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  • richardmitnick 7:24 am on August 30, 2018 Permalink | Reply
    Tags: An eternal cycle of Big Bang events, Big Bang, , Conformal Cyclic Cosmology, , Hawking Points- anomalous high energy features in the CMB, , Roger Penrose, Stephen Hawking,   

    From University of Oxford via COSMOS: “Black holes from a previous universe shine light on our own” 

    U Oxford bloc

    From University of Oxford

    via

    COSMOS

    30 August 2018
    Stephanie Rowlands

    Cold spots are a hot topic in Conformal Cyclic Cosmology.

    1
    Stephen Hawking suggested evidence of previous universes could be detected in the cosmic microwave background. Has he been proved right? Jemal Countess/Getty Images

    Cosmologists say they have found remnants of a bygone universe in the afterglow of the Big Bang found in the Cosmic Microwave Background (CMB).

    CMB per ESA/Planck


    ESA/Planck 2009 to 2013

    The discovery gives weight to the controversial theory of Conformal Cyclic Cosmology, or CCC, that suggests our universe is just one of many, built from the remains of a previous one in the Big Bang 13.6 billion years ago.

    The theory describes an eternal cycle of Big Bang events, repeating into the far distant future, the end of our universe giving rise to a new one.

    A team led by Oxford University mathematics emeritus Roger Penrose, a former collaborator of the late Stephen Hawking, claims in a new paper lodged on the preprint server arXiv to have found signs of so-called Hawking Points, anomalous high energy features in the CMB.

    3
    Inside Penrose’s universe
    06 Dec 2010
    Cycles of Time: An Extraordinary New View of the Universe
    Roger Penrose
    2010 Bodley Head £25.00 hb 320pp

    https://people.maths.ox.ac.uk/lmason/RP80/paul.pdf

    Penrose and colleagues say that these anomalies were made from the last moments of black holes evaporating through “Hawking radiation”.

    Although black holes are famous for never releasing any light, Hawking proposed a subtle way for light and particles to escape over time.

    Through quantum mechanical effects, every black hole slowly shrinks and fades, losing its energy through Hawking radiation.

    “This burst of energy from a now decayed black hole then spreads out quickly in our newly formed universe, leaving a warm central point with a cooling spot around it,” says astronomer Alan Duffy from Australia’s Swinburne University and Lead Scientist of the Royal Institution of Australia, who was not involved in the research.

    “In other words, they have proposed that we can search for an echo of a previous universe in the CMB.”

    Conformal Cyclic Cosmology strongly conflicts with the current standard model explaining the evolution of the universe.

    “Unlike previous cyclic universe models, there is no ‘Big Crunch’ where everything comes together again,” explains Duffy.

    “Instead CCC links the similarity of the current accelerating expansion of the universe by dark energy with early expansion of inflation in the Big Bang.”

    While mathematically the two epochs of expansion are similar, not all cosmologists are convinced that the Big Bang eventually leads to another Big Bang from a future empty universe.

    The results from Penrose and colleagues are likely to be met with skepticism by many mainstream cosmologists.

    Penrose first claimed [Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity] to have detected Hawking points in 2010. Other researchers shot down the claim in flames, arguing that his discoveries were nothing more than random noise contained in the data.

    NASA/WMAP 2001 to 2010


    Inflationary Universe. NASA/WMAP


    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    See the full article here.


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    Oxford is a collegiate university, consisting of the central University and colleges. The central University is composed of academic departments and research centres, administrative departments, libraries and museums. The 38 colleges are self-governing and financially independent institutions, which are related to the central University in a federal system. There are also six permanent private halls, which were founded by different Christian denominations and which still retain their Christian character.

    The different roles of the colleges and the University have evolved over time.

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  • richardmitnick 6:37 am on August 30, 2018 Permalink | Reply
    Tags: , , , Black Hole Firewalls Could Be Too Tepid to Burn, , , , Stephen Hawking,   

    From Nautilus: “Black Hole Firewalls Could Be Too Tepid to Burn” 

    Nautilus

    From Nautilus

    Aug 29, 2018
    Charlie Wood

    Artist’s conception of two merging black holes similar to those detected by LIGO Credit LIGO-Caltech/MIT/Sonoma State /Aurore Simonnet

    1
    String theorists elide a paradox about black holes by extinguishing the walls of fire feared to surround them. NASA

    Despite its ability to bend both minds and space, an Einsteinian black hole looks so simple a child could draw it. There’s a point in the center, a perfectly spherical boundary a bit farther out, and that’s it

    The point is the singularity, an infinitely dense, unimaginably small dot contorting space so radically that anything nearby falls straight in, leaving behind a vacuum. The spherical boundary marks the event horizon, the point of no return between the vacuum and the rest of the universe. But according to Einstein’s theory of gravity, the event horizon isn’t anything that an unlucky astronaut would immediately notice if she were to cross it. “It’s like the horizon outside your window,” said Samir Mathur, a physicist at Ohio State University. “If you actually walked over there, there’s nothing.”

    In 2012, however, this placid picture went up in flames. A team of four physicists took a puzzle first put forward by Stephen Hawking about what happens to all the information that falls into the black hole, and turned it on its head. Rather than insisting that an astronaut (often named Alice) pass smoothly over the event horizon, they prioritized a key postulate of quantum mechanics: Information, like matter and energy, must never be destroyed. That change ended up promoting the event horizon from mathematical boundary to physical object, one they colorfully named the wall of fire.

    “It can’t be empty, and it turns out it has to be full of a lot of stuff, a lot of hot stuff,” said Donald Marolf, a physicist at the University of California, Santa Barbara, and one of the four co-authors [no cited paper]. The argument caused an uproar in the theoretical physics community, much as if cartographers suggested that instead of an imaginary line on their maps, Earth’s equator was actually a wall of bright red bricks.

