A Wrinkle in Space-Time: Math Shows How Shockwaves Could Crinkle Space

A Wrinkle in Space-Time: Math Shows How Shockwaves Could Crinkle Space

  11:20:00 AM    Science Lover

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Mathematicians at UC Davis have come up with a new way to crinkle up the fabric of space-time -- at least in theory.

Illustration of twisted space-time around Earth. (Credit: NASA)

"We show that space-time cannot be locally flat at a point where two shock waves collide," said Blake Temple, professor of mathematics at UC Davis. "This is a new kind of singularity in general relativity."

The results are reported in two papers by Temple with graduate students Moritz Reintjes and Zeke Vogler, respectively, both published in the journal Proceedings of the Royal Society A.

Einstein's theory of general relativity explains gravity as a curvature in space-time. But the theory starts from the assumption that any local patch of space-time looks flat, Temple said.

A singularity is a patch of space-time that cannot be made to look flat in any coordinate system, Temple said. One example of a singularity is inside a black hole, where the curvature of space becomes extreme.

Temple and his collaborators study the mathematics of how shockwaves in a perfect fluid can affect the curvature of space-time in general relativity. In earlier work, Temple and collaborator Joel Smoller, Lamberto Cesari professor of mathematics at the University of Michigan, produced a model for the biggest shockwave of all, created from the Big Bang when the universe burst into existence.

A shockwave creates an abrupt change, or discontinuity, in the pressure and density of a fluid, and this creates a jump in the curvature. But it has been known since the 1960s that the jump in curvature created by a single shock wave is not enough to rule out the locally flat nature of space-time.

Vogler's doctoral work used mathematics to simulate two shockwaves colliding, while Reintjes followed up with an analysis of the equations that describe what happens when shockwaves cross. He found this created a new type of singularity, which he dubbed a "regularity singularity."

What is surprising is that something as mild as interacting waves could create something as extreme as a space-time singularity, Temple said.

Temple and his colleagues are investigating whether the steep gradients in the space-time fabric at a regularity singularity could create any effects that are measurable in the real world. For example, they wonder whether they might produce gravity waves, Temple said. General relativity predicts that these are produced, for example, by the collision of massive objects like black holes, but they have not yet been observed in nature. Regularity singularities could also be formed within stars as shockwaves pass within them, the researchers theorize.

Reintjes, now a postdoctoral scholar at the University of Regensburg, Germany presented the work at the International Congress on Hyperbolic Problems in Padua, in June.

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Roll over Einstein: Law of physics challenged

Roll over Einstein: Law of physics challenged

  12:58:00 PM    Science Lover

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One of the very pillars of physics and Einstein's theory of relativity - that nothing can go faster than the speed of light - was rocked Thursday by new findings from one of the world's foremost laboratories.

This undated file photo shows famed physicist Albert Einstein. Scientists at the European Organization for Nuclear Research, or CERN, the world's largest physics lab, say they have clocked subatomic particles, called neutrinos, traveling faster than light, a feat that, if true, would break a fundamental pillar of science, the idea that nothing is supposed to move faster than light, at least according to Einstein's special theory of relativity: The famous E (equals) mc2 equation. That stands for energy equals mass times the speed of light squared. The readings have so astounded researchers that they are asking others to independently verify the measurements before claiming an actual discovery. (AP Photo)

European researchers said they clocked an oddball type of subatomic particle called a neutrino going faster than the 186,282 miles per second that has long been considered the cosmic speed limit.

The claim was met with skepticism, with one outside physicist calling it the equivalent of saying you have a flying carpet. In fact, the researchers themselves are not ready to proclaim a discovery and are asking other physicists to independently try to verify their findings.

"The feeling that most people have is this can't be right, this can't be real," said James Gillies, a spokesman for the European Organization for Nuclear Research, or CERN, which provided the particle accelerator that sent neutrinos on their breakneck 454-mile trip underground from Geneva to Italy.

