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  • richardmitnick 6:31 am on July 30, 2016 Permalink | Reply
    Tags: , NS, Personal water treatment plants   

    From NS: “Bacteria made to turn sewage into clean water – and electricity” 


    New Scientist

    27 July 2016
    Sally Adee

    The usual way is a bit of a grind. Jupiterimages/Getty

    THEY’RE miraculous in their own way, even if they don’t quite turn water into wine. Personal water treatment plants could soon be recycling our waste water and producing energy on the side.

    Last month, Boston-based Cambrian Innovation began field tests of what’s known as a microbial fuel cell at the Naval Surface Warfare Center in Maryland. Called BioVolt, in one day it can convert 2250 litres of sewage into enough clean water for at least 15 people. Not only that, it generates the electricity to power itself – plus a bit left over.

    This is a big deal, as conventional treatment plants guzzle energy – typically consuming 1.5 kilowatt-hours for every kilogram of pollutants removed. In the US, this amounts to a whopping 3 per cent of the total energy demand. If the plants could be self-powered, recycling our own waste water could become as commonplace as putting a solar panel on a roof.

    Existing treatment plants use bacteria to metabolise the organic material in waste water. “There’s lots of food for them, so they reproduce fast,” says Cambrian chief technology officer Justin Buck. At the end of the process, the microbes can make up a third by weight of the leftovers to be disposed of. Before being put in landfill, this “microbe cake” itself needs to be heat-sterilised and chemically treated, which uses a lot of energy.

    Microbial fuel cells have long been touted as the way forward. The idea is that the biochemistry involved in metabolising the contaminants can yield electricity to help power the process. But fuel cells of this kind have been very difficult to scale up outside the lab.

    BioVolt uses strains of Geobacter and another microbe called Shewanella oneidensis to process the sludge. Its proprietary mix of organisms has one key advantage – the bacteria liberate some electrons as they respire, effectively turning the whole set-up into a battery. This has the added benefit of slowing bacterial growth, so that at the end of the process you have electricity and no microbe cake.

    A number of teams are working on their own versions of these cells. Orianna Bretschger at the J. Craig Venter Institute in San Diego, California, is testing hers at a farm run by the San Pasqual High School in nearby Escondido, using it to process about 630 litres of pig waste per day.

    Bretschger is in the early stages of building a larger pilot system, to be commissioned in Tijuana, Mexico, later this year. “I think that we will still be on track for commercialisation in the next three to five years,” she says.

    Her system goes a step beyond BioVolt and traditional plants in that it can rid water of pharmaceuticals – synthetic oestrogens, for example. Bretschger is now looking at ways to add pain relief drugs to the list.

    Cambrian CEO Matt Silver sees a future in which different kinds of microbial fuel cells treat different kinds of waste, perhaps recovering useful by-products. Another of the firm’s designs, EcoVolt, generates methane as it cleans up waste water produced by a Californian brewery. It has also cut the brewery’s energy use by 15 per cent and its water use by 40 per cent.

    Cambrian hopes BioVolt will scale up to processing more than 20,000 litres per day. Microbial fuel cells, Silver thinks, will do for renewable water what solar and wind did for renewable energy.

    See the full article here .

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  • richardmitnick 6:11 am on July 30, 2016 Permalink | Reply
    Tags: , Desalination, Israel,   

    From SA: “Israel Proves the Desalination Era is Here” 

    Scientific American

    Scientific American

    July 29, 2016
    Rowan Jacobsen

    One of the driest countries on earth now makes more freshwater than it needs.

    Sorek Desalination Plant. Credit: Photo courtesy of IDE Technologies.

    Ten miles south of Tel Aviv, I stand on a catwalk over two concrete reservoirs the size of football fields and watch water pour into them from a massive pipe emerging from the sand. The pipe is so large I could walk through it standing upright, were it not full of Mediterranean seawater pumped from an intake a mile offshore.