    The news of a structure at the boundary didn’t shock Mathur, however. For more than a decade he had been arguing that black holes are really balls of strings (from string theory) with hot, fuzzy surfaces. “As you come closer and closer it gets hotter and hotter, and that’s what causes the burning,” he explained.

    In recent years, Mathur has been refining his “fuzzball” description, and his most recent calculations bring marginally good news for Alice. While she wouldn’t live a long and healthy life, the horizon’s heat might not be what does her in.

    Fuzzballs are what you get when you apply string theory, a description of nature that replaces particles with strings, to extremely dense objects. Energize a particle and it can only speed up, but strings stretch and swell as well. That ability to expand, combined with additional flexibility from postulated extra dimensions, makes strings fluff up when enough of them are packed into a small space. They form a fuzzy ball that looks from afar like an ordinary black hole—it has the same size (for a given mass) and emits the same kind of “Hawking radiation” that all black holes emit. As a bonus, the slightly bumpy surface changes the way it emits particles and declaws Hawking’s information puzzle, according to Mathur. “It’s more like a planet,” he said, “and it radiates from that surface just like anything else.”

    33
    Olena Shmahalo / Quanta Magazine

    His new work extends arguments from 2014, which asked what would happen to Alice if she were to fall onto a supermassive fuzzball akin to the one at the heart of our galaxy—one with the mass of millions of suns. In such situations, the force of gravity dominates all others. Assuming this constraint, Mathur and his collaborator found that an incoming Alice particle had almost no chance of smashing into an outgoing particle of Hawking radiation. The surface might be hot, he said, but the way the fuzzball expands to swallow new material prevents anything from getting close enough to burn, so Alice should make it to the surface.


    In response, Marolf suggested that a medium-size fuzzball might still be able to barbecue Alice in other ways. It wouldn’t drag her in as fast, and in a collision at lower energies, forces other than gravity could singe her, too.

    Mathur’s team recently took a more detailed look at Alice’s experience with new calculations published in the Journal of High Energy Physics. They concluded that for a modest fuzzball—one as massive as our sun—the overall chance of an Alice particle hitting a radiation particle was slightly higher than they had found before, but still very close to zero. Their work suggested that you’d have to shrink a fuzzball down to a thousand times smaller than the nanoscale before burning would become likely.

    By allowing Alice to reach the surface more or less intact (she would still undergo an uncontroversial and likely fatal stretching), the theory might even end up restoring the Einsteinian picture of smooth passage across the boundary, albeit in a twisted form. There might be a scenario in which Alice went splat on the surface while simultaneously feeling as if she were falling through open space, whatever that might mean.

    “If you jump onto [fuzzballs] in one description, you break up into little strings. That’s the splat picture,” Mathur said. We typically assume that once her particles start breaking up, Alice ceases to be Alice. A bizarre duality in string theory, however, allows her strings to spread out across the fuzzball in an orderly way that preserves their connections, and, perhaps, her sense of self. “If you look carefully at what [the strings] are doing,” Mathur continued, “they’re actually spreading in a very coherent ball.”

    The details of Mathur’s picture remain rough. And the model rests entirely on the machinery of string theory, a mathematical framework with no experimental evidence. What’s more, not even string theory can handle the messiness of realistic fuzzballs. Instead, physicists focus on contrived examples such as highly organized, extra-frigid bodies with extreme features, said Marika Taylor, a string theorist at the University of Southampton in the U.K.

    Mathur’s calculations are exploratory, she said, approximate generalizations from the common features of the simple models. The next step is a theory that can describe the fuzzball’s surface at the quantum level, from the point of view of the string. Nevertheless, she agreed that the hot firewall idea has always smelled fishy from a string-theory perspective. “You suddenly transition from ‘I’m falling perfectly happily’ to ‘Oh my God, I’m completely destroyed’? That’s unsatisfactory,” she said.

    Marolf refrained from commenting on the latest results until he finished discussing them with Mathur, but said that he was interested in learning more about how the other forces had been accounted for and how the fuzzball surface would react to Alice’s visit. He also pointed out that Mathur’s black hole model was just one of many tactics for resolving Hawking’s puzzle, and there was no guarantee that anyone had hit on the right one. “Maybe the real world is crazier than even the things we’ve thought of yet,” he said, “and we’re just not being clever enough.”

    See the full article here .

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    Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

     
  • richardmitnick 1:03 am on May 13, 2018 Permalink | Reply
    Tags: , , Stephen Hawking   

    From Michigan State University: “Black holes aren’t totally black, and other insights from Stephen Hawking’s groundbreaking work” 

    Michigan State Bloc

    From Michigan State University

    May 8, 2018
    Chris Adami Microbiology and Molecular Genetics; Physics and Astronomy office
    (517) 884-5068
    adami@msu.edu

    1
    No image caption or credit.

    1
    What goes in doesn’t go out? NASA Goddard, CC BY Christoph Adami, Michigan State University

    Mathematical physicist and cosmologist Stephen Hawking was best known for his work exploring the relationship between black holes and quantum physics. A black hole is the remnant of a dying supermassive star that’s fallen into itself; these remnants contract to such a small size that gravity is so strong even light cannot escape from them. Black holes loom large in the popular imagination – schoolchildren ponder why the whole universe doesn’t collapse into one. But Hawking’s careful theoretical work filled in some of the holes in physicists’ knowledge about black holes.

    Why do black holes exist?

    The short answer is: Because gravity exists, and the speed of light is not infinite.

    Imagine you stand on Earth’s surface, and fire a bullet into the air at an angle. Your standard bullet will come back down, someplace farther away. Suppose you have a very powerful rifle. Then you may be able to shoot the bullet at such a speed that, rather than coming down far away, it will instead “miss” the Earth. Continually falling, and continually missing the surface, the bullet will actually be in an orbit around Earth. If your rifle is even stronger, the bullet may be so fast that it leaves Earth’s gravity altogether. This is essentially what happens when we send rockets to Mars, for example.