Going faster than light is something that is just not supposed to happen according to Einstein's 1905 special theory of relativity - the one made famous by the equation E equals mc2. But no one is rushing out to rewrite the science books just yet.

It is "a revolutionary discovery if confirmed," said Indiana University theoretical physicist Alan Kostelecky, who has worked on this concept for a quarter of a century.

Stephen Parke, who is head theoretician at the Fermilab near Chicago and was not part of the research, said: "It's a shock. It's going to cause us problems, no doubt about that - if it's true."

Even if these results are confirmed, they won't change at all the way we live or the way the world works. After all, these particles have presumably been speed demons for billions of years. But the finding will fundamentally alter our understanding of how the universe operates, physicists said.

Einstein's special relativity theory, which says that energy equals mass times the speed of light squared, underlies "pretty much everything in modern physics," said John Ellis, a theoretical physicist at CERN who was not involved in the experiment. "It has worked perfectly up until now."

France's National Institute for Nuclear and Particle Physics Research collaborated with Italy's Gran Sasso National Laboratory on the experiment at CERN. CERN reported that a neutrino beam fired from a particle accelerator near Geneva to a lab 454 miles (730 kilometers) away in Italy traveled 60 nanoseconds faster than the speed of light. Scientists calculated the margin of error at just 10 nanoseconds. (A nanosecond is one-billionth of a second.)

Given the enormous implications of the find, the researchers spent months checking and rechecking their results to make sure there were no flaws in the experiment.

A team at Fermilab had similar faster-than-light results in 2007, but a large margin of error undercut its scientific significance.

If anything is going to throw a cosmic twist into Einstein's theories, it's not surprising that it's the strange particles known as neutrinos. These are odd slivers of an atom that have confounded physicists for about 80 years.

The neutrino has almost no mass, comes in three different "flavors," may have its own antiparticle and has been seen shifting from one flavor to another while shooting out from our sun, said physicist Phillip Schewe, communications director at the Joint Quantum Institute in Maryland.

Columbia University physicist Brian Greene, author of the book "Fabric of the Cosmos," said neutrinos theoretically can travel at different speeds depending on how much energy they have. And some mysterious particles whose existence is still only theorized could be similarly speedy, he said.



Fermilab team spokeswoman Jenny Thomas, a physics professor at the University College of London, said there must be a "more mundane explanation" for the European findings. She said Fermilab's experience showed how hard it is to measure accurately the distance, time and angles required for such a claim.

Nevertheless, Fermilab, which shoots neutrinos from Chicago to Minnesota, has already begun working to try to verify or knock down the new findings.

And that's exactly what the team in Geneva wants.

Gillies told The Associated Press that the readings have so astounded researchers that "they are inviting the broader physics community to look at what they've done and really scrutinize it in great detail, and ideally for someone elsewhere in the world to repeat the measurements."

Only two labs elsewhere in the world can try to replicate the work: Fermilab and a Japanese installation that has been slowed by the tsunami and earthquake. And Fermilab's measuring systems aren't nearly as precise as the Europeans' and won't be upgraded for a while, said Fermilab scientist Rob Plunkett.

Drew Baden, chairman of the physics department at the University of Maryland, said it is far more likely that the CERN findings are the result of measurement errors or some kind of fluke. Tracking neutrinos is very difficult, he said.

"This is ridiculous what they're putting out," Baden said. "Until this is verified by another group, it's flying carpets. It's cool, but ..."

So if the neutrinos are pulling this fast one on Einstein, how can it happen?

Parke said there could be a cosmic shortcut through another dimension - physics theory is full of unseen dimensions - that allows the neutrinos to beat the speed of light.

Indiana's Kostelecky theorizes that there are situations when the background is different in the universe, not perfectly symmetrical as Einstein says. Those changes in background may alter both the speed of light and the speed of neutrinos.

But that doesn't mean Einstein's theory is ready for the trash heap, he said.

"I don't think you're going to ever kill Einstein's theory. You can't. It works," Kostelecky said. There are just times when an additional explanation is needed, he said.

