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Evidence of second fast northsouth pole flip found

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Evidence of second fast north-south pole flip found (2010, September 6) retrieved 18 August 2019 from https://phys.org/news/2010-09-evidence-fast-north-south-pole-flip.html (PhysOrg.com) — The Earth’s magnetic poles flip around every 200,000 years or so, with north becoming south and vice versa. Normally, the process takes 4-5,000 years and it ought to be impossible for the flip to be much faster, if models of the Earth’s core are correct, but now for the second time evidence has been found of a flip that appears to have taken only a few years. The first time evidence was discovered of a rapid geomagnetic field reversal was in 1995 when well-preserved lava flows were found at Steens Mountain in Oregon in the US. Research on the rocks by a team led by geologist Scott Bogue of the Occidental College in Los Angeles revealed the lava flow had an unusual magnetic pattern that suggested the magnetic field had been shifting over 10,000 times faster than normal, at six degrees a day. The magnetic patterns are preserved within the magnetic crystals in the lava, formed as the lava flow cooled.The first findings remained controversial and many scientists have challenged the fast flip-flop theory, but now Bogue and colleague Jonathan Glen of the US Geological Survey have found evidence in ancient lava rock in Battle Mountain, Nevada of a second fast flip, dated around 15 million years ago.The record in one particular lava flow in Nevada suggests the magnetic field moved by 53 degrees in a single year. The lava started to cool, but was then heated again within a year as it was buried under fresh lava. The crystals in the rock were re-magnetized by the fresh lava, producing a shift of 53 degrees. This finding could mean the poles swapped over a period of only four years, but Brogue said it could also suggest there was a rapid acceleration period within the steady movement of the field.According to some geologists a polarity reversal is overdue, since the Earth’s magnetic field has been weakening for the last century, and the last stable reversal was about 780,000 years ago. Even if it was a super-fast flip-flop, however, it would not be noticeable to most people. No one is certain why such reversals take place, although many scientists believe they are connected in some way with the convective movements of the liquid iron in the Earth’s outer core.The findings are due to appear in Geophysical Research Letters. This wide angle view of the Earth is centered on the Atlantic Ocean between South America and Africa. Lava flows reveal clues to magnetic field reversals © 2010 PhysOrg.com More information: Bogue, S. W et al., Very rapid geomagnetic field change recorded by the partial remagnetization of a lava flow, Geophysical Research Letters, doi:10.1029/2010GL044286 , in press. Explore furtherlast_img read more

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Design student creates GAUNTLET glove that allows single handed typing w Video

first_img Citation: Design student creates G.A.U.N.T.L.E.T. glove that allows single handed typing (w/ Video) (2012, July 17) retrieved 18 August 2019 from https://phys.org/news/2012-07-student-gauntlet-glove-video.html (Phys.org) — Jiake Liu, co-founder of Kabob.it has been demonstrating his G.A.U.N.T.L.E.T. glove at this year’s TechCrunch meetup in Atlanta. The name of the glove is an acronym meant to describe both its function and looks. It has metallic letters affixed to parts of the front of the fingers and another metal piece on the thumb that allows for connections to be made when pressing the thumb against the letters, effectively allowing a person to use the glove as a Bluetooth enabled wireless keyboard that works with just one hand. Glove designers plan messaging path for deaf-blind The keyboard/glove is just one of many devices currently under development by researchers around the world to respond to the difficulties users have faced when trying to type on small smartphone screens or even on iPads. Though there are several Bluetooth enabled standard keyboards available for purchase, using them requires that they be toted around, a bulky proposition to be sure. Thus the search is on to find a way to allow users to type on their handheld devices in a reasonably elegant way.Liu told John Biggs of TechCrunch that he came up with the idea for his glove while still attending the University of Alabama in Huntsville as a senior design project after being inspired by some of the technology in such movies as Minority Report and has been tinkering with the idea ever since. He’s now a co-partner of Kabob.it a company that makes smart menus for people with food allergies to help them figure out which foods in restaurants are safe to eat. That venture has allowed him the funds to pursue the glove technology that he believes some people are looking for.The letters on the glove are arranged so that the most used letters are the easiest to reach; it also has an Enter key, spacebar and other function keys that allow the wearer to switch between keymaps, e.g. letters, numbers or special characters. It also has an accelerometer to allow for adjusting controls.The glove is not yet ready to be sold to consumers as Liu believes there is more work to be done to improve both the typing functionality and the overall look of the gloves, which clearly needs some work as it does still look like a work in progress. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.center_img © 2012 Phys.org Explore further More information: gauntletkeyboard.com/last_img read more