    Now imagine that gravity is much, much stronger. No rifle could accelerate bullets enough to leave that planet, so instead you decide to shoot light. While photons (the particles of light) do not have mass, they are still influenced by gravity, bending their path just as a bullet’s trajectory is bent by gravity. Even the heaviest of planets won’t have gravity strong enough to bend the photon’s path enough to prevent it from escaping.

    But black holes are not like planets or stars, they are the remnants of stars, packed into the smallest of spheres, say, just a few kilometers in radius. Imagine you could stand on the surface of a black hole, armed with your ray gun. You shoot upwards at an angle and notice that the light ray instead curves, comes down and misses the surface! Now the ray is in an “orbit” around the black hole, at a distance roughly what cosmologists call the Schwarzschild radius, the “point of no return.”

    Thus, as not even light can escape from where you stand, the object you inhabit (if you could) would look completely black to someone looking at it from far away: a black hole.

    3
    Hawking worked to popularize his cosmological insights. AP Photo/Keystone, Salvatore Di Nolfi

    But Hawking discovered that black holes aren’t completely black?

    The short answer is: Yes.

    My previous description of black holes used the language of classical physics – basically, Newton’s theory applied to light. But the laws of physics are actually more complicated because the universe is more complicated.

    In classical physics, the word “vacuum” means the total and complete absence of any form of matter or radiation. But in quantum physics, the vacuum is much more interesting, in particular when it is near a black hole. Rather than being empty, the vacuum is teeming with particle-antiparticle pairs that are created fleetingly by the vacuum’s energy, but must annihilate each other shortly thereafter and return their energy to the vacuum.

    You will find all kinds of particle-antiparticle pairs produced, but the heavier ones occur much more rarely. It’s easiest to produce photon pairs because they have no mass. The photons must always be produced in pairs so they’re moving away from each other and don’t violate the law of momentum conservation.

    3
    No light can be seen coming from a black hole outside the Schwarzschild radius. SubstituteR, CC BY-SA

    Now imagine that a pair is created just at that distance from the center of the black hole where the “last light ray” is circulating: the Schwarzschild radius. This distance could be far from the surface or close, depending on how much mass the black hole has. And imagine that the photon pair is created so that one of the two is pointing inward – toward you, at the center of the black hole, holding your ray gun. The other photon is pointing outward. (By the way, you’d likely be crushed by gravity if you tried this maneuver, but let’s assume you’re superhuman.)

    4
    A pair of photons that annihilate each other is labeled A. In a second pair of photons, labeled B, one enters the black hole while the other heads outward, setting up an energy debt that is paid by the black hole. Christoph Adami, CC BY-ND

    Now there’s a problem: The one photon that moved inside the black hole cannot come back out, because it’s already moving at the speed of light. The photon pair cannot annihilate each other again and pay back their energy to the vacuum that surrounds the black hole. But somebody must pay the piper and this will have to be the black hole itself. After it has welcomed the photon into its land of no return, the black hole must return some of its mass back to the universe: the exact same amount of mass as the energy the pair of photons “borrowed,” according to Einstein’s famous equality E=mc².

    This is essentially what Hawking showed mathematically. The photon that is leaving the black hole horizon will make it look as if the black hole had a faint glow: the Hawking radiation named after him. At the same time he reasoned that if this happens a lot, for a long time, the black hole might lose so much mass that it could disappear altogether (or more precisely, become visible again).

    Do black holes make information disappear forever?

    Short answer: No, that would be against the law.

    Many physicists began worrying about this question shortly after Hawking’s discovery of the glow. The concern is this: The fundamental laws of physics guarantee that every process that happens “forward in time,” can also happen “backwards in time.”

    This seems counter to our intuition, where a melon that splattered on the floor would never magically reassemble itself. But what happens to big objects like melons is really dictated by the laws of statistics. For the melon to reassemble itself, many gazillions of atomic particles would have to do the same thing backwards, and the likelihood of that is essentially zero. But for a single particle this is no problem at all. So for atomic things, everything you observe forwards could just as likely occur backwards.

    Now imagine that you shoot one of two photons into the black hole. They only differ by a marker that we can measure, but that does not affect the energy of the photon (this is called a “polarization”). Let’s call these “left photons” or “right photons.” After the left or right photon crosses the horizon, the black hole changes (it now has more energy), but it changes in the same way whether the left or right photon was absorbed.

    Two different histories now have become one future, and such a future cannot be reversed: How would the laws of physics know which of the two pasts to choose? Left or right? That is the violation of time-reversal invariance. The law requires that every past must have exactly one future, and every future exactly one past.

    Some physicists thought that maybe the Hawking radiation carries an imprint of left/right so as to give an outside observer a hint at what the past was, but no. The Hawking radiation comes from that flickering vacuum surrounding the black hole, and has nothing to do with what you throw in. All seems lost, but not so fast.

    In 1917, Albert Einstein showed that matter (even the vacuum next to matter) actually does react to incoming stuff, in a very peculiar way. The vacuum next to that matter is “tickled” to produce a particle-antiparticle pair that looks like an exact copy of what just came in. In a very real sense, the incoming particle stimulates the matter to create a pair of copies of itself – actually a copy and an anti-copy. Remember, random pairs of particle and antiparticle are created in the vacuum all the time, but the tickled-pairs are not random at all: They look just like the tickler.

    This copy process is known as the “stimulated emission” effect and is at the origin of all lasers. The Hawking glow of black holes, on the other hand, is just what Einstein called the “spontaneous emission” effect, taking place near a black hole.