If the European findings are correct, "this would change the idea of how the universe is put together," Columbia's Greene said. But he added: "I would bet just about everything I hold dear that this won't hold up to scrutiny."


More information: The results are pre-published on ArXiv: http://arxiv.org/abs/1109.4897

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Squeezed light from single atoms

Squeezed light from single atoms

  9:11:00 PM    Science Lover

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Max Planck Institute of Quantum Optics scientists generate amplitude-squeezed light fields using single atoms trapped inside optical cavities.

A single rubidium atom in a cavity squeezes the quantum
fluctuations of a weak laser beam, decreasing the fluctuations
of the amplitude at the expense of the phase.
The effect is exaggerated for clarity.

In classical optics light is usually described as a wave, but at the most fundamental quantum level this wave consists of discrete particles called photons. Over the time, physicists developed many tools to manipulate both the wave-like and the particle-like quantum properties of the light. For instance, they created single photon sources with single atoms, using their ability to absorb and emit photons one by one. A team around Professor Gerhard Rempe, Director at the Max Planck Institute of Quantum Optics (Garching near Munich) and head of the Quantum Dynamics Division, has now observed that the light emitted by a single atom may exhibit much richer dynamics (Nature 474, 623, June 30, 2011). Strongly interacting with light inside a cavity, the atom modifies the wave-like properties of the light field, reducing its amplitude or phase fluctuations below the level allowed for classical electromagnetic radiation. This is the very first observation of “squeezed” light produced by a single atom.

The “graininess” of the photons in a light wave causes small fluctuations of the wave’s amplitude and phase. For classical beams, the minimal amount of amplitude and phase fluctuations is equal. However, by creating interactions between the photons, one can “squeeze” the fluctuations of the amplitude below this so-called “shot noise” level at the expense of increasing the fluctuations of the phase, and vice-versa. Unfortunately, the photonic interactions inside standard optical media are very weak, and require bright light beams to be observed. Single atoms are promising candidates to enable such interactions at a few-photon level. Their ability to generate squeezed light has been predicted 30 years ago, but the amount of light they emit is very tiny and so far all attempts to set this idea into realization have failed. In the Quantum Dynamics Division at MPQ sophisticated methods for cooling, isolating and manipulating single atoms have been developed over many years, and made this observation possible.



A single rubidium atom is trapped inside a cavity made of two very reflective mirrors in a distance of about a tenth of a millimetre from each other. When weak laser light is injected into this cavity, the atom can interact with one photon many times, and forms a kind of artificial molecule with the photons of the light field. As a consequence, two photons can enter the system at the same time and become correlated. “According to the model of Bohr, a single atom emits exactly one single energy quantum, i.e., one photon. That means that the number of photons is exactly known, but the phase of the light is not defined”, Professor Gerhard Rempe explains. “But the two photons that are emitted by this strongly coupled atom are indistinguishable and oscillate together. Therefore this time the wave-like properties of the propagating light field are modified.”

When the physicists use a laser beam which is resonant with the excitation frequency of the atom, the measurements show a suppression of the phase fluctuations. If the laser light is resonant with the cavity, they observe a squeezing of the amplitude instead.

The latter situation is illustrated in the figure: The atom in the cavity turns a laser beam into light which has less amplitude and more phase fluctuations than the shot-noise limit. “Our experiment shows that the light emitted by single atoms is much more complex than in the simple view of Albert Einstein concerning photo-emission”, Dr. Karim Murr emphasizes. “The squeezing that we observe is due to the coherent interaction between the two photons emitted from the system. Our measurement is in excellent agreement with the predictions of quantum electrodynamics in the strong-coupling regime.” And Dr. Alexei Ourjoumtsev, who has been working on the experiment as a post doc, adds: “Usually single quantum objects are used to manipulate the particle-like properties of light. It is interesting to see that they can also modify its wave-like properties, and create observable squeezing with excitations beams containing only two photons on average”.

