A new set of codes that, for the first time, are able to apply Einstein's complete general theory of relativity to simulate how our universe evolved, have been independently developed by two international teams of physicists. They pave the way for cosmologists to confirm whether our interpretations of observations of large-scale structure and cosmic expansion are telling us the true story.
The impetus to develop codes designed to apply general relativity to cosmology stems from the limitations of traditional numerical simulations of the universe. Currently, such models invoke Newtonian gravity and assume a homogenous universe when describing cosmic expansion, for reasons of simplicity and computing power. On the largest scales the universe is homogenous and isotropic, meaning that matter is distributed evenly in all directions; but on smaller scales the universe is clearly inhomogeneous, with matter clumped into chains of galaxies and filaments of dark matter assembled around vast voids.
Quantum computer makes first high-energy physics simulation
Physicists have performed the first full simulation of a high-energy physics experiment — the creation of pairs of particles and their antiparticles — on a quantum computer1. If the team can scale it up, the technique promises access to calculations that would be too complex for an ordinary computer to deal with.
To understand exactly what their theories predict, physicists routinely do computer simulations. They then compare the outcomes of the simulations with actual experimental data to test their theories.
In some situations, however, the calculations are too hard to allow predictions from first principles. This is particularly true for phenomena that involve the strong nuclear force, which governs how quarks bind together into protons and neutrons and how these particles form atomic nuclei, says Christine Muschik, a theoretical physicist at the University of Innsbruck in Austria and a member of the simulation team.
Many researchers hope that future quantum computers will help to solve this problem. These machines, which are still in the earliest stages of development, exploit the physics of objects that can be in multiple states at once, encoding information in ‘qubits’, rather than in the on/off state of classical bits. A computer made of a handful of qubits can perform many calculations simultaneously, and can complete certain tasks exponentially faster than an ordinary computer.
Esteban Martinez, an experimental physicist at the University of Innsbruck, and his colleagues completed a proof of concept for a simulation of a high-energy physics experiment in which energy is converted into matter, creating an electron and its antiparticle, a positron.
The team used a tried-and-tested type of quantum computer in which an electromagnetic field traps four ions in a row, each one encoding a qubit, in a vacuum. They manipulated the ions’ spins — their magnetic orientations — using laser beams. This coaxed the ions to perform logic operations, the basic steps in any computer calculation.
After sequences of about 100 steps, each lasting a few milliseconds, the team looked at the state of the ions using a digital camera. Each of the four ions represented a location, two for particles and two for antiparticles, and the orientation of the ion revealed whether or not a particle or an antiparticle had been created at that location.
The team’s quantum calculations confirmed the predictions of a simplified version of quantum electrodynamics, the established theory of the electromagnetic force. “The stronger the field, the faster we can create particles and antiparticles,” Martinez says. He and his collaborators describe their results on 22 June in Nature1.
Four qubits constitute a rudimentary quantum computer; the fabled applications of future quantum computers, such as for breaking down huge numbers into prime factors, will require hundreds of qubits and complex error-correction codes. But for physical simulations, which can tolerate small margins of error, 30 to 40 qubits could already be useful, Martinez says.
John Chiaverini, a physicist who works on quantum computing at the Massachusetts Institute of Technology in Cambridge, says that the experiment might be difficult to scale up without significant modifications. The linear arrangement of ions in the trap, he says, is “particularly limiting for attacking problems of a reasonable scale”. Muschik says that her team is already making plans to use two-dimensional configurations of ions.
Are we there yet?
“We are not yet there where we can answer questions we can’t answer with classical computers,” Martinez says, “but this is a first step in that direction.” Quantum computers are not strictly necessary for understanding the electromagnetic force. However, the researchers hope to scale up their techniques so that they can simulate the strong nuclear force. This may take years, Muschik says, and will require not only breakthroughs in hardware, but also the development of new quantum algorithms.
These scaled-up quantum computers could help in understanding what happens during the high-speed collision of two atomic nuclei, for instance. Faced with such a problem, classical computer simulations just fall apart, says Andreas Kronfeld, a theoretical physicist who works on simulations of the strong nuclear force at the Fermi National Accelerator Laboratory (Fermilab) near Chicago, Illinois.
Another example, he says, is understanding neutron stars. Researchers think that these compact celestial objects consist of densely packed neutrons, but they’re not sure. They also don’t know the state of matter in which those neutrons would exist.
E.T. Phones Earth? 1,500 Years Until Contact, Experts Estimate
"Communicating with anybody is an incredibly slow, long-duration endeavor," said Evan Solomonides at a press conference June 14 at the American Astronomical Society's summer meeting in San Diego, California. Solomonides is an undergraduate student at Cornell University in New York, where he worked with Cornell radio astronomer Yervant Terzian to explore the mystery of the Fermi paradox: If life is abundant in the universe, the argument goes, it should have contacted Earth, yet there's no definitive sign of such an interaction.
We could be on the brink of a shockingly big discovery in physics
It's December 15, 2015, and an auditorium in Geneva is packed with physicists. The air is filled with tension and excitement because everybody knows that something important is about to be announced. The CERN Large Hadron Collider (LHC) has recently restarted operations at the highest energies ever achieved in a laboratory experiment, and the first new results from two enormous, complex detectors known as ATLAS and CMS are being presented. This announcement has been organized hastily because both detectors have picked up something completely unexpected. Rumors have been circulating for days about what it might be, but nobody knows for sure what is really going on, and the speculations are wild.
Scientists have detected gravitational waves for the second time
Scientists with the LIGO collaboration claim they have once again detected gravitational waves — the ripples in space-time produced by objects moving throughout the Universe. It’s the second time these researchers have picked up gravitational wave signals, after becoming the first team in history to do so earlier this year.
No Escape From Black Holes? Stephen Hawking Points to a Possible Exit
“A black hole has no hair.”
That mysterious, koan-like statement by the theorist and legendary phrasemaker John Archibald Wheeler of Princeton has stood for half a century as one of the brute pillars of modern physics.
It describes the ability of nature, according to classical gravitational equations, to obliterate most of the attributes and properties of anything that falls into a black hole, playing havoc with science’s ability to predict the future and tearing at our understanding of how the universe works.
Now it seems that statement might be wrong.
Recently Stephen Hawking, who has spent his entire career battling a form of Lou Gehrig’s disease, wheeled across the stage in Harvard’s hoary, wood-paneled Sanders Theater to do battle with the black hole. It is one of the most fearsome demons ever conjured by science, and one partly of his own making: a cosmic pit so deep and dense and endless that it was long thought that nothing — not even light, not even a thought — could ever escape.
But Dr. Hawking was there to tell us not to be so afraid.
In a paper to be published this week in Physical Review Letters, Dr. Hawking and his colleagues Andrew Strominger of Harvard and Malcolm Perry of Cambridge University in England say they have found a clue pointing the way out of black holes.
“They are not the eternal prisons they were once thought,” Dr. Hawking said in his famous robot voice, now processed through a synthesizer. “If you feel you are trapped in a black hole, don’t give up. There is a way out.”
Black holes are the most ominous prediction of Einstein’s general theory of relativity: Too much matter or energy concentrated in one place would cause space to give way, swallowing everything inside like a magician’s cloak.
An eternal prison was the only metaphor scientists had for these monsters until 40 years ago, when Dr. Hawking turned black holes upside down — or perhaps inside out. His equations showed that black holes would not last forever. Over time, they would “leak” and then explode in a fountain of radiation and particles. Ever since, the burning question in physics has been: When the black hole finally goes, does it give up the secrets of everything that fell in?
Dr. Hawking’s calculation was, and remains, hailed as a breakthrough in understanding the connection between gravity and quantum mechanics, between the fabric of space and the subatomic particles that live inside it — the large and the small in the universe.
But there was a hitch. By Dr. Hawking’s estimation, the radiation coming out of the black hole as it fell apart would be random. As a result, most of the “information” about what had fallen in — all of the attributes and properties of the things sucked in, whether elephants or donkeys, Volkswagens or Cadillacs — would be erased.
In a riposte to Einstein’s famous remark that God does not play dice, Dr. Hawking said in 1976, “God not only plays dice with the universe, but sometimes throws them where they can’t be seen.”
But his calculation violated a tenet of modern physics: that it is always possible in theory to reverse time, run the proverbial film backward and reconstruct what happened in, say, the collision of two cars or the collapse of a dead star into a black hole.
The universe, like a kind of supercomputer, is supposed to be able to keep track of whether one car was a green pickup truck and the other was a red Porsche, or whether one was made of matter and the other antimatter. These things may be destroyed, but their “information” — their essential physical attributes — should live forever.
In fact, the information seemed to be lost in the black hole, according to Dr. Hawking, as if part of the universe’s memory chip had been erased. According to this theorem, only information about the mass, charge and angular momentum of what went in would survive.
Nothing about whether it was antimatter or matter, male or female, sweet or sour.
A war of words and ideas ensued. The information paradox, as it is known, was no abstruse debate, as Dr. Hawking pointed out from the stage of the Sanders Theater in April. Rather, it challenged foundational beliefs about what reality is and how it works.
If the rules break down in black holes, they may be lost in other places as well, he warned. If foundational information disappears into a gaping maw, the notion of a “past” itself may be in jeopardy — we couldn’t even be sure of our own histories. Our memories could be illusions.
“It’s the past that tells us who we are. Without it we lose our identity,” he said.
Fortunately for historians, Dr. Hawking conceded defeat in the black hole information debate 10 years ago, admitting that advances in string theory, the so-called theory of everything, had left no room in the universe for information loss.
At least in principle, then, he agreed, information is always preserved — even in the smoke and ashes when you, say, burn a book. With the right calculations, you should be able reconstruct the patterns of ink, the text.
Dr. Hawking paid off a bet with John Preskill, a Caltech physicist, with a baseball encyclopedia, from which information can be easily retrieved.
But neither Dr. Hawking nor anybody else was able to come up with a convincing explanation for how that happens and how all this “information” escapes from the deadly erasing clutches of a black hole.
Indeed, a group of physicists four years ago tried to figure it out and suggested controversially that there might be a firewall of energy just inside a black hole that stops anything from getting out or even into a black hole.
The new results do not address that issue. But they do undermine the famous notion that black holes have “no hair” — that they are shorn of the essential properties of the things they have consumed.
About four years ago, Dr. Strominger started noodling around with theoretical studies about gravity dating to the early 1960s. Interpreted in a modern light, the papers — published in 1962 by Hermann Bondi, M. G. J. van der Burg, A. W. K. Metzner and Rainer Sachs, and in 1965 by Steven Weinberg, later a recipient of the Nobel Prize — suggested that gravity was not as ruthless as Dr. Wheeler had said.
Looked at from the right vantage point, black holes might not be not be bald at all.
The right vantage point is not from a great distance in space — the normal assumption in theoretical calculations — but from a far distance in time, the far future, technically known as “null infinity.”
“Null infinity is where light rays go if they are not trapped in a black hole,” Dr. Strominger tried to explain over coffee in Harvard Square recently.From this point of view, you can think of light rays on the surface of a black hole as a bundle of straws all pointing outward, trying to fly away at the speed of, of course, light. Because of the black hole’s immense gravity, they are stuck.
But the individual straws can slide inward or outward along their futile tracks, slightly advancing or falling back, under the influence of incoming material. When a particle falls into a black hole, it slides the straws of light back and forth, a process called a supertranslation.
That leaves a telltale pattern on the horizon, the invisible boundary that is the point of no return of a black hole — a halo of “soft hair,” as Dr. Strominger and his colleagues put it. That pattern, like the pixels on your iPhone or the wavy grooves in a vinyl record, contains information about what has passed through the horizon and disappeared.
“One often hears that black holes have no hair,” Dr. Strominger and a postdoctoral researcher, Alexander Zhiboedov, wrote in a 2014 paper. Not true: “Black holes have a lush infinite head of supertranslation hair.”
Enter Dr. Hawking.
For years, he and Dr. Strominger and a few others had gotten together to work in seclusion at a Texas ranch owned by the oilman and fracking pioneer George P. Mitchell. Because Dr. Hawking was discouraged from flying, in April 2014 the retreat was in Hereford, Britain. It was there that Dr. Hawking first heard about soft hair — and was very excited. He, Dr. Strominger and Dr. Perry began working together.
In Stockholm that fall, he made a splash when he announced that a resolution to the information paradox was at hand — somewhat to the surprise of Dr. Strominger and Dr. Perry, who has been trying to maintain an understated stance.
Although information gets hopelessly scrambled, Dr. Hawking declared, it “can be recovered in principle, but it is lost for all practical purposes.”
In January, Dr. Hawking, Dr. Strominger and Dr. Perry posted a paper online titled “Soft Hair on Black Holes,” laying out the basic principles of their idea.
In the paper, they are at pains to admit that knocking the pins out from under the no-hair theorem is a far cry from solving the information paradox. But it is progress.
Their work suggests that science has been missing something fundamental about how black holes evaporate, Dr. Strominger said. And now they can sharpen their questions. “I hope we have the tiger by the tail,” he said.
Whether or not soft hair is enough to resolve the information paradox, nobody really knows. Reaction from other physicists has been reserved.
Surprise! The Universe Is Expanding Faster Than Scientists Thought
The universe is expanding 5 to 9 percent faster than astronomers had thought, a new study suggests.
"This surprising finding may be an important clue to understanding those mysterious parts of the universe that make up 95 percent of everything and don't emit light, such as dark energy, dark matter and dark radiation," study leader Adam Riess, an astrophysicist at the Space Telescope Science Institute and Johns Hopkins University in Baltimore, said in a statement.
Riess — who shared the 2011 Nobel Prize in physics for the discovery that the universe's expansion is accelerating — and his colleagues used NASA's Hubble Space Telescope to study 2,400 Cepheid stars and 300 Type Ia supernovas.
Building Blocks of Life Found in Comet's Atmosphere
For the first time, scientists have directly detected a crucial amino acid and a rich selection of organic molecules in the dusty atmosphere of a comet, further bolstering the hypothesis that these icy objects delivered some of life's ingredients to Earth.
The amino acid glycine, along with some of its precursor organic molecules and the essential element phosphorus, were spotted in the cloud of gas and dust surrounding Comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft, which has been orbiting the comet since 2014. While glycine had previously been extracted from cometary dust samples that were brought to Earth by NASA's Stardust mission, this is the first time that the compound has been detected in space, naturally vaporized.
The discovery of those building blocks around a comet supports the idea that comets could have played an essential role in the development of life on early Earth, researchers said.
Quantum cats here and there
The story of Schrödinger's cat being hidden away in a box and being both dead and alive is often invoked to illustrate the how peculiar the quantum world can be. On a twist of the dead/alive behavior, Wang et al. now show that the cat can be in two separate locations at the same time. Constructing their cat from coherent microwave photons, they show that the state of the “electromagnetic cat” can be shared by two separated cavities. Going beyond common-sense absurdities of the classical world, the ability to share quantum states in different locations could be a powerful resource for quantum information processing.