    “Now, that’s a pump!” Edo Bar-Zeev shouts to me over the din of the motors, grinning with undisguised awe at the scene before us. The reservoirs beneath us contain several feet of sand through which the seawater filters before making its way to a vast metal hangar, where it is transformed into enough drinking water to supply 1.5 million people.

    We are standing above the new Sorek desalination plant, the largest reverse-osmosis desal facility in the world, and we are staring at Israel’s salvation. Just a few years ago, in the depths of its worst drought in at least 900 years, Israel was running out of water. Now it has a surplus. That remarkable turnaround was accomplished through national campaigns to conserve and reuse Israel’s meager water resources, but the biggest impact came from a new wave of desalination plants.

    Bar-Zeev, who recently joined Israel’s Zuckerberg Institute for Water Research after completing his postdoc work at Yale University, is an expert on biofouling, which has always been an Achilles’ heel of desalination and one of the reasons it has been considered a last resort. Desal works by pushing saltwater into membranes containing microscopic pores. The water gets through, while the larger salt molecules are left behind. But microorganisms in seawater quickly colonize the membranes and block the pores, and controlling them requires periodic costly and chemical-intensive cleaning. But Bar-Zeev and colleagues developed a chemical-free system using porous lava stone to capture the microorganisms before they reach the membranes. It’s just one of many breakthroughs in membrane technology that have made desalination much more efficient. Israel now gets 55 percent of its domestic water from desalination, and that has helped to turn one of the world’s driest countries into the unlikeliest of water giants.

    Driven by necessity, Israel is learning to squeeze more out of a drop of water than any country on Earth, and much of that learning is happening at the Zuckerberg Institute, where researchers have pioneered new techniques in drip irrigation, water treatment and desalination. They have developed resilient well systems for African villages and biological digesters than can halve the water usage of most homes.

    Bar-Zeev believes that Israel’s solutions can help its parched neighbors, too — and in the process, bring together old enemies in common cause.The institute’s original mission was to improve life in Israel’s bone-dry Negev Desert, but the lessons look increasingly applicable to the entire Fertile Crescent. “The Middle East is drying up,” says Osnat Gillor, a professor at the Zuckerberg Institute who studies the use of recycled wastewater on crops. “The only country that isn’t suffering acute water stress is Israel.”

    That water stress has been a major factor in the turmoil tearing apart the Middle East, but Bar-Zeev believes that Israel’s solutions can help its parched neighbors, too — and in the process, bring together old enemies in common cause.

    Bar-Zeev acknowledges that water will likely be a source of conflict in the Middle East in the future. “But I believe water can be a bridge, through joint ventures,” he says. “And one of those ventures is desalination.”

    Driven to Desperation

    In 2008, Israel teetered on the edge of catastrophe. A decade-long drought had scorched the Fertile Crescent, and Israel’s largest source of freshwater, the Sea of Galilee, had dropped to within inches of the “black line” at which irreversible salt infiltration would flood the lake and ruin it forever. Water restrictions were imposed, and many farmers lost a year’s crops.

    Their counterparts in Syria fared much worse. As the drought intensified and the water table plunged, Syria’s farmers chased it, drilling wells 100, 200, then 500 meters (300, 700, then 1,600 feet) down in a literal race to the bottom. Eventually, the wells ran dry and Syria’s farmland collapsed in an epic dust storm. More than a million farmers joined massive shantytowns on the outskirts of Aleppo, Homs, Damascus and other cities in a futile attempt to find work and purpose.

    Water is driving the entire region to desperate acts.And that, according to the authors of “Climate Change in the Fertile Crescent and Implications of the Recent Syrian Drought,” a 2015 paper in the Proceedings of the National Academy of Sciences, was the tinder that burned Syria to the ground. “The rapidly growing urban peripheries of Syria,” they wrote, “marked by illegal settlements, overcrowding, poor infrastructure, unemployment, and crime, were neglected by the Assad government and became the heart of the developing unrest.”

    Similar stories are playing out across the Middle East, where drought and agricultural collapse have produced a lost generation with no prospects and simmering resentments. Iran, Iraq and Jordan all face water catastrophes. Water is driving the entire region to desperate acts.

