Researchers who created the first so-called invisibility cloak in 2006, have made significant advances that could lead to an invisibility cloak for visible light in as little as six months. “A large number of folks are looking at it, and I think it’s a matter of coupling the right material to the right device,” [Discovery News] said researcher David Smith. His team has developed an algorithm that speeds up the design of materials that can bend light around an object. Using the new algorithm, they were able to create an invisibility cloak that can bend much wider spectrum of microwaves than previous versions.
Invisibility cloaks rely on metamaterials, ones with unique properties that derive from [their] physical structure, not [their] chemical make up [Discovery News]. Smith compares the effect of metamaterials on light to mirages that appear over a road on sweltering days. “You see what looks like water hovering over the road, but it is in reality a reflection from the sky,” Smith said. “In that example, the mirage you see is cloaking the road below. In effect, we are creating an engineered mirage with this latest cloak design” [AFP].
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The sound of scientific discovery isn’t the clichéd “Eureka!” It’s much more like this recent exclamation from NASA astrophysicist Alan Kogut: “What the heck is this?” Dr. Kogut remembered exclaiming when he first saw the data. “This shouldn’t be here” [The New York Times].
Kogut was looking at a measurement of cosmic radio signals detected by sensitive antennas borne aloft in a balloon, which floated 21 miles above Texas for several hours. While scanning the sky, the instruments found a booming, uniformly distributed radio noise six times louder than anyone had predicted…. The researchers calculate that the radio noise is much too large to be accounted for by the combined emissions of all the galaxies in the universe that emit radio waves [Science News].
When researchers started to contemplate where that signal may have come from, things began to get interesting. It’s possible, says Kogut, that the radio waves may have been emitted during the death of the universe’s first stars. Those stellar pioneers were brutish monsters, so the story believed by most astronomers goes, lumbering clouds of hydrogen and helium hundreds of times more massive than the Sun. They lived fast and bright and died hard, exploding or collapsing into massive black holes less than a billion years after the Big Bang, never to be seen again [The New York Times]. When they collapsed into black holes, they may have spewed forth jets of charged particles that emitted these radio waves.
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By harnessing a quantum mechanic force of repulsion researchers have caused nanoparticles to repel each other, and in their next experiment they plan to levitate a tiny gold nanosphere. The quantum force is part of the Casimir effect, first predicted in 1948 by the Dutch physicist Hendrik Casimir, which describes both the attraction and repulsion that occur between two tiny objects held close together in a vacuum. While the attractive force has previously been demonstrated, the new experiment marks the first time the repulsive force has been seen in a lab.
But the experiment wasn’t just a neat physics trick; the researchers say the repulsive force may one day be used in nanoscale devices. Lead author Jeremy Munday says the research may lend itself to producing ultrasensitive detectors and almost friction-free devices by separating their components via Casimir repulsion. “Where you would normally have friction,” he says, “you can start to greatly reduce that by having a repulsive interaction that doesn’t let the surfaces come into contact” [Scientific American].
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The mysterious force known as dark energy that is causing the universe’s expansion to accelerate is also preventing galaxy clusters from getting too big for their britches, a new study suggests. The existence of dark energy was first proposed a decade ago but the stuff has never been directly detected, and there’s much we don’t know about it. However, all the indirect studies have agreed that it acts like a kind of anti-gravity: A repulsive force that permeates empty space and, bizarrely, grows stronger with distance, precisely the opposite of what happens with gravity [Washington Post].
In the new study, researchers used NASA’s orbiting Chandra X-ray observatory to examine the growth patterns of galaxy clusters. After bulking up rapidly in the first 10 billion years of cosmic time, clusters of galaxies, the cloudlike swarms that are the largest conglomerations of matter in the universe, have grown anemically or not at all during the last five billion years, like sullen teenagers who suddenly refuse to eat. “This result could be explained as arrested development of the universe” [The New York Times], said lead researcher Alexey Vikhlinin. He says the findings support the idea that the gravity of the clusters drew in more and more matter for billions of years during their growth spurts. But gravity’s alter ego, dark energy, was tugging at the edges of the clusters, pulling matter away from the galaxies and stalling growth.
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President-elect Barack Obama has thrilled the scientific community with the leaked news that he plans to nominate a Nobel Prize-winning physicist with a passion for green technology for the post of energy secretary. The likely nominee, Steven Chu, currently heads the Lawrence Berkeley National Laboratory, and shared the Nobel in physics in 1997 for developing a method to cool and trap atoms.
Recently, however, Chu’s interests have shifted away from particle physics and towards finding scientific solutions for global warming. In an interview last year, Chu said he began to turn his attention to energy and climate change several years ago. “I was following it just as a citizen and getting increasingly alarmed,” he said. “Many of our best basic scientists [now] realize that this is getting down to a crisis situation” [Washington Post]. Since he became director of Lawrence Berkeley Lab in 2004 he has focused on making it a world leader in alternative energy research, spearheading research initiatives on solar energy and biofuels.