    Now imagine that the tickling creates this copy, so that the left photon tickles a left photon pair, and a right photon gives a right photon pair. Since one partner of the tickled pairs must stay outside the black hole (again from momentum conservation), that particle creates the “memory” that is needed so that information is preserved: One past has only one future, time can be reversed, and the laws of physics are safe.

    In a cosmic accident, Hawking died on Einstein’s birthday, whose theory of light – it just so happens – saves Hawking’s theory of black holes.

    See the full article here .

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    Michigan State University (MSU) is a public research university located in East Lansing, Michigan, United States. MSU was founded in 1855 and became the nation’s first land-grant institution under the Morrill Act of 1862, serving as a model for future land-grant universities.

    MSU pioneered the studies of packaging, hospitality business, plant biology, supply chain management, and telecommunication. U.S. News & World Report ranks several MSU graduate programs in the nation’s top 10, including industrial and organizational psychology, osteopathic medicine, and veterinary medicine, and identifies its graduate programs in elementary education, secondary education, and nuclear physics as the best in the country. MSU has been labeled one of the “Public Ivies,” a publicly funded university considered as providing a quality of education comparable to those of the Ivy League.

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  • richardmitnick 2:57 pm on May 4, 2018 Permalink | Reply
    Tags: A model of the Big Bang, , Stephen Hawking, Theory-the universe is more uniform and simpler than scientists had previously believed, Thomas Hertog   

    From Horizon The EU Research &amp Innovation Magazine: “‘I opened a bottle with Stephen Hawking to celebrate our eureka moment’ – Prof. Thomas Hertog” 

    Horizon-The EU Research & Innovation Magazine

    03 May 2018
    Kevin Casey
    Interview

    1
    A new model by Stephen Hawking and Thomas Hertog says that the universe is more uniform and simpler than scientists had previously believed. Image credit – ESO/T. Preibisch, licensed under CC BY 4.0

    A theory developed with the late Professor Stephen Hawking stating that the universe is more simple and uniform than current models suggest was so shocking that it had to be sat on for a while before it was released to the world, according to co-author Professor Thomas Hertog from KU Leuven in Belgium.

    He and Prof. Hawking used an obscure branch of mathematics called string theory to study the Big Bang itself. In a paper published on 2 May [JHEP], they propose that instead of there being infinite universes, there is actually a rather limited variety, all of which have the same laws of physics as our own.

    What question are you and the late Stephen Hawking addressing with this theory?

    ‘We are trying to get a model of the Big Bang. Why do we want that? Because we want to understand what kind of universe can emerge from the Big Bang, what kind of universe can come into existence, and what’s special about our universe.’

    What is new about the model proposed in your paper?

    ‘The prevailing theory of the Big Bang says that there are many Big Bangs, creating many different kinds of universes – which people called the multiverse. We are very much reducing that multiverse. Our new theory of the Big Bang makes our universe more unique again. So that’s why it’s different.’

    Does it bring us closer to the much sought-after ‘theory of everything’ – a master theory to link together all the physical aspects of the universe?

    ‘It’s one step in a much bigger programme to come to a fully-fledged view of the Big Bang based, ultimately, perhaps, on a theory of everything.’

    How does this theory comply with the notion of an initial singularity – a single point of infinite density which contained all the matter in the universe – at the Big Bang?

    ‘With Einstein’s Theory of Relativity, you can show that the universe had a beginning, that it had a Big Bang, but you couldn’t show anything about how it had begun because the Big Bang was a singularity. We are introducing new techniques from string theory to be able to say something about that beginning so we’re going beyond Einstein’s theory.’

    ‘Loosely speaking, you could say that this is a theory of what used to be the singularity in Einstein’s theory. It’s a theory that describes how time emerges from something more abstract and timeless.’

    What was on the other side of the Big Bang?

    ‘Absolutely nothing.’

    Nothing we can know, or nothing that there is?

    ‘I looked for something in my theory and I didn’t find anything. There is no other side because we used the technique from string theory called holography, so everything which might exist before or on the other side is projected on to the surface at the beginning. There is literally nothing.

    ‘In all my equations, the other side – or before the Big Bang as you would say – is just simply not there. There’s no notion of time.’

    Is there a relic gravitational wave echoing out there from the Big Bang that we have not detected yet?

    ‘The universe arises with a short burst of inflation in our theory and that comes together with gravitational waves. Their relics, as you say, should leave their imprint on the polarisation of the cosmic microwave background radiation.

    ‘Gravitational waves had not been detected when we began this work. With future technologies and satellites we might hope to see gravitational waves from the Big Bang which are, in my view, one of the key observables we can use to test the theory.

    ‘Those gravitational waves from the Big Bang are the holy grail of the field of gravitational wave astronomy. And the hardest ones to get.’

    What can studying the Big Bang tell us about the world today?

    ‘We study the Big Bang in order to get a deeper understanding of what we see, how the laws of physics arise, why they are what they are and whether they’re unique. That’s the basic motivation for our work.

    ‘All these features which characterise the world today, they didn’t exist forever, they (crystallised) after the Big Bang when the universe expanded and cooled. So there must be some process, some physical conditions at the Big Bang which describe how this happened.’

    2
    Thomas Hertog and Stephen Hawking spent years collaborating on a new theory of the Big Bang. Image credit – Stephen Hawking

    Describe the feeling you had when you realised that your observation changed the global picture of the universe? Was it a ‘eureka’ moment?

    ‘With Stephen, yeah sure, we opened a bottle. A eureka moment is evidently very special and rare. This one happened a while ago. The result was, in a way, so shocking that we sat on it for a while and gathered more evidence and looked at the problem from different angles before we decided to go ahead and proceed towards publication.’

    Your work on holographic quantum cosmology is currently funded by the EU’s European Research Council. What’s next?

