull, and this means that they can cause frame dragging. In 1991, J. Richard Gott (who, with William Hiscock, solved Einstein’s field equations for cosmic strings in 1985) realized that two cosmic strings could actually allow time travel.

        The way this works is that two cosmic strings cross paths with each other in a certain way, moving at very high speeds. A spaceship traveling along the curves could take a very precise path (several of which were worked out by Curt Cutler in the months after Gott’s publication) and arrive at its starting position, in both space and time, allowing for travel in time.

        Like other time machines, the spaceship couldn’t travel further back than when the cosmic strings originally got in position to allow the travel — in essence, the time travel is limited to when the cosmic string time machine was activated.

        Gott’s was the second time machine (following Kip Thorne’s) to have been published in a major journal in the early 1990s, and it sparked a wave of work in the area. In May 1991, Gott was featured in Time magazine.

        In the summer of 1992, physicists held a conference on time travel at the Aspen Center for Physics (the same place where, nearly a decade earlier, John Schwartz and Michael Green had determined that string theory could be consistent).

        When Gott proposed this model, cosmic strings were believed to have nothing to do with string theory. In recent years, physicists have grown to believe that cosmic strings, if they exist, may actually be very closely related to string theory.

        We're the first in the Constitution, the legislative branch, what we're supposed to do is legislate and not make up excuses as to why we don't. ~ Nancy Pelosi

        by anyname on Tue Feb 11, 2014 at 03:06:50 AM PST

        [ Parent ]

        •  Asoen Center For Physics (1+ / 0-)
          Recommended by:
          maggiejean

          http://aspenphys.org/...

          2014

          EXCERPT

          Strongly interacting quantum systems exhibit an astonishing variety of emergent behaviors, the study of which has long been central to many branches of physics and materials science.

          In recent years, many of the most intensive studies have been motivated by the discovery of various materials, which exhibit unconventional superconductivity, along with a variety of electronic phases with unusual broken symmetries, and/or behavior beyond the expectations of conventional Fermi–liquid theory.

          The problems involved are deep and important. The reasons for designing a workshop in this general area are to assess the progress made in the past year or two and to search for promising new directions.

          This conference will focus on recent advances in the understanding of unconventional forms of electronic order – both superconducting and non–superconducting.

          We're the first in the Constitution, the legislative branch, what we're supposed to do is legislate and not make up excuses as to why we don't. ~ Nancy Pelosi

          by anyname on Tue Feb 11, 2014 at 03:14:49 AM PST

          [ Parent ]

        •  Curt Cutler (1+ / 0-)
          Recommended by:
          maggiejean

          http://www.stanford.edu/...

          LISA and Cosmic (super-) Strings

          By Curt Cutler

          Jet Propulsion Laboratory, CA Institute of Technology

          We're the first in the Constitution, the legislative branch, what we're supposed to do is legislate and not make up excuses as to why we don't. ~ Nancy Pelosi

          by anyname on Tue Feb 11, 2014 at 03:21:50 AM PST

          [ Parent ]

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