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  • richardmitnick 7:11 am on November 27, 2017 Permalink | Reply
    Tags: , , Wormholes   

    From Ethan Siegel: “How Traveling Back In Time Could Really, Physically Be Possible” 

    From Ethan Siegel

    Nov 21, 2017

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    The idea of traveling back in time has long fascinated humans, such as in Back To The Future’s Delorean DMC-12. After decades of research, we may have hit upon a solution that’s physically possible. Image credit: Ed g2s of Wikimedia Commons.

    And you don’t even need a Delorean at 88 MPH.

    It’s one of the greatest tropes in movies, literature, and television shows: the idea that we could travel back in time to alter the past. From the time turner in Harry Potter to Back To The Future to Groundhog Day, traveling back in time provides us with the possibility of righting wrongs in our own past. To most people, it’s an idea that’s relegated to the realm of fiction, as every law of physics indicates that motion forward through time is an absolute necessity. Philosophically, there’s also a famous paradox that seems to indicate the absurdity of such a possibility: if traveling backwards through time were possible, you’d be able to go back and kill your grandfather before your parents were ever conceived, rendering your own existence impossible. For a long time, there seemed to be no way to go back. But thanks to some very interesting properties of space and time in Einstein’s General Relativity, traveling back in time may be possible after all.

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    An illustration of the early Universe as consisting of quantum foam, where quantum fluctuations are large, varied, and important on the smallest of scales. Positive and negative energy fluctuations can create minuscule, quantum wormholes. Image credit: NASA/CXC/M.Weiss.

    The place to start is with the physical idea of a wormhole. In our known Universe, we have tiny, minuscule quantum fluctuations in the fabric of spacetime on the smallest of scales. These include energy fluctuations in both the positive and negative directions, often very close by one another. A very strong, dense, positive energy fluctuation would create curved space in one particular fashion, while a strong, dense, negative energy fluctuation would curve space in exactly the opposite fashion. If you connected these two curvature regions together, you could — for a brief instant — arrive at the notion of a quantum wormhole. If the wormhole lasted for long enough, you could even potentially transport a particle through it, allowing it to instantly disappear from one location in spacetime and reappear in another.

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    Exact mathematical plot of a Lorentzian wormhole. If one end of a wormhole is built out of positive mass/energy, while the other is built of negative mass/energy, the wormhole can become traversible. Image credit: Wikimedia Commons user Kes47.

    If we want to scale that up, however, to allow something like a human being through, that’s going to take some work. While every known particle in our Universe has positive energy and either positive or zero mass, it’s eminently possible to have negative mass/energy particles in the framework of General Relativity. Sure, we haven’t discovered any yet, but according to all the rules of theoretical physics, there’s nothing forbidding it.

    If this negative mass/energy matter exists, then creating both a supermassive black hole and the negative mass/energy counterpart to it, while then connecting them, should allow for a traversible wormhole. No matter how far apart you took these two connected objects from one another, if they had enough mass/energy — of both the positive and negative kind — this instantaneous connection would remain. All of that is great for instantaneous travel through space. But what about time? Here’s where the laws of special relativity come in.

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    A “light clock” will appear to run different for observers moving at different relative speeds, but this is due to the constancy of the speed of light. Einstein’s law of special relativity governs how these time and distance transformations take place, but it means that the stationary and the moving parties age at different rates. Image credit: John D. Norton, via http://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/Special_relativity_clocks_rods/.

    If you travel close to the speed of light, you experience a phenomenon known as time dilation. Your motion through space and your motion through time are related by the speed of light: the greater your motion through space, the less your motion through time. Imagine you had a destination that was 40 light years away, and you were able to travel at incredibly high speeds: over 99.9% the speed of light. If you got into a spaceship and traveled very close to the speed of light towards that star, then stopped, turned around, and returned back to Earth, you’d find something odd.

    Due to time dilation and length contraction, you might reach your destination in only a year, and then come back in just another year. But back on Earth, 82 years would have passed. Everyone you know would have aged tremendously. This is the standard way time travel physically works: it takes you into the future, with the amount of travel forward in time dependent only on your motion through space.

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    Is time travel possible? With a large enough wormhole, such as one created by a supermassive black hole connected to its negative mass/energy counterpart, it just might be. Image credit: Wikimedia Commons user Kjordand.