So far squeezed light has only been generated with systems containing many atoms, such as crystals, using very high intensity beams, i.e. many photons. For the first time now physicists have succeeded in generating this kind of non-classical radiation with single atoms and extremely weak light fields. The ability of a single atom to induce strong coherent interactions between propagating photons opens up new perspectives for photonic quantum logic with single emitters.

More information: A. Ourjoumtsev, A. Kubanek, M. Koch, C. Sames, P. W. H. Pinkse, G. Rempe, & K. Murr

Observation of squeezed light from one atom excited with two photons , Nature 474, 623, 30 June 2011. Provided by Max-Planck-Gesellschaft

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Genius of Einstein, Fourier key to new humanlike computer vision

Genius of Einstein, Fourier key to new humanlike computer vision

  1:46:00 AM    Science Lover

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Two new techniques for computer-vision technology mimic how humans perceive three-dimensional shapes by instantly recognizing objects no matter how they are twisted or bent, an advance that could help machines see more like people.

This graphic illustrates a new computer-vision technology
that builds on the basic physics and mathematical equations
related to how heat diffuses over surfaces. The technique
mimics how humans perceive three-dimensional shapes
by instantly recognizing objects no matter how they are
twisted or bent, an advance that could help machines see
more like people. Here, a "heat mean signature" of a human
hand model is used to perceive the six segments of the
overall shape and define the fingertips. (Purdue University
image/Karthik Ramani and Yi Fang)

The techniques, called heat mapping and heat distribution, apply mathematical methods to enable machines to perceive three-dimensional objects, said Karthik Ramani, Purdue University's Donald W. Feddersen Professor of Mechanical Engineering.

"Humans can easily perceive 3-D shapes, but it's not so easy for a computer," he said. "We can easily separate an object like a hand into its segments - the palm and five fingers - a difficult operation for computers."

Both of the techniques build on the basic physics and mathematical equations related to how heat diffuses over surfaces.

"Albert Einstein made contributions to diffusion, and 18th century physicist Jean Baptiste Joseph Fourier developed Fourier's law, used to derive the heat equation," Ramani said. "We are standing on the shoulders of giants in creating the algorithms for these new approaches using the heat equation."

As heat diffuses over a surface it follows and captures the precise contours of a shape. The system takes advantage of this "intelligence of heat," simulating heat flowing from one point to another and in the process characterizing the shape of an object, he said.

Findings will be detailed in two papers being presented during the IEEE Computer Vision and Pattern Recognition conference on June 21-23 in Colorado Springs. The paper was written by Ramani, Purdue doctoral students Yi Fang and Mengtian Sun, and Minhyong Kim, a professor of pure mathematics at the University College London.

A major limitation of existing methods is that they require "prior information" about a shape in order for it to be analyzed.

Researchers developing a new machine-vision technique tested
their method on certain complex shapes, including the human form
or a centaur – a mythical half-human, half-horse creature. The heat
mapping allows a computer to recognize the objects no matter how
the figures are bent or twisted and is able to ignore "noise" introduced
by imperfect laser scanning or other erroneous data. (Purdue University
image/Karthik Ramani and Yi Fang)

"For example, in order to do segmentation you have to tell the computer ahead of time how many segments the object has," Ramani said. "You have to tell it that you are expecting, say, 10 segments or 12 segments."

The new methods mimic the human ability to properly perceive objects because they don't require a preconceived idea of how many segments exist.

"We are trying to come as close as possible to human segmentation," Ramani said. "A hot area right now is unsupervised machine learning. This means a machine, such as a robot, can perceive and learn without having any previous training. We are able to estimate the segmentation instead of giving a predefined number of segments."



The work is funded partially by the National Science Foundation. A patent on the technology is pending.

The methods have many potential applications, including a 3-D search engine to find mechanical parts such as automotive components in a database; robot vision and navigation; 3-D medical imaging; military drones; multimedia gaming; creating and manipulating animated characters in film production; helping 3-D cameras to understand human gestures for interactive games; contributing to progress of areas in science and engineering related to pattern recognition; machine learning; and computer vision.