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Study finds semiclassical gravity counterintuitive but on the horizon of testability

first_img More information: Huan Yang, et al. “Macroscopic Quantum Mechanics in a Classical Spacetime.” PRL 110, 170401 (2013). DOI: 10.1103/PhysRevLett.110.170401 Citation: Study finds semiclassical gravity counterintuitive, but on the horizon of testability (2013, May 8) retrieved 18 August 2019 from https://phys.org/news/2013-05-semiclassical-gravity-counterintuitive-horizon-testability.html The physicists, Huan Yang, et al., at the California Institute of Technology in Pasadena, California, and the National Dong Hwa University in Hua-Lien, Taiwan, have published their paper, called “Macroscopic Quantum Mechanics in a Classical Spacetime,” in a recent issue of Physical Review Letters.Most theories of quantum gravity predict that gravity should be quantized. However, as Richard Feynman once said, “Quantum theory does not absolutely guarantee that gravity has to be quantized. … I would like to suggest that it is possible that quantum mechanics fails at large distances and for larger objects.” Since concrete, unambiguous experimental signatures of the quantum nature of gravity still do not exist (other than when assuming the “many-world” interpretation of quantum mechanics), the physicists here thought it would be worthwhile to investigate if a theory of quantum gravity could involve classical gravity.”Semiclassical gravity is one of the existing models which tries to unify quantum mechanics and general relativity,” Yang told Phys.org on behalf of his coauthors. “Instead of trying to quantize space and time (as in string theory, loop quantum gravity, etc.), in this model the spacetime is assumed to be a classical entity, although the matter particles in the spacetime are quantum. Our findings show the imminent possibility of verifying or falsifying the semiclassical gravity experimentally. More importantly, we point out that both self-gravitational effects and quantum effects are important for macroscopic objects—the only regime accessible by table-top experiments so far. This opens up the possibility for testing other models that try to unify quantum mechanics and general relativity, as well: gravity decoherence models, stochastic gravity models, emergent gravity models, etc. We don’t necessarily believe any of these models, but we believe it is important to test signatures/predictions of these models experimentally and let nature tell us what the true physics is, as we don’t have a conclusive theory of quantum gravity yet.” Physicists propose test for loop quantum gravity (Phys.org) —One of the more controversial theories of quantum gravity, which attempts to unify quantum mechanics and general relativity, is semiclassical gravity, which was proposed in the 1960s. As its name suggests, semiclassical gravity involves a combination of quantum and classical components. Specifically, matter obeys the rules of quantum mechanics while gravity and the spacetime structure obey classical laws. Many physicists think that integrating quantum and classical systems in this way creates physical contradictions and mathematical inconsistencies. However, in a new paper, physicists have closely analyzed exactly how classical gravity might affect the quantum properties of macroscopic objects, and found that the effects of semiclassical gravity may be experimentally detectable with state-of-the-art technology. Combining gravity and quantum mechanicsIn their paper, the scientists used a non-relativistic version of a semi-classical gravity model, which describes how the quantum state of a system changes over time under the influence of classical gravity, called the Schrödinger-Newton (SN) equation.Although physicists have extensively used the SN equation to