    But if you construct a wormhole like we just described, the story changes. Imaging one end of the wormhole remains close to motionless, such as remaining close to Earth, while the other one goes off on a relativistic journey close to the speed of light. You then enter the rapidly-moving end of the wormhole after it’s been in motion for perhaps a year. What happens?

    Well, a year isn’t the same for everyone, particularly if they’re moving through time and space differently! If we talk about the same speeds as we did earlier, the “in motion” end of the wormhole would have aged 40 years, but the “at rest” end would only have aged by 1 year. Step into the relativistic end of the wormhole, and you arrive back on Earth only one year after the wormhole was created, while you yourself may have had 40 years of time to pass.

    If, 40 years ago, someone had created such a pair of entangled wormholes and sent them off on this journey, it would be possible to step into one of them today, in 2017, and wind up back in time at the mouth of the other one… back in 1978. The only issue is that you yourself couldn’t also have been at that location back in 1978; you needed to be with the other end of the wormhole, or traveling through space to try and catch up with it.

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    Warp travel, as envisioned for NASA. If you created a wormhole between two points in space, with one mouth moving relativistically relative to the other, observers at either traversible end would have aged by vastly different amounts. Image credit: NASA / Digital art by Les Bossinas (Cortez III Service Corp.), 1998.

    Satisfyingly, we discover that this form of time travel also forbids the grandfather paradox! Even if the wormhole were created before your parents were conceived, there’s no way for you to exist at the other end of the wormhole early enough to go back and find your grandfather prior to that critical moment. The best you can do is to put your newborn father and mother on a ship to catch the other end of the wormhole, have them live, age, conceive you, and then send yourself back through the wormhole. You’ll be able to meet your grandfather when he’s still very young — perhaps even younger than you are now — but it will still, by necessity, occur at a moment in time after your parents were born.

    A great many unusual things become possible in the Universe if negative mass/energy is real, abundant, and controllable, but traveling backwards in time might be the wildest one we’ve ever imagined. Owing to the oddities of both special and general relativity, time travel to the past might not be forbidden after all!

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 3:21 pm on November 26, 2017 Permalink | Reply
    Tags: Einstein, ER - for Einstein-Rosen bridges, ER = EPR - (the EPR paradox named for its authors - Einstein Boris Podolsky and Nathan Rosen), Eventually Susskind — in a discovery that shocked even him — realized (with Gerard ’t Hooft) that all the information that fell down the hole was actually trapped on the black hole’s two-dimen, , , , , , The particles still inside the hole would be directly connected to particles that left long ago, Wormholes   

    From Quanta: “Wormholes Untangle a Black Hole Paradox” 2015 but Worth It. 

    Quanta Magazine
    Quanta Magazine

    April 24, 2015
    K.C. Cole

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    Hannes Hummel for Quanta Magazine

    One hundred years after Albert Einstein developed his general theory of relativity, physicists are still stuck with perhaps the biggest incompatibility problem in the universe. The smoothly warped space-time landscape that Einstein described is like a painting by Salvador Dalí — seamless, unbroken, geometric. But the quantum particles that occupy this space are more like something from Georges Seurat: pointillist, discrete, described by probabilities. At their core, the two descriptions contradict each other. Yet a bold new strain of thinking suggests that quantum correlations between specks of impressionist paint actually create not just Dalí’s landscape, but the canvases that both sit on, as well as the three-dimensional space around them. And Einstein, as he so often does, sits right in the center of it all, still turning things upside-down from beyond the grave.

    Like initials carved in a tree, ER = EPR, as the new idea is known, is a shorthand that joins two ideas proposed by Einstein in 1935. One involved the paradox implied by what he called “spooky action at a distance” between quantum particles (the EPR paradox, named for its authors, Einstein, Boris Podolsky and Nathan Rosen). The other showed how two black holes could be connected through far reaches of space through “wormholes” (ER, for Einstein-Rosen bridges). At the time that Einstein put forth these ideas — and for most of the eight decades since — they were thought to be entirely unrelated.

