Welcome to the Saturday Science Edition of Overnight News Digest
Overnight News Digest is a regular daily feature which provides noteworthy news items and commentary from around the world. The editorial staff includes side pocket, maggiejean, wader, Doctor RJ, rfall, and JML9999.
Neon Vincent is our editor-in-chief.
Special thanks go to Magnifico for starting this venerable series.
Astronomy
The Planet That Lost An Ocean’s Worth Of Water A primitive ocean on Mars held more water than Earth’s Arctic Ocean and covered a greater portion of the planet’s surface than the Atlantic Ocean does on Earth, according to new results published today. An international team of scientists used the European Southern Observatory’s (ESO) Very Large Telescope (VLT), along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility, to monitor the atmosphere of the planet and map out the properties of the water in different parts of Mars’ atmosphere over a six-year period. These new maps are the first of their kind. About 4 billion years ago, the young planet would have had enough water to cover its entire surface in a liquid layer about 460 feet (140 meters) deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere and in some regions reaching depths greater than 1 mile (1.6 kilometers). “Our study provides a solid estimate of how much water Mars once had by determining how much water was lost to space,” said Geronimo Villanueva from NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “With this work, we can better understand the history of water on Mars.” The new estimate is based on detailed observations of two slightly different forms of water in Mars’s atmosphere. One is the familiar form of water made with two hydrogen atoms and one oxygen — H2O. The other is HDO, or semi-heavy water, a naturally occurring variation in which one hydrogen atom is replaced by a heavier form called deuterium. As the deuterated form is heavier than normal water, it is less easily lost into space through evaporation. So the greater the water loss from the planet, the greater the ratio of HDO to H2O in the water that remains. The researchers distinguished the chemical signatures of the two types of water using ESO’s VLT in Chile along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility in Hawaii. By comparing the ratio of HDO to H2O, scientists can measure by how much the fraction of HDO has increased and thus determine how much water has escaped into space. This in turn allows the amount of water on Mars at earlier times to be estimated. astronomy
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Dawn Orbiter Reaches Dwarf-Planet Ceres If the best things in life are worth waiting for, then it's been totally worth it for the team of scientists and engineers involved in NASA's Dawn mission. After a 7½-year journey that covered 3.1 billion miles (4.9 billion km), the spacecraft has finally settled into orbit around its second and final destination: the giant asteroid 1 Ceres. The orbital capture occurred today [Mar 6] at 4:39 a.m. Pacific Standard Time (12:39 Universal Time), with the spacecraft about 38,000 miles (61,000 km) from Ceres and out of contact with Earth. [...] Although Dawn has been recording images of Ceres for weeks, some of which show provocative features, the real science at Ceres won't begin for a while. The thruster will lower and circularize the initial orbit until, next month, the spacecraft will start to characterize all of Ceres from an altitude of 8,400 miles (13,500 km). Then Dawn will be lowered to 920 miles (1,480 km) by August, where it remains in this high-altitude mapping orbit (HAMO) for two months. The spacecraft's German-built framing camera and Italian-built visible-infrared mapping spectrometer will be very busy during this phase of the mission. Another long firing of the ion thruster will then nudge Dawn even closer, bottoming out at an altitude of about 230 miles (375 km) by no later than mid-December. From this low-altitude mapping orbit (LAMO), Dawn’s gamma-ray and neutron detector (GRaND) has a chance to map elemental abundances around the globe. Moreover, careful tracking of the spacecraft's motion should reveal subtle perturbations that are used to map the body's gravity field and internal structure. Scientists believe that Ceres consists of a rock-and-metal core surrounded by a thick mantle of water ice, with water constituting perhaps 25% of the body's mass. skyandtelescope