The heat-mapping method works by first breaking an object into a mesh of triangles, the simplest shape that can characterize surfaces, and then calculating the flow of heat over the meshed object. The method does not involve actually tracking heat; it simulates the flow of heat using well-established mathematical principles, Ramani said.

Heat mapping allows a computer to recognize an object, such as a hand or a nose, no matter how the fingers are bent or the nose is deformed and is able to ignore "noise" introduced by imperfect laser scanning or other erroneous data.

"No matter how you move the fingers or deform the palm, a person can still see that it's a hand," Ramani said. "But for a computer to say it's still a hand is going to be hard. You need a framework - a consistent, robust algorithm that will work no matter if you perturb the nose and put noise in it or if it's your nose or mine."

The method accurately simulates how heat flows on the object while revealing its structure and distinguishing unique points needed for segmentation by computing the "heat mean signature." Knowing the heat mean signature allows a computer to determine the center of each segment, assign a "weight" to specific segments and then define the overall shape of the object.

"Being able to assign a weight to segments is critical because certain points are more important than others in terms of understanding a shape," Ramani said. "The tip of the nose is more important than other points on the nose, for example, to properly perceive the shape of the nose or face, and the tips of the fingers are more important than many other points for perceiving a hand."

In temperature distribution, heat flow is used to determine a signature, or histogram, of the entire object.

"A histogram is a two-dimensional mapping of a three-dimensional shape," Ramani said. "So, no matter how a dog bends or twists, it gives you the same signature."

The temperature distribution technique also uses a triangle mesh to perceive 3-D shapes. Both techniques, which could be combined in the same system, require modest computer power and recognize shapes quickly, he said.

"It's very efficient and very compact because you're just using a two-dimensional histogram," Ramani said. "Heat propagation in a mesh happens very fast because the mathematics of matrix computations can be done very quickly and well."

The researchers tested their method on certain complex shapes, including hands, the human form or a centaur, a mythical half-human, half-horse creature.

Sources: Karthik Ramani, 765-494-5725, ramani@purdue.edu

Yi Fang, fang4@purdue.edu

Note to Journalists: The papers are available by contacting Emil Venere, Purdue News Service, at 765-494-4709, venere@purdue.edu

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Dark Energy Is Driving Universe Apart: NASA's Galaxy Evolution Explorer Finds Dark Energy Repulsive

Dark Energy Is Driving Universe Apart: NASA's Galaxy Evolution Explorer Finds Dark Energy Repulsive

  8:53:00 PM    Science Lover

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A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds.

New results from NASA's Galaxy Evolution Explorer
and the Anglo-Australian Telescope atop Siding Spring
Mountain in Australia confirm that dark energy (represented
by purple grid) is a smooth, uniform force that now
dominates over the effects of gravity (green grid). The
observations follow from careful measurements of the
separations between pairs of galaxies (examples of such
pairs are illustrated here). (Credit: NASA/JPL-Caltech)

The survey used data from NASA's space-based Galaxy Evolution Explorer and the Anglo-Australian Telescope on Siding Spring Mountain in Australia.

The findings offer new support for the favored theory of how dark energy works -- as a constant force, uniformly affecting the universe and propelling its runaway expansion. They contradict an alternate theory, where gravity, not dark energy, is the force pushing space apart. According to this alternate theory, with which the new survey results are not consistent, Albert Einstein's concept of gravity is wrong, and gravity becomes repulsive instead of attractive when acting at great distances.

"The action of dark energy is as if you threw a ball up in the air, and it kept speeding upward into the sky faster and faster," said Chris Blake of the Swinburne University of Technology in Melbourne, Australia. Blake is lead author of two papers describing the results that appeared in recent issues of the Monthly Notices of the Royal Astronomical Society. "The results tell us that dark energy is a cosmological constant, as Einstein proposed. If gravity were the culprit, then we wouldn't be seeing these constant effects of dark energy throughout time."

