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Spacetime Invisibility Cloaks

Spacetime Invisibility Cloaks

Here are 10,000 reasons to be excited about deep-space exploration They'll ask why we continue to strive to see further and deeper into space than ever before, without knowing what we'll find. They'll ask why we insist upon exploring a solar system that, by their account, has no immediate bearing on our lives. And they'll ask why, in light of recent budgetary crises, space agencies the world over deserve funding to seek out answers to the mysteries of a Universe that we will never fully understand. Strawmen are made of straw. The first two questions are asked by ignoramuses. To use an analogy, I love travel. But even if we all can agree on the value of travel, is it still not grossly irresponsible to pay for your vacation to Europe or your study-abroad in India when you can't pay your rent, utilities or student loans without a credit card? I loved Hubble, and I'm sure I'll equally love the Webb telescope. But let's not kid ourselves by pretending that we are not in a place today that forces us to make budgetary priorities.

Scientists Discover The Oldest, Largest Body Of Water In Existence--In Space Scientists have found the biggest and oldest reservoir of water ever--so large and so old, it’s almost impossible to describe. The water is out in space, a place we used to think of as desolate and desert dry, but it's turning out to be pretty lush. Researchers found a lake of water so large that it could provide each person on Earth an entire planet’s worth of water--20,000 times over. The water is in a cloud around a huge black hole that is in the process of sucking in matter and spraying out energy (such an active black hole is called a quasar), and the waves of energy the black hole releases make water by literally knocking hydrogen and oxygen atoms together. The official NASA news release describes the amount of water as “140 trillion times all the water in the world’s oceans," which isn’t particularly helpful, except if you think about it like this. That one cloud of newly discovered space water vapor could supply 140 trillion planets that are just as wet as Earth is.

Motion Mountain - The Free Physics Textbook for Download STEPHEN HAWKING: How to build a time machine By STEPHEN HAWKING Created: 18:47 GMT, 27 April 2010 All you need is a wormhole, the Large Hadron Collider or a rocket that goes really, really fast 'Through the wormhole, the scientist can see himself as he was one minute ago. Hello. Time travel was once considered scientific heresy. To see how this might be possible, we need to look at time as physicists do - at the fourth dimension. But there is another kind of length, a length in time. To see what that means, let's imagine we're doing a bit of normal, everyday car travel. Let's indulge in a little science fiction for a moment. Physicists have been thinking about tunnels in time too, but we come at it from a different angle. Enlarge A wormhole is a theoretical 'tunnel' or shortcut, predicted by Einstein's theory of relativity, that links two places in space-time - visualised above as the contours of a 3-D map, where negative energy pulls space and time into the mouth of a tunnel, emerging in another universe. Nothing is flat or solid.

The History of the Universe in 200 Words or Less Quantum fluctuation. Inflation. Expansion. Copyright 1996-1997 by Eric Schulman. This piece was the inspiration for the book A Briefer History of Time and led to the Annals of Improbable Research Universal History Translation Project. Interested in learning more about any of these events? Meaning of Halflife I'd like to illustrate what this really means. If living creatures had halflives the way radioactive atoms do, the world would be a very different place. What do you mean? Suppose there's an alien species with a halflife of, say, 70 years. You randomly pick out 16 baby aliens and track them to see how long they live. That doesn't sound so weird. True...but remember that the halflife is always the same, regardless of how old the aliens are. That is kind of strange. It gets stranger. Methuselah isn't going to make it, though. Methuselah has just as much chance of surviving the next 70 years as any one of the 15 babies.

How To Destroy A Black Hole The idea of a body so massive that its escape velocity exceeds the speed of light dates back to the English geologist John Michell who first considered it in 1783. In his scenario, a beam of light would travel away from the massive body until it reached a certain height and then returned to the surface. Modern thinking about black holes is somewhat different, not least because special relativity tells us that the speed of light is a universal constant. The event horizon is somewhat of a disappointment to many astrophysicists because the interesting physics, the stuff beyond the known laws of the universe, all occurs inside it and is therefore hidden from us. What physicists would like, therefore, is way to get rid of the event horizon and expose the inner workings to proper scrutiny. Today, Ted Jacobson at the University of Maryland and Thomas Sotiriou and the University of Cambridge explain how this might be done in an entertaining and remarkably accessible account of the challenge.