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Use Of Rover Arm Expected To Resume In A Few Days Managers of NASA's Curiosity Mars rover mission expect to approve resumption of rover arm movements as early as next week while continuing analysis of what appears to be an intermittent short circuit in the drill. A fluctuation in current on Feb. 27 triggered a fault-protection response that immediately halted action by the rover during the mission's 911th Martian day, or sol. Since then, the rover team has avoided driving Curiosity or moving the rover's arm, while engineers have focused on diagnostic tests. Science observations with instruments on the rover's mast have continued, along with environmental monitoring by its weather station. "Diagnostic testing this week has been productive in narrowing the possible sources of the transient short circuit," said Curiosity Project Manager Jim Erickson of NASA's Jet Propulsion Laboratory, Pasadena, California. "The most likely cause is an intermittent short in the percussion mechanism of the drill. After further analysis to confirm that diagnosis, we will be analyzing how to adjust for that in future drilling." [...] The short on Sol 911 occurred while the rover was transferring rock-powder sample from the grooves of the drill into a mechanism that sieves and portions the powder. The percussion action was in use, to shake the powder loose from the drill. Engineers received results Thursday, March 5, from a test on Curiosity that similarly used the drill's percussion action. During the third out of 180 up-and-down repeats of the action, an apparent short circuit occurred for less than one one-hundredth of a second. Though small and fleeting, it would have been enough to trigger the fault protection that was active on Sol 911 under the parameters that were in place then. nasa
Biology
Mantises Exchange Angular Momentum Between Three Rotating Body Parts To Jump Precisely To Targets Summary: Flightless animals have evolved diverse mechanisms to control their movements in air, whether falling with gravity or propelling against it. Many insects jump as a primary mode of locomotion and must therefore precisely control the large torques generated during takeoff. For example, to minimize spin (angular momentum of the body) at takeoff, plant-sucking bugs apply large equal and opposite torques from two propulsive legs. Interacting gear wheels have evolved in some to give precise synchronization of these legs. Once airborne, as a result of either jumping or falling, further adjustments may be needed to control trajectory and orient the body for landing. Tails are used by geckos to control pitch and by Anolis lizards to alter direction. When falling, cats rotate their body, while aphids and ants manipulate wind resistance against their legs and thorax. Falling is always downward, but targeted jumping must achieve many possible desired trajectories. We show that when making targeted jumps, juvenile wingless mantises first rotated their abdomen about the thorax to adjust the center of mass and thus regulate spin at takeoff. Once airborne, they then smoothly and sequentially transferred angular momentum in four stages between the jointed abdomen, the two raptorial front legs, and the two propulsive hind legs to produce a controlled jump with a precise landing. Experimentally impairing abdominal movements reduced the overall rotation so that the mantis either failed to grasp the target or crashed into it head first. cell.com
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People Use Handshakes To Sniff Each Other Out Limp or firm, your handshake conveys subliminal social cues. Now, research reveals it also transmits chemical signals that could explain why the greeting evolved in the first place. In the study, published in the journal eLife, scientists from Israel's Weizmann Institute of Science found that people use the touch of a handshake to sample and sniff signalling molecules. During the experiment, around 280 people were greeted either with or without a handshake. They were filmed using hidden cameras and observed to see how many times they touched their face. One finding of the study was that people constantly sniff their own hands -- keeping a hand at their nose about 22% of the time. Subjects greeted with a handshake significantly increased touching of their faces with their right hand. However, this only seemed to be the case when the subject had been greeted by a person of the same gender. To check that the observed face-touching was being used as a way to subtly sniff the hand used in handshaking, subjects were fitted with nasal catheters to measure airflow. They found that when a hand was in close proximity to the nose airflow through the nasal passages doubled. In other words, the subject was sniffing.
""It is well-known that we emit odours that influence the behaviour and perception of others but, unlike other mammals, we don't sample those odours from each other overtly," says Professor Noam Sobel, Chair of Neurobiology at the Weizmann Institute of Science. "Instead, our experiments reveal handshakes as a discreet way to actively search for social chemosignals," he said.
biologynews
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Nutrient Pollution From Nitrogen And Phosphorus Reduces Streams' Ability To Support Aquatic Life Nutrient pollution from nitrogen and phosphorus in streams has long been known to increase carbon production by algae, often causing nuisance and harmful algal blooms. But according to results of a new study, nutrient pollution can also result in the loss of forest-derived carbon--leaves and twigs--from stream ecosystems, reducing the ability of streams to support aquatic life.