Dark energy is thought to dominate our universe, making up about 74 percent of it. Dark matter, a slightly less mysterious substance, accounts for 22 percent. So-called normal matter, anything with atoms, or the stuff that makes up living creatures, planets and stars, is only approximately four percent of the cosmos.

The idea of dark energy was proposed during the previous decade, based on studies of distant exploding stars called supernovae. Supernovae emit constant, measurable light, making them so-called "standard candles," which allows calculation of their distance from Earth. Observations revealed dark energy was flinging the objects out at accelerating speeds.

The new survey provides two separate methods for independently checking these results. This is the first time astronomers performed these checks across the whole cosmic timespan dominated by dark energy. Astronomers began by assembling the largest three-dimensional map of galaxies in the distant universe, spotted by the Galaxy Evolution Explorer.

"The Galaxy Evolution Explorer helped identify bright, young galaxies, which are ideal for this type of study," said Christopher Martin, principal investigator for the mission at the California Institute of Technology in Pasadena. "It provided the scaffolding for this enormous 3-D map."

The team acquired detailed information about the light for each galaxy using the Anglo-Australian Telescope and studied the pattern of distance between them. Sound waves from the very early universe left imprints in the patterns of galaxies, causing pairs of galaxies to be separated by approximately 500 million light-years.

Blake and his colleagues used this "standard ruler" to determine the distance from the galaxy pairs to Earth. As with the supernovae studies, this distance data was combined with information about the speeds the pairs are moving away from us, revealing, yet again, the fabric of space is stretching apart faster and faster.

The team also used the galaxy map to study how clusters of galaxies grow over time like cities, eventually containing many thousands of galaxies. The clusters attract new galaxies through gravity, but dark energy tugs the clusters apart. It slows down the process, allowing scientists to measure dark energy's repulsive force.

"Observations by astronomers over the last 15 years have produced one of the most startling discoveries in physical science; the expansion of the universe, triggered by the big bang, is speeding up," said Jon Morse, astrophysics division director at NASA Headquarters in Washington. "Using entirely independent methods, data from the Galaxy Evolution Explorer have helped increase our confidence in the existence of dark energy."

For more information about NASA's Galaxy Evolution Explorer, visit: http://www.nasa.gov/galex and http://www.galex.caltech.edu .

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Quantum Networks: Photons and Qubits Entangled

Quantum Networks: Photons and Qubits Entangled

  1:57:00 AM    Science Lover

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A team of Harvard physicists led by Mikhail D. Lukin has achieved the first-ever quantum entanglement of photons and solid-state materials. The work marks a key advance toward practical quantum networks, as the first experimental demonstration of a means by which solid-state quantum bits, or "qubits," can communicate with one another over long distances.

Physicists have achieved the first-ever quantum entanglement of photons and solid-state materials -- a key advance toward practical quantum networks in which solid-state quantum bits, or "qubits," can communicate with one another over long distances. (Credit: iStockphoto/Andrey Prokhorov)

Quantum networking applications such as long-distance communication and distributed computing would require the nodes that process and store quantum data in qubits to be connected to one another by entanglement, a state where two different atoms become indelibly linked such that one inherits the properties of the other.

"In quantum computing and quantum communication, a big question has been whether or how it would be possible to actually connect qubits, separated by long distances, to one another," says Lukin, professor of physics at Harvard and co-author of a paper describing the work in the journal Nature.

"Demonstration of quantum entanglement between a solid-state material and photons is an important advance toward linking qubits together into a quantum network."

Quantum entanglement has previously been demonstrated only with photons and individual ions or atoms.

"Our work takes this one step further, showing how one can engineer and control the interaction between individual photons and matter in a solid-state material," says first author Emre Togan, a graduate student in physics at Harvard. "What's more, we show that the photons can be imprinted with the information stored in a qubit."