Obama is also expected to nominate Carol Browner, the EPA administrator under President Clinton, as the top White House official on climate and energy policy, and Lisa Jackson, who was until recently was New Jersey’s environmental protection chief, to head the EPA. Along with Chu, these people will be at the center of Obama administration’s energy and environment policy, which aims to reduce greenhouse gas emissions growth and have energy efficiency play an important role in an expected economic stimulus package [CNET].
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Astronomers have determined beyond all reasonable doubt that the heart of the Milky Way is a supermassive black hole, two research teams say. Astronomers have inferred the existence of a gravitational monster in the center of our galaxy for years, but the new results are “the best empirical evidence that super-massive black holes do really exist” [CNN], said researcher Reinhard Genzel.
Similar supermassive black holes are thought to form the center of many spiral and elliptical galaxies, and astronomer Robert Massey says the results suggest that galaxies form around giant black holes in the way that a pearl forms around grit. Dr Massey said: “Although we think of black holes as somehow threatening, in the sense that if you get too close to one you are in trouble, they may have had a role in helping galaxies to form – not just our own, but all galaxies” [BBC News]. Massey explains that if a black holes brings enough matter together in a dense cluster, it creates ripe conditions for the formations of stars and galaxies.
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The long-cherished dream of creating nearly limitless clean energy from nuclear fusion–the same process that powers our sun–is looking slightly more possible thanks to a new series of experiments. Researchers working with a reactor at MIT’s Plasma Science and Fusion Center have managed to control the motion of million-degree plasma using high-power radio waves. “Ours is the first definitive result showing that high-power radio waves can significantly affect the flow of the plasma,” said physicist Earl Marmar [EE Times]. The radio waves successfully propelled the plasma inside the dount-shaped chamber without hitting the cooler vessel walls, which would halt the fusion reaction, and also prevented the plasma from causing turbulence, which can interfere with reactions.
Fusion is thought to have enormous potential for future power generation, because fusion plant operation would produce no emissions, fuel sources are potentially abundant, and it produces relatively little (and short-lived) radioactive waste. That’s unlike nuclear fission (the splitting apart of a heavy atom to release energy), the process that powers all existing nuclear plants [LiveScience]. However, researchers stress that commercial fusion power plants are still a long way off. Physicists still don’t know how to make a reactor that generates more power than it consumes, a rather large problem for a potential energy source.
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The standard model of physics got it right when it predicted where the mass of ordinary matter comes from, according to a massive new computational effort. Particle physics explains that the bulk of atoms is made up of protons and neutrons, which are themselves composed of smaller particles known as quarks, which in turn are bound by gluons. The odd thing is this: the mass of gluons is zero and the mass of quarks [accounts for] only five percent. Where, therefore, is the missing 95 percent? [AFP]
The answer, according to theory, is that the energy from the interactions between quarks and gluons accounts for the excess mass (because as Einstein’s famous E=mc² equation proved, energy and mass are equivalent). Gluons are the carriers of the strong nuclear force that binds three quarks together to form one proton or neutron; these gluons are constantly popping into existence and disappearing again. The energy of these vacuum fluctuations has to be included in the total mass of the proton and neutron [New Scientist]. The new study finally crunched the numbers on how much energy is created in these fluctuations and confirmed the theory, but it took a supercomputer over a year to do so.
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An enormous helium balloon floating about 24 miles above Antarctica has detected a mix of high-energy electrons so exotic that researchers say the particles must have been created by some fascinating process: They may have been formed when dark matter particles collided and annihilated each other, or else a surprisingly close astronomical object like a pulsar could be spitting the electrons at Earth.
Researchers can’t yet determine which answer is correct, but say the dark matter explanation is more exciting. Dark matter is one of astrophysics’ greatest enigmas. It is thought to be five times more common than visible matter, but there is no proof of what it is made of. The existence of dark matter has largely been inferred from its gravitational effects, such as the fact that most galaxies have enough mass to remain as well-defined objects despite having too little visible matter to account for the necessary gravity [National Geographic News]. If the research balloon did detect the signature of dark matter through the particles left over from collisions, it would be the closest researchers have ever gotten to seeing the mysterious stuff.
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Fixing the glitches that shut down the Large Hadron Collider (LHC) in September will apparently be no easy task: A spokesman for the particle physics lab CERN has announced that the repairs will cost $21 million and will probably not be completed until late June. Cern spokesman James Gillies said: “If we can do it sooner, all well and good. But I think we can do it realistically (in) early summer” [BBC News].