"Most people think of nitrogen and phosphorus pollution in streams as contributing to algae blooms," said Diane Pataki, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research. "But streams contain a lot of leaf litter, and this study shows that nutrient pollution can also stimulate carbon losses from streams by accelerating the breakdown of that litter. That helps us better understand how fertilizer runoff affects carbon transport and emissions from streams and rivers."
[...]
"This study shows that excess nutrients reduce stream health in a way that was previously unknown," said Amy Rosemond, an ecologist at the University of Georgia (UGA) and the paper's lead author. "By increasing nutrients, we stimulate decomposition, and that can cause the loss of carbon that stream life depends on."
nationalsciencefoundation
Chemistry
Alchemy On The Page If you think today’s chemistry textbooks can be hard to follow, consider what a student of alchemy might have been faced with in the late 16th century: ‘Antimony is the true bath of gold. Philosophers call it the examiner and the stilanx. Poets say that in this bath Vulcan washed Phoebus, and purified him from all dirt and imperfection. It is produced from the purest mercury and sulfur, under the genus of vitriol, in metallic form and brightness. Some philosophers call it the White Lead of the Wise Men, or simply the Lead…’ This comes from The aurora of the philosophers – a book attributed to Swiss alchemist and physician Philippus Aureolus Theophrastus Bombastus von Hohenheim, or Paracelsus as he styled himself (1493–1541) – and describes a synthesis of the ‘Arcanum of Antimony’, apparently a component of the philosopher’s stone that transformed base metals into gold. It is, Paracelsus stated, a ‘very red oil, like the colour of a ruby…with a most fragrant smell and a very sweet taste’. The book contains very detailed instructions for making it, provided that you know what ‘aquafortis’, ‘crocus of Mars’ and ‘calcined tutia’ are and that you take care to control the heat of the furnace, in case (the author warns) your glass vessels and perhaps even the furnace itself should shatter. All this fits the famous image of alchemy depicted by the Dutch artist Pieter Bruegel the Elder around 1558. His engraving The Alchemist shows a laboratory in turmoil, littered with paraphernalia and smoky from the fire, where a savant works urgently to make gold while his household descends into disarray all around him. Bruegel’s engraving set the tone for pictures of alchemists at work over the next few centuries, in which they were often shown as figures of fun, engaged on a fool’s quest and out of touch with reality. But that caricature doesn’t quite stand up to scrutiny. For one thing, despite its mysterious language that only other alchemical adepts would understand, Paracelsus’s experimental procedure is carefully recorded. It’s not that different, once you grasp the arcane names and techniques, from something you’d find in textbooks of chemistry four centuries later. The aim – transmutation of metals – might seem misguided with the benefit of hindsight, but there’s nothing crazy about the methods. Secondly, the experimentation depicted in Bruegel’s picture isn’t as random as it might first appear. It is being carefully directed by a scholar who sits at the back reading a book. (The text is, however, satirical: the scholar points to the words ‘Alge mist’, a pun on ‘alchemist’ meaning ‘all is failed’, and we see the alchemist’s future in the window as he leads his family to the poorhouse.) chemistryworld
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Rubbery Glass Arrives Glass is strong—until it shatters. If it could stretch more like a rubber band, glass could be used in shatter-proof windows and flexible electronic displays or fashioned into mechanical sensors that could operate at the high temperatures encountered in such fields as aeronautics. Materials scientists led by Seiji Inaba of the Tokyo Institute of Technology have created the first such elastic glass. Glass is typically made up of phosphorus- or silicon-based molecules tightly bound to one another in orderly but noncrystalline three-dimensional structures. Inaba and his colleagues designed their glass so its molecular structure would instead resemble chains of rubbery materials; its relatively long chains of phosphorus oxide are weakly connected to one another. After the scientists stretched this glass at high temperatures, its fibers shrank by about 35 percent—demonstrating elasticity, a behavior not seen in glasses before. [...] Inaba, who now works at Asahi Glass in Yokohama, says he still has work to do. So far the glass contracts well at 220 to 250 degrees Celsius, but ultimately designers want such performance closer to room temperature. Michael Demkowicz, a materials scientist at the Massachusetts Institute of Technology, notes that engineers could use Inaba's recipe to modify a glass that is, say, already known as a good conductor and make it elastic, too. Maybe someday soon a dropped phone or wineglass will be a far less shattering experience. scientificamerican