Quantum entanglement, famously termed "spooky action at a distance" by a skeptical Albert Einstein, is a fundamental property of quantum mechanics. It allows one to distribute quantum information over tens of thousands of kilometers, limited only by how fast and how far members of the entangled pair can propagate in space.

The new result builds upon earlier work by Lukin's group to use single atom impurities in diamonds as qubits. Lukin and colleagues have previously shown that these impurities can be controlled by focusing laser light on a diamond lattice flaw where nitrogen replaces an atom of carbon. That previous work showed that the so-called spin degrees of freedom of these impurities make excellent quantum memory.

Lukin and his co-authors now say that these impurities are also remarkable because, when excited with a sequence of finely tuned microwave and laser pulses, they can emit photons one at a time, such that photons are entangled with quantum memory. Such a stream of single photons can be used for secure transmission of information.

"Since photons are the fastest carriers of quantum information, and spin memory can robustly store quantum information for relatively long periods of time, entangled spin-photon pairs are ideal for the realization of quantum networks," Lukin says. "Such a network, a quantum analog to the conventional internet, could allow for absolutely secure communication over long distances."

Lukin and Togan's co-authors on the Nature paper are Yiwen Chu, Alexei Trifonov, Jeronimo Maze, and Alexander S. Zibrov, all at Harvard; Liang Jiang of Harvard and the California Institute of Technology; Lilian I. Childress of Harvard and Bates College; M.V. Gurudev Dutt of Harvard and the University of Pittsburgh; A.S. Sorensen at the University of Copenhagen; and Phillip R. Hemmer of Texas A&M University. The work was supported by the Defense Advanced Research Projects Agency, the Harvard-MIT Center for Ultracold Atoms, the National Science Foundation, the National Defense Science & Engineering Graduate Fellowship, and the Packard Foundation.

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Scientists Create a Solar Energy Device from a Plant Protein Structure

Scientists Create a Solar Energy Device from a Plant Protein Structure

  9:46:00 PM    Science Lover

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If harnessing the unlimited solar power of the sun were easy, we wouldn't still have the greenhouse gas problem that results from the use of fossil fuel. And while solar energy systems work moderately well in hot desert climates, they are still inefficient and contribute only a small percentage of the general energy demand. A new solution may be coming from an unexpected source -- a source that may be on your dinner plate tonight.

New research suggests that minute crystals from peas can be illuminated and used as small battery chargers or form the core of more efficient artificial solar cells. (Credit: iStockphoto/Andrea Skjold)

"Looking at the most complicated membrane structure found in a plant, we deciphered a complex membrane protein structure which is the core of our new proposed model for developing 'green' energy," says structural biologist Prof. Nathan Nelson of Tel Aviv University's Department of Biochemistry. Isolating the minute crystals of the PSI super complex from the pea plant, Prof. Nelson suggests these crystals can be illuminated and used as small battery chargers or form the core of more efficient artificial solar cells.

Nanoscience is the science of small particles of materials and is one of the most important research frontiers in modern technology. In nature, positioning of molecules with sub-nanometer precision is routine, and crucial to the operation of biological complexes such as photosynthetic complexes. Prof. Nelson's research concentrates on this aspect.

The mighty PSI

To generate useful energy, plants have evolved very sophisticated "nano-machinery" which operates with light as its energy source and gives a perfect quantum yield of 100%. Called the Photosystem I (PSI) complex, this complex was isolated from pea leaves, crystalized and its crystal structure determined by Prof. Nelson to high resolution, which enabled him to describe in detail its intricate structure.

"My research aims to come close to achieving the energy production that plants can obtain when converting sun to sugars in their green leaves," explains Prof. Nelson.

Described in 1905 by Albert Einstein, quantum physics and photons explained the basic principles of how light energy works. Once light is absorbed in plant leaves, it energizes an electron which is subsequently used to support a biochemical reaction, like sugar production.

"If we could come even close to how plants are manufacturing their sugar energy, we'd have a breakthrough. It's therefore important to solve the structure of this nano-machine to understand its function," says Prof. Nelson, whose lab is laying the foundations for this possibility.