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    When Einstein, Podolsky and Rosen published their seminal paper pointing out puzzling features of what we now call entanglement, The New York Times treated it as front-page news. The New York Times

    But if ER = EPR is correct, the ideas aren’t disconnected — they’re two manifestations of the same thing. And this underlying connectedness would form the foundation of all space-time. Quantum entanglement — the action at a distance that so troubled Einstein — could be creating the “spatial connectivity” that “sews space together,” according to Leonard Susskind, a physicist at Stanford University and one of the idea’s main architects. Without these connections, all of space would “atomize,” according to Juan Maldacena, a physicist at the Institute for Advanced Study in Princeton, N.J., who developed the idea together with Susskind. “In other words, the solid and reliable structure of space-time is due to the ghostly features of entanglement,” he said. What’s more, ER = EPR has the potential to address how gravity fits together with quantum mechanics.

    Not everyone’s buying it, of course (nor should they; the idea is in “its infancy,” said Susskind). Joe Polchinski, a researcher at the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara, whose own stunning paradox about firewalls in the throats of black holes triggered the latest advances, is cautious, but intrigued. “I don’t know where it’s going,” he said, “but it’s a fun time right now.”

    The Black Hole Wars

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    Juan Maldacena at the Institute for Advanced Study in Princeton, N.J. Andrea Kane/Institute for Advanced Study

    The road that led to ER = EPR is a Möbius strip of tangled twists and turns that folds back on itself, like a drawing by M.C. Escher.

    A fair place to start might be quantum entanglement. If two quantum particles are entangled, they become, in effect, two parts of a single unit. What happens to one entangled particle happens to the other, no matter how far apart they are.

    Maldacena sometimes uses a pair of gloves as an analogy: If you come upon the right-handed glove, you instantaneously know the other is left-handed. There’s nothing spooky about that. But in the quantum version, both gloves are actually left- and right-handed (and everything in between) up until the moment you observe them. Spookier still, the left-handed glove doesn’t become left until you observe the right-handed one — at which moment both instantly gain a definite handedness.

    Entanglement played a key role in Stephen Hawking’s 1974 discovery that black holes could evaporate. This, too, involved entangled pairs of particles. Throughout space, short-lived “virtual” particles of matter and anti-matter continually pop into and out of existence. Hawking realized that if one particle fell into a black hole and the other escaped, the hole would emit radiation, glowing like a dying ember. Given enough time, the hole would evaporate into nothing, raising the question of what happened to the information content of the stuff that fell into it.

    But the rules of quantum mechanics forbid the complete destruction of information. (Hopelessly scrambling information is another story, which is why documents can be burned and hard drives smashed. There’s nothing in the laws of physics that prevents the information lost in a book’s smoke and ashes from being reconstructed, at least in principle.) So the question became: Would the information that originally went into the black hole just get scrambled? Or would it be truly lost? The arguments set off what Susskind called the “black hole wars,” which have generated enough stories to fill many books. (Susskind’s was subtitled My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics.)

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    Leonard Susskind at home in Palo Alto, Calif. Jeff Singer

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    Stephen Hawking. No image credit

    Eventually Susskind — in a discovery that shocked even him — realized (with Gerard ’t Hooft) that all the information that fell down the hole was actually trapped on the black hole’s two-dimensional event horizon, the surface that marks the point of no return. The horizon encoded everything inside, like a hologram. It was as if the bits needed to re-create your house and everything in it could fit on the walls. The information wasn’t lost — it was scrambled and stored out of reach.

    Susskind continued to work on the idea with Maldacena, whom Susskind calls “the master,” and others. Holography began to be used not just to understand black holes, but any region of space that can be described by its boundary. Over the past decade or so, the seemingly crazy idea that space is a kind of hologram has become rather humdrum, a tool of modern physics used in everything from cosmology to condensed matter. “One of the things that happen to scientific ideas is they often go from wild conjecture to reasonable conjecture to working tools,” Susskind said. “It’s gotten routine.”

    Holography was concerned with what happens on boundaries, including black hole horizons. That left open the question of what goes on in the interiors, said Susskind, and answers to that “were all over the map.” After all, since no information could ever escape from inside a black hole’s horizon, the laws of physics prevented scientists from ever directly testing what was going on inside.

    Then in 2012 Polchinski, along with Ahmed Almheiri, Donald Marolf and James Sully, all of them at the time at Santa Barbara, came up with an insight so startling it basically said to physicists: Hold everything. We know nothing.