    ‘Like every discovery (in) theoretical sciences, on the one hand it’s a milestone, but on the other hand, it raises more questions than it answers. The model we propose must be worked out and refined, developed further. I’m curious to see where this will take us. Our paper ends with a conjecture and a lot of further development is needed, I believe, before we will know this is the way the universe came to be. So there’s plenty of work to do.’

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  • richardmitnick 3:51 pm on April 8, 2018 Permalink | Reply
    Tags: , , , , , Stephen Hawking, The Black Hole Information Paradox, The Black Hole War Stephen Hawking and Leonard Susskind   

    From Ethan Siegel: “The Black Hole Information Paradox, Stephen Hawking’s Greatest Puzzle, Is Still Unsolved” 

    Ethan Siegel
    Apr 5, 2018

    1
    Outside the event horizon of a black hole, General Relativity and quantum field theory are completely sufficient for understanding the physics of what occurs; that is what Hawking radiation is. But even the combination of those two leads to an information paradox that has not yet been resolved. (NASA)

    The paradox is one that Hawking himself claimed to have a solution to many times, but none of the proposals have held up to scrutiny. The paradox is still unresolved.

    With the passing of Stephen Hawking, science has lost not only its most recognizable public figure, but also a remarkable researcher into the nature of black holes.

    Stephen Hawking

    While his final paper may have focused more on some of the existential challenges facing cosmology today, his greatest scientific contributions were in uncovering some incredible quantum truths about the Universe by examining its most extreme objects.

    Black holes, once thought to be static, unchanging, and defined only by their mass, charge, and spin, were transformed through his work into ever-evolving engines that had a temperature, emitted radiation, and eventually evaporated over time. Yet this now-accepted scientific conclusion — inferring the presence and properties of Hawking radiation — had a tremendous implication: that black holes provided a way to destroy information about the Universe. Despite 40+ years of work on the problem by the world’s brightest minds, the black hole information paradox still remains unresolved.

    The Black Hole War Stephen Hawking and Leonard Susskind

    2
    When a mass gets devoured by a black hole, the amount of entropy the matter has is determined by its physical properties. But inside a black hole, only properties like mass, charge, and angular momentum matter. This poses a big conundrum if the second law of thermodynamics must remain true. Illustration: (NASA/CXC/M.Weiss; X-ray (top): NASA/CXC/MPE/S.Komossa et al. (L); Optical: ESO/MPE/S.Komossa (R))

    NASA/Chandra Telescope

    MPG Institute for Extraterrestial Physics

    MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres

    The second law of thermodynamics is one of the most inviolable rules of the Universe: take any system you like, don’t allow anything to enter or leave it, and its entropy will never spontaneously decrease. Eggs don’t spontaneously unscramble themselves, warm water never separates into hot and cold sections, and ashes don’t reassemble into the shape of the object they were before they were burned. All of these would be an example of decreasing entropy, and this doesn’t happen, in nature, on its own. Entropy can remain the same; under most circumstance it increases; but it can never return to a lower-entropy state. In fact, the only way to artificially decrease entropy is to pump energy into a system, “cheating” the second law by increasing the entropy external to the system by a larger amount than it decreases within your system. (Cleaning your house is one such example.) Put simply, entropy can never be destroyed.

    3
    The mass of a black hole is the sole determining factor of the radius of the event horizon, for a non-rotating, isolated black hole. For a long time, it was thought that black holes were static objects in the spacetime of the Universe. (SXS team; Bohn et al 2015)

    For black holes, the thought — for a long time — was that they had zero entropy, but that couldn’t be right. If the matter that you made black holes out of had a non-zero entropy, then by throwing that material into a black hole, entropy would have to go up or stay the same; it could never go down. The idea for a black hole’s entropy traces back to John Wheeler, who was thinking about what happens to an object as it fall into a black hole from the point of view of an observer well outside the event horizon. From far away, someone falling in would appear to asymptotically approach the event horizon, turning redder and redder due to gravitational redshift, and taking an infinitely long time to reach the horizon, as relativistic time dilation took effect. The information, therefore, from whatever fell in would appear to be encoded on the surface area of the black hole itself.

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    Encoded on the surface of the black hole can be bits of information, proportional to the event horizon’s surface area. (T.B. Bakker / Dr. J.P. van der Schaar, Universiteit van Amsterdam)

    Since a black hole’s mass determines the size of its event horizon, this gave a natural place for the entropy of a black hole to exist: on the surface area of the event horizon. All of a sudden, black holes had an enormous entropy, based on the number of quantum bits that could be encoded on an event horizon of a particular size. But anything that has an entropy also has a temperature, which means it radiates. As Hawking famously demonstrated, black holes emit radiation of a particular (blackbody) spectrum and temperature, defined by the mass of the black hole that it’s coming from. Over time, that emission of energy means that the black hole is losing mass, owing to Einstein’s famous E = mc2; if energy is being released, it has to come from somewhere, and that “somewhere” must be the black hole itself. Over time, the black hole will lose mass faster and faster, until in a brilliant flash of light far in the future, it evaporates entirely.

    5
    Against a seemingly eternal backdrop of everlasting darkness, a single flash of light will emerge: the evaporation of the final black hole in the Universe. (ortega-pictures / pixabay).

    This is a great story, but it has a problem. The radiation it emits is purely blackbody, meaning it has the same properties as if we took a completely black object and heated it up to a particular temperature. The radiation, therefore, is exactly the same for all black holes of a particular mass — and this is the kicker — regardless of what information is or isn’t imprinted on the event horizon.

    According to the laws of thermodynamics, however, this can’t be! That’s the equivalent of destroying information, and is specifically the one things that’s disallowed.