study the quantum states of single particles, in the new paper the physicists use the equation to study the quantum states of macroscopic objects consisting of many particles. They show that the SN equation can be used to describe the quantum evolution of a macroscopic crystal’s center of mass, the point at which the object’s weight is perfectly balanced. The center-of-mass gives information on the self-gravitational effect that depends on the object’s internal structure, which enables physicists to investigate how the object’s quantum properties may be affected by classical gravity.The physicists’ calculations revealed several unique signatures of classical gravity on macroscopic quantum mechanics. Most interestingly, they found that the center-of-mass motion of a crystal is found to deviate slightly from standard quantum mechanics, obeying the SN equation where the center-of-mass wave function evolves nonlinearly due to self-gravitating effects.The calculations also revealed other interesting insights. For instance, the classical gravity of a single macroscopic crystal is much stronger in relation to itself than it is between two separate crystals. The physicists explain that this effect arises because the mass of a macroscopic crystal is concentrated near its lattice sites. Another signature of classical gravity acting on macroscopic quantum objects is that classical gravity cannot be used to transfer quantum uncertainties between two objects. In addition, the scientists discovered a unique signature regarding the evolution frequency of expectation values of position and momentum.Searching for semiclassical signaturesAlthough these effects are extremely weak, the physicists predict that one or more effects may induce visible signatures that are detectable with state-of-the-art optomechanics experiments. This kind of experiment could monitor and manipulate a macroscopic object’s center-of-mass at quantum levels. Although the individual particles in a macroscopic object cannot be accessed separately, a light beam could probe the average displacement of the atoms in the first few layers of a reflective coating on a macroscopic object. Since the motion of these surface atoms is related to the center-of-mass motion of the entire object, the experiment could potentially probe some of the unique effects hinting at semiclassical gravity.”If the future experiment sees the effects predicted by the SN equation, this means gravity/spacetime is classical, and previous attempts for quantizing gravity were on the wrong track, which is unlikely but nevertheless possible,” Yang said. “However, if the experiment shows null results, it is highly possible that gravity is quantum. The third possibility is that the experiment sees some non-null result which is not consistent with SN prediction either. This may inspire physicists to formulate new theories of quantum gravity, given the experimental results.”Overall, the results show that semiclassical gravity involves effects that are counterintuitive, but not necessarily contradictory. Although experimentally detecting such effects is unlikely, their detection would open up many new opportunities in the search for quantum gravity. “We talked to several experimental groups, including Nergis Mavalvala’s group at MIT, Thomas Corbitt’s group at Louisiana State Universiity, Markus Aspelmeyer’s group at the University of Vienna, and Michael Tobar’s group at Western Australia University,” Yang said. “They were very excited about the idea and the possibility of doing the experiment. We will collaborate with experimentalists in performing such an experiment in the future.”center_img © 2013 Phys.org. All rights reserved. Journal information: Physical Review Letters This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore furtherlast_img read more