    The so-called AMPS paper (after its authors’ initials) presented a doozy of an entanglement paradox — one so stark it implied that black holes might not, in effect, even have insides, for a “firewall” just inside the horizon would fry anyone or anything attempting to find out its secrets.

    Scaling the Firewall

    Here’s the heart of their argument: If a black hole’s event horizon is a smooth, seemingly ordinary place, as relativity predicts (the authors call this the “no drama” condition), the particles coming out of the black hole must be entangled with particles falling into the black hole. Yet for information not to be lost, the particles coming out of the black hole must also be entangled with particles that left long ago and are now scattered about in a fog of Hawking radiation. That’s one too many kinds of entanglements, the AMPS authors realized. One of them would have to go.

    The reason is that maximum entanglements have to be monogamous, existing between just two particles. Two maximum entanglements at once — quantum polygamy — simply cannot happen, which suggests that the smooth, continuous space-time inside the throats of black holes can’t exist. A break in the entanglement at the horizon would imply a discontinuity in space, a pileup of energy: the “firewall.”


    Video: David Kaplan explores one of the biggest mysteries in physics: the apparent contradiction between general relativity and quantum mechanics. Filming by Petr Stepanek. Editing and motion graphics by MK12. Music by Steven Gutheinz.

    The AMPS paper became a “real trigger,” said Stephen Shenker, a physicist at Stanford, and “cast in sharp relief” just how much was not understood. Of course, physicists love such paradoxes, because they’re fertile ground for discovery.

    Both Susskind and Maldacena got on it immediately. They’d been thinking about entanglement and wormholes, and both were inspired by the work of Mark Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, who had conducted a pivotal thought experiment suggesting that entanglement and space-time are intimately related.

    “Then one day,” said Susskind, “Juan sent me a very cryptic message that contained the equation ER = EPR. I instantly saw what he was getting at, and from there we went back and forth expanding the idea.”

    Their investigations, which they presented in a 2013 paper, “Cool Horizons for Entangled Black Holes,” argued for a kind of entanglement they said the AMPS authors had overlooked — the one that “hooks space together,” according to Susskind. AMPS assumed that the parts of space inside and outside of the event horizon were independent. But Susskind and Maldacena suggest that, in fact, particles on either side of the border could be connected by a wormhole. The ER = EPR entanglement could “kind of get around the apparent paradox,” said Van Raamsdonk. The paper contained a graphic that some refer to half-jokingly as the “octopus picture” — with multiple wormholes leading from the inside of a black hole to Hawking radiation on the outside.

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    The ER = EPR idea posits that entangled particles inside and outside of a black hole’s event horizon are connected via wormholes. Olena Shmahalo/Quanta Magazine.

    In other words, there was no need for an entanglement that would create a kink in the smooth surface of the black hole’s throat. The particles still inside the hole would be directly connected to particles that left long ago. No need to pass through the horizon, no need to pass Go. The particles on the inside and the far-out ones could be considered one and the same, Maldacena explained — like me, myself and I. The complex “octopus” wormhole would link the interior of the black hole directly to particles in the long-departed cloud of Hawking radiation.

    Holes in the Wormhole

    No one is sure yet whether ER = EPR will solve the firewall problem. John Preskill, a physicist at the California Institute of Technology in Pasadena, reminded readers of Quantum Frontiers, the blog for Caltech’s Institute for Quantum Information and Matter, that sometimes physicists rely on their “sense of smell” to sniff out which theories have promise. “At first whiff,” he wrote, “ER = EPR may smell fresh and sweet, but it will have to ripen on the shelf for a while.”

    Whatever happens, the correspondence between entangled quantum particles and the geometry of smoothly warped space-time is a “big new insight,” said Shenker. It’s allowed him and his collaborator Douglas Stanford, a researcher at the Institute for Advanced Study, to tackle complex problems in quantum chaos through what Shenker calls “simple geometry that even I can understand.”

    To be sure, ER = EPR does not yet apply to just any kind of space, or any kind of entanglement. It takes a special type of entanglement and a special type of wormhole. “Lenny and Juan are completely aware of this,” said Marolf, who recently co-authored a paper describing wormholes with more than two ends. ER = EPR works in very specific situations, he said, but AMPS argues that the firewall presents a much broader challenge.