    6
    Anything that burns might appear to be destroyed, but everything about the pre-burned state is, in principle, recoverable, if we track everything that comes out of the fire. (Public domain)

    If you burn two identically-sized books with very different content, you might be practically unable to reconstruct the text of either book, but the patterns of ink on the paper, the variations in molecular structures, and other minute differences all contain information, and that information remains encoded in the smoke, ash, the surrounding air, and all the other particles in play. If you could monitor the environment around and including the books to arbitrary accuracy, you would be able to reconstruct all the information you wanted; it’s scrambled, but not lost.

    The black hole information paradox, however, is that all the information that was imprinted on the event horizon of the black hole, once it evaporates, has left no trace in our observable Universe.

    7
    The simulated decay of a black hole not only results in the emission of radiation, but the decay of the central orbiting mass that keeps most objects stable. Black holes are not static objects, but rather change over time. However, black holes formed of different materials should have different information encoded on their event horizons.(EU’s Communicate Science)

    This loss of information should be forbidden by the rules of quantum mechanics. Any system can be described by a quantum wavefunction, and every wavefunction is unique. If you evolve your quantum system forwards in time, there’s no way that two different systems should arrive at the same final state, but that’s exactly what the information paradox implies. As far as we understand it, one of two things must be happening:

    Either information is truly destroyed somehow when a black hole evaporates, teaching us that there are new rules and laws in place for black hole evaporation,
    Or the radiation that’s emitted somehow contains this information, meaning that there’s more to Hawking radiation than the calculations we’ve done so far imply.

    This paradox, more than forty years after it was first noticed, has still never been resolved.

    8
    An illustration of the quantum fluctuations that permeate through all of space. If these fluctuations are imprinted, somehow, on the outgoing Hawking radiation emanating from a black hole, it’s possible that the information encoded on an event horizon will be preserved after all. (NASA/CXC/M.Weiss)

    While Hawking’s original calculations demonstrate that evaporation via Hawking radiation destroys whatever information was imprinted on the black hole’s event horizon, modern thought is that something must happen to encode that information in the outgoing radiation. Many physicists appeal to the holographic principle, noting that the information encoded on the black hole’s surface applies quantum corrections to the purely thermal Hawking radiation state, imprinting itself on the radiation as the black hole evaporates away and the event horizon shrinks. Despite the fact that Hawking, John Preskill, Kip Thorne, Gerard ‘t Hooft, and Leonard Susskind made bets and declared victory and defeat with respect to this problem, the paradox remains very much alive and unresolved, with many hypothesized solutions other than the one presented here.

    9
    The event horizon of a black hole is a spherical or spheroidal region from which nothing, not even light, can escape. But outside the event horizon, the black hole is predicted to emit radiation. Hawking’s 1974 work was the first to demonstrate this, and it was arguably his greatest scientific achievement. (NASA; Jörn Wilms (Tübingen) et al.; ESA)

    Despite our best efforts, we still don’t understand whether information leaks out of a black hole when it radiates energy (and mass) away. If it does leak information away, it’s unclear how that information is leaked out, and when or where Hawking’s original calculations break down. Hawking himself, despite conceding the argument more than a decade ago, continued to actively publish on the topic, often declaring that he had finally solved the paradox. But the paradox remains unresolved, without a clear solution. Perhaps that’s the greatest legacy one can hope to achieve in science: to uncover a new problem so complex that it will take multiple generations to arrive at the solution. In this particular case, most everyone agrees on what the solution ought to look like, but nobody knows how to get there. Until we do, it will remain just another part of Hawking’s incomparable, enigmatic gifts that he shared with the world.

    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 2:25 pm on November 30, 2017 Permalink | Reply
    Tags: (HPE) supercomputer the new Superdome Flex, , , , , , Stephen Hawking, The Stephen Hawking Center for Theoretical Cosmology   

    From Futurism: “Hawking’s Institute Is Using a Supercomputer to Uncover the Nature of Space and Time” 

    futurism-bloc

    Futurism

    11.30.17
    Chelsea Gohd

    The history of the universe still has many mysteries we have yet to fully understand. A new collaboration between HPE’s newest supercomputer and Stephen Hawking’s research group COSMOS hope to answer some of these questions.

    2

    3
    Stephen Hawking

    Supercomputing

    Hewlett-Packard Enterprise’s (HPE) supercomputer, the new Superdome Flex, is more than an impressive, technological marvel.

    1
    Hewlett-Packard Enterprise’s (HPE) supercomputer, the new Superdome Flex

    It’s a tool capable of unlocking some of the most complex mysteries of the universe, and Professor Stephen Hawking’s Centre for Theoretical Cosmology (COSMOS) will be using the computer to do exactly that.

    The supercomputer’s high-speed memory can hold a staggering 48 terabytes of data. Because this data is stored in the newly-designed memory system instead of a more traditional storage system, the computer can process enormous amounts of data at lightning speed. This is great news for COSMOS, as they plan to sort through 14 billion years of data with the goal of filling in gaps in our knowledge of the physical history of the universe.

    This computer might be just the beginning of this quest for knowledge, as it’s merely the precursor to “The Machine,” — HPE’s highly anticipated “ultimate vision” for computing. Their prototype will supposedly be able to store 160 terabytes of data in memory and can be built in a similar way to the Superdome Flex. Until this ambitious model becomes a more realistic option, Professor Hawking’s research group will use the immense capabilities of their existing supercomputer in their quest to discover more about the universe.

    Mysterious Universe

    COSMOS has already been making use of one HPE supercomputer and has been utilizing supercomputing power since 1997, their recent project is a natural progression for the researchers. Still, they hope that the latest advancement will allow them to achieve more than they ever have before.

    With the Superdome Flex, COSMOS intends to create the most detailed 3-dimensional map of the early universe to date. They hope to show the location and position of cosmic bodies like supernovas, black holes, galaxies, and much more. The project is officially named “Beyond the Horizon – Tribute to Stephen Hawking. It was dubbed as such because “Hawking is a great theorist but he always wants to test his theories against observations. What will emerge is a 3D map of the universe with the positions of billions of galaxies,” said Professor Shellard in a Cambridge press release.