    More Water Than Needs

    Except Israel. Amazingly, Israel has more water than it needs. The turnaround started in 2007, when low-flow toilets and showerheads were installed nationwide and the national water authority built innovative water treatment systems that recapture 86 percent of the water that goes down the drain and use it for irrigation — vastly more than the second-most-efficient country in the world, Spain, which recycles 19 percent.

    But even with those measures, Israel still needed about 1.9 billion cubic meters (2.5 billion cubic yards) of freshwater per year and was getting just 1.4 billion cubic meters (1.8 billion cubic yards) from natural sources. That 500-million-cubic-meter (650-million-cubic-yard) shortfall was why the Sea of Galilee was draining like an unplugged tub and why the country was about to lose its farms.

    The country faces a previously unfathomable question: What to do with its extra water?Enter desalination. The Ashkelon plant, in 2005, provided 127 million cubic meters (166 million cubic yards) of water. Hadera, in 2009, put out another 140 million cubic meters (183 million cubic yards). And now Sorek, 150 million cubic meters (196 million cubic yards). All told, desal plants can provide some 600 million cubic meters (785 million cubic yards) of water a year, and more are on the way.

    The Sea of Galilee is fuller. Israel’s farms are thriving. And the country faces a previously unfathomable question: What to do with its extra water?

    Water Diplomacy

    Inside Sorek, 50,000 membranes enclosed in vertical white cylinders, each 4 feet high and 16 inches wide, are whirring like jet engines. The whole thing feels like a throbbing spaceship about to blast off. The cylinders contain sheets of plastic membranes wrapped around a central pipe, and the membranes are stippled with pores less than a hundredth the diameter of a human hair. Water shoots into the cylinders at a pressure of 70 atmospheres and is pushed through the membranes, while the remaining brine is returned to the sea.

    Desalination used to be an expensive energy hog, but the kind of advanced technologies being employed at Sorek have been a game changer. Water produced by desalination costs just a third of what it did in the 1990s. Sorek can produce a thousand liters of drinking water for 58 cents. Israeli households pay about US$30 a month for their water — similar to households in most U.S. cities, and far less than Las Vegas (US$47) or Los Angeles (US$58).

    The International Desalination Association claims that 300 million people get water from desalination, and that number is quickly rising. IDE, the Israeli company that built Ashkelon, Hadera and Sorek, recently finished the Carlsbad desalination plant in Southern California, a close cousin of its Israel plants, and it has many more in the works. Worldwide, the equivalent of six additional Sorek plants are coming online every year. The desalination era is here.

    What excites Bar-Zeev the most is the opportunity for water diplomacy.What excites Bar-Zeev the most is the opportunity for water diplomacy. Israel supplies the West Bank with water, as required by the 1995 Oslo II Accords, but the Palestinians still receive far less than they need. Water has been entangled with other negotiations in the ill-fated peace process, but now that more is at hand, many observers see the opportunity to depoliticize it. Bar-Zeev has ambitious plans for a Water Knows No Boundaries conference in 2018, which will bring together water scientists from Egypt, Turkey, Jordan, Israel, the West Bank and Gaza for a meeting of the minds.

    Even more ambitious is the US$900 million Red Sea–Dead Sea Canal, a joint venture between Israel and Jordan to build a large desalination plant on the Red Sea, where they share a border, and divide the water among Israelis, Jordanians and the Palestinians. The brine discharge from the plant will be piped 100 miles north through Jordan to replenish the Dead Sea, which has been dropping a meter per year since the two countries began diverting the only river that feeds it in the 1960s. By 2020, these old foes will be drinking from the same tap.

    On the far end of the Sorek plant, Bar-Zeev and I get to share a tap as well. Branching off from the main line where the Sorek water enters the Israeli grid is a simple spigot, a paper cup dispenser beside it. I open the tap and drink cup after cup of what was the Mediterranean Sea 40 minutes ago. It tastes cold, clear and miraculous.