The startup of the LHC on September 10th may win an award for anticlimax of the year: Physicists talked for months about the mysteries of physics that the particle collider would reveal, while nervous laypeople worried that when engineers flipped the switch on the machine it would create a miniature black hole that could destroy the earth. But instead of either of these scenarios coming true, the LHC broke within two weeks before getting a chance to perform any experiments.
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The Fermi Gamma-ray Space Telescope may have just gotten a hint in its hunt for the mysterious dark matter that is thought to make up the bulk of the universe’s mass. A group of astrophysicists has run a simulation of the distribution of dark matter in a galaxy like our Milky Way, and say that if the telescope scans the right region of space it may be able to detect gamma rays given off by collisions between the particles that are thought to make up dark matter (which have never been directly detected, and are still speculative).
Previously, some cosmologists have proposed that the best chance of a detection lies in nearby dwarf galaxies, since they should contain dense nuggets of dark matter that could be relatively easy to pinpoint. But a new study argues that a diffuse dark matter ‘halo’ surrounding the Milky Way offers an even better shot at glimpsing the mysterious stuff. “I would bet on it,” says lead author Volker Springel…. “And I’d be willing to risk a bit of money as well” [New Scientist].
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Strange things are afoot at the Tevatron particle collider at Fermilab, and the aging U.S. particle smasher is getting an unexpected moment in the spotlight while physicists wait for the repairs of the Large Hadron Collider in Switzerland. Researchers say experiments at the Tevatron have produced particles that they are unable to explain using the standard model of physics, and say it’s possible that they’ve detected a previously unknown particle. If the result does turn out to be due to some unexpected new process, it would be the most significant discovery in particle physics for decades [Physics World].
Bloggers and theorists are already lining up explanations that involve unseen particles, hypothetical strings, or modifications of conventional physics. The finding is so controversial that about one-third of the 600-person experiment that detected it are refusing to put their names on the 69-page paper purporting its discovery [Nature News], which was posted in advance of publication on the server arXiv.
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Peeling a roll of ordinary sticky tape can generate 100 milliwatt pulses of X-rays, enough to capture a human finger on X-ray film, according to a new study by UCLA scientists. They claim to have found the cheapest way to produce X-rays of that scale. “At some point we were a little bit scared,” says Juan Escobar, a member of the research team. But he and his co-workers soon realized that the X-rays were only emitted when the kit was used in a vacuum [Nature News].
Their kit consisted of a vacuum-enclosed machine, reminiscent of a video casette player, that peeled a roll of Photo Safe 3M Scotch tape at a rate of 3 cm per second. Rapid pulses of X-rays, each about a billionth of a second long, emerged from very close to where the tape was coming off the roll. That’s where electrons jumped from the roll to the sticky underside of the tape that was being pulled away, a journey of about two-thousandths of an inch, Escobar said. When those electrons struck the sticky side they slowed down, and that slowing made them emit X-rays [AP]. This type of energy release is known as triboluminescence — the same principle behind the fun trick of crunching on Wint-O-Green Live Savers to produce blue sparks.
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Encryption systems that rely on the “spooky” properties of quantum mechanics have long been hyped as the ultimate in spy- and hack-proof communication, and recently governments and large companies have begun sampling early examples of the technology. Now, scientists in Vienna have demonstrated a commercial telecommunications network protected by quantum cryptography, and say the system could be generally available in less than 10 years.
One of the researchers who worked out the basic idea behind quantum cryptography 25 years ago, Gilles Brassard, was on hand in Vienna to explain the mechanism. “All quantum security schemes are based on the Heisenberg Uncertainty Principle, on the fact that you cannot measure quantum information without disturbing it,” he explained. “Because of that, one can have a communications channel between two users on which it’s impossible to eavesdrop without creating a disturbance. An eavesdropper would create a mark on it. That was the key idea” [BBC News].
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Three scientists who probed the mysteries of particle physics have been awarded the Nobel Prize in physics, the Royal Swedish Academy of Sciences announced today. The winners are Yoichiro Nambu, a Tokyo-born American citizen, and Makoto Kobayashi and Toshihide Maskawa of Japan. Nambu identified a mechanism called spontaneous broken symmetry in subatomic physics. Kobayashi and Maskawa work predicted the existence of three families of elementary particles known as quarks. According to the Standard Model of particle physics, quarks are the sub-units of protons and neutrons, which together make up the nuclei of atoms [BBC News].
“Spontaneous broken symmetry conceals nature’s order under an apparently jumbled surface,” the academy said in its citation. “Nambu’s theories permeate the standard model of elementary particle physics. The model unifies the smallest building blocks of all matter and three of nature’s four forces in one single theory.” Kobayashi and Maskawa “explained broken symmetry within the framework of the standard model but required that the model be extended to three families of quarks” [AP].
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