    Data from the ESA’s Euclid probe, set to launch in 2020, will support these efforts, allowing the team to gain better insight into what researchers refer to as the “dark universe.”

    ESA/Euclid spacecraft

    The team hopes that this combination of data will also allow them to more deeply peer into, and understand dark matter and dark energy, and their influence on the geometry, structure, and inner workings of the universe.

    In addition to advancing our knowledge, the 3D map could potentially confirm existing theories about the universe. From our current understanding of black holes to the age of the universe and the standard model, the insights the map provides could challenge much of what we believe to be true about our universe. It may not be what leads humankind to a universal “theory of everything,” but it will allow physicists to get closer than humanity has ever come before.

    See the full article here .

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  • 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, , , , , Stephen Hawking, The particles still inside the hole would be directly connected to particles that left long ago,   

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

    Quanta Magazine
    Quanta Magazine

    April 24, 2015
    K.C. Cole

    1
    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.

    1
    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

    3
    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.)

    4
    Leonard Susskind at home in Palo Alto, Calif. Jeff Singer

    5
    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.

    4
    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 1:19 pm on September 24, 2017 Permalink | Reply
    Tags: , , , , , , Stephen Hawking   

    From Futurism: “Stephen Hawking Has Flawed Ideas About Alien Life, According to Former SETI Scientist” 

    futurism-bloc

    Futurism

    September 24, 2017
    Christianna Reedy

    Calling All Aliens

    As autumn brings with it cooler temperatures and clearer night skies, Douglas Vakoch, president of Messaging Extraterrestrial Intelligence (METI), wants you to take the opportunity to survey the glory of our galaxy — and to contemplate the existence of alien life.

    METI (Messaging Extraterrestrial Intelligence) International has announced plans to start sending signals into space

    “You look at the night sky — virtually all of those stars have planets,” Rosenberg said in an exclusive interview with Futurism. “Maybe one out of five has it at just the right zone where there’s liquid water. And so we know there are a lot of places that there could be life. Now the big question is, are they actually trying to make contact, or do they want us to try?”

    METI’s stance is that we should assume the latter, and the collection of scientists have taken it upon themselves to reach out to any potential alien civilizations. In fact, the next transmission planned for next year. However, there have long been voices opposed to this strategy — perhaps the most prominent of which being Stephen Hawking.

    Hawking, a noted physicist and author, supports the search for aliens, but regularly cautions against attempting contact. Hawking argued in “Stephen Hawking’s Favorite Places,” a video on the platform CuriosityStream, that aliens could be “vastly more powerful and may not see us as any more valuable than we see bacteria.”

    Paying Our Dues?

    These are not warnings that Vakoch takes lightly. “Well, when Stephen Hawking, a brilliant cosmologist, has said, ‘whatever you do, don’t transmit, we don’t want the aliens to come to Earth,’ You’ve got to take it seriously,” Vakoch told Futurism.

    But there’s one key point that Hawking really doesn’t seem to take into consideration in this assessment, Vakoch said.

    “It’s the fact that every civilization that does have the ability to travel to Earth could already pick up I Love Lucy. So we have been sending our existence into space with radio signals for 78 years. Even before that, two and a half billion years, we have been telling the Universe that there is life on here because of the oxygen in our atmosphere. So if there’s any alien out there paranoid about competition, it could have already come and wipe us out. If they’re on their way, it’s a lot better strategy to say we’re interested in being conversational partners. Let’s strike up a new conversation.”

    It’s Vakoch’s belief that humanity’s first contact with alien life will occur within our lifetimes. But even if it does not, he believes the METI project will be foundational to any relationship our world builds with others.

    “Sometimes people talk about this interstellar communication as an effort to join the galactic club. What I find so strange is no one ever talks about paying our dues or even submitting an application. And that’s what METI does,” Vakoch said. “It’s actually contributing something to the galaxy instead of saying gimme gimme gimme me. What can we do for someone else.”

    See the full article here .

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  • richardmitnick 11:25 am on May 31, 2017 Permalink | Reply
    Tags: , , , Patients’ stem cells point to potential treatments for motor neuron disease, Stephen Hawking   

    From COSMOS: “Patients’ stem cells point to potential treatments for motor neuron disease” 

    Cosmos Magazine bloc

    COSMOS

    31 May 2017
    Andrew Masterson

    Researchers have ‘replayed’ the growth of motor neurons to see where it goes wrong for people with the crippling degenerative disease.

    1
    Physicist Stephen Hawking is perhaps the most famous sufferer of motor neuron disease, a crippling degenerative condition that affects an estimated 150,00 people around the world.
    Karwai Tang / Getty

    In news that may bring hope to Stephen Hawking and hundreds of thousands of others around the world, British scientists have used reprogrammed skin cells to study the development of motor neuron disease.

    “It’s like changing the postcode of a house without actually moving it,” explains neuroscientist Rickie Patani, referring to research offering startling new insights into the progress and treatment of the crippling degenerative condition, also known as amyotrophic lateral sclerosis (ALS).

    Patani, together with colleague Sonia Gandhi, both from the Francis Crick Institute and University College London, in the UK, led a team of researchers investigating how the disease destroys the nerve cells that govern muscle movement.

    The results, published in the journal Cell Reports, comprise the most fine-grained work to date on how ALS operates on a molecular level – and suggest powerful new treatment methods based on stem cells.

    Indeed, so exciting are the implications of the research that Ghandi and Patani are already working with pharmaceutical companies to develop their discoveries.

    The neurologists uncovered two key interlinked interactions in the development of motor neuron disease, the first concerning a particular protein, and the second concerning an auxiliary nerve cell type called astrocytes.