Planet 1,200 Light-years Away Is A Good Prospect For Habitability
A distant planet known as Kepler-62f could be habitable, a team of astronomers reports.
The planet, which is about 1,200 light-years from Earth in the direction of the constellation Lyra, is approximately 40 percent larger than Earth. At that size, Kepler-62f is within the range of planets that are likely to be rocky and possibly could have oceans, said Aomawa Shields, the study's lead author and a National Science Foundation astronomy and astrophysics postdoctoral fellow in UCLA's department of physics and astronomy.
NASA's Kepler mission discovered the planetary system that includes Kepler-62f in 2013, and it identified Kepler-62f as the outermost of five planets orbiting a star that is smaller and cooler than the sun. But the mission didn't produce information about Kepler-62f's composition or atmosphere or the shape of its orbit.
Shields collaborated on the study with astronomers Rory Barnes, Eric Agol, Benjamin Charnay, Cecilia Bitz and Victoria Meadows, all of the University of Washington, where Shields earned her doctorate. To determine whether the planet could sustain life, the team came up with possible scenarios about what its atmosphere might be like and what the shape of its orbit might be.
"We found there are multiple atmospheric compositions that allow it to be warm enough to have surface liquid water," said Shields, a University of California President's Postdoctoral Program Fellow. "This makes it a strong candidate for a habitable planet."
Has a Hungarian Physics Lab Found a Fifth Force of Nature?
A laboratory experiment in Hungary has spotted an anomaly in radioactive decay that could be the signature of a previously unknown fifth fundamental force of nature, physicists say—if the finding holds up.
Attila Krasznahorkay at the Hungarian Academy of Sciences’s Institute for Nuclear Research in Debrecen, Hungary, and his colleagues reported their surprising result in 2015 on the arXiv preprint server, and this January in the journal Physical Review Letters. But the report – which posited the existence of a new, light boson only 34 times heavier than the electron—was largely overlooked.
Then, on April 25, a group of US theoretical physicists brought the finding to wider attention by publishing its own analysis of the result on arXiv. The theorists showed that the data didn’t conflict with any previous experiments—and concluded that it could be evidence for a fifth fundamental force. “We brought it out from relative obscurity,” says Jonathan Feng, at the University of California, Irvine, the lead author of the arXiv report.
Four days later, two of Feng's colleagues discussed the finding at a workshop at the SLAC National Accelerator Laboratory in Menlo Park, California. Researchers there were sceptical but excited about the idea, says Bogdan Wojtsekhowski, a physicist at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. “Many participants in the workshop are thinking about different ways to check it,” he says. Groups in Europe and the United States say that they should be able to confirm or rebut the Hungarian experimental results within about a year.
Silicon quantum computers take shape in Australia
Silicon is at the heart of the multibillion-dollar computing industry. Now, efforts to harness the element to build a quantum processor are taking off, thanks to elegant designs from an Australian collaboration.
In July, the Centre for Quantum Computation and Communication Technology, which is based at the University of New South Wales (UNSW) in Sydney, will receive the first instalment of a Aus$46-million (US$33-million) investment. The money comes from government and industry sources whose goal is to create a practical quantum computer.
At an innovation forum in London on 6 May, hosted by Nature and start-up accelerator Entrepreneur First, two physicists from a group at the UNSW pitched a plan to reach that goal. Their audience was a panel of entrepreneurs and scientists, who critiqued ideas for commercializing a range of quantum technologies, including sensors, computer security and a quantum internet as well as quantum computers.
So far, the UNSW team has demonstrated a system with quantum bits, or qubits, only in a single atom. Useful computations will require linking qubits in multiple atoms. But the team’s silicon qubits hold their quantum state nearly a million times longer than do systems made from superconducting circuits, a leading alternative, UNSW physicist Guilherme Tosi told participants at the event. This helps the silicon qubits to perform operations with one-sixth of the errors of superconducting circuits.
If the team can pull off this low error rate in a larger system, it would be “quite amazing”, said Hartmut Neven, director of engineering at Google and a member of the panel. But he cautioned that in terms of performance, the system is far behind others. The team is aiming for ten qubits in five years, but both Google and IBM are already approaching this with superconducting systems. And in five years, Google plans to have ramped up to hundreds of qubits.
New Support for Alternative Quantum View
An experiment claims to have invalidated a decades-old criticism against pilot-wave theory, an alternative formulation of quantum mechanics that avoids the most baffling features of the subatomic universe.
Of the many counterintuitive features of quantum mechanics, perhaps the most challenging to our notions of common sense is that particles do not have locations until they are observed. This is exactly what the standard view of quantum mechanics, often called the Copenhagen interpretation, asks us to believe. Instead of the clear-cut positions and movements of Newtonian physics, we have a cloud of probabilities described by a mathematical structure known as a wave function. The wave function, meanwhile, evolves over time, its evolution governed by precise rules codified in something called the Schrödinger equation. The mathematics are clear enough; the actual whereabouts of particles, less so. Until a particle is observed, an act that causes the wave function to “collapse,” we can say nothing about its location. Albert Einstein, among others, objected to this idea. As his biographer Abraham Pais wrote: “We often discussed his notions on objective reality. I recall that during one walk Einstein suddenly stopped, turned to me and asked whether I really believed that the moon exists only when I look at it.”
But there’s another view — one that’s been around for almost a century — in which particles really do have precise positions at all times. This alternative view, known as pilot-wave theory or Bohmian mechanics, never became as popular as the Copenhagen view, in part because Bohmian mechanics implies that the world must be strange in other ways. In particular, a 1992 study claimed to crystalize certain bizarre consequences of Bohmian mechanics and in doing so deal it a fatal conceptual blow. The authors of that paper concluded that a particle following the laws of Bohmian mechanics would end up taking a trajectory that was so unphysical — even by the warped standards of quantum theory — that they described it as “surreal.”
Nearly a quarter-century later, a group of scientists has carried out an experiment in a Toronto laboratory that aims to test this idea. And if their results, first reported earlier this year, hold up to scrutiny, the Bohmian view of quantum mechanics — less fuzzy but in some ways more strange than the traditional view — may be poised for a comeback.
Dark matter does not include certain axion-like particles
Scientists believe 80 percent of the universe is made up of dark matter. What exactly constitutes dark matter? Scientists still aren't sure. A new study, published this week in the journal Physical Review Letters, grows the list of particles not found in dark matter. Astronomers have previously hypothesized that axion-like particles, or ALPs, might make up dark matter. Given their diminutive size -- registering at a billionth the mass of a single electron -- it was a logical guess.
But when researchers at Stockholm University used NASA's gamma-ray telescope on the Fermi satellite to look for ALPs in the Perseus galaxy cluster, they came up empty-handed. ALPs can be briefly transformed into light-emitting matter when they travel through intense electromagnetic fields. Likewise, light particles like gamma radiation can briefly transform into ALPs. No such transformations, however, were detected near the center of the Perseus cluster.
While the research didn't offer any revelations on the makeup of dark matter, scientists believe they can now exclude certain types of ALPs in the ongoing search for the elusive matter.
"The ALPs we have been able to exclude could explain a certain amount of dark matter," Manuel Meyer, a physicist at Stockholm University, said in a news release. "What is particularly interesting is that with our analysis we are reaching a sensitivity that we thought could only be obtained with dedicated future experiments on Earth."
So, the hunt for dark matter details continues.
Scientists discover new form of light
Researchers in Ireland have discovered a new form of light. Their discovery is expected to reshape scientists' understanding of light's basic nature.
Angular momentum describes the rotation of a light beam around its axis. Until now, researchers believed the angular momentum was always a multiple of Planck's constant -- a constant ratio that describes the relationship between photon energy and frequency, and also sets the scale for quantum mechanics.
The newly discovered form of light, however, features photons with an angular momentum of just half the value of Planck's constant. The difference sounds small, but researchers say the significance of the discovery is great.
"For a beam of light, although traveling in a straight line it can also be rotating around its own axis," John Donegan, a professor at Trinity College Dublin's School of Physics, explained in a news release. "So when light from the mirror hits your eye in the morning, every photon twists your eye a little, one way or another."
"Our discovery will have real impacts for the study of light waves in areas such as secure optical communications," Donegan added.
Researchers made their discovery after passing light through special crystals to create a light beam with a hollow, screw-like structure. Using quantum mechanics, the physicists theorized that the beam's twisting photons were being slowed to a half-integer of Planck's constant.
The team of researchers then designed a device to measure the beam's angular momentum as it passed through the crystal. As they had predicted, they registered a shift in the flow of photons caused by quantum effects.
The researchers described their discovery in a paper published this week in the journal Science Advances.
"What I think is so exciting about this result is that even this fundamental property of light, that physicists have always thought was fixed, can be changed," concluded Paul Eastham, assistant professor of physics at Trinity.
How light is detected affects the atom that emits it
Flick a switch on a dark winter day and your office is flooded with bright light, one of many everyday miracles to which we are all usually oblivious. A physicist would probably describe what is happening in terms of the particle nature of light. An atom or molecule in the fluorescent tube that is in an excited state spontaneously decays to a lower energy state, releasing a particle called a photon.
When the photon enters your eye, something similar happens but in reverse. The photon is absorbed by a molecule in the retina and its energy kicks that molecule into an excited state. Light is both a particle and a wave, and this duality is fundamental to the physics that rule the Lilliputian world of atoms and molecules. Yet it would seem that in this case the wave nature of light can be safely ignored.
Kater Murch, assistant professor of physics in Arts and Sciences at Washington University in St. Louis, might give you an argument about that. His lab is one of the first in the world to look at spontaneous emission with an instrument sensitive to the wave rather than the particle nature of light, work described in the May 20th issue of Nature Communications.
His experimental instrument consists of an artificial atom (actually a superconducting circuit with two states, or energy levels) and an interferometer, in which the electromagnetic wave of the emitted light interferes with a reference wave of the same frequency.
This manner of detection turns everything upside down, he said. All that a photon detector can tell you about spontaneous emission is whether an atom is in its excited state or its ground state. But the interferometer catches the atom diffusing through a quantum "state space" made up of all the possible combinations, or superpositions, of its two energy states.
This is actually trickier than it sounds because the scientists are tracking a very faint signal (the electromagnetic field associated with one photon), and most of what they see in the interference pattern is quantum noise. But the noise carries complementary information about the state of the artificial atom that allows them to chart its evolution.
When viewed in this way, the artificial atom can move from a lower energy state to a higher energy one even as its follows the inevitable downward trajectory to the ground state. "You'd never see that if you were detecting photons," Murch said.
So different detectors see spontaneous emission very differently. "By looking at the wave nature of light, we are able see this lovely diffusive evolution between the states," Murch said.
But it gets stranger. The fact that an atom's average excitation can increase even when it decays is a sign that how we look at light might give us some control over the atoms that emitted the light, Murch said.
This might sound like a reversal of cause and effect, with the effect pushing on the cause. It is possible only because of one of the weirdest of all the quantum effects: When an atom emits light, quantum physics requires the light and the atom to become connected, or entangled, so that measuring a property of one instantly reveals the value of that property for the other, no matter how far away it is.
Or put another way, every measurement of an entangled object perturbs its entangled partner. It is this quantum back-action, Murch said, that could potentially allow a light detector to control the light emitter.
"Quantum control has been a dream for many years," Murch said. "One day, we may use it to enhance fluorescence imaging by detecting the light in a way that creates superpositions in the emitters. "That's very long term, but that's the idea," he said.
AI learns and recreates Nobel-winning physics experiment
Australian physicists, perhaps searching for a way to shorten the work week, have created an AI that can run and even improve a complex physics experiment with little oversight. The research could eventually allow human scientists to focus on high-level problems and research design, leaving the nuts and bolts to a robotic lab assistant.
The experiment the AI performed was the creation of a Bose-Einstein condensate, a hyper-cold gas, the process for which won three physicists the Nobel Prize in 2001. It involves using directed radiation to slow a group of atoms nearly to a standstill, producing all manner of interesting effects.
The Australian National University team cooled a bit of gas down to 1 microkelvin — that’s a thousandth of a degree above absolute zero — then handed over control to the AI. It then had to figure out how to apply its lasers and control other parameters to best cool the atoms down to a few hundred nanokelvin, and over dozens of repetitions, it found more and more efficient ways to do so.
“It did things a person wouldn’t guess, such as changing one laser’s power up and down, and compensating with another,” said ANU’s Paul Wigley, co-lead researcher, in a news release. “I didn’t expect the machine could learn to do the experiment itself, from scratch, in under an hour. It may be able to come up with complicated ways humans haven’t thought of to get experiments colder and make measurements more precise.”
Bose-Einstein condensates have strange and wonderful properties, and their extreme sensitivity to fluctuations in energy make them useful for other experiments and measurements. But that same sensitivity makes the process of creating and maintaining them difficult. The AI monitors many parameters at once and can adjust the process quickly and in ways that humans might not understand, but which are nevertheless effective.
The result: condensates can be created faster, under more conditions, and in greater quantities. Not to mention the AI doesn’t eat, sleep, or take vacations.
“It’s cheaper than taking a physicist everywhere with you,” said the other co-lead researcher, Michael Hush, of the University of New South Wales. “You could make a working device to measure gravity that you could take in the back of a car, and the artificial intelligence would recalibrate and fix itself no matter what.”
This AI is extremely specific in its design, of course, and can’t be applied as-is to other problems; for more flexible automation, physicists will still have to rely on the general-purpose research units called “graduate students.”
Scientists Talk Privately About Creating a Synthetic Human Genome
Scientists are now contemplating the fabrication of a human genome, meaning they would use chemicals to manufacture all the DNA contained in human chromosomes.
The prospect is spurring both intrigue and concern in the life sciences community because it might be possible, such as through cloning, to use a synthetic genome to create human beings without biological parents.
While the project is still in the idea phase, and also involves efforts to improve DNA synthesis in general, it was discussed at a closed-door meeting on Tuesday at Harvard Medical School in Boston. The nearly 150 attendees were told not to contact the news media or to post on Twitter during the meeting.
Organizers said the project could have a big scientific payoff and would be a follow-up to the original Human Genome Project, which was aimed at reading the sequence of the three billion chemical letters in the DNA blueprint of human life. The new project, by contrast, would involve not reading, but rather writing the human genome — synthesizing all three billion units from chemicals.
But such an attempt would raise numerous ethical issues. Could scientists create humans with certain kinds of traits, perhaps people born and bred to be soldiers? Or might it be possible to make copies of specific people?
“Would it be O.K., for example, to sequence and then synthesize Einstein’s genome?” Drew Endy, a bioengineer at Stanford, and Laurie Zoloth, a bioethicist at Northwestern University, wrote in an essay criticizing the proposed project. “If so how many Einstein genomes should be made and installed in cells, and who would get to make them?”
Dr. Endy, though invited, said he deliberately did not attend the meeting at Harvard because it was not being opened to enough people and was not giving enough thought to the ethical implications of the work.
Continue reading the main story
Scientists Seek Moratorium on Edits to Human Genome That Could Be Inherited DEC. 3, 2015
British Researcher Gets Permission to Edit Genes of Human Embryos FEB. 1, 2016
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George Church, a professor of genetics at Harvard Medical School and an organizer of the proposed project, said there had been a misunderstanding. The project was not aimed at creating people, just cells, and would not be restricted to human genomes, he said. Rather it would aim to improve the ability to synthesize DNA in general, which could be applied to various animals, plants and microbes.
“They’re painting a picture which I don’t think represents the project,” Dr. Church said in an interview.
He said the meeting was closed to the news media, and people were asked not to tweet because the project organizers, in an attempt to be transparent, had submitted a paper to a scientific journal. They were therefore not supposed to discuss the idea publicly before publication. He and other organizers said ethical aspects have been amply discussed since the beginning.
The project was initially called HGP2: The Human Genome Synthesis Project, with HGP referring to the Human Genome Project. An invitation to the meeting at Harvard said that the primary goal “would be to synthesize a complete human genome in a cell line within a period of 10 years.”
Boiling Water May Be Cause of Martian Streaks
The results of Earth-bound lab experiments appear to back up the theory that dark lines on Martian slopes are created by water — though in an otherworldly manner, scientists said Monday.A team from France, Britain and the United States constructed models and simulated Mars conditions to follow up on a 2015 study which proffered “the strongest evidence yet” for liquid water — a prerequisite for life — on the Red Planet. That finding had left many scientists scratching their heads as the low pressure of Mars’ atmosphere means that water does not survive long in liquid form. It either boils or freezes.
Three Newly Discovered Planets Are the Best Bets for Life Outside the Solar System
An international team of astronomers has discovered three Earth-like exoplanets orbiting an ultra-cool dwarf star—the smallest and dimmest stars in the Galaxy—now known as TRAPPIST-1. The discovery, made with the TRAPPIST telescope at ESO's La Silla Observatory, is significant not only because the three planets have similar properties to Earth, suggesting they could harbor life, but also because they are relatively close (just 40 light years away) and they are the first planets ever discovered orbiting such a dim star. A research paper detailing the teams findings was published today in the journal Nature.
"What is super exciting is that for the first time, we have extrasolar worlds similar in size and temperature to Earth—planets that could thus, in theory, harbor liquid water and host life on at least a part of their surfaces—for which the atmospheric composition can be studied in detail with current technology," lead researcher Michaël Gillon of the University of Liège in Belgium said in an email to Popular Mechanics.
The real reasons nothing can go faster than the speed of light
We are told that nothing can travel faster than light. This is how we know it is true
Physicists Abuzz About Possible New Particle as CERN Revs Up
Scientists around the globe are revved up with excitement as the world's biggest atom smasher — best known for revealing the Higgs boson four years ago — starts whirring again to churn out data that may confirm cautious hints of an entirely new particle.
Such a discovery would all but upend the most basic understanding of physics, experts say.
The European Center for Nuclear Research, or CERN by its French-language acronym, has in recent months given more oomph to the machinery in a 27-kilometer (17-mile) underground circuit along the French-Swiss border known as the Large Hadron Collider.
In a surprise development in December, two separate LHC detectors each turned up faint signs that could indicate a new particle, and since then theorizing has been rife.
Are we the only intelligent life in cosmos? Probably not, say astronomers
Alien life: A new paper shows that the discoveries of exoplanets, plus a revised Drake's equation, produces a new, empirically valid probability of whether any other advanced civilizations have ever existed. Astronomers revised the half-century old Drake equation, which attempts to calculate the probability of the existence of advanced alien civilizations, to determine whether any such civilizations have existed at any point in the history of the universe.
They found that the chances that a human civilization evolved on Earth and nowhere else in the universe are less than about one in 10 billion trillion.
Could 'black hole' in a lab finally help Stephen Hawking win a Nobel Prize?
ne of Stephen Hawking's most brilliant and disturbing theories may have been confirmed by a scientist who created a sound “black hole” in his laboratory, potentially paving the way for a Nobel Prize.
Research by Professor Hawking, a cosmologist at Cambridge University, disputes the notion that black holes are a gravitational sinkhole, pulling in matter and never allowing anything to escape, even light. His model, developed in the 1970s, instead suggested that black holes could actually emit tiny particles, allowing energy to escape. If true, it would mean some black holes could simply evaporate completely with profound implications for our understanding of the universe.But such is the weakness of the emitted particle combined with the remoteness of even the nearest of black holes, his mathematical discovery has yet to be verified by observation.
Instead Jeff Steinhauer, professor of physics at the Technion university in Haifa, created something analagous to a “black hole” for sound in his laboratory.
In a paper published on the physics website arXiv, and reported by The Times, he described how he cooled helium to close to absolute zero before manipulating it in such a way that sound could not cross it, like a black hole's event horizon. He said he found evidence that phonons – the sound equivalent of light's photons - were leaking out, rather as Prof Hawking had predicted for black holes.The results have yet to be replicated elsewhere and scientists say they will want to check the effect is not caused by another factor.
If confirmed, it would strengthen Prof Hawking's case for science's greatest prize.
Although his theory has a lot of support, Nobel Prizes for Physics are not awarded without experimental proof.
Earlier this year, Prof Hawking used the BBC's Reith Lecture to make the case that his work was close to being proven, both in the laboratory and from echoes of the very earliest moments of our universe.“I am resigned to the fact that I won’t see proof of Hawking radiation directly.
“There are solid state analogues of black holes and other effects, that the Nobel committee might accept as proof,” he said. “But there’s another kind of Hawking radiation, coming from the cosmological event horizon of the early inflationary universe. “I am now studying whether one might detect Hawking radiation in primordial gravitational waves . . . so I might get a Nobel prize after all.”
Gravitational lens reveals hiding dwarf dark galaxy
Originally, scientists were simply trying to capture an image of the gravitational lens SDP.81 using the Atacama Large Millimeter Array. Their efforts were part of a 2014 survey aimed at testing ALMA's new, high-resolution capabilities. More than a year later, however, the image revealed a surprise -- a dwarf dark galaxy hiding in the halo of a larger galaxy, positioned some 4 billion light-years from Earth.A gravitational lens, or gravitational lensing, is a phenomenon whereby the gravity of a closer galaxy bends the light of a more distant galaxy, creating a magnifying lens-like effect. The phenomenon is often used to study galaxies that would otherwise be too far away to see.
Astronomers initially assumed SDP.81 revealed the light of two galaxies -- that of a more distant galaxy, 12 billion light-years away, and that of the a closer galaxy, 4 billion light-years away.
But new analysis of the image by researchers at Stanford University has revealed evidence of a dwarf dark galaxy.
"We can find these invisible objects in the same way that you can see rain droplets on a window. You know they are there because they distort the image of the background objects," astronomer Yashar Hezaveh explained in a news release.
The gravitational influence of dark matter distorted the light bending through the gravitational lens.
Hezaveh and his colleagues recruited the power of several supercomputers to scan the radio telescope data for anomalies within the halo of SDP.81. They succeeded in identifying a unique clump of distortion, less than one-thousandth the mass of the Milky Way. The work may pave the way for the discovery of more collections of dark matter and also solve a discrepancy that's long plagued cosmologists and astronomers.
Leonardo Da Vinci's Living Relatives Found
Leonardo da Vinci lives on, according to two Italian researchers who have tracked down the living relatives of the Renaissance genius.
It was believed that no traces were left of the painter, engineer, mathematician, philosopher and naturalist. The remains of Leonardo, who died in 1519 in Amboise, France, were dispersed in the 16th century during religious wars. But according to historian Agnese Sabato and art historian Alessandro Vezzosi, director of the Museo Ideale in the Tuscan town of Vinci, where the artist was born in 1452, Da Vinci's family did not go extinct.
Stephen Hawking: We Probably Won't Find Aliens Anytime Soon
Will humanity find intelligent alien life anytime soon? Probably not, according to theoretical physicist Stephen Hawking.
Hawking made the prediction yesterday (April 12) during the Breakthrough Starshot announcement in New York City. At the news conference, Hawking, along with Russian billionaire investor Yuri Milner and a group of scientists, detailed a new project that aims to send a multitude of tiny, wafer-size spaceships into space to the neighboring star system Alpha Centauri.
If these tiny spaceships travel at 20 percent the speed of light, they'll be able to reach Alpha Centauri in just 20 years, Milner said. Once there, the spacecraft will be able to do a 1-hour flyby of Alpha Centauri and collect data that's impossible to gather from Earth, such as taking close-up photos of the star system, probing space dust molecules and measuring magnetic fields, said Avi Loeb, chairman of the Breakthrough Starshot Advisory Committee and a professor of science at Harvard University.
Measurement of Universe's expansion rate creates cosmological puzzle
The most precise measurement ever made of the current rate of expansion of the Universe has produced a value that appears incompatible with measurements of radiation left over from the Big Bang1. If the findings are confirmed by independent techniques, the laws of cosmology might have to be rewritten.This might even mean that dark energy — the unknown force that is thought to be responsible for the observed acceleration of the expansion of the Universe — has increased in strength since the dawn of time.
“I think that there is something in the standard cosmological model that we don't understand,” says astrophysicist Adam Riess, a physicist at Johns Hopkins University in Baltimore, Maryland, who co-discovered dark energy in 1998 and led the latest study. Kevork Abazajian, a cosmologist at the University of California, Irvine, who was not involved in the study, says that the results have the potential of “becoming transformational in cosmology”.
Stephen Hawking Helps Launch Project 'Starshot' for Interstellar Space Exploration
The famed cosmologist, along with a group of scientists and billionaire investor Yuri Milner, unveiled an ambitious new $100 million project today (April 12) called Breakthrough Starshot, which aims to build the prototype for a tiny, light-propelled robotic spacecraft that could visit the nearby star Alpha Centauri after a journey of just 20 years.
"The limit that confronts us now is the great void between us and the stars, but now we can transcend it," Hawking said today during a news conference here at One World Observatory.
'Bizarre' Group of Distant Black Holes are Mysteriously Aligned
A highly sensitive radio telescope has seen something peculiar in the depths of our cosmos: A group of supermassive black holes are mysteriously aligned, as if captured in a synchronized dance.These black holes, which occupy the centers of galaxies in a region of space called ELAIS-N1, appear to have no relation to one another, separated by millions of light-years. But after studying the radio waves generated by the twin jets blasting from the black holes’ poles, astronomers using data from the Giant Metrewave Radio Telescope (GMRT) in India realized that all the jets were pointed in the same direction, like arrows on compasses all pointing “north.”This is the first time a group of supermassive black holes in galactic cores have been seen to share this bizarre relationship and, at first glance, the occurrence should be impossible. What we are witnessing is a cluster of galaxies, that all have central supermassive black holes that have their axes of rotation pointed in the same direction.
“Since these black holes don’t know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe,” said Andrew Russ Taylor, director of the Inter-University Institute for Data Intensive Astronomy in Cape Town, South Africa. Taylor is lead author of the study published in the journal Monthly Notices of the Royal Astronomical Society.
Isaac Newton: handwritten recipe reveals fascination with alchemy
A 17th-century recipe written by Isaac Newton is now going online, revealing more about the physicist’s relationship with the ancient science of alchemy.
Calling for ingredients such as "one part Fiery Dragon" and "at least seven Eagles of mercury," the handwritten recipe describes how to make "sophick mercury," seen at the time as an essential element in creating the "philosopher’s stone," a fabled substance with the power to turn base metals, like lead, into gold.
The manuscript, which is written in Latin and English, was acquired in February by Philadelphia-based nonprofit the Chemical Heritage Foundation, National Geographic reports. The foundation is now working to upload digital images and transcriptions of the text to an online database.
If there is a planet beyond Neptune, what is it like?
Scientists may not have been able to spot the proposed ninth planet in our solar system, or even confirm that it exists, but that hasn't stopped them from imagining how it looks. Astrophysicists from the University of Bern recently showed off a new model of the possible evolution of Planet Nine, a planet hypothesized to explain the movement bodies at our solar system's edge.
Published in the Journal Astronomy and Astrophysics, the model shows the possible size, temperature, and brightness of the mysterious planet.
The "R" in RNA can easily be made in space, and that has implications for life beyond Earth
New research suggests that the sugar ribose -- the "R" in RNA -- is probably found in comets and asteroids that zip through the solar system and may be more abundant throughout the universe than was previously thought.
The finding has implications not just for the study of the origins of life on Earth, but also for understanding how much life there might be beyond our planet.
Scientists already knew that several of the molecules necessary for life including amino acids, nucleobases and others can be made from the interaction of cometary ices and space radiation. But ribose, which makes up the backbone of the RNA molecule, had been elusive -- until now.
The new work, published Thursday in Science, fills in another piece of the puzzle, said Andrew Mattioda, an astrochemist at NASA Ames Research Center, who was not involved with the study.
Surprise! Gigantic Black Hole Found in Cosmic Backwater
One of the biggest black holes ever found sits in a cosmic backwater, like a towering skyscraper in a small town.
Astronomers have spotted a supermassive black hole containing 17 billion times the mass of the sun — only slightly smaller than the heftiest known black hole, which weighs in at a maximum of 21 billion solar masses — at the center of the galaxy NGC 1600.
That's a surprise, because NGC 1600, which lies 200 million light-years from Earth in the constellation Eridanus, belongs to an average-size galaxy group, and the monster black holes discovered to date tend to be found in dense clusters of galaxies. So researchers may have to rethink their ideas about where gigantic black holes reside, and how many of them might populate the universe, study team members said.
New Bizarre State of Matter Seems to Split Fundamental Particles
A bizarre new state of matter has been discovered — one in which electrons that usually are indivisible seem to break apart.
The new state of matter, which had been predicted but never spotted in real life before, forms when the electrons in an exotic material enter into a type of "quantum dance," in which the spins of the electrons interact in a particular way, said Arnab Banerjee, a physicist at Oak Ridge National Laboratory in Tennessee. The findings could pave the way for better quantum computers, Banerjee said.
Is Mysterious 'Planet Nine' Tugging on NASA Saturn Probe?
The hunt is on to find "Planet Nine" — a large undiscovered world, perhaps 10 times as massive as Earth and four times its size — that scientists think could be lurking in the outer solar system. After Konstantin Batygin and Mike Brown, two planetary scientists from the California Institute of Technology, presented evidence for its existence this January, other teams have searched for further proof by analyzing archived images and proposing new observations to find it with the world's largest telescopes.
Just this month, evidence from the Cassini spacecraft orbiting Saturn helped close in on the missing planet. Many experts suspect that within as little as a year someone will spot the unseen world, which would be a monumental discovery that changes the way we view our solar system and our place in the cosmos. "Evidence is mounting that something unusual is out there — there's a story that's hard to explain with just the standard picture," says David Gerdes, a cosmologist at the Universityof Michigan who never expected to find himself working on Planet Nine. He is just one of many scientists who leapt at the chance to prove — or disprove — the team's careful calculations.
Researchers made the smallest diode using a DNA molecule
The study could lead to nanoscale electronic components and devices. A team of researchers from the University of Georgia and Ben-Gurion University has developed an electronic component so tiny, you can't even see it under an ordinary microscope. See, the team used a single DNA molecule to create a diode, a component that conducts electricity mostly in one direction. Further, the DNA molecule they designed for the study only has 11 base pairs. That makes it a pretty short helix, considering a human genome has approximately 3 billion pairs.
To allow a current to flow through the DNA, the team inserted a molecule called "coralyne" into the helix. What the team came up with was a diode, because the current was 15 times stronger for negative voltages than for positive. The study's lead author Bingqian Xu decided to experiment on DNA to create minuscule components, since we can't exactly use silicon for parts that size.
Astronomers Discover Colossal 'Super Spiral' Galaxies
A strange new kind of galactic beast has been spotted in the cosmic wilderness. Dubbed "super spirals," these unprecedented galaxies dwarf our own spiral galaxy, the Milky Way, and compete in size and brightness with the largest galaxies in the universe.
Super spirals have long hidden in plain sight by mimicking the appearance of typical spiral galaxies. A new study using archived NASA data reveals these seemingly nearby objects are in fact distant, behemoth versions of everyday spirals. Rare, super spiral galaxies present researchers with the major mystery of how such giants could have arisen.
"We have found a previously unrecognized class of spiral galaxies that are as luminous and massive as the biggest, brightest galaxies we know of," said Patrick Ogle, an astrophysicist at the Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology in Pasadena and lead author of a new paper on the findings published in The Astrophysical Journal. "It's as if we have just discovered a new land animal stomping around that is the size of an elephant but had shockingly gone unnoticed by zoologists."
How a distant planet could have killed the dinosaurs
A new paper revamps the age-old theory of Planet X – a distant planet with an gravitational pull that dislodges stray comets and sends them toward Earth.A theoretical giant planet orbiting at the far edges of our solar system may be redirecting stray comets and asteroids into the inner solar system, one or some of which could have caused the dinosaur extinction event on Earth.
The theory might seem like science fiction, but a study by astrophysicist Daniel Whitmire offers scientific data to back up the claim. Dr. Whitmire, who now teaches math at the University of Arkansas, says the mysterious planet has been causing extinction events at regular intervals – every 27 million years – on Earth. Sound familiar? The new paper, published in the Monthly Notices of the Royal Astronomical Society, is a revision of a previous study Whitmore and his partner John Matese proposed in 1985.
Search for alien signals expands to 20,000 star systems
The search for radio signals from alien worlds is expanding to 20,000 star systems that were previously considered poor targets for intelligent extraterrestrial life, US researchers said Wednesday.
Video: ESA Euronews - Is there life on the Red Planet?
The ExoMars spacecraft has blasted off from the Baikonur Cosmodrome in Kazakhstan to search for signs of life on the Red Planet. It's a mission that presents incredible scientific and engineering challenges - as it looks to unravel some of the mysteries of our Solar System. Watch this European Space Agency video to understand this mission.
New Tetraquark Particle Sparks Doubts
Exotic particles can be incredibly ephemeral, sticking around for tiny fractions of a second before decaying. The recent discovery of a new type of particle called a tetraquark may turn out to be equally short-lived, according to a new study casting doubt on the finding, although the issue is not yet settled.
The new tetraquark — an arrangement of four quarks, the fundamental particles that build up the protons and neutrons inside atoms — was first announced in late February by physicists taking part in the DZero experiment at the Tevatron collider at the Fermi National Accelerator Laboratory (Fermilab) in Illinois. The finding represented a surprising configuration of quarks of four different flavors that was not predicted and could help elucidate the maddeningly complex rules that govern these particles. But now scientists at the Large Hadron Collider (LHC) — the world's largest particle accelerator, buried beneath Switzerland and France — say they have tried and failed to find confirming evidence for the particle in their own data. "We don't see any of these tetraquarks at all," says Sheldon Stone, a Syracuse University physicist who led the analysis for the Large Hadron Collider Beauty (LHCb) experiment. "We contradict their result."
7 Theories on the Origin of Life
Life on Earth began more than 3 billion years ago, evolving from the most basic of microbes into a dazzling array of complexity over time. But how did the first organisms on the only known home to life in the universe develop from the primordial soup? One theory involved a “shocking” start. Another idea is utterly chilling. And one theory is out of this world! This article reveals the different scientific theories on the origins of life on Earth.
NIST Creates Fundamentally Accurate Quantum Thermometer
Better thermometers might be possible as a result of a discovery at the National Institute of Standards and Technology (NIST), where physicists have found a way to calibrate temperature measurements by monitoring the tiny motions of a nanomechanical system that are governed by the often counterintuitive rules of quantum mechanics.
While the method is not yet ready for commercialization, it reveals how an object’s thermal energy—its heat—can be determined precisely by observing its physical properties at the quantum scale. While the initial demonstration has an absolute accuracy only within a few percentage points, the NIST approach works over a wide temperature range encompassing cryogenic and room temperatures. It is also accomplished with a small, nanofabricated photonic device, which opens up possible applications that are not practical with conventional temperature standards.
DNA data storage could last thousands of years
Researchers in Switzerland have developed a method for writing vast amounts of information in DNA and storing it inside a synthetic fossil, potentially for thousands of years. In past centuries, books and scrolls preserved the knowledge of our ancestors, even though they were prone to damage and disintegration. In the digital era, most of humanity's collective knowledge is stored on servers and hard drives. But these have a limited lifespan and need constant maintenance. Scientists from ETH Zurich have taken inspiration from the natural world in a bid to devise a storage medium that could last for potentially thousands of years. They say that genetic material found in fossils hundreds of thousands of years old can be isolated and analyzed as it has been protected from environmental stresse
Hints of new LHC particle get slightly stronger
Hints of a mysterious new particle at the world's largest particle accelerator just got a little stronger. The excess of photons produced by particle collisions at the Large Hadron Collider (LHC) has kept physicists abuzz since it was discovered three months ago: it is now slightly more statistically significant but still falls well short of the certainty needed to claim a discovery.
In December, physicists announced that they had seen an excess of pairs of γ-ray photons with a combined energy of around 750 gigaelectronvolts. The data came from ATLAS and CMS, the two largest detectors at the 27-kilometre LHC, which is at CERN, the European particle physics laboratory near Geneva, Switzerland.
That excess of photons seen by the CMS experiment has now become slightly more significant, owing to a fresh analysis reported on 17 March at a conference in La Thuile, Italy. But to the disappointment of many, the significance seen by ATLAS actually went down a bit, as a result of a more conservative interpretation of the data.
The data used in the latest CMS analysis is 23% larger as it includes collisions from early in the LHC’s 2015 run, when the detector’s magnet was switched off due to a problem in its cooling system. The magnetic field affects detector electronics, so data taken without the field needed careful and separate calibration. “The good news is, we now we have almost as much data as ATLAS,” says James Olsen, CMS physics coordinator and a physicist at Princeton University in New Jersey.
Snake walk: The physics of slithering
Innumerable critters have evolved superb ways to scuttle and slither - or even burrow and "swim" - across the most unhelpful of terrains: those that flow.
If you've ever tried to walk up a sand dune, then you are familiar with the problem: unstable ground makes a mission out of locomotion. Now, imagine doing it on your belly. This is why a team of physicists is playing with snakes in a custom-built sand pit. The way they move is a marvel. (The snakes, not the physicists.) If you've ever tried to walk up a sand dune, then you are familiar with the problem: unstable ground makes a mission out of locomotion. Now, imagine doing it on your belly.
Ms Perrin Schiebel is studying for a PhD in physics at the Georgia Institute of Technology in Atlanta, US. She has spent many months putting 10 of these snakes through their slippery paces in a sand-filled aquarium. "One of the things that's really interesting about snakes is that their entire body is, in this type of locomotion, in sliding contact with the ground," Ms Schiebel explains.
Astronomers discover a new galaxy far, far(ther) away
A team of astronomers say they have discovered a hot, star-popping galaxy that – at 13.4 billion light years away – is much farther than any galaxy previously identified, both in time and distance.
Using a technique that has raised some skepticism among rival astronomers, they say they’ve identified a galaxy from a time when the universe was only about 400 million years old. That’s a time period commonly believed to be impossible to observe with today’s technology.
The discovery far surpasses previous records for distance and time, and may be farthest that can be seen until a new space telescope is launched, the astronomers report in a paper published Thursday in Astrophysical Journal.
Space experts warn Congress that NASA’s “Journey to Mars” is illusory
For the last half-decade, NASA has resolutely declared that it has embarked on a Journey to Mars. Virtually every agency achievement has, in one way or another, been characterized as furthering this ambition. Even last summer when the New Horizons spacecraft flew by Pluto, NASA Administrator Charles Bolden said it represented “one more step” on the Journey to Mars.
But as the end of President Obama’s second term in office nears, Congress has begun to assess NASA’s Mars ambitions. On Wednesday during a House space subcommittee hearing, legislators signaled that they were not entirely pleased with those plans. Comments from lawmakers, and the three witnesses called to the hearing, indicate NASA’s Journey to Mars may receive some pushback in the next year or two.
Some of the most critical testimony came from John Sommerer, a space scientist who spent more than a year as chairman of a National Research Council technical panel reviewing NASA’s human spaceflight activities. That panel’s work, summarized in a 2014 report titled Pathways to Exploration, considered possible pathways to Mars.
Never-Seen-Before Tetraquark Particle Possibly Spotted in Atom Smasher
Evidence for a never-before-seen particle containing four types of quark has shown up in data from the Tevatron collider at the Fermi National Accelerator Laboratory (Fermilab) in Illinois. The new particle, a class of "tetraquark," is made of a bottom quark, a strange quark, an up quark and a down quark. The discovery could help elucidate the complex rules that govern quarks — the tiny fundamental particles that make up the protons and neutrons inside all the atoms in the universe.
Protons and neutrons each contain three quarks, which is by far the most stable grouping. Pairs of quarks, called mesons, also commonly appear, but larger conglomerations of quarks are extremely rare. Scientists at the Large Hadron Collider (LHC) in Switzerland last year saw the first signs of a pentaquark—a grouping of five quarks—which had long been predicted but never seen. The first tetraquark was found in 2003 at the Belle experiment in Japan, and since then physicists have encountered a half dozen different arrangements. But the new one, if confirmed, would be special. “What’s unique in this case is that we basically have four quarks, which are all different—bottom, up, strange and down,” says Dmitri Denisov, co-spokesperson for the DZero experiment. “In all previous configurations usually two quarks are the same. Is this telling us something? I hope yes.”
The unusual arrangement, dubbed X(5568) in a paper submitted toPhysical Review Letters, could reflect some deeper rule about how the different types, or “flavors,” of quarks bind together—a process enabled by the strongest force in nature, called, appropriately, the strong force. Physicists have a theory—called quantum chromodynamics—that describes how the strong force works, but it is incredibly unwieldy and difficult to make predictions with. “While we understand many features of the strong force, we don’t understand everything, especially how the strong force acts on large distances,” Denisov says. “And on a fundamental level we still don’t have a very good model of how quarks interact when there are quite a few of them joined together.”
ET search: Look for the aliens looking for Earth
By watching how the light dims as a planet orbits in front of its parent star, NASA’s Kepler spacecraft has discovered more than 1,000 worlds since its launch in 2009. Now, astronomers are flipping that idea on its head in the hope of finding and talking to alien civilizations.
Scientists searching for extraterrestrial intelligence should target exoplanets from which Earth can be seen passing in front of the Sun, says René Heller, an astronomer at the Max Planck Institute for Solar System Research in Göttingen, Germany. By studying these eclipses, known as transits, civilizations on those planets could see that Earth has an atmosphere that has been chemically altered by life. “They have a higher motivation to contact us, because they have a better means to identify us as an inhabited planet,” Heller says.
About 10,000 stars that could harbour such planets should exist within about 1,000 parsecs (3,260 light years) of Earth, Heller and Ralph Pudritz, an astronomer at McMaster University in Hamilton, Canada, report in the April issue of Astrobiology1. They argue that future searches for signals from aliens, such as the US$100-million Breakthrough Listen project, should focus on these stars, which fall in a band of space formed by projecting the plane of the Solar System out into the cosmos. Breakthrough Listen currently has no plans to search this region; it is targeting both the centre and the plane of our galaxy, which is not the same as the plane of the Solar System, as well as stars and galaxies across other parts of the sky.
Physicists create first photonic Maxwell's demon
Maxwell's demon, a hypothetical being that appears to violate the second law of thermodynamics, has been widely studied since it was first proposed in 1867 by James Clerk Maxwell. But most of these studies have been theoretical, with only a handful of experiments having actually realized Maxwell's demon. Now in a new paper, physicists have reported what they believe is the first photonic implementation of Maxwell's demon, by showing that measurements made on two light beams can be used to create an energy imbalance between the beams, from which work can be extracted. One of the interesting things about this experiment is that the extracted work can then be used to charge a battery, providing direct evidence of the "demon's" activity.
The physicists, Mihai D. Vidrighin, et al., carried out the experiment at the University of Oxford and published a paper on their results in a recent issue of Physical Review Letters.
Black holes banish matter into cosmic voids
In recent decades, astronomers have cultivated a picture of the universe dominated by unseen matter, in which – on the largest scales – galaxies and everything they contain are concentrated into honeycomb-like filaments stretching around the edge of enormous voids. Until a recent study, the voids were thought to be almost empty. Now astronomers in Austria, Germany and the United States say these dark areas in space could contain as much as 20% of the ordinary matter of our cosmos. They also say that galaxies make up only 1/500th of the volume of the universe. The team, led by Dr. Markus Haider of the Institute of Astro- and Particle Physics at the University of Innsbruck in Austria, published these results in a new paper in Monthly Notices of the Royal Astronomical Society on February 24, 2016.
How NASA's new telescope could unlock some mysteries of the universe
One of the most highly anticipated astronomical missions of the next decade is now officially in the works at the NASA.
The Wide Field Infrared Survey Telescope, or WFIRST, has been under study for years and it was formally decided Wednesday that the project would be moving forward.
“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble [Space Telescope] has,” said NASA Science Mission Directorate associate administrator John Grunsfeld in an agency release. “This mission uniquely combines the ability to discover and characterize planets beyond our own solar system with the sensitivity and optics to look wide and deep into the universe in a quest to unravel the mysteries of dark energy and dark matter.”
5D Black Holes Could Break Relativity
Ring-shaped, five-dimensional black holes could break Einstein's theory of general relativity, new research suggests.
There's a catch, of course. These 5D "black rings" don't exist, as far as anyone can tell. Instead, the new theoretical model may point out one reason why we live in a four-dimensional universe: Any other option could be a hot mess.
"Here we may have a first glimpse that four space-time dimensions is a very, very good choice, because otherwise, something pretty bad happens in the universe," said Ulrich Sperhake, a theoretical physicist at the University of Cambridge in England.
Reactor data hint at existence of fourth neutrino
n tunnels deep inside a granite mountain at Daya Bay, a nuclear reactor facility some 55 kilometers from Hong Kong, sensitive detectors are hinting at the existence of a new form of neutrino, one of nature’s most ghostly and abundant elementary particles.
Neutrinos, electrically neutral particles that sense only gravity and the weak nuclear force, interact so feebly with matter that 100 trillion zip unimpeded through your body every second. They come in three known types: electron, muon and tau. The Daya Bay results suggest the possibility that a fourth, even more ghostly type of neutrino exists — one more than physicists’ standard theory allows.
Dubbed the sterile neutrino, this phantom particle would carry no charge of any kind and would be impervious to all forces other than gravity. Only when shedding its invisibility cloak by transforming into an electron, muon or tau neutrino could the sterile neutrino be detected. Definitive evidence “would open up a whole new avenue of research,” says particle physicist Stephen Parke of the Fermi National Accelerator Laboratory in Batavia, Ill.
Possible evidence for the sterile particle comes from a mismatch between theory and experiment. If a nuclear reactor produces a beam of just one type of neutrino, theory predicts that some should change their identity as they travel to a far-off detector (SN Online: 10/6/15). Analyzing more than 300,000 electron antineutrinos (the antimatter counterpart of the electron neutrino) collected from the Daya Bay nuclear reactors during 217 days of operation, researchers found 6 percent fewer of the particles than predicted by the standard particle physics model. Particle physicist Kam-Biu Luk of the University of California, Berkeley and the Lawrence Berkeley National Laboratory and colleagues report the findings in the Feb. 12 Physical Review Letters.
One explanation for the deficit is that some of the electron antineutrinos have transformed into an undetectable, lightweight sterile neutrino, about one-millionth the mass of an electron, says Luk. Other nuclear reactor studies, including an experiment at the Bugey reactor in Saint-Vulbas, France, have seen similar electron antineutrino deficits, he notes. Studies with muon antineutrino beams at some particle accelerators have seen an excess of electron antineutrinos, which might be attributed to a different kind of sleight-of-hand by the unseen sterile neutrinos.
The Daya Bay result provides the most precise measure yet of the energies of antielectron neutrinos at a nuclear reactor. Even so, the statistical significance of the deficit is not high enough to rate the finding a discovery. The result is a “three-sigma” finding, meaning that there’s about a 0.3 percent probability that such a paucity of electron antineutrinos would have occurred if no sterile neutrino exists. Physicists generally want a discrepancy to have a significance of five-sigma, or a 0.00003 percent chance of being a fluke, before they will label it a discovery.
Besides the hint of sterile neutrinos, the Daya Bay results reveal a second strange feature — an excess of electron antineutrinos (compared with theoretical predictions) at an energy of around 5 million electron volts. That could be a sign of completely new physics awaiting discovery (or simply that scientists don’t have a detailed enough grasp of the output of nuclear reactors). A revised understanding of that feature might even do away with the need for a lightweight sterile neutrino to explain the overall deficit in electron antineutrinos.
But if definitive evidence for a light sterile neutrino is eventually found, it “would turn the theory community on its head,” says Parke, and could have a bigger impact than the discovery of the Higgs boson, the Nobel-winning finding that explains why elementary particles have mass.
“Finding a sterile neutrino is extremely important because it would be the first discovery of a particle which cannot be accommodated in the framework of the so-called standard model,” says particle physicist Carlo Giunti of the University of Turin in Italy.
One of the earliest experiments that suggested the presence of sterile neutrinos was the Liquid Scintillator Neutrino Detector, which operated at the Los Alamos National Laboratory in New Mexico from 1993 to 1998. The LSND found that muon antineutrinos beamed into 167 tons of mineral oil had morphed into electron antineutrinos in a way that seemed to require a fourth type of neutrino to exist. A follow-up experiment at Fermilab, called MiniBooNE, ran from 2002 to 2012, with equivocal results. Another Fermilab experiment, MicroBooNE, began operation last October. MicroBooNE is the first of three liquid argon detectors, spaced at different distances near neutrino sources at Fermilab, that will track with unprecedented precision the transformation of neutrinos from one type to another.
Located 470 meters from Fermilab’s Booster Neutrino Beamline, MicroBooNE is the middle of the trio, to be joined in 2018 by ICARUS, the farthest detector, at a distance of about 600 meters from the beamline, and the Short-Baseline Near Detector, placed just 100 meters from the source. First results from the trio are expected in 2021, says experimental particle physicist Peter Wilson of Fermilab.
The detectors will also serve as a prototype for the Deep Underground Neutrino Experiment, a large-scale experiment that will send Fermilab-generated neutrinos on a 1,300-kilometer journey to the Sanford Underground Research Facility near Lead, S.D.
In the meantime, the Daya Bay collaboration has teamed up with another Fermilab experiment, the Main Injector Neutrino Oscillation Search, to continue to seek signs of the sterile neutrinos. Although data from accelerator and reactor experiments do not yet paint a consistent picture, “we will soon know better whether a light sterile neutrino is waiting for us to unveil,” says Luk.
If a light sterile neutrino exists, it might have siblings about 1,000 times heavier. These particles could contribute to the as-yet-unidentified dark matter, the invisible gravitational glue that keeps galaxies from flying apart and shapes the large-scale structure of the universe. Fingerprints of this particle will be sought with an experiment called KATRIN, which examines the radioactive decay of tritium, a heavy isotope of hydrogen, at the Karlsruhe Institute of Technology in Germany.
Sterile neutrinos that are even more massive, more than a trillion times heavier than the electron, could explain an ever bigger cosmic mystery — the mismatch between the amounts of matter and antimatter in the cosmos. Possessing an energy at least a million times greater than can be produced at the Large Hadron Collider, the world’s most powerful particle accelerator, a superheavy sterile neutrino in the early universe would have made a smidgen more matter than antimatter. Over time, the tiny imbalance, reproduced in countless nuclear reactions, would have generated the matter-dominated universe seen today (SN: 1/26/13, p. 18).
“For cosmology, the [lightweight] sterile neutrino that we are talking about cannot solve the problem of the matter-antimatter asymmetry, but it is likely that the sterile neutrino is connected with other new particles that can solve the problem,” says Giunti.
Scientists see another, more practical, benefit for studying neutrinos. By recording the antineutrino output of nuclear reactors, detectors can discern the relative amounts of plutonium and uranium, the raw materials for making nuclear weapons. Gram for gram, fissioned plutonium and uranium have distinctive fingerprints in both the energy and rate of antineutrinos they produce, says physicist Adam Bernstein of the Lawrence Livermore National Laboratory in California. Closeup monitoring of reactors, from a distance of 10 to 500 meters, has already been demonstrated; detectors capable of monitoring weapons activity from several hundred kilometers away is possible but will require additional research and funding, Bernstein says.
Single-particle ‘spooky action at a distance’ finally demonstrated
For the first time, researchers have demonstrated what Albert Einstein called "spooky action at a distance" using a single particle. And not only is it a huge deal for our understanding of quantum mechanics, it also proves that the physics genius got something wrong.
Spooky action at a distance, or quantum entanglement, in a single particle is a strange form of entanglement that could greatly help to improve quantum computing and communications. Unlike regular quantum entanglement, which involves two particles being defined only by being opposites of each other, single particles that are entangled have a wave function that's spread over huge distances, but are never actually in more than one place
NASA and 'Star Trek' Combine Forces to Make Replicators a Reality
While it isn't quite the magical wave of hand envisioned in Star Trek, 3D printers are still pretty close to the replicators seen from The Next Generation on, able to fabricate body parts, cars, and even food from raw materials. It's no wonder NASA wants them to build tools, rocket engines, and even housing on Mars. But now, NASA has launched a challenge meant to bring kids into the mix: it wants 3D printed food implements.
It's not quite the same as, say, a 3D printed pizza. But what NASA wants is, essentially, kitchenware and food growing aides. In the Star Trek Replicator competition, it wants "non-edible, food-related item for astronauts to 3D print in the year 2050," which is around when we'll supposedly be on Mars. Ish.
The design guidelines are fairly open ended, but there are a few ground rules. It must not be bigger than 6 inches cubed (6"x6"x6".) The K-12 student designing it must designate where it will be 3D printed, and why it's suited for that environment. It must advance long term space exploration. And it must involve only a single material (so there's no printing, say, a metal alloy and plastic into the same object.)
The contest kicks off today, with entries due by May 1. Four finalists will win a 3D printer for their school and a PancakeBot for themselves, while the grand prize is a tour of the Intrepid Sea, Air, & Space Museum in New York with an astronaut, a bunch of Star Trek swag, and more. There are multiple eligible age groups, so if you have a school aged child, this could be just the contest for them. More information is available here.
'Five-dimensional' glass discs can store data for up to 13.8 billion years
Photographs fade, books rot, and even hard drives eventually fester. When you take the long view, preserving humanity's collective culture isn't a marathon, it's a relay — with successive generations passing on information from one slowly-failing storage medium to the next. However, this could change. Scientists from the University of Southampton in the UK have created a new data format that encodes information in tiny nanostructures in glass. A standard-sized disc can store around 360 terabytes of data, with an estimated lifespan of up to 13.8 billion years even at temperatures of 190°C. That's as old as the Universe, and more than three times the age of the Earth.
The method is called five-dimensional data storage, and was first demonstrated in a paper in 2013. Since then, the scientists behind it say they've more or less perfected their technique, and are now looking to move the technology forward and perhaps even commercialize it. "We can encode anything," Aabid Patel, a postgraduate student involved in the research tells The Verge. "We’re not limited to anything — just give us the file and we can print it [onto a disc]."
In order to demonstrate the format's virtues, the team from the University of Southampton have created copies of the King James Bible, Isaac Newton's Opticks (the foundational text of the study of light and lenses), and the United Nations' Universal Declaration of Human Rights, which was presented to the UN earlier this month. A new paper on the format will be given tomorrow by the team's lead researcher, Professor Peter Kazinsky, at the Society for Optical Engineering Conference in San Francisco.
To understand why these discs can store so much information for such a long time, it's best to compare them to a regular CD. Data is read from a normal CD by shining a laser at a tiny line with bumps in it. Whenever the laser hits a bump. it's reflected back and recorded as a 1; whenever there's no bump, it's recorded as a 0. These are just two "dimensions" of information — on or off — but from them, CDs can store anything: music, books, images, videos, or software. But because this bumpy line is stored on the surface of the CD, it's vulnerable. It can be eroded either by physical scratches and scuffs, or by exposure to oxygen, heat, and humidity.
5D discs, by comparison, store information within their interior using tiny physical structures known as "nanogratings." Much like those bumpy lines in the CDs, these change how light is reflected, but instead of doing so in just two "dimensions," the reflected light encodes five — hence the name. The changes to the light can be read to obtain pieces of information about the nanograting's orientation, the strength of the light it refracts, and its location in space on the x, y, and z axes. These extra dimensions are why 5D discs can store data so densely compared to regular optical discs. A Blu-ray disc can hold up to 128GBs of data (the same as the biggest iPhone), while a 5D disc of the same size could store nearly 3,000 times that: 360 terabytes of information.
These discs can potentially last for so long because glass is a tough material which needs a lot of heat to melt or warp it, and it's chemically stable too. (Think about all those science experiments that use glass beakers to contain reactive materials without anything bad happening to them.) This makes the 5D discs safe up to temperatures of 1,000°C, say the researchers.
The Hubble Space Telescope Just Snapped Photos of the Biggest Black Hole We've Ever Observed
A new photograph of galaxy NGC 4889 may look peaceful from such a great distance, but it’s actually home to one of the biggest black holes that astronomers have ever identified. The Hubble Space Telescope allowed scientists to capture photos of the galaxy, located in the Coma Cluster about 300 million light-years away. The supermassive black hole hidden away in NGC 4889 breaks all kinds of records, even though it is currently classified as dormant.
So how big is it, exactly? Well, according to our best estimates, the supermassive black hole is roughly 21 billion times the size of the Sun, and its event horizon (an area so dense and powerful that light can’t escape its gravity) measures 130 billion kilometers in diameter. That’s about 15 times the diameter of Neptune’s orbit around the Sun, according to scientists at the Hubble Space Telescope. At one point, the black hole was fueling itself on a process called hot accretion. Space stuff like gases, dust, and galactic debris fell towards the black hole and created an accretion disk. Then that spinning disk of space junk, accelerated by the strong gravitational pull of the largest known black hole, emitted huge jets of energy out into the galaxy.
LIGO Discovers the Merger of Two Black Holes
Big news: the Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected its first gravitational-wave signal! Not only is the detection of this signal a major technical accomplishment and an exciting confirmation of general relativity, but it also has huge implications for black-hole astrophysics.
What did LIGO see?
LIGO is designed to detect the ripples in space-time created by two massive objects orbiting each other. These waves can reach observable amplitudes when a binary system consisting of two especially massive objects — i.e., black holes or neutron stars — reach the end of their inspiral and merge.
LIGO has been unsuccessfully searching for gravitational waves since its initial operations in 2002, but a recent upgrade in its design has significantly increased its sensitivity and observational range. The first official observing run of Advanced LIGO began 18 September 2015, but the instruments were up and running in “engineering mode” several weeks before that. And it was in this time frame — before official observing even began! — that LIGO spotted its first gravitational wave signal: GW150914.
One of LIGO’s two detection sites, located near Hanford in eastern Washington. [LIGO] The signal, detected on 14 September, 2015, provides astronomers with a remarkable amount of information about the merger that caused it. From the detection, the LIGO team has extracted the masses of the two black holes that merged, 36+5-4 and 29+4-4 solar masses, as well as the mass of the final black hole formed by the merger, ~62 solar masses. The team also determined that the merger happened roughly a billion light-years away (at a redshift of z~0.1), and the direction of the signal was localized to an area of ~600 square degrees (roughly 1% of the sky).
Why is this detection a big deal?
This is the first direct detection of gravitational waves, providing spectacular further confirmation of Einstein’s general theory of relativity. But the implications of GW150914 go far beyond this confirmation. This detection is a huge deal for astrophysics because it’s the first direct evidence we’ve had that:
“Heavy” stellar-mass black holes exist.
We’ve reliably measured black holes of masses up to 10–20 solar masses in X-ray binaries (binary systems in which a single neutron star or black hole accretes matter from a donor star). But this is the first proof we’ve found that stellar-mass black holes of >25 solar masses can form in nature.
Binaries consisting of two black holes can form in nature.
As we’ll discuss shortly, there are two theorized mechanisms for the formation of these black-hole binaries. Until now, however, there was no guarantee that either of those mechanisms worked!
These black-hole binaries can inspiral and merge within the age of the universe.
The formation of a black-hole binary is no guarantee that it will merge on a reasonable timescale: if the binary forms with enough separation, it could take longer than the age of the universe to merge. This detection proves that black-hole binaries can form with small enough separation to merge on observable timescales.
What can we learn from GW150914?
One of the key questions we’d like to answer is: how do binary black holes form? Two primary mechanisms have been proposed:
A binary star system contains two stars that are each massive enough to individually collapse into a black hole. If the binary isn’t disrupted during the two collapse events, this forms an isolated black-hole binary. Single black holes form in dense cluster environments and then — because they are the most massive objects — sink to the center of the cluster. There they form pairs through dynamical interactions. Now that we’re able to observe black-hole binaries through gravitational-wave detections, one way we could distinguish between the two formation mechanisms is from spin measurements. If we discover a clear preference for the misalignment of the two black holes’ spins, this would favor formation in clusters, where there’s no reason for the original spins to be aligned.
The current, single detection is not enough to provide constraints, but if we can compile a large enough sample of events, we can start to present a statistical case favoring one channel over the other.
What does GW150914 mean for the future of gravitational-wave detection?
The fact that Advanced LIGO detected an event even before the start of its first official observing run is certainly promising! The LIGO team estimates that the volume the detectors can probe will still increase by at least a factor of ~10 as the observing runs become more sensitive and of longer duration.
In addition, LIGO is not alone in the gravitational-wave game. LIGO’s counterpart in Europe, Virgo, is also undergoing design upgrades to increase its sensitivity. Within this year, Virgo should be able to take data simultaneously with LIGO, allowing for better localization of sources. And the launch of (e)LISA, ESA’s planned space-based interferometer, will grant us access to a new frequency range, opening a further window to the gravitational-wave sky.
The detection of GW150914 marks the dawn of a new field: observational gravitational-wave astronomy. This detection alone confirms much that was purely theory before now — and given that instrument upgrades are still underway, the future of gravitational-wave detection looks incredibly promising.
This awesome video (produced by SXS lensing) shows an actual simulation of the black-hole merger GW150914. Time is slowed by a factor of 100, compared to the actual merger. The two black holes — of 29 and 36 solar masses — warp the space-time around them, causing the distorted view.
Einstein's gravitational waves 'seen' from black holes
Scientists are claiming a stunning discovery in their quest to fully understand gravity. They have observed the warping of space-time generated by the collision of two black holes more than a billion light-years from Earth.
The international team says the first detection of these gravitational waves will usher in a new era for astronomy. It is the culmination of decades of searching and could ultimately offer a window on the Big Bang. The research, by the Ligo Collaboration, has been published today in the journal Physical Review Letters.
The collaboration operates a number of labs around the world that fire lasers through long tunnels, trying to sense ripples in the fabric of space-time.
The signals they detect are incredibly subtle and disturb the machines, known as interferometers, by just fractions of the width of an atom. But this black hole merger was picked up almost simultaneously by two widely separated Ligo facilities in the US. The merger radiated three times the mass of the sun in pure gravitational energy. "We have detected gravitational waves," Prof David Reitze, executive director of the Ligo project, told journalists at a news conference in Washington DC. "It's the first time the Universe has spoken to us through gravitational waves. Up until now, we've been deaf."
Prof Karsten Danzmann, from the Max Planck Institute for Gravitational Physics and Leibniz University in Hannover, Germany, is a European leader on the collaboration. He said the detection was one of the most important developments in science since the discovery of the Higgs particle, and on a par with the determination of the structure of DNA. "There is a Nobel Prize in it - there is no doubt," he told the BBC. "It is the first ever direct detection of gravitational waves; it's the first ever direct detection of black holes and it is a confirmation of General Relativity because the property of these black holes agrees exactly with what Einstein predicted almost exactly 100 years ago."
Gravitational waves are prediction of the Theory of General Relativity
Their existence has been inferred by science but only now directly detected
They are ripples in the fabric of space and time produced by violent events
Accelerating masses will produce waves that propagate at the speed of light
Detectable sources ought to include merging black holes and neutron stars
Ligo fires lasers into long, L-shaped tunnels; the waves disturb the light
Detecting the waves opens up the Universe to completely new investigations
That view was reinforced by Prof Stephen Hawking, who is an expert on black holes. Speaking exclusively to BBC News, he said he believed that the detection marked a key moment in scientific history.
"Gravitational waves provide a completely new way at looking at the Universe. The ability to detect them has the potential to revolutionise astronomy. This discovery is the first detection of a black hole binary system and the first observation of black holes merging," he said.
"Apart from testing (Albert Einstein's theory of) General Relativity, we could hope to see black holes through the history of the Universe. We may even see relics of the very early Universe during the Big Bang at some of the most extreme energies possible." Team member Prof Gabriela González, from Louisiana State University, said: "We have discovered gravitational waves from the merger of black holes. It's been a very long road, but this is just the beginning. "Now that we have the detectors to see these systems, now that we know binary black holes are out there - we'll begin listening to the Universe."
The Ligo laser interferometers in Hanford, in Washington, and Livingston, in Louisiana, were only recently refurbished and had just come back online when they sensed the signal from the collision. This occurred at 10.51 GMT on 14 September last year. On a graph, the data looks like a symmetrical, wiggly line that gradually increases in height and then suddenly fades away. "We found a beautiful signature of the merger of two black holes and it agrees exactly - fantastically - with the numerical solutions to Einstein equations... it looked too beautiful to be true," said Prof Danzmann.
Prof Sheila Rowan, who is one of the lead UK researchers involved in the project, said that the first detection of gravitational waves was just the start of a "terrifically exciting" journey.
"The fact that we are sitting here on Earth feeling the actual fabric of the Universe stretch and compress slightly due to the merger of black holes that occurred just over a billion years ago - I think that's phenomenal. It's amazing that when we first turned on our detectors, the Universe was ready and waiting to say 'hello'," the Glasgow University scientist told the BBC.
Being able to detect gravitational waves enables astronomers finally to probe what they call "dark" Universe - the majority part of the cosmos that is invisible to the light telescopes in use today.
Not only will they be able to investigate black holes and strange objects known as neutron stars (giant suns that have collapsed to the size of cities), they should also be able to "look" much deeper into the Universe - and thus farther back in time. It may even be possible eventually to sense the moment of the Big Bang.
"Gravitational waves go through everything. They are hardly affected by what they pass through, and that means that they are perfect messengers," said Prof Bernard Schutz, from Cardiff University, UK. "The information carried on the gravitational wave is exactly the same as when the system sent it out; and that is unusual in astronomy. We can't see light from whole regions of our own galaxy because of the dust that is in the way, and we can't see the early part of the Big Bang because the Universe was opaque to light earlier than a certain time.
"With gravitational waves, we do expect eventually to see the Big Bang itself," he told the BBC. In addition, the study of gravitational waves may ultimately help scientists in their quest to solve some of the biggest problems in physics, such as the unification of forces, linking quantum theory with gravity. At the moment, General Relativity describes the cosmos on the largest scales tremendously well, but it is to quantum ideas that we resort when talking about the smallest interactions. Being able to study places in the Universe where gravity is really extreme, such as at black holes, may open a path to new, more complete thinking on these issues.
A laser is fed into the machine and its beam is split along two paths
The separate paths bounce back and forth between damped mirrors
Eventually, the two light parts are recombined and sent to a detector Gravitational waves passing through the lab should disturb the set-up
Theory holds they should very subtly stretch and squeeze its space. This ought to show itself as a change in the lengths of the light arms (green). The photodetector captures this signal in the recombined beam Scientists have sought experimental evidence for gravitational waves for more than 40 years.
Einstein himself actually thought a detection might be beyond the reach of technology. His theory of General Relativity suggests that objects such as stars and planets can warp space around them - in the same way that a billiard ball creates a dip when placed on a thin, stretched, rubber sheet. Gravity is a consequence of that distortion - objects will be attracted to the warped space in the same way that a pea will fall in to the dip created by the billiard ball.
Einstein predicted that if the gravity in an area was changed suddenly - by an exploding star, say - waves of gravitational energy would ripple across the Universe at light-speed, stretching and squeezing space as they travelled.
Although a fantastically small effect, modern technology has now risen to the challenge. Much of the R&D work for the Washington and Louisiana machines was done at Europe's smaller GEO600 interferometer in Hannover. "I think it's phenomenal to be able to build an instrument capable of measuring [gravitational waves]," said Prof Rowan. "It is hugely exciting for a whole generation of young people coming along, because these kinds of observations and this real pushing back of the frontiers is really what inspires a lot of young people to get into science and engineering."
Earth-like Planets Have Earth-like Interiors
Every school kid learns the basic structure of the Earth: a thin outer crust, a thick mantle, and a Mars-sized core.
But is this structure universal? Will rocky exoplanets orbiting other stars have the same three layers? New research suggests that the answer is yes - they will have interiors very similar to Earth.
"We wanted to see how Earth-like these rocky planets are. It turns out they are very Earth-like," says lead author Li Zeng of the Harvard-Smithsonian Center for Astrophysics (CfA).
To reach this conclusion Zeng and his co-authors applied a computer model known as the Preliminary Reference Earth Model (PREM), which is the standard model for Earth's interior. They adjusted it to accommodate different masses and compositions, and applied it to six known rocky exoplanets with well-measured masses and physical sizes.
They found that the other planets, despite their differences from Earth, all should have a nickel/iron core containing about 30 percent of the planet's mass. In comparison, about a third of the Earth's mass is in its core. The remainder of each planet would be mantle and crust, just as with Earth.
"We've only understood the Earth's structure for the past hundred years. Now we can calculate the structures of planets orbiting other stars, even though we can't visit them," adds Zeng.
The new code also can be applied to smaller, icier worlds like the moons and dwarf planets in the outer solar system. For example, by plugging in the mass and size of Pluto, the team finds that Pluto is about one-third ice (mostly water ice but also ammonia and methane ices).
The model assumes that distant exoplanets have chemical compositions similar to Earth. This is reasonable based on the relevant abundances of key chemical elements like iron, magnesium, silicon, and oxygen in nearby systems. However, planets forming in more or less metal-rich regions of the galaxy could show different interior structures. The team expects to explore these questions in future research.
Physicists find signs of four-neutron nucleus
The suspected discovery of an atomic nucleus with four neutrons but no protons has physicists scratching their heads. If confirmed by further experiments, this “tetraneutron” would be the first example of an uncharged nucleus, something that many theorists say should not exist. “It would be something of a sensation,” says Peter Schuck, a nuclear theorist at the National Center for Scientific Research in France who was not involved in the work. Details on the tetraneutron appear in the Feb. 5 Physical Review Letters.
Have Gravitational Waves Finally Been Spotted?
Astronomers may finally have found elusive gravitational waves, the mysterious ripples in the fabric of spacetime whose existence was first predicted by Albert Einstein in 1916, in his famous theory of general relativity.
Scientists are holding a news conference Thursday (Feb. 11) at 10:30 a.m. EST (1530 GMT) at the National Press Club in Washington, D.C., to discuss the search for gravitational waves, which zoom through space at the speed of light.
A media advisory describing the news conference is brief and somewhat vague, promising merely a "status report" on the ongoing hunt by the scientists using the Laser Interferometer Gravitational-Wave Observatory, or LIGO. But there's reason to suspect that researchers will announce a big discovery at the Thursday event.
Astronomers build Earth-sized telescope to see Milky Way black hole
An Earth-sized telescope will allow astronomers to glimpse the black hole at the centre of the Milky Way.
Scientists across the globe are currently linking up telescopes across the globe to form the Event Horizon Telescope which will be the first instrument ever to take detailed pictures of a black hole.
Even though the Milky Way’s black hole, known as Sagittarius A* (pronounced ‘Sagittarius A-star’), is four million times more massive than the sun, it is tiny to the eyes of astronomers.
It is the equivalent of standing in New York and reading the date on a penny in Germany or seeing a grapefruit on the Moon for someone standing on Earth.
But if successful, it will prove for the first time that black holes have ‘event horizons’ – an edge from which nothing can escape, not even light.
"The goals of the EHT are to test Einstein's theory of general relativity, understand how black holes eat and generate relativistic outflows, and to prove the existence of the event horizon, or 'edge,' of a black hole," says Dan Marrone.
The telescope gets its first major upgrade in centuries
The general design of a telescope has remained more or less the same since the techology was first invented in the 17th century.
Like an eye, the telescope collects light, and that light is then reflected to form an image. If you want to use one to see a really long way - into the depths of space, say - you'll need a really big one.
“We can only scale the size and weight of telescopes so much before it becomes impractical to launch them into orbit and beyond,” says Danielle Wuchenich, senior research scientist at Lockheed Martin’s Advanced Technology Center in California. “Besides, the way our eye works is not the only way to process images from the world around us.”
Lockheed Martin is now working on a new technology that promises to drastically reduce the size of telescope needed to see long distances.
Its new system, SPIDER, (or 'Segmented Planar Imaging Detector for Electro-optical Reconnaissance', to give it its full title) does away with the large lenses or mirrors found in traditional refracting and reflecting telescopes, and replaces them with hundreds or thousands of tiny lenses. Dr Alan Duncan at Lockheed Martin explains: "SPIDER is a new way of collecting light to form images ... We collect the light, couple it into the silicon chip, move it around and combine it in a way that we can measure it with just ordinary detectors like you would have in your cellphone camera. And then (we) take all that data that's collected by those detectors, process it in a computer and form an image."
New Theory of Secondary Inflation Expands Options for Avoiding an Excess of Dark Matter
Standard cosmology -- that is, the Big Bang Theory with its early period of exponential growth known as inflation -- is the prevailing scientific model for our universe
It suggest that he entirety of space and time ballooned out from a very hot, very dense point into a homogeneous and ever-expanding vastness. This theory accounts for many of the physical phenomena we observe. But what if that's not all there was to it?
A new theory from physicists at the U.S. Department of Energy's Brookhaven National Laboratory, Fermi National Accelerator Laboratory, and Stony Brook University, which will publish online on January 18 in Physical Review Letters, suggests a shorter secondary inflationary period that could account for the amount of dark matter estimated to exist throughout the cosmos.
"In general, a fundamental theory of nature can explain certain phenomena, but it may not always end up giving you the right amount of dark matter," said Hooman Davoudiasl, group leader in the High-Energy Theory Group at Brookhaven National Laboratory and an author on the paper. "If you come up with too little dark matter, you can suggest another source, but having too much is a problem."
Measuring the amount of dark matter in the universe is no easy task. It is dark after all, so it doesn't interact in any significant way with ordinary matter. Nonetheless, gravitational effects of dark matter give scientists a good idea of how much of it is out there. The best estimates indicate that it makes up about a quarter of the mass-energy budget of the universe, while ordinary matter -- which makes up the stars, our planet, and us -- comprises just 5 percent. Dark matter is the dominant form of substance in the universe, which leads physicists to devise theories and experiments to explore its properties and understand how it originated.
Some theories that elegantly explain perplexing oddities in physics -- for example, the inordinate weakness of gravity compared to other fundamental interactions such as the electromagnetic, strong nuclear, and weak nuclear forces -- cannot be fully accepted because they predict more dark matter than empirical observations can support.
This new theory solves that problem. Davoudiasl and his colleagues add a step to the commonly accepted events at the inception of space and time.
In standard cosmology, the exponential expansion of the universe called cosmic inflation began perhaps as early as 10-35 seconds after the beginning of time -- that's a decimal point followed by 34 zeros before a 1. This explosive expansion of the entirety of space lasted mere fractions of a fraction of a second, eventually leading to a hot universe, followed by a cooling period that has continued until the present day. Then, when the universe was just seconds to minutes old -- that is, cool enough -- the formation of the lighter elements began. Between those milestones, there may have been other inflationary interludes, said Davoudiasl.
"They wouldn't have been as grand or as violent as the initial one, but they could account for a dilution of dark matter," he said.
In the beginning, when temperatures soared past billions of degrees in a relatively small volume of space, dark matter particles could run into each other and annihilate upon contact, transferring their energy into standard constituents of matter-particles like electrons and quarks. But as the universe continued to expand and cool, dark matter particles encountered one another far less often, and the annihilation rate couldn't keep up with the expansion rate.
"At this point, the abundance of dark matter is now baked in the cake," said Davoudiasl. "Remember, dark matter interacts very weakly. So, a significant annihilation rate cannot persist at lower temperatures. Self-annihilation of dark matter becomes inefficient quite early, and the amount of dark matter particles is frozen."
However, the weaker the dark matter interactions, that is, the less efficient the annihilation, the higher the final abundance of dark matter particles would be. As experiments place ever more stringent constraints on the strength of dark matter interactions, there are some current theories that end up overestimating the quantity of dark matter in the universe. To bring theory into alignment with observations, Davoudiasl and his colleagues suggest that another inflationary period took place, powered by interactions in a "hidden sector" of physics. This second, milder, period of inflation, characterized by a rapid increase in volume, would dilute primordial particle abundances, potentially leaving the universe with the density of dark matter we observe today.
"It's definitely not the standard cosmology, but you have to accept that the universe may not be governed by things in the standard way that we thought," he said. "But we didn't need to construct something complicated. We show how a simple model can achieve this short amount of inflation in the early universe and account for the amount of dark matter we believe is out there."
Proving the theory is another thing entirely. Davoudiasl said there may be a way to look for at least the very feeblest of interactions between the hidden sector and ordinary matter.
"If this secondary inflationary period happened, it could be characterized by energies within the reach of experiments at accelerators such as the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider," he said. Only time will tell if signs of a hidden sector show up in collisions within these colliders, or in other experimental facilities.
Stephen Hawking: Black Holes Have 'Hair
Black holes may sport a luxurious head of "hair" made up of ghostly, zero-energy particles, says a new hypothesis proposed by Stephen Hawking and other physicists.
The new paper, which was published online Jan. 5 in the preprint journal arXiv, proposes that at least some of the information devoured by a black hole is stored in these electric hairs.
Still, the new proposal doesn't prove that all the information that enters a black hole is preserved.
the Riemann Hypothesis has finally been SOLVED by a Nigerian professor
Riemann Hypothesis is considered one of the hardest maths problem Devised in 1859, it has been resolved by professor Dr Opeyemi Enoch He has been given $1million (£658,000) for the work into prime numbers Riemann Hypothesis was one of the seven Millennium Problems in Mathematics set by the Clay Mathematics Institute in 2000 Read more: http://www.dailymail.co.uk/sciencetech/article-3321924/It-pays-good-maths-Nigerian-professor-solves-156-year-old-Riemann-problem-scoop-1million-prize.html#ixzz3rmUdR0Iu
Physicists propose the first scheme to teleport the memory of an organism
In "Star Trek", a transporter can teleport a person from one location to a remote location without actually making the journey along the way. Such a transporter has fascinated many people. Quantum teleportation shares several features of the transporter and is one of the most important protocols in quantum information.
In a recent study, Prof. Tongcang Li at Purdue University and Dr. Zhang-qi Yin at Tsinghua University proposed the first scheme to use electromechanical oscillators and superconducting circuits to teleport the internal quantum state (memory) and center-of-mass motion state of a microorganism.
They also proposed a scheme to create a Schrodinger's cat state in which a microorganism can be in two places at the same time. This is an important step towards potentially teleporting an organism in future.
Scientists struggle to stay grounded after possible gravitational wave signal
Not for the first time, the world of physics is abuzz with rumours that gravitational waves have been detected by scientists in the US.
Lawrence Krauss, a cosmologist at Arizona State university, tweeted that he had received independent confirmation of a rumour that has been in circulation for months, adding: “Gravitational waves may have been discovered!!”
My earlier rumor about LIGO has been confirmed by independent sources. Stay tuned! Gravitational waves may have been discovered!! Exciting.
— Lawrence M. Krauss (@LKrauss1) January 11, 2016">
The excitement centres on a longstanding experiment known as the Advanced Laser Interferometer Gravitational-Wave Observatory (Ligo) which uses detectors in Hanford, Washington, and Livingston, Louisiana to look for ripples in the fabric of spacetime.
According to the rumours, scientists on the team are in the process of writing up a paper that describes a gravitational wave signal. If such a signal exists and is verified, it would confirm one of the most dramatic predictions of Albert Einstein’s century-old theory of general relativity.
Krauss said he was 60% confident that the rumour was true, but said he would have to see the scientists’ data before drawing any conclusions about whether the signal was genuine or not.
Researchers on a large collaboration like Ligo will have any such paper internally vetted before sending it for publication and calling a press conference. In 2014, researchers on another US experiment, called BICEP2, called a press conference to announce the discovery of gravitational waves, but others have since pointed out that the signal could be due entirely to space dust.
Speaking about the LIGO team, Krauss said: “They will be extremely cautious. There’s no reason for them to make a claim they are not certain of.”
If gravitational waves have been discovered, astronomers could use them to observe the cosmos in a way that has been impossible to date. “We would have a new window on the universe,” Krauss said. “Gravitational waves are generated in the most exotic, strange locations in nature, such as at the edge of black holes at the beginning of time. We are pretty certain they exist, but we’ve not been able to use them to probe the universe.”
NASA's Kepler Comes Roaring Back with 100 New Exoplanet Finds
Kepler has now discovered more than 100 confirmed alien planets during its second-chance K2 mission, researchers announced today (Jan. 5) here at the 227th Meeting of the American Astronomical Society (AAS). The $600 million Kepler mission launched in March 2009, tasked with determining how commonly Earth-like planets occur throughout the Milky Way galaxy. Kepler has been incredibly successful, finding more than 1,000 alien worlds to date, more than half of all exoplanets ever discovered.
Physicists figure out how to retrieve information from a black hole
Black holes earn their name because their gravity is so strong not even light can escape from them. Oddly, though, physicists have come up with a bit of theoretical sleight of hand to retrieve a speck of information that's been dropped into a black hole. The calculation touches on one of the biggest mysteries in physics: how all of the information trapped in a black hole leaks out as the black hole "evaporates." Many theorists think that must happen, but they don't know how.
Unfortunately for them, the new scheme may do more to underscore the difficulty of the larger "black hole information problem" than to solve it. "Maybe others will be able to go further with this, but it's not obvious to me that it will help," says Don Page, a theorist at the University of Alberta in Edmonton, Canada, who was not involved in the work.
You can shred your tax returns, but you shouldn't be able to destroy information by tossing it into a black hole. That's because, even though quantum mechanics deals in probabilities—such as the likelihood of an electron being in one location or another—the quantum waves that give those probabilities must still evolve predictably, so that if you know a wave's shape at one moment you can predict it exactly at any future time. Without such "unitarity" quantum theory would produce nonsensical results such as probabilities that don't add up to 100%.
But suppose you toss some quantum particles into a black hole. At first blush, the particles and the information they encode is lost. That's a problem, as now part of the quantum state describing the combined black hole-particles system has been obliterated, making it impossible to predict its exact evolution and violating unitarity.
Physicists think they have a way out. In 1974, British theorist Stephen Hawking argued that black holes can radiate particles and energy. Thanks to quantum uncertainty, empty space roils with pairs of particles flitting in and out of existence. Hawking realized that if a pair of particles from the vacuum popped into existence straddling the black hole's boundary then one particle could fly into space, while the other would fall into the black hole. Carrying away energy from the black hole, the exiting Hawking radiation should cause a black hole to slowly evaporate. Some theorists suspect information reemerges from the black hole encoded in the radiation—although how remains unclear as the radiation is supposedly random.
Now, Aidan Chatwin-Davies, Adam Jermyn, and Sean Carroll of the California Institute of Technology in Pasadena have found an explicit way to retrieve information from one quantum particle lost in a black hole, using Hawking radiation and the weird concept of quantum teleportation.
New study asks: Why didn't the universe collapse?
he models that best describe the Big Bang and birth of the universe have one glaring problem. Most of them predict a collapse almost immediately after inflation.
There was nothing, then there was something. And then there was nothing again.
As we know from living and breathing and looking up at a sky action-packed with cosmic activity, there's definitely something more than nothing out there. So why is there still something? Why did the universe's tendency to expand overcome its tendency to collapse?
A new study published in the Physical Review Letters is just the latest to try to inch closer to a place where physicists might be able to answer those questions.
In this particular paper, researchers try to work out the details of the relationship between Higgs boson particles and gravity -- a relationship scientists believe kept an early, unstable universe from collapsing.
Their latest calculations confirm that the stronger the bond between Higgs fields and gravity, the greater the chance of instability and a transition to a negative energy vacuum state, a place with little energy only a few particles popping in and out of existence.
A coupling strength above one would have certainly spelled doom for the early universe, scientists at the University of Copenhagen determined. The new math helps narrow the likely coupling range to between 0.1 and 1.
Physicists in Europe Find Tantalizing Hints of a Mysterious New Particl
Two teams of physicists working independently at the Large Hadron Collider
at CERN, the European Organization for Nuclear Research, reported on Tuesday
that they had seen traces of what could be a new fundamental particle of nature. One possibility, out of a gaggle of wild and not-so-wild ideas springing to life's the day went on, is that the particle — assuming it is real — is a heavier version of the Higgs boson, a particle that explains why other particles have mass. Another is that it is a graviton, the supposed quantum carrier of gravity, whose discovery could imply the existence of extra dimensions of space-time.
At the end of a long chain of “ifs” could be a revolution, the first clues to a
theory of nature that goes beyond the so-called Standard Model, which has ruled physics for the last quarter-century. It is, however, far too soon to shout “whale ahoy,” physicists both inside and outside CERN said, noting that the history of particle physics is rife with statistical flukes and anomalies that disappeared when more data was compiled. A coincidence is the most probable explanation for the surprising bumps in data from the collider, physicists from the experiments cautioned, saying that a lot more data was needed and would in fact soon be available. “I don’t think there is anyone around who thinks this is conclusive,” said Kyle Cranmer, a physicist from New York University who works on one of the CERN teams, known as Atlas. “But it would be huge if true,” he said, noting that many theorists had put their other work aside to study the new result.
German physicists see landmark in nuclear fusion quest
Scientists in Germany said Thursday they had reached a milestone in a quest to derive energy from nuclear fusion, billed as a potentially limitless, safe and cheap source.
Nuclear fusion entails fusing atoms together to generate energy -- a process similar to that in the Sun -- as opposed to nuclear fission, where atoms are split, which entails worries over safety and long-term waste.
After spending a billion euros ($1.1 billion) and nine years' construction work, physicists working on a German project called the "stellarator" said they had briefly generated a super-heated helium plasma inside a vessel -- a key point in the experimental process.
Scientists detect the magnetic field that powers our galaxy’s supermassive black hole
The Milky Way, like most galaxies, has a supermassive black hole sitting right in its center. Now, for the first time, scientists have detected a magnetic field just outside the event horizon — or outer boundary — of that black hole. Why do we care? Because that magnetic field is probably what makes our neighborhood black hole so powerful.
Controversial experiment sees no evidence that the universe is a hologram
It's a classic underdog story: Working in a disused tunnel with a couple of lasers and a few mirrors, a plucky band of physicists dreamed up a way to test one of the wildest ideas in theoretical physics—a notion from the nearly inscrutable realm of "string theory" that our universe may be like an enormous hologram. However, science doesn't indulge sentimental favorites. After years of probing the fabric of spacetime for a signal of the "holographic principle," researchers at Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, have come up empty, as they will report tomorrow at the lab.
The null result won't surprise many people, as some of the inventors of the principle had complained that the experiment, the $2.5 million Fermilab Holometer, couldn't test it. But Yanbei Chen, a theorist at the California Institute of Technology in Pasadena, says the experiment and its inventor, Fermilab theorist Craig Hogan, deserve some credit for trying. "At least he's making some effort to make an experimental test," Chen says. "I think we should do more of this, and if the string theorists complain that this is not testing what they're doing, well, they can come up with their own tests."
The holographic principle springs from the theoretical study of black holes, spherical regions where gravity is so intense that not even light can escape. Theorists realized that a black hole has an amount of disorder, or entropy, that is proportional to its surface area. As entropy is related to information content, some theorists suggested that an information-area connection might be extended to any properly defined volume of space and time, or spacetime. Thus, crudely speaking, the maximum amount of information contained in a 3D region of space would be proportional its 2D surface area. The universe would then work a bit like a hologram, in which a 2D pattern captures a 3D image.
How to encrypt a message in the afterglow of the big bang
If you’ve got a secret to keep safe, look to the skies. Physicists have proposed using the afterglow of the big bang to make encryption keys.
The security of many encryption methods relies on generating large random numbers to act as keys to encrypt or decipher information. Computers can spawn these keys with certain algorithms, but they aren’t truly random, so another computer armed with the same algorithm could potentially duplicate the key. An alternative is to rely on physical randomness, like the thermal noise on a chip or the timing of a user’s keystrokes. Now Jeffrey Lee and Gerald Cleaver at Baylor University in Waco, Texas, have taken that to the ultimate extreme by looking at the cosmic microwave background (CMB), the thermal radiation left over from the big bang.
LISA Pathfinder Heads to Space
A trailblazing mission took to the skies early this morning as a Vega rocket carrying the LISA Pathfinder lit up the night over Kourou, French Guiana.
Originally known as the Small Missions for Advanced Research in Technology (SMART 2) and a forerunner to the full-fledged Evolved Laser Interferometer Space Antenna (eLISA) project, LISA Pathfinder will test the technologies key to conducting long-baseline laser interferometry in space. Coming almost exactly 100 years after Einstein proposed his theory of general relativity, this mission will prove vital in the hunt for one of the theory’s more bizarre predictions: gravitational waves.
The equations of general relativity say that accelerating massive objects, such as exploding stars or a pair of whirling black holes, ought to send ripples through spacetime. There’s solid indirect evidence that gravitational waves exist, but direct detection has eluded scientists so far.
LISA Pathfinder paves the way for eLISA, which will take that hunt into space. Slated for launch in 2034, eLISA will use three free-flying spacecraft to create a triangular baseline a million kilometers on a side — a feat impossible on Earth. Lasers will measure the position of two masses suspended at the end of each arm, and then researchers will analyze the data to look for the very slight jiggling induced by gravitational waves passing by. The unique setup and location will give eLISA an unprecedented sensitivity .
Scientists Create New Kind Of Diamond At Room Temperature
Researchers have created a new phase of solid carbon with qualities previously thought to be impossible that can be used to create diamonds at room temperature and the same atmospheric pressure as the ambient air. Scientists at North Carolina State University call it Q-carbon and say it is distinct from the other known solid forms of carbon – graphite and diamond.
“The only place it may be found in the natural world would be possibly in the core of some planets,” says NC State’s Jay Narayan, lead author of three papers on the findings, including one published today in Journal of Applied Physics. Q-carbon is ferromagnetic, which he says was thought to be impossible,and is also harder than diamond and can glow when exposed to even a small amount of energy.
Japanese scientists create touchable holograms
A group of Japanese scientists have created touchable holograms, three dimensional virtual objects that can be manipulated by human hand. Using femtosecond laser technology the researchers developed 'Fairy Lights, a system that can fire high frequency laser pulses that last one millionth of one billionth of a second. The pulses respond to human touch, so that - when interrupted - the hologram's pixels can be manipulated in mid-air.
Positrons Are Plentiful In Ultra-Intense Laser Blasts
Physicists from Rice University and the University of Texas at Austin have found a new recipe for using intense lasers to create positrons — the antiparticle of electrons — in record numbers and density.
In a series of experiments described recently in the online journal Scientific Reports published by Nature, the researchers used UT’s Texas Petawatt Laser to make large number of positrons by blasting tiny gold and platinum targets.
Although the positrons were annihilated in a fraction of a microsecond, the experiments have implications for new realms of physics and astrophysics research, medical therapy and perhaps even space travel, said Rice physicist Edison Liang, lead author of the study.
“There are many futuristic technologies related to antimatter that people have been dreaming about for the last 50 years,” said Liang, the Andrew Hays Buchanan Professor of Astrophysics. “One is that antimatter is the most efficient form of energy storage. When antimatter annihilates with matter, it becomes pure energy. Nothing is left behind, unlike in fusion or fission or chemical-based reactions.”
Scientists Link Moon’s Tilt and Earth’s Gold
At its birth, the moon was quite close to the Earth, probably within 20,000 miles. Because of the tidal pulls between the Earth and moon, the moon’s orbit has slowly been spiraling outward ever since, and as it does, Earth’s pull diminishes, and the pull of the sun becomes more dominant.
By now, with the moon a quarter million miles from Earth, the sun’s gravity should have tipped the moon’s orbit to lie in the same plane as the orbits of the planets. But it has not. The moon’s orbit is about 5 degrees askew. “That the lunar inclination is as small as it is gives us some confidence that the basic idea of lunar formation from an equatorial disk of debris orbiting the proto-Earth is a good one,” said Kaveh Pahlevan, a planetary scientist at the Observatory of the Côte d’Azur in Nice, France. “But the story must have a twist.”
Writing in this week’s issue of the journal Nature, Dr. Pahlevan and his observatory colleague Alessandro Morbidelli propose the twist. The moon did indeed form in the Earth’s equatorial plane, the scientists said, but then a few large objects, perhaps as large as the moon, zipping through the inner solar system repeatedly passed nearby over a few tens of millions of years and tipped the moon’s orbit.
NASA's New 'Star Trek' Tech Is Designed to Detect Alien Life
New NASA technology straight out of "Star Trek" could help scientists detect life on other worlds.
The device, dubbed the "chemical laptop," is a miniature, portable laboratory that resembles the TV show's famous tricorder scanning device, and is designed to make data collection easier and faster than ever before.
The laptop, currently in development at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, is a chemical analyzer made to detect both amino acids and fatty acids, often called "the building blocks of life," in samples from extraterrestrial terrain. Amino acids bind together to create proteins, which are vital to almost all processes that occur within a cell, and fatty acids are an important component of cell membranes, so researchers believe finding both could indicate that life is now or was once present.
A Century Ago, Einstein’s Theory of Relativity Changed Everything
By the fall of 1915, Albert Einstein was a bit grumpy. And why not? Cheered on, to his disgust, by most of his Berlin colleagues, Germany had started a ruinous world war. He had split up with his wife, and she had decamped to Switzerland with his sons.
He was living alone. A friend, Janos Plesch, once said, “He sleeps until he is awakened; he stays awake until he is told to go to bed; he will go hungry until he is given something to eat; and then he eats until he is stopped.”
Worse, he had discovered a fatal flaw in his new theory of gravity, propounded with great fanfare only a couple of years before. And now he no longer had the field to himself. The German mathematician David Hilbert was breathing down his neck.
So Einstein went back to the blackboard. And on Nov. 25, 1915, he set down the equation that rules the universe. As compact and mysterious as a Viking rune, it describes space-time as a kind of sagging mattress where matter and energy, like a heavy sleeper, distort the geometry of the cosmos to produce the effect we call gravity, obliging light beams as well as marbles and falling apples to follow curved paths through space.
Is Earth Growing a Hairy Dark Matter 'Beard'?
Dark matter is thought to be everywhere, literally, but we can’t see it; we can only detect its gravitational presence over large cosmic scales. Now, theoretical physicists are theorizing what configuration the dark stuff may take around Earth. And it’s becoming a bit of a hairy subject.
If we are to take the findings of a recent computer simulation to heart, it looks as if the planets in our solar system are growing rather trendy dark matter “beards,” an idea that not only reveals previously unknown interplanetary fashion trend, it could also provide a guide as to where to seek out direct evidence of the invisible matter that is thought to make up 85 percent of the mass of the entire universe.
Scientists caught a new planet forming for the first time ever
When a new star is born, it creates a disk full of gas and dust — the stuff of planetary formation. But it's hard to catch alien stars in the process of planetary baby-making, because the same dust that creates planets helps obscure these distant solar systems from our sight. We've found young planets and old ones alike, but none of them have actually been in the process of forming — until now.
This new study was led by University of Arizona graduate student Stephanie Sallum and Kate Follette, a former fellow graduate student who has since moved on to postdoctoral research at Stanford University. The two women were working on separate PhD projects, but had decided to focus on the same star — LkCa15, located 450 light years from Earth.
"The reason we selected this system is because it’s built around a very young star that has material left over from the star-formation process," Follette said in a statement. "It’s like a big doughnut. This system is special because it’s one of a handful of disks that has a solar-system size gap in it. And one of the ways to create that gap is to have planets forming in there."
The women and their colleagues set high-powered telescopes to look at the system and used a new technique to look for protoplanets. They searched for the light emitted by hydrogen as the gas falls toward a newly forming planet. That process is hot — roughly 17,500 degrees Fahrenheit — and it produces a signature red glow.
Experiment records extreme quantum weirdness
An experiment in Singapore has pushed quantum weirdness close to its absolute limit. Researchers from the Centre for Quantum Technologies (CQT) at the National University of Singapore and the University of Seville in Spain have reported the most extreme 'entanglement' between pairs of photons ever seen in the lab. The result was published 30 October 2015 in Physical Review Letters.
The achievement is evidence for the validity of quantum physics and will bolster confidence in schemes for quantum cryptography and quantum computing designed to exploit this phenomenon. "For some quantum technologies to work as we intend, we need to be confident that quantum physics is complete," says Poh Hou Shun, who carried out the experiment at CQT. "Our new result increases that confidence," he says.
The researchers looked at 33.2 million optimized photon pairs. Each pair was split up and the photons measured separately, then the correlation between the results quantified.
In such a Bell test, the strength of the correlation says whether or not the photons were entangled. The measures involved are complex, but can be reduced to a simple number. Any value bigger than 2 is evidence for quantum effects at work. But there is also an upper limit.
Quantum physics predicts the correlation measure cannot get any bigger than 2sqrt(2) ~2.82843. In the experiment at CQT, they measure 2.82759 +/- 0.00051 - within 0.03% of the limit. If the peak value were the top of Everest, this would be only 2.6 metres below the summit.
Scientists look into hydrogen atom, find old recipe for pi
Published in 1655 by the English mathematician John Wallis, the Wallis product is an infinite series of fractions that, when multiplied, equal pi divided by 2. It has not appeared in physics at all until now, when University of Rochester scientists Carl Hagen and Tamar Friedmann collaborated on a problem set that Dr. Hagen had developed for his quantum mechanics class.
Instead of using Niels Bohr’s near-century-old calculations for the energy states of hydrogen, Hagen had his students use a method called the variational principle, just to see what might happen. Ultimately, the calculations demanded mathematical expertise, which came in the form of Dr. Friedmann, who is both a mathematician and a physicist.
“One of the things that I’m able to do is talk to both mathematicians and physicists, and that basically requires translating between two languages,” says Friedmann, who studied mathematics as an undergraduate student at Princeton, where she also earned a PhD. in Theoretical and Mathematical Physics.
Friedmann says that asking new questions in math from physics and seeking to understand the physical systems from a mathematical standpoint enriched her understanding of problems in both disciplines. Friedmann tends to take on problems that might not even have an answer; she thinks that’s the type of approach that can lead to new discoveries. “And when they happen,” Friedmann says, “it’s really amazing.”
Strong forces make antimatter stick
Antimatter is a shadowy mirror image of the ordinary matter we are familiar with. For the first time, scientists have measured the forces that make certain antimatter particles stick together. The findings, published in Nature, may yield clues to what led to the scarcity of antimatter in the cosmos today.
The forces between antimatter particles - in this case antiprotons - had not been measured before. If antiprotons were found to behave in a different way to their "mirror images" (the ordinary proton particles that are found in atoms) it might provide a potential explanation for what is known as "matter/antimatter asymmetry".
Birth of universe modeled in massive data simulation
Researchers are sifting through an avalanche of data produced by one of the largest cosmological simulations ever performed, led by scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory.
The simulation, run on the Titan supercomputer at DOE's Oak Ridge National Laboratory, modeled the evolution of the universe from just 50 million years after the Big Bang to the present day - from its earliest infancy to its current adulthood. Over the course of 13.8 billion years, the matter in the universe clumped together to form galaxies, stars and planets; but we're not sure precisely how.
Modern Mystery: Ancient Comet Is Spewing Oxygen
The Rosetta spacecraft has detected molecular oxygen in the gas streaming off comet 67P/Churyumov-Gerasimenko, a curious finding that has scientists rethinking the ingredients that were present in the early solar system.
What's mystifying astronomers about the new find is why the oxygen wasn't annihilated during the solar system's formation. Molecular oxygen is extremely reactive with hydrogen, which was swirling in abundance as the sun and planets were created. Current solar system models suggest the molecular oxygen should have disappeared by the time 67P was created, about 4.6 billion years ago.
Ingredients for Life Were Always Present on Earth, Comet Suggests
The basic building blocks of life may have been present on Earth from the very beginning.
Astronomers detected 21 different complex organic molecules streaming from Comet Lovejoy during its highly anticipated close approach to the sun this past January. Many of these same carbon-containing compounds have also been spotted around newly forming sunlike stars, researchers said.
"This suggests that our proto-planetary nebula was already enriched in complex organic molecules (as disk models suggested) when comets and planets formed," study lead author Nicolas Biver, of the Paris Observatory, told Space.com via email.
Life May Have Begun 4.1 Billion Years Ago on an Infant Earth
Life may have emerged on Earth 4.1 billion years ago, much earlier than scientists had thought, and relatively soon after the planet formed, researchers say.
Previous research suggested life may have arisen on Earth 3.83 billion years ago. The new findings suggest life started 270 million years earlier, and only about 440 million years after Earth formed about 4.54 billion years ago.
If life on Earth did spring up relatively quickly, that suggests life could be abundant in the universe, scientists added.
Earth Bloomed Early: A Fermi Paradox Solution?
Our place in the universe is a conundrum — life on Earth evolved to create a technologically-savvy race that is now looking for other technologically-savvy intelligences populating our galaxy. But there’s a problem; it looks like humanity is the only “intelligent” species in our little corner of the universe — what gives?
This question forms the basis of the Fermi Paradox: given the age of the universe and the apparent high probability of life evolving on other planets orbiting other stars, where are all the smart aliens? According to a new study based on data collected by the NASA/ESA Hubble Space Telescope and NASA’s Kepler Space Telescope, it might be that Earth (and all life on it) is an early bloomer. By extension, the logical progression from this new study is that we’re not hearing from advanced alien civilizations because, in short, the universe hasn’t had the time to spawn many more habitable worlds.
Perfectly accurate clocks turn out to be impossible
Can the passage of time be measured precisely, always and everywhere? The answer will upset many watchmakers. A team of physicists from the universities of Warsaw and Nottingham have just shown that when we are dealing with very large accelerations, no clock will actually be able to show the real passage of time, known as "proper time".
Our Universe: It's the 'Simplest' Thing We Know
Our universe is actually really simple, it's just our cosmological theories that are getting needlessly complex, argues one of the world's leading theoretical physicists.
This conclusion may sound counterintuitive; after all, to fully understand the true complexities of Nature, you need to think bigger, study things on finer and finer scales, add new variables to equations, and think up "new" and "exotic" physics. Eventually we'll discover what dark matter is; eventually we'll gain a grasp of where those gravitational waves are hiding – if only our theoretical models were more advanced and more... complex.
Baylor Physicist Appointed to Management Team of Major Scientific Experiment at CERN