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Persistence Pays Off In Studying Persistent Organic Pollutants As an organic analytical chemist, Ronald A. Hites of Indiana University has been taking the measure of persistent organic pollutants in the environment for decades. In a career spanning 50 years, Hites has watched some of these chemicals survive only a few days in the atmosphere. But to his surprise, they never seem to go away completely—some have stuck around as long as he has. For example, traces of the infamous malaria-fighting insecticide DDT remain 40 years after it was banned in the U.S.—nearly everyone has tiny amounts in their blood. Hites knows firsthand of at least one place it originated. “Growing up in Detroit in the 1950s, the streets were lined by big elm trees that formed a beautiful canopy,” Hites recalls. “In the summer, men wearing yellow rain slickers would come down the street following a truck and spraying DDT up into the trees to kill mosquitoes and other bugs.” Hites is one of a persistent group of environmental scientists who develop testing methods and make long-term measurements to track the fate of DDT and other chemicals such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and brominated flame retardants. These compounds were once widely used for industrial and agricultural applications and as key components of consumer products. But scientists discovered that the properties that make them useful also make them stable to natural degradation. As a result, the chemicals accumulate globally in water, soil, plants, and animals. They accumulate in people too—in blood, fat tissues, and milk—where, in some cases, they can cause neurotoxic and other negative health effects. Many of these chemicals were banned or voluntarily discontinued starting in the 1970s. Some of their replacements were also found to be problematic and have been replaced. Each time a problematic compound is replaced, the researchers add more chemicals to the list they study.
“The questions we want to answer are simple ones,” Hites says. “Where do the chemicals come from? How fast are the concentrations decreasing? How are the concentrations varying from location to location? Are they ever going to go away?”
chemicalandengineeringnews
Earth Science
Amazon Deforestation 'Threshold' Causes Species Loss To Accelerate One of the largest area studies of forest loss impacting biodiversity shows that a third of the Amazon is headed toward or has just past a threshold of forest cover below which species loss is faster and more damaging. Researchers call for conservation policy to switch from targeting individual landowners to entire regions. One of the first studies to map the impact of deforestation on biodiversity across entire regions of the Amazon has found a clear ‘threshold’ for forest cover below which species loss becomes more rapid and widespread. By measuring the loss of a core tranche of dominant species of large and medium-sized mammals and birds, and using the results as a bellwether, the researchers found that for every 10% of forest loss, one to two major species are wiped out. This is until the threshold of 43% of forest cover is reached, beyond which the rate of biodiversity loss jumps from between two to up to eight major species gone per 10% of disappeared forest. While current Brazilian law requires individual landowners in the Amazon to retain 80% forest cover, this is rarely achieved or enforced. Researchers say that the focus should be shifted to maintaining 50% cover – just half the forest – but over entire landscapes rather than individual farms, in a bid to stop whole regions losing untold biodiversity by slipping below the 43% threshold at which species loss accelerates. enn
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Lack Of Snow Leaves California's 'Water Tower' Running Low Snowpack—which essentially serves as a water tower for the western United States—produces vital meltwater that flows off the mountains each spring. Like a time-release capsule, snowpack refills streams and reservoirs and waters crops and cities through the dry summer in this largely semiarid region. But the snowpack is becoming more like a snow gap, as temperatures in the Cascades and Sierra Nevada become too warm for the snow that replenishes the ecosystem each winter. Temperatures in the West are rising, and winter storms—which have been in infrequent for years—are bringing more rain and less snow. As a result, the water tower of stored mountain snow—which typically provides one-third of California's water—is no longer refilling each winter, leaving a gap in summer water supplies. California now faces a fourth year of severe surface water shortages, and there isn't a broad plan to deal with the scarcity of water that's being created by persistent shortfalls of snow. Groundwater has served as a Band-Aid by compensating for the lost water, but aquifers are being pumped faster than they can replenish, and like snowmelt, aquifers are shrinking. A California snowpack survey on Tuesday found less than one inch of water stored in snowpack, or 5 percent of historical average, at a site in the Sierra Nevada 90 miles east of Sacramento. Statewide snowpack on March 3 was about 19 percent of the multidecade average. As winter—the region's wet season—nears its end, the harsh reality of another year with little mountain snowpack and resulting tight water supplies comes into focus. nationalgeographic