    To make their findings, the team developed stem cells from the skin of healthy volunteers and a cohort carrying a genetic mutation that leads to ALS. The stem cells were then guided into becoming motor neurons and astrocytes.

    “We manipulated the cells using insights from developmental biology, so that they closely resembled a specific part of the spinal cord from which motor neurons arise,” says Patani.

    “We were able to create pure, high-quality samples of motor neurons and astrocytes which accurately represent the cells affected in patients with ALS.”

    The scientists then closely monitored the two sets of cells – healthy and mutated – to see how their functioning differed over time.

    The first thing they noted was that a particular protein – TDP-43 – behaved differently. In the patient-derived samples TDP-43 leaked out of the cell nucleus, catalysing a damaging chain of events inside the cell and causing it to die.

    The observation provided a powerful insight into the molecular mechanics of motor neuron disease.

    “Knowing when things go wrong inside a cell, and in what sequence, is a useful approach to define the ‘critical’ molecular event in disease,” says Ghandi.

    “One therapeutic approach to stop sick motor neurons from dying could be to prevent proteins like TDP-43 from leaving the nucleus, or try to move them back.”

    The second critical insight was derived from the behaviour of astrocytes, which turned out to function as a kind of nursemaid, supporting motor neuron cells when they began to lose function because of protein leakage.

    During the progression of motor neuron disease, however, the astrocytes – like nurses during an Ebola outbreak – eventually fell ill themselves and died, hastening the death of the neurons.

    To test this, the team did a type of “mix and match” exercise, concocting various combinations of neurons and astrocytes from healthy and diseased tissue.

    They discovered that healthy astrocytes could prolong the functional life of ALS-affected motor neurons, but damaged astrocytes struggled to keep even healthy motor neurons functioning.

    The research reveals both TDP-43 and astrocytes as key therapeutic targets, raising the possibility that the progress of ALS might be significantly slowed, or perhaps even halted.

    “Our work, along with other studies of ageing and neurodegeneration, would suggest that the cross-talk between neurons and their supporting cells is crucial in the development and progression of ALS,” says Patani.

    See the full article here .

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  • richardmitnick 10:01 am on January 26, 2017 Permalink | Reply
    Tags: Accelerating mirror, , Black hole paradox, , , , , Shooting electron waves through plasma could reveal if black holes permanently destroy information, Stephen Hawking   

    From Science Alert: “Shooting electron waves through plasma could reveal if black holes permanently destroy information” 

    ScienceAlert

    Science Alert

    25 JAN 2017
    MIKE MCRAE

    1
    Interstellar/Paramount Pictures

    Without having to enter a black hole ourselves…

    One of the greatest dilemmas in astrophysics is the black hole paradox – if black holes really do destroy every scrap of information that enters them.

    Now, physicists might have finally come up with a way to test the paradox once and for all, by accelerating a wave of negatively charged electrons through a cloud of plasma.

    As far as objects in space go, black holes need little introduction. Get too close, and their concentrated mass will swallow you, never to return.

    But in the 1970s, physicists including Stephen Hawking proposed that black holes weren’t necessarily forever.

    Thanks to the peculiarities of quantum mechanics, particles did indeed radiate away from black holes, Hawking hypothesised, which means, theoretically, black holes could slowly evaporate away over time.

    This poses the paradox. Information – the fundamental coding of stuff in the Universe – can’t just disappear. That’s a big rule. But when a black hole evaporates away, where does its bellyful of information go?

    A clue might be found in the nature of the radiation Hawking described. This form of radiation arises when a pair of virtual particles pops into existence right up against a black hole’s line of no return – the ‘event horizon’.

    Usually, such paired particles cancel each other out, and the Universe is none the wiser. But in the case of Hawking radiation, one of these particles falls across the horizon into the gravitational grip of the black hole. The other barely escapes off into the Universe as a bona fide particle.

    Physicists have theorised that this escaped particle preserves the information of its twin thanks to the quirks of quantum dynamics. In this case, the phenomenon of entanglement would allow the particles to continue share a connection, even separated by time and space, leaving a lasting legacy of whatever was devoured by the black hole.

    To demonstrate this, physicists could catch a particle that has escaped a black hole’s event horizon, and then wait for the black hole to spill its guts in many, many years, to test if there’s indeed a correlation between one of the photons and its entangled twin. Which, let’s face it, isn’t exactly practical.

    Now, Pisin Chen from the National Taiwan University and Gerard Mourou from École Polytechnique in France have described a slightly easier method.

    They suggest that a high-tech ‘accelerating mirror’ should provide the same opportunity of separating entangled particles.

    That sounds strange, but as a pair of particles zips into existence in this hypothetical experiment, one would reflect from the accelerating mirror as the other became trapped at the boundary. Just as it might happen in a black hole.

    Once the mirror stopped moving, the ‘trapped’ photon would be freed, just as the energy would be released from a dying black hole.

    Chen’s and Mourou’s mirror would be made by pulsing an X-ray laser through a cloud of ionised gas in a plasma wakefield accelerator. The pulse would leave a trail of negatively charged electrons, which would serve nicely as a mirror.

    By altering the density of the plasma on a small enough scale, the ‘mirror’ would accelerate away from the laser pulse.

    As clever as the concept is, the experiment is still in its ‘thought bubble ‘stage. Even with established methods and trusted equipment, entanglement is tricky business to measure.

    And Hawking radiation itself has yet to be observed as an actual thing.

    Yet Chen’s and Mourou’s model could feasibly be built using existing technology, and as the researchers point out in their paper, could also serve to test other hypotheses on the physics of black holes.

    It sounds far more appealing than waiting until the end of time in front of a black hole, at least.

    This research was published in Physical Review Letters.

    See the full article here .

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