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Water ice detected at the surface of a distant stars disk

first_img © 2016 Phys.org Astronomers peer into the ‘amniotic sac’ of a planet-hosting star HD 100546 is a 10 million-year-old star located some 320 light years from the Earth. It is accompanied by a fairly flat circumstellar disk in an advanced evolutionary state residing at a distance of 0.2 to four AU, and again from 13 to a few hundred AU from the star. The Hubble Space Telescope revealed that the disk features some complex spiral patterns. However, the nature and origin of these patterns remains uncertain.The star was observed using NICI on Mar. 31, 2012. This instrument is a coronagraphic camera designed to survey for and image large, extra-solar gaseous planets. It allows astronomers to search for large Jupiter planets around nearby stars by spectrally differencing two images taken in or next to strong, near-infrared methane features found in the atmosphere of large, Jovian-type planets.The scientists extracted the scattered light spectra of different regions of the protoplanetary disk around HD 100546. Scattered light observations complement thermal observations and constrain models based on spectroscopic data. NICI helped them unveil the 3.1 µm absorption feature in the scattered light spectrum of the observed disk. They link this feature with the presence of water ice grains.According to the research team, the shallowness of this ice absorption feature can be explained by the loss of ice grains at the disk surface.”In almost all the regions, relatively shallow three µm absorption feature is present in their spectra likely due to water ice grains, indicating that the water ice grains present in the disk surface,” the paper reads.Previous studies claimed that the water ice grains can be quickly destroyed at the disk surface around stars like HD 100546 due to a strong ultraviolet photodesorption.The discovery made by Honda and colleagues could provide new insights on planet formation theories as water ice is believed to play many important roles in the process of forming planetesimals. For instance, ice enhances the surface density of solid material in the cold outer part of a protoplanetary disk, which promotes the formation of massive cores of gaseous planets.”The ice sublimation/condensation front called snowline is considered to be the boundary of the forming regions of the terrestrial and Jovian planets. Snowline is also suggested as a possible forming site of the planetesimals,” the researchers wrote in the paper.The astronomers noted that in order to comprehensively understand the water ice distribution in the protoplanetary disks, other effects on the depth of water ice absorption should be investigated in future theoretical studies. They suggest that further investigations should focus on the grain size, shape and its structure, as well as ice/rock ratio (abundance), dust settling, turbulent mixing, and so on.”Further observations with better photometric accuracy are strongly desired,” the scientists concluded. Citation: Water ice detected at the surface of a distant star’s disk (2016, April 7) retrieved 18 August 2019 from https://phys.org/news/2016-04-ice-surface-distant-star-disk.html More information: Water ice at the surface of HD 100546 disk, arXiv:1603.09512 [astro-ph.EP] arxiv.org/abs/1603.09512AbstractWe made near infrared multicolor imaging observations of a disk around Herbig Be star HD100546 using Gemini/NICI. K (2.2,μm), H2O ice (3.06,μm), and L'(3.8,μm) disk images were obtained and we found the 3.1,μm absorption feature in the scattered light spectrum, likely due to water ice grains at the disk surface. We compared the observed depth of the ice absorption feature with the disk model based on cite{Oka2012} including water ice photodesorption effect by stellar UV photons. The observed absorption depth can be explained by the both disk models with/without photodesorption effect within the measurement accuracy, but slightly favors the model with photodesorption effects, implying that the UV photons play an important role on the survival/destruction of ice grains at the Herbig Ae/Be disk surface. Further improvement on the accuracy of the observations of the water ice absorption depth is needed to constrain the disk models. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (Phys.org)—A team of Japanese astronomers has recently discovered water ice at the surface of a distant star’s disk. Using the Near-Infrared Coronagraphic Imager (NICI) installed on the Gemini South Telescope in Chile, the researchers, led by Mitsuhiko Honda at the Kurume University School of Medicine’s Department of Physics, found that a circumstellar disk around the star HD 100546 contains water ice grains. The findings are reported in a paper published online on Mar. 31 in the arXiv repository. Positions of the spectra extracted region shown in the L’ image of HD100546 disk. A 0.162′′ square regions were set along the major (SE-NW) and minor (SW-NE) axis of the disk at the position of 0.360′′, 0.522′′, 0.684′′, 0.846′′, and 1.008′′ from the central star. Credit: Honda et al., 2016.last_img read more

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Algorithm ensures that random numbers are truly random

first_img Citation: Algorithm ensures that random numbers are truly random (2016, June 24) retrieved 18 August 2019 from https://phys.org/news/2016-06-algorithm-random.html (Phys.org)—Generating a sequence of random numbers may be more difficult than it sounds. Although the numbers may appear random, how do you know for sure that they don’t actually follow some complex, underlying pattern? For this reason, finding a way to certify that a sequence of numbers is truly random is often more challenging than generating the sequence in the first place. In the new study, the researchers use the first method, by measuring the quantum states of some physical system. However, the physical method has its own problems: How do you know for sure that the measurement devices used to measure the physical system don’t have some underlying predictability due to the way they were constructed? To overcome this problem, scientists have developed strict requirements on the devices, but these “device-independent” protocols are so strict that they are very slow at generating large amounts of random numbers.As a compromise between security and efficiency, researchers have developed “semi-device-independent” protocols that don’t have such strict requirements, but do place limits on the device capacity. These protocols can generate truly random numbers, but they still require a large amount of post-processing computational power to certify that the sequences are random. More randomness with more computing powerIn the new paper, the researchers’ main contributions is showing that a tradeoff exists for semi-device-independent protocols. The more computational power that is available to analyze the experimental data and certify its randomness, the less strict the requirements need to be on the measurement devices that generate the random data in the first place.Based on this tradeoff, the researchers designed a new algorithm that can extract more data from the experiment, and then, using a large amount of computing power, can certify a large amount of randomness—more than any other method developed to date. Even more importantly, it can do so faster and even work in cases where slower methods don’t work at all.”Our method allows to certify more randomness than the standard one,” Pawłowski said. “Let’s assume that you are using the latter and get 1 bit/second and using ours you get 2 bits/second. It means that the same device certified with our method need half the time to produce the required mount of bits. It’s nice. “But there are cases when our method certifies 1 bit/sec and the standard one 0. Now our method becomes really important because without it we have a completely useless device. I think this is its biggest advantage—making useless devices useful.”The new method also has the advantage that it doesn’t require altering the physical quantum system like other methods do, although it does come at the cost of requiring greater computing power. Nevertheless, the researchers believe that this is a worthwhile tradeoff, and expect that the new approach will guide future research on random number certification.”We have demonstrated the usefulness of our method in one case, but we have preliminary results and hand-weaving arguments that suggest that our method may be applied for different experimental setups and scenarios (for example, fully device-independent or with one party fully trusted),” Pawłowski said. “We are now trying to prove this and see in which situations it is most useful. Our second goal is to try to reduce the time of computation required for certifying more randomness. We have some preliminary results here too, which suggest it can be done.” New method of producing random numbers could improve cybersecurity Explore further Researchers have developed a method to certify more randomness in long sequences of random numbers than other methods can. Credit: Mironowicz et al. CC-BY-3.0 More information: Piotr Mironowicz et al. “Increased certification of semi-device independent random numbers using many inputs and more post-processing.” New Journal of Physics. DOI: 10.1088/1367-2630/18/6/065004 Journal information: New Journal of Physics © 2016 Phys.org. All rights reserved. In a new study, researchers have developed a new algorithm that increases the amount of certified randomness in a sequence of seemingly random numbers that has been generated experimentally. The researchers, Piotr Mironowicz et al., at universities in Poland, Sweden, and Brazil, have published their paper on the new random number certification algorithm in a recent issue of the New Journal of Physics.As the scientists explain, generating long sequences of numbers with certified randomness is critical for ensuring security in computers, cell phones, and other electronic devices.”Every electronic device needs randomness and needs a lot of it,” coauthor Marcin Pawłowski at the University of Gdańsk in Poland told Phys.org. “Randomness is necessary whenever you need security. Whenever you want secure communication, a cryptographic key must be generated. It has to be generated randomly so that no adversary can easily guess it. Nowadays, every communication is encrypted that way. Whenever you call someone on your mobile phone or send a text, a sequence of random numbers has to be generated. If someone can predict these numbers (it doesn’t have to be perfect—if he or she can guess some of them it’s enough), they can listen to your conversation. “Random numbers are constantly being generated by every machine that can communicate. And even if it does not communicate, every computer needs randomness to allocate programs in the memory. It is trivial to hack a computer which assigns the same place in its memory for the same program every time it’s run. Exploiting backdoors or malfunctions in random number generators is one of the most common ways to attack communication or computer systems.” Lots of numbers, no patternAlthough it’s relatively easy to generate and certify short sequences of random numbers, cryptographic applications require long sequences of random numbers, and the length is what makes the task much more challenging.In general, researchers use two main methods to generate long sequences of random numbers. The first method is based on exploiting the randomness inherent in physical systems, such as the optical noise in lasers and radioactive decay in atoms. This randomness can be traced back to these systems’ quantum properties. The second method uses computer software that can perform complicated arithmetical procedures. Technically, only the first method produces truly random numbers. The computer-generated numbers are considered “pseudorandom” because knowing how the program develops its computations makes it possible to predict these numbers, which only appear random. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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