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Report On A Better Aral Sea Elections are the order of the day in Uzbekistan, as sitting President Islam Karimov attempts to be re-elected once more. Other Central Asian interests are more international as the 3rd Aral Sea Basin Program, utilising resources from the IFAS founder countries, Kazakhstan, Tajikistan, Turkmenistan, Uzbekistan and the Kyrgyz Republic is now invigorated. Particular thanks are due to support from the World Bank. Saroj Kumar the Bank�s Regional Director stated that, together we have committed, by definition, a number of important activities that will support the well-being of millions of people who depend on the flow of the rivers of Amudarya and Syrdarya. The meaning of even more aid to the Aralkum desert area will be that new issues for management of water supplies and use can be addressed. Millions of people there need support because of the loss of industry and the health problems associated with the dust from the dying Sea. Saroj stressed the importance of stable economic growth and health, but climate change can be seen as yet another hazard for the extremes of the hot summers and the freezing winters. [...] Regional and national investment projects are already being identified, as the sharing of each country�s capabilities becomes more widespread. Management information systems could well prove to be one of the key products of the agreement, as the complexity of the technical issues is matched by the number of different regions involved, from several nations. Many examples of international aid were offered in a significant conference last October in Urgench (Uzbekistan.) a Hubert Gijzen represented UNESCO there, indicating that the Aral Sea Basin requires such strong global and regional cooperation. 31 projects were identified in Urgench, with signatories from many governments� financial institutions and donor nations themselves. A sum of $3 billion was to finance these projects, supplemented by $1.9 billion loans and grants of $200 million. The draft program for 2015-2018 is eagerly awaited from specialist developers at Uzbek Ministries including Economy, Finance, Foreign Economic Relations, Investments and Trade and the Executive Committee of the International Fund for saving the Aral Sea (IFAS). In this draft program (hopefully this month,) we expect social and economic progress in the form of job creation for former fishing communities, improved hospital facilities, ecological recovery programs to create lakes around the former Aral Sea and restoration of the Muynak wetlands when irrigation and rivers can flow effectively. Water saving projects will also be essential, as we heard in the conference last October. This resolution of one of the planet�s worst environmental disasters may not be complete. But the local people can be encouraged by these socio-economic moves and several countries will be aided. Uzbekistan is presently in need of help because of the state of the desiccated southern half of the Aral Sea, particularly in the autonomous republic of Karakalpakstan. earthtimes
Physics
Buckybomb Shows Potential Power Of Nanoscale Explosives Scientists have simulated the explosion of a modified buckminsterfullerene molecule (C60), better known as a buckyball, and shown that the reaction produces a tremendous increase in temperature and pressure within a fraction of a second. The nanoscale explosive, which the scientists nickname a "buckybomb," belongs to the emerging field of high-energy nanomaterials that could have a variety of military and industrial applications. The researchers, Vitaly V. Chaban, Eudes Eterno Fileti, and Oleg V. Prezhdo at the University of Southern California in Los Angeles, have published a paper on the simulated buckybomb explosion in a recent issue of The Journal of Physical Chemistry Letters. Chaban is also with the Federal University of São Paulo, Brazil. The buckybomb combines the unique properties of two classes of materials: carbon structures and energetic nanomaterials. Carbon materials such as C60 can be chemically modified fairly easily to change their properties. Meanwhile, NO2 groups are known to contribute to detonation and combustion processes because they are a major source of oxygen. So, the scientists wondered what would happen if NO2 groups were attached to C60 molecules: would the whole thing explode? And how? The simulations answered these questions by revealing the explosion in step-by-step detail. Starting with an intact buckybomb (technically called dodecanitrofullerene, or C60(NO2)12), the researchers raised the simulated temperature to 1000 K (700 °C). Within a picosecond (10-12 second), the NO2 groups begin to isomerize, rearranging their atoms and forming new groups with some of the carbon atoms from the C60. As a few more picoseconds pass, the C60 structure loses some of its electrons, which interferes with the bonds that hold it together, and, in a flash, the large molecule disintegrates into many tiny pieces of diatomic carbon (C2). What's left is a mixture of gases including CO2, NO2, and N2, as well as C2. Although this reaction requires an initial heat input to get going, once it's going it releases an enormous amount of heat for its size. Within the first picosecond, the temperature increases from 1000 to 2500 K. But at this point the molecule is unstable, so additional reactions over the next 50 picoseconds raise the temperature to 4000 K. At this temperature, the pressure can reach as high as 1200 MPa (more than 10,000 times normal atmospheric pressure), depending on the density of the material. phys.org