    The contrasts couldn’t be starker. A few miles from here, water disappeared and civilization crumbled. Here, a galvanized civilization created water from nothingness. As Bar-Zeev and I drink deep, and the climate sizzles, I wonder which of these stories will be the exception, and which the rule.

    See the full article here .

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  • richardmitnick 6:03 am on July 30, 2016 Permalink | Reply
    Tags: , , Grand Tack model, Scientists Must Look Beyond It, , To Uncover Earth’s Origins   

    From Smithsonian: “To Uncover Earth’s Origins, Scientists Must Look Beyond It” 


    July 29, 2016
    Julia Rosen

    The great mysteries of the universe often revolve around distant, invisible phenomena. Scientists puzzle over inexplicable bursts of radio waves, the elusive nature of gravity and whether dark energy pervades the cosmos. But other enigmas can be found in our own corner of the galaxy, staring us right in the face—like how Earth became the planet it is today.

    This question continues to fascinate researchers working to understand how Earth formed and why it’s so well suited to hosting life. It could have turned out differently—just look at our nearest neighbor and almost twin, Venus, which has no liquid water and whose surface is a sweltering 870 degrees Fahrenheit. “Venus and Earth are kind of the ultimate control case,” says Sue Smrekar of NASA’s Jet Propulsion Laboratory. “We don’t fully understand how Earth ended up so habitable and Venus so uninhabitable.”

    That’s a bit surprising, given that Earth is by far the best-studied planet in the universe. But geologic processes like plate tectonics constantly recycle evidence of the past, and much of the critical information about Earth’s makeup lies hidden in its vast, inaccessible depths. “You are trying to understand a planet that you can only sample at the surface,” says James Badro, a geophysicist at the Institute of Earth Physics in Paris. Although scientists have gleaned a wealth of knowledge from studying the ground beneath our feet, the full story of Earth’s construction and evolution remains unknown.

    So researchers have turned to the skies for help. They have studied other star systems looking for clues, and searched for the building blocks of Earth among the detritus of the solar system. Now, a suite of planned and proposed space missions could help scientists fill in more of the missing pieces.

    From studying new aspects of protoplanetary bodies to sleuthing out where they came from and how they got mixed together, researchers hope to pin down the processes of planetary formation that created Earth. For many, it’s as much a philosophical quest as a scientific one. “It’s a question of our origins,” Badro says.


    NASA Targets Metal Asteroid in Proposed Mission

    Most researchers now agree on the general history of our solar system. It began 4.6 billion years ago, when a vast cloud of gas and dust floating in space collapsed onto itself, perhaps triggered by the shock wave of a nearby supernova. The flattened cloud then swirled into a spinning disk from which—about 100 million years later—our solar system emerged in more or less its current state: the sun surrounded by eight planets and innumerable smaller bodies scattered throughout.

    The finer details of how our cosmic neighborhood formed, however, remain contentious. For instance, scientists still debate what the planets are made of. “We know what the cake looks like,” says Lindy Elkins-Tanton of Arizona State University, “but we would like to know what all those individual ingredients look like too,” she says.

    Scientists think that the terrestrial planets grew by gobbling up smaller planetesimals—objects up to tens of miles in diameter that accumulated from protoplanetary dust. But the composition and structure of those planetesimals has been hard to determine. Studying our collection of meteorites—fragments of asteroids that have fallen to Earth—is a good place to start, says Francis Nimmo, a planetary scientist at the University of California, Santa Cruz. But it’s not enough.

    That’s because we don’t necessarily have samples of everything that went into the planets—some components may be missing or may no longer exist at all. Some meteorites do appear to be a decent match for Earth, but scientists cannot come up with any combination of meteorite types that fully explains Earth’s chemical composition. “This is kind of uncomfortable because it means that we don’t really know how the Earth was put together,” Nimmo says.

    Elkins-Tanton hopes that a proposed future mission—one of five finalists for NASA’s Discovery program—might be able to help. The project, led by Elkins-Tanton, would send an unmanned spacecraft to visit an object called Psyche, