Keyword: stringtheory
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Its inventors are comparing it to the Star Trek phaser: a way of exploiting an on-off 'switch' in nematodes that paralyzes them when they're exposed to a beam of ultraviolet light. The animals stay paralyzed even when the light is turned off. But when exposed to ordinary light, they become unparalyzed and wake up. It's the first time that photoswitching has been demonstrated in a living animal. The report describes the development and successful testing of a photoswitch composed of the light-sensitive material, dithienylethene. The scientists grew the transparent, pinhead-sized worms - C. elegans - and fed them dithienylethene. When...
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As a practising priest, there was great scope for mediation when Reiss took on such a key role in such a renowned scientific institution, but sadly science and religion really do not good bedfellows make. Yet if the CERN experiment succeeds in its quest to re-create the conditions just after the Big Bang, maybe a way can be found to understand the role of a creator in the building blocks of science. Some scientists believe in the concept of a creator at work behind the Big Bang and that among the possible revelations about ‘dark matter’, anti-matter and space-time dimensions...
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Math theories may hold clues to origin, future of life in universe June 9th, 2009 How did we get here and where are we headed? These are some of life's biggest questions. To get the answers, one Kansas State University professor is doing the math. Louis Crane, K-State professor of mathematics, is studying new theories about why the universe is the way it is. He has a grant from the Foundational Questions Institute to study new approaches to the quantum theory of gravity, his primary research area as both a mathematician and a physicist. Crane hopes to uncover implications of...
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What if the discrepancy arises from a flaw in our theory of gravity rather than from some provider of mass that we cannot see? In the 1980s physicist Mordehai Milgrom of the Weizmann Institute of Science in Rehovot, Israel, proposed a modification to Newtonian dynamics that would explain many of the observational discrepancies without requiring significant mass to be hidden away in dark matter. But it fell short of describing all celestial objects, and to incorporate the full span of gravitational interactions, a modification to Albert Einstein's theory of general relativity is needed. A review article in the November 6...
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Fermi telescope finds evidence that positrons, not just electrons, are in storms on EarthWashington — Designed to scan the heavens thousands to billions of light-years beyond the solar system for gamma rays, the Fermi Gamma-ray Space Telescope has also picked up a shocking vibe from Earth. During its first 14 months of operation, the flying observatory has detected 17 gamma-ray flashes associated with terrestrial storms — and some of those flashes have contained a surprising signature of antimatter.
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The Large Hadron Collider, the world's most powerful particle accelerator, just cannot catch a break. First, a coolant leak destroyed some of the magnets that guide the energy beam. Then LHC officials postponed the restart of the machine to add additional safety features. Now, a bird dropping a piece of bread on a section of the accelerator has, according to the Register, shut down the whole operation. The bird dropped some bread on a section of outdoor machinery, eventually leading to significant over heating in parts of the accelerator. The LHC was not operational at the time of the incident,...
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Finding Critics for Science Allie Winegar Duzett, November 4, 2009 There are many fields with rigorous critics; many writers make a living critiquing music, dance, art, and literature. At Accuracy in Media and other media watchdog groups, employees critique the claims of major news organizations. But one crucial field regularly goes without any public criticism: the field of science, and scientific discovery. “Science lacks for critics,” David Berlinski claimed at a recent Heritage Foundation Bloggers’ Briefing. “It is really remarkable that in the sense in which literature or dance or music has always entered public consciousness with a very rich...
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Next month, Prof. Ada Yonath will be awarded the Nobel Prize in chemistry, becoming the fifth Israeli scientist to win this award. This has sharpened, once again, the grim statistics regarding the scarcity of Nobel laureates in the Muslim and Arab worlds. While Jews, who are only around 0.2 percent of the world population, have won a quarter of all Nobel Prizes awarded in the sciences, Muslims, who are one quarter of the world population, have won only a handful, even by the most generous accounts. And while relative to its size, Israel's tiny academia has been the world's leading...
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A gigantic, previously unknown set of galaxies has been found in the distant universe, shedding light on the underlying skeleton of the cosmos. "Matter is not distributed uniformly in the universe," said Masayuki Tanaka, an astronomer with the European Southern Observatory (ESO) who helped discover the galactic assemblage. "In our cosmic vicinity, stars form in galaxies and galaxies usually form groups and clusters of galaxies." But those collections of matter are just small potatoes compared to larger structures long-theorized to exist. "The most widely accepted cosmological theories predict that matter also clumps on a larger scale in the so-called 'cosmic...
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Rethinking relativity: Is time out of joint? EVER since Arthur Eddington travelled to the island of Príncipe off Africa to measure starlight bending around the sun during a 1919 eclipse, evidence for Einstein’s theory of general relativity has only become stronger. Could it now be that starlight from distant galaxies is illuminating cracks in the theory’s foundation? .... Yet it is still not clear how well general relativity holds up over cosmic scales, at distances much larger than the span of single galaxies. Now the first, tentative hint of a deviation from general relativity has been found. While the evidence...
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As we recently noted, Stephen Hawking has stepped down from the Lucasian Chair at Cambridge. The chair didn't stay empty for long. It has been announced that Michael Green will become the new Lucasian Professor. Green is one of the pioneers of string theory, and is already at Cambridge. I'm not sure he even switches offices, or chairs for that matter. Hawking did seminal work in general relativity. He proved a number of singularity theorems (with Roger Penrose). He wrote The Large Scale Structure of Spacetime (with George Ellis). John Wheeler conjectured that quiescent black holes have "no hair" (i.e.,...
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As promised, Brian Cox was on The Colbert Report last night, and hit it out of the park. The whole show was better than average (which is saying a lot) but Brian truly rocked! If you missed it (and live in the States) the whole episode is online (Brian's segment is about 13:50 into the episode). Comedy Central won't allow embedding the whole show (sigh), and Brian's segment isn't separated out on the CC site, but right before he was on Colbert ragged on physics and the LHC... In the full segment, they talk about Brian's book Why E=mc2, which...
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When the Fermi team did the calculations, using the most conservative estimates for how astrophysics plays into this, they determined that the mass scale must be at least 1.2 times the Planck mass, and by using reasonable but less conservative assumptions, they derived lower limits on the mass scale of up to 100 times the Planck mass. One way to interpret this is to say that there is no variation of the speed of light coming from any quantum gravity effects at less than 1.2 times the Planck mass. And given that some quantum gravity frameworks predict that effects should...
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PARIS (AFP) – It took 13 billion years to reach Earth, but astronomers have seen the light of an exploding mega-star that is the most distant object ever detected, two studies published Thursday reported. The stunning gamma-ray burst (GRB) was observed by two teams of researchers in April, and opens a window onto a poorly known period when the Universe was in its infancy.
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Crystals that can confine both light and vibrations could create better biosensors.The crystal traps vibrations and light in the same place.Eichenfield M., et al. Light and mechanical vibrations have been imprisoned together for the first time ever in the same place. An artificial crystal that traps both could lead to ultra-sensitive biosensors, create an interface for devices on a chip and provide an elegant cooling mechanism to help test quantum limits. The communications industry has long used specially patterned materials, called photonic crystals, to guide light through optical fibres. Similar structures, known as phononic crystals, manipulate mechanical vibrations and are...
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Enlarge ImageBoom! After being hit with laser beams, a small plastic pellet (sunlike object) emits x-rays, some of which bombard a pellet of silicon (blue and purple). Credit: Adapted from S. Fujioka et al., Nature Physics, Advance Online Publication A team of researchers has created conditions analogous to those found outside of a black hole by blasting a plastic pellet with high-energy laser beams. The advance should sharpen insights into the behavior of matter and energy in extreme conditions. Astronomers can't observe black holes directly because their immense gravity won't let light escape. Instead, they have focused on what...
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PARIS — For decades, scientists have dreamed about turning thorium — an element that is less radioactive and produces less nuclear waste than uranium — into an alternative fuel for nuclear energy. Recent technological developments may be bringing the dream closer to reality. As a naturally occurring metal that is substantially more abundant than uranium, its most common isotopic form, thorium-232, can be converted by irradiation to uranium-233, which is suitable for use in nuclear fuels. The United States is estimated to have 400,000 tons of thorium, Turkey 344,000 tons and India 319,000 tons, according to a 2008 joint report...
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Mini-hole made of metamaterials ensnares microwave light.The artificial 'black hole' sucks up microwaves.Q. Cheng and T. J. Cui Physicists have created a black hole for light that can fit in your coat pocket. Their device, which measures just 22 centimetres across, can suck up microwave light and convert it into heat. The hole is the latest clever device to use 'metamaterials', specially engineered materials that can bend light in unusual ways. Previously, scientists have used such metamaterials to build 'invisibility carpets' and super-clear lenses. This latest black hole was made by Qiang Chen and Tie Jun Cui of Southeast University...
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The strongest limit on the number of possible universes is the human ability to distinguish between different universes. (PhysOrg.com) -- Over the past few decades, the idea that our universe could be one of many alternate universes within a giant multiverse has grown from a sci-fi fantasy into a legitimate theoretical possibility. Several theories of physics and astronomy have hypothesized the existence of a multiverse made of many parallel universes. One obvious question that arises, then, is exactly how many of these parallel universes might there be. In a new study, Stanford physicists Andrei Linde and Vitaly Vanchurin have calculated...
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In the past 5 years, no material has excited more interest from condensed matter physicists than graphene, a sheet of carbon only one atom thick. Electrons zing through the stuff in an unusual way, and they flow so easily that graphene could someday replace silicon and other semiconductors as the material of choice for microchips. Now, a team of physicists has taken a key step in fulfilling graphene's promise as a hotbed of exotic physics by showing that the electrons within it can team up to behave like particles with a fraction of the electron's charge. The effect is called...
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