    Like Polchinski and others, Marolf worries that ER = EPR modifies standard quantum mechanics. “A lot of people are really interested in the ER = EPR conjecture,” said Marolf. “But there’s a sense that no one but Lenny and Juan really understand what it is.” Still, “it’s an interesting time to be in the field.”

    See the full article here .

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    Formerly known as Simons Science News, Quanta Magazine is an editorially independent online publication launched by the Simons Foundation to enhance public understanding of science. Why Quanta? Albert Einstein called photons “quanta of light.” Our goal is to “illuminate science.” At Quanta Magazine, scientific accuracy is every bit as important as telling a good story. All of our articles are meticulously researched, reported, edited, copy-edited and fact-checked.

     
  • richardmitnick 12:34 pm on December 5, 2015 Permalink | Reply
    Tags: , , UAB, Wormholes   

    From UAB: “Magnetic wormhole created for first time” 

    UAB bloc

    Universitat Autònoma de Barcelona

    25/08/2015

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    Experimental magnetic wormhole

    Wormholes are cosmic tunnels that can connect two distant regions of the universe, and have been popularised by the dissemination of theoretical physics and by works of science fiction like Stargate, Star Trek or, more recently, Interstellar. Using present-day technology it would be impossible to create a gravitational wormhole, as the field would have to be manipulated with huge amounts of gravitational energy, which no-one yet knows how to generate. In electromagnetism, however, advances in metamaterials and invisibility have allowed researchers to put forward several designs to achieve this.

    Scientists in the Department of Physics at the Universitat Autònoma de Barcelona have designed and created in the laboratory the first experimental wormhole that can connect two regions of space magnetically. This consists of a tunnel that transfers the magnetic field from one point to the other while keeping it undetectable – invisible – all the way.

    The researchers used metamaterials and metasurfaces to build the tunnel experimentally, so that the magnetic field from a source, such as a magnet or a an electromagnet, appears at the other end of the wormhole as an isolated magnetic monopole. This result is strange enough in itself, as magnetic monopoles – magnets with only one pole, whether north or south – do not exist in nature. The overall effect is that of a magnetic field that appears to travel from one point to another through a dimension that lies outside the conventional three dimensions.

    The wormhole in this experiment is a sphere made of different layers: an external layer with a ferromagnetic surface, a second inner layer, made of superconducting material, and a ferromagnetic sheet rolled into a cylinder that crosses the sphere from one end to the other. The sphere is made in such a way as to be magnetically undetectable – invisible, in magnetic field terms – from the exterior.

    The magnetic wormhole is an analogy of gravitational ones, as it “changes the topology of space, as if the inner region has been magnetically erased from space”, explains Àlvar Sánchez, the lead researcher.

    These same researchers had already built a magnetic fibre in 2014: a device capable of transporting the magnetic field from one end to the other. This fibre was, however, detectable magnetically. The wormhole developed now, though, is a completely three-dimensional device that is undetectable by any magnetic field.

    This means a step forward towards possible applications in which magnetic fields are used: in medicine for example. This technology could, for example, increase patients’ comfort by distancing them from the detectors when having MRI scans in hospital, or allow MRI images of different parts of the body to be obtained simultaneously.

    This study, published in Scientific Reports, involved the UAB Department of Physics researchers Jordi Prat, Carles Navau and Àlvar Sánchez, who is also a lecturer at ICREA Academy.

    See the full article here .

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    UAB campus

    The Autonomous University of Barcelona also known as UAB (Catalan: Universitat Autònoma de Barcelona; Spanish: Universidad Autónoma de Barcelona) is a public university mostly located in Cerdanyola del Vallès, near the city of Barcelona in Catalonia, Spain.

    As of 2012, it consists of 57 departments in the experimental, life, social and human sciences, spread among 13 faculties/schools. All these centers together award a total of 85 qualifications in the form of first degrees, diplomas, and engineering degrees. Moreover, almost 80 doctoral programs, and more than 80 other postgraduate programs are offered. UAB has more than 40,000 students and more than 3,600 academic and research staff. The UAB is a pioneering institution in terms of fostering research. There are many research institutes in the campus, as well as other research centers, technical support services and service-providing laboratories. It should be noted that ALBA (synchrotron) located in the Barcelona Synchrotron Park is very close to the UAB. The UAB is considered to be the best University in Spain by the 2012 QS World University Rankings,[1] which ranked the university 176th overall in the world. Its subject rankings were: 144th in Life Sciences & Biomedicine, 92th[clarification needed] in Arts & Humanities, 106th in Natural Sciences, 95th in Social Sciences and 203rd in Engineering & IT.

     
  • richardmitnick 1:09 pm on August 21, 2015 Permalink | Reply
    Tags: , , Wormholes   

    From phys.org: “Trio create artificial magnetic wormhole” 

    physdotorg
    phys.org

    1
    Universitat Autonoma de Barcelona

    August 21, 2015
    Bob Yirka

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    a) The field of a magnetic source (right) is appearing as an isolated magnetic monopole when passing through the magnetostatic wormhole; the whole spherical device is magnetically undetectable. (b) The wormhole is composed of (from left to right) an outer spherical ferromagnetic metasurface, a spherical superconducting layer, and an inner spirally wound ferromagnetic sheet. Credit: Scientific Reports 5, Article number: 12488 (2015) doi:10.1038/srep12488

    A trio of physicists with the Autonomous University of Barcelona has built what they claim is the first artificial magnetic wormhole. In their paper published in the journal Scientific Reports, Jordi Prat-Camps, Carles Navau and Alvaro Sanchez describe how they built the device and why they believe it might prove useful in building a more user-friendly MRI machine.

    People have grown familiar with the term wormhole as it applies to physics and science-fiction. It has been described as a portal in space-time, where an object, or perhaps a person, could be transported from one region of space to another, nearly instantaneously. And while the theory has stood the test of time, no one has ever been able to prove that they actually exist. In this new effort, the researchers built a much simpler version, one that applies only to a magnetic field. Their device essentially allows for a magnetic field to be conveyed from one point to another, while remaining magnetically invisible.

    The device is a three layered sphere—at its center they placed a magnetized metal tube. The tube was then surrounded by a sphere made of strips of a superconducting material (yttrium barium copper oxide)—it served to deflect incoming fields. Another sphere was then placed over the whole works to make the deflection of the inner sphere undetectable. To make the device work as intended it was put into a liquid nitrogen bath to bring the temperature inside the sphere down to the point where the yttrium barium copper oxide behaved as a superconductor. The end result was a device that made it appear that a magnetic field suddenly disappeared, then reappeared at another place.

    The team tested their device by placing it in an external magnetic field that that they created and then placed magnetic probes at either end of the sphere. The first probe indicated the presence of a monopole-like field. The second probe was moved back and forth across the length of the sphere and indicated no magnetic field was present—temporarily removing either shell revealed that there was indeed a field inside the sphere.

    Beyond its research value, the team believes that their device could serve as the basis for a new type of MRI machine, one that could relieve patients from having to sit inside of a big loud shell while their insides are examined.

    See the full article here.

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 6:38 am on June 20, 2015 Permalink | Reply
    Tags: , , , Wormholes   

    From Space.com: “What is a Wormhole?” 

    space-dot-com logo

    SPACE.com

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    A model of ‘folded’ space-time illustrates how a wormhole bridge might form with at least two mouths that are connected to a single throat or tube. Credit: edobric | Shutterstock

    A wormhole is a theoretical passage through space-time that could create shortcuts for long journeys across the universe. Wormholes are predicted by the theory of general relativity. But be wary: wormholes bring with them the dangers of sudden collapse, high radiation and dangerous contact with exotic matter.

    Wormhole theory

    In 1935, physicists Albert Einstein and Nathan Rosen used the theory of general relativity to propose the existence of “bridges” through space-time. These paths, called Einstein-Rosen bridges or wormholes, connect two different points in space-time, theoretically creating a shortcut that could reduce travel time and distance.

    Wormholes contain two mouths, with a throat connecting the two. The mouths would most likely be spheroidal. The throat might be a straight stretch, but it could also wind around, taking a longer path than a more conventional route might require.

    Einstein’s theory of general relativity mathematically predicts the existence of wormholes, but none have been discovered to date. A negative mass wormhole might be spotted by the way its gravity affects light that passes by.

    Certain solutions of general relativity allow for the existence of wormholes where the mouth of each is a black hole. However, a naturally occurring black hole, formed by the collapse of a dying star, does not by itself create a wormhole.

    Exotic matter, which should not be confused with dark matter or antimatter, contains negative energy density and a large negative pressure. Such matter has only been seen in the behavior of certain vacuum states as part of quantum field theory.

    If a wormhole contained sufficient exotic matter, whether naturally occurring or artificially added, it could theoretically be used as a method of sending information or travelers through space.

    Wormholes may not only connect two separate regions within the universe, they could also connect two different universes. Similarly, some scientists have conjectured that if one mouth of a wormhole is moved in a specific manner, it could allow for time travel. However, British cosmologist Stephen Hawking has argued that such use is not possible. [Weird Science: Wormholes Make the Best Time Machines]

    “A wormhole is not really a means of going back in time, it’s a short cut, so that something that was far away is much closer,” NASA’s Eric Christian wrote.

    Although adding exotic matter to a wormhole might stabilize it to the point that human passengers could travel safely through it, there is still the possibility that the addition of “regular” matter would be sufficient to destabilize the portal.

    Today’s technology is insufficient to enlarge or stabilize wormholes, even if they could be found. However, scientists continue to explore the concept as a method of space travel with the hope that technology will eventually be able to utilize them.

    See the full article here.

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  • richardmitnick 2:08 pm on January 29, 2015 Permalink | Reply
    Tags: , , , Wormholes   

    From SEN: “Does Milky Way hide a portal to the distant Universe?” 

    SEN
    SEN

    1

    29 January 2015
    Kulvinder Singh

    Our Milky Way could be harbouring a cosmic “wormhole“—that exotic short cut across the Universe made famous in science fiction shows and films—according to a team of scientists in India, Italy and the USA.

    Such a wormhole could offer an alternative to Dark Matter as an explanation for the missing mass in our Galaxy, say the scientists in a paper submitted to The Annals of Physics.

    It could even be traversable, according to the team. However, they do not believe their calculations actually proves the existence of a Galactic wormhole.

    So-called cosmic wormholes have been a staple of science fiction for decades as a means of travelling to distant worlds by literally taking a short-cut through the Universe itself. Just such a wormhole features in the blockbuster film Interstellar. And far from being fanciful plot devices, wormholes have a respectable origin in physics, where they’re known as Einstein-Rosen bridges.

    “The distribution of Dark Matter in our Galaxy mimics the presence of a stable wormhole, which we inferred by solving the standard equation for General Relativity,” Dr Paolo Salucci of the International School for Advanced Studies, Italy, told Sen.

    Salucci is referring to [Albert] Einstein’s General Theory of Relativity, which tells us that there should be more mass in the Milky Way than what we see from all of the stars, planets, dust and gas clouds it contains.

    2
    Map of the Milky Way Galaxy, showing the location of a possible cosmic wormhole. Image credit: David and Paolo Salucci.

    This is a problem. Not just for the Milky Way, but other galaxies too. Galaxies—like stars and planets, rotate. But the amount of visible matter in them just isn’t enough to stop them from flying apart. They seem to have more gravitational “pull” than they should. Scientists say this comes from haloes of Dark Matter—so-called because it’s completely invisible—in which galaxies are embedded.

    Einstein’s Theory of General Relativity, which deals successfully with gravity on cosmic scales, can be used to calculate the amounts of Dark Matter present. But what exactly is it? Is it made of exotic particles? Is it a force from another dimension? Do our theories of gravity need to be modified?

    Cosmologists have been working on these and other theories for years to explain Dark Matter’s true nature. In fact it is one of the biggest mysteries in modern cosmology.

    Salucci’s team, led by Dr Farook Rahaman of the University of Jadavpur, India, found that the same General Relativity equations that describe Dark Matter could also explain the existence of wormholes.

    They achieved this by combining the equations with a detailed Dark Matter distribution map they obtained in 2013. The effect of a wormhole’s presence should have same effect as that attributed to a galactic Dark Matter halo.

    But wormholes usually have an opening through which matter should be able to travel. Where is the one for the Milky Way? Our Galaxy, like all large galaxies, show strong evidence for supermassive black holes at their centres—in the so-called ‘bulge region’. Could these in fact be the openings?