Einstein for Everyone Einstein for Everyone Nullarbor Press 2007revisions 2008, 2010, 2011, 2012, 2013 Copyright 2007, 2008, 2010, 2011, 2012, 2013 John D. Norton Published by Nullarbor Press, 500 Fifth Avenue, Pittsburgh, Pennsylvania 15260 with offices in Liberty Ave., Pittsburgh, Pennsylvania, 15222 All Rights Reserved John D. An advanced sequel is planned in this series:Einstein for Almost Everyone 2 4 6 8 9 7 5 3 1 ePrinted in the United States of America no trees were harmed web*bookTM This book is a continuing work in progress. January 1, 2015. Preface For over a decade I have taught an introductory, undergraduate class, "Einstein for Everyone," at the University of Pittsburgh to anyone interested enough to walk through door. With each new offering of the course, I had the chance to find out what content worked and which of my ever so clever pedagogical inventions were failures. At the same time, my lecture notes have evolved. This text owes a lot to many. i i i

Not-quite-so elementary, my dear electron Electrons in atoms behave like waves, and when researchers excite them to higher orbits, those waves can split up, revealing the constituent characteristics of the electron. In a feat of technical mastery, condensed-matter physicists have managed to detect the elusive third constituent of an electron — its 'orbiton'. The achievement could help to resolve a long-standing mystery about the origin of high-temperature superconductivity, and aid in the construction of quantum computers. Isolated electrons cannot be split into smaller components, earning them the designation of a fundamental particle. “These quasiparticles can move with different speeds and even in different directions in the material,” says Jeroen van den Brink, a condensed-matter physicist at the Institute for Theoretical Solid State Physics in Dresden, Germany. In 1996, physicists split an electron into a holon and spinon2.

Quantum decision affects results of measurements taken earlier in time Quantum entanglement is a state where two particles have correlated properties: when you make a measurement on one, it constrains the outcome of the measurement on the second, even if the two particles are widely separated. It's also possible to entangle more than two particles, and even to spread out the entanglements over time, so that a system that was only partly entangled at the start is made fully entangled later on. This sequential process goes under the clunky name of "delayed-choice entanglement swapping." And, as described in a Nature Physics article by Xiao-song Ma et al., it has a rather counterintuitive consequence. Delayed-choice entanglement swapping consists of the following steps. Two independent sources (labeled I and II) produce pairs photons such that their polarization states are entangled. The results of all four measurements are then compared. The practicalities of delayed-choice entanglement swapping bears many similarities to other entanglement experiments.

Radio telescopes capture best-ever snapshot of black hole jets An international team, including NASA-funded researchers, using radio telescopes located throughout the Southern Hemisphere has produced the most detailed image of particle jets erupting from a supermassive black hole in a nearby galaxy. "These jets arise as infalling matter approaches the black hole, but we don't yet know the details of how they form and maintain themselves," said Cornelia Mueller, the study's lead author and a doctoral student at the University of Erlangen-Nuremberg in Germany. The new image shows a region less than 4.2 light-years across -- less than the distance between our sun and the nearest star. Radio-emitting features as small as 15 light-days can be seen, making this the highest-resolution view of galactic jets ever made. The study will appear in the June issue of Astronomy and Astrophysics and is available online. Mueller and her team targeted Centaurus A (Cen A), a nearby galaxy with a supermassive black hole weighing 55 million times the sun's mass.

Quantum teleportation achieved over ten miles of free space Quantum teleportation has achieved a new milestone or, should we say, a new ten-milestone: scientists have recently had success teleporting information between photons over a free space distance of nearly ten miles, an unprecedented length. The researchers who have accomplished this feat note that this brings us closer to communicating information without needing a traditional signal, and that the ten miles they have reached could span the distance between the surface of the earth and space. As we've explained before, "quantum teleportation" is quite different from how many people imagine teleportation to work. When one of the items is sent a distance away, entanglement ensures that changing the state of one causes the other to change as well, allowing the teleportation of quantum information, if not matter. Teleportation over distances of a few hundred meters has previously only been accomplished with the photons traveling in fiber channels to help preserve their state.