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The Taming Of Magnetic Vortices: A Unified Theory For Skyrmion-Materials Magnetic vortex structures, so-called skyrmions, could in future store and process information very efficiently. They could also be the basis for high-frequency components. For the first time, a team of physicists succeeded in characterizing the electromagnetic properties of insulating, semiconducting and conducting skyrmion-materials and developed a unified theoretical description of their behavior. This lays the foundation for future electronic components with purpose-designed properties. More than six years ago, physicists at the Technische Universität München discovered extremely stable magnetic vortex structures in a metallic alloy of manganese and silicon. Since then, they have driven this technology further together with theoretical physicists from the University of Cologne. Since magnetic vortices are microscopic and easy to move, computer components may need 10,000 times less electricity than today with this technology and store much larger amounts of data. Recent research results showed that the unique electromagnetic properties of skyrmions could also be used for the construction of efficient and very small microwave receivers and transmitters. [...] The production of computer chips requires insulating, semiconducting and conducting materials. Today, magnetic vortex structures are available for all these three classes of materials. An important advantage is that these vortices respond easily to alternating fields so that information can be processed at high rates. A team of physicists at the TU München, the University of Cologne and the École Polytechnique Fédérale de Lausanne (Switzerland) has examined the dynamic behavior of the three materials. With the results of their measurements, the team developed a theoretical description of behavior valid for all three material classes. "With this theory, we have laid an important foundation for further developments," says Professor Dirk Grundler, Chair of Physics of Functional Multilayers at the TU München. "In the future, we will therefore be able to identify materials with the specific properties we need for functional devices." sciencedaily
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Focus: Single-Frequency Mirror Ordinary mirrors reflect light over a broad range of frequencies, but a new mirror design can reflect a single frequency while allowing all others through. This “metamirror,” an array of subwavelength pieces of shaped metal embedded in a transparent medium, can also be made to reflect light in a chosen direction or focus it like a curved mirror. Flat metamirrors could replace dish-shaped receivers, or they could cover satellite solar panels and allow sunlight through while reflecting microwave communication signals. Mirrors are typically flat, metal-coated sheets that reflect all incoming light waves at an angle that is equal but opposite to the incident angle. Researchers have, however, created thin, structured sheets that, when placed over a normal flat mirror, disturb the passage of light and cause it to be reflected at any desired angle [1]. Often, these structured surfaces are made of metamaterials—engineered materials with complex structures at scales smaller than a wavelength of light. All of these metasurfaces have relied on an underlying metal surface for the reflection, but Sergei Tretyakov of Aalto University in Finland and his colleagues realized that a metasurface can reflect light all by itself. Taking away the conventional reflector makes the metamirror transparent to all but a selected range of frequencies, whose reflections can be controlled to a large degree, says team member Viktar Asadchy of Aalto University and Francisk Skorina Gomel State University in Belarus. The researchers designed a metasurface for microwaves, but they say the same concepts could be applied to a visible light mirror. The thin metamirror is made of millimeter-sized metal components embedded in a microwave-transparent medium. The components, a combination of straight copper wires and loops, are called “omega inclusions” because many of them look like the Greek letter omega (Ω). When a microwave with the resonant frequency (determined by the size of the omega inclusion) strikes the metamirror, it generates currents in the wires and loops, and they, in turn, re-emit, or scatter, microwaves at the same frequency. The shape of the inclusion affects the phase of the scattered microwave light—the timing of its wave crests in relation to the incoming light—and the net effect of the right combination of shapes is to reinforce one specific direction for the scattered waves. physics.aps.org