    As Salucci told Sen, “they do not coincide and actually, we haven’t solved Einstein’s equation for the bulge region. What we’re advocating is a wormhole as big as the Galaxy.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The vision of Sen—space exploration network—is to create a global space content network. Sen provides space news and information on the science, economics and government of space and in so doing aims to:
    —promote interest in space;
    —raise awareness of the reality of humankind and Earth in the Universe, providing a different perspective to life on this planet;
    —educate and encourage consideration of the physics, economics and government of space;
    —create a community in which people can learn, debate and share information about space;
    —further the exploration of space;
    —film the universe forever building an electronic version of the universe, a never ending work of art, creating Sen Universe – a computerised to scale 3D universe, starting with the Solar System. Sen Universe will replace computer imagery with real film and imagery as our exploration of the universe continues, forever building an electronic version of the universe, a never ending work of art and science.
    —Ultimately, in achieving the above, Sen aims to be a business without boundary in space and time.

    Space is everything, it affects everything – it defines our environment, the government of mankind, relations, the future. By promoting interest and awareness of space a different perspective of our conduct and government of life on the planet can be obtained in the hope of creating a united planet.

    Sen will aim to be an enterprise that represents the best human effort at creating an enterprise without boundary in space and time.

     
  • richardmitnick 9:51 pm on December 26, 2014 Permalink | Reply
    Tags: , , , , , Wormholes   

    From SPACE.com: “What is a Wormhole?” 

    space-dot-com logo

    SPACE.com

    April 29, 2013
    Nola Taylor Redd

    A wormhole is a theoretical passage through space-time that could create shortcuts for long journeys across the universe. Wormholes are predicted by the theory of general relativity. But be wary: wormholes bring with them the dangers of sudden collapse, high radiation and dangerous contact with exotic matter.

    Wormhole theory

    1
    A model of ‘folded’ space-time illustrates how a wormhole bridge might form with at least two mouths that are connected to a single throat or tube.

    In 1935, physicists Albert Einstein and Nathan Rosen used the theory of general relativity to propose the existence of “bridges” through space-time. These paths, called Einstein-Rosen bridges or wormholes, connect two different points in space-time, theoretically creating a shortcut that could reduce travel time and distance.

    Wormholes contain two mouths, with a throat connecting the two. The mouths would most likely be spheroidal. The throat might be a straight stretch, but it could also wind around, taking a longer path than a more conventional route might require.

    Einstein’s theory of general relativity mathematically predicts the existence of wormholes, but none have been discovered to date. A negative mass wormhole might be spotted by the way its gravity affects light that passes by.

    Certain solutions of general relativity allow for the existence of wormholes where the mouth of each is a black hole. However, a naturally occurring black hole, formed by the collapse of a dying star, does not by itself create a wormhole.

    Through the wormhole

    Science fiction is filled with tales of traveling through wormholes. But the reality of such travel is more complicated, and not just because we’ve yet to spot one.

    The first problem is size. Primordial wormholes are predicted to exist on microscopic levels, about 10–33 centimeters. However, as the universe expands, it is possible that some may have been stretched to larger sizes.

    Another problem comes from stability. The predicted Einstein-Rosen wormholes would be useless for travel because they collapse quickly. But more recent research found that a wormhole containing “exotic” matter could stay open and unchanging for longer periods of time.

    Exotic matter, which should not be confused with dark matter or antimatter, contains negative energy density and a large negative pressure. Such matter has only been seen in the behavior of certain vacuum states as part of quantum field theory.

    If a wormhole contained sufficient exotic matter, whether naturally occurring or artificially added, it could theoretically be used as a method of sending information or travelers through space.

    Wormholes may not only connect two separate regions within the universe, they could also connect two different universes. Similarly, some scientists have conjectured that if one mouth of a wormhole is moved in a specific manner, it could allow for time travel. However, British cosmologist Stephen Hawking has argued that such use is not possible.

    Although adding exotic matter to a wormhole might stabilize it to the point that human passengers could travel safely through it, there is still the possibility that the addition of “regular” matter would be sufficient to destabilize the portal.

    Today’s technology is insufficient to enlarge or stabilize wormholes, even if they could be found. However, scientists continue to explore the concept as a method of space travel with the hope that technology will eventually be able to utilize them.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
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