Since the PSI reaction center is a pigment-protein complex responsible for the photosynthetic conversion of light energy to another form of energy like chemical energy, these reaction centers, thousands of which are precisely packed in the crystals, may be used to convert light energy to electricity and serve as electronic components in a variety of different devices.

"One can imagine our amazement and joy when, upon illumination of those crystals placed on gold covered plates, we were able to generate a voltage of 10 volts. This won't solve our world's energy problem, but this could be assembled in power switches for low-power solar needs, for example," he concludes.

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Scientists compute odds of interplanetary merger

Scientists compute odds of interplanetary merger

  8:54:00 PM    Science Lover

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Clash of the titans: Artist illustration depicts
collision between Earth and Venus

According to a study released Wednesday, there is a small, one-in-2500 chance that Earth will collide with Venus or Mars in 3.5 billion years.

Using powerful computers, Jacques Laskar, a researcher at the Observatoire de Paris, France, generated numerical simulations of orbital instability over the next five billion years.

Unlike previous models, they took into account Albert Einstein’s theory of general relativity. It resulted in dramatically different orbital paths.

The researchers looked at 2,501 possible scenarios, 25 of which ended with a severely disrupted Solar System.

“There is one scenario in which Mars passes 794 kilometres from Earth,” said Laskar. “When you come that close, it is the same as a collision as the planets gets torn apart.”

Laskar and colleagues ran additional two hundred computer models, slightly changing the path of Mars each time.

All but five of them ended in a two-way collision involving the Sun, Earth, Mercury, Venus or Mars. A quarter of them saw Earth smashed to pieces.

The cause of orbital chaos was the planet Mercury, found the study, published in the British journal Nature.

“Mercury is the trigger, and would be the first planet to be destabilised because it has the smallest mass,” explained Laskar. At some point Mercury’s orbit would get into resonance with that of Jupiter, throwing the smaller orb even more out of kilter, he said.

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I think, therefore I, robot

I think, therefore I, robot

  9:49:00 PM    Science Lover

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Human researchers have developed their mechanical counterparts: ‘robo-scientists’ that can think independently,

Two separate teams of researchers, reporting on Thursday in the journal Science, said that they had created machines that could reason, formulate theories and discover scientific knowledge on their own, marking a major advance in the field of artificial intelligence.

Such “robo-scientists” could be put to work unravelling complex biological systems, designing new drugs, modelling the world’s climate or understanding the cosmos.

For the moment, though, they are performing more humble tasks...

Meet Adam: The first robot scientist to make an independent discovery

A robot developed by UK scientists, which can think up scientific theories and test them with almost no human help, has ushered in a new era in artificial intelligence.

In tests, the machine – named Adam – was able to identify previously unknown genetic processes in baker’s yeast.

It produced hypotheses about how certain genes should work and devised tests to prove its ideas were right.

Professor Ross King of Aberystwyth University, Wales – who helped create Adam – said: “This is the first time we believe such a system has discovered novel scientific knowledge. We are very excited about it.”

The robot takes up 15 square metres of space at the university and is equipped with an arm and a range of devices, including an automated freezer and an incubator.

“It is not the management and analysis of complex data that is the big deal about Adam. What’s amazing is the ability of the machine to reason with those data and make proposals about how a living thing works,” said Stephen Oliver, who co-authored the study on the project.

A second robot, called Eve, will work alongside it to help find new medicines for diseases such as malaria.

Professor Douglas Kell, whose biotech group BBSRC funded the research, said: “Computers play a fundamental role in the scientific process, which is becoming increasingly automated, for instance, in drug design and DNA sequencing.”

“Ultimately, we hope to have teams of human and robot scientists working together in labs,” King said.

Although Adam’s discoveries were simple, experts believe future models may one day rival Albert Einstein for genius.

King said: “I wouldn’t rule out the possibility, but it probably wouldn’t be in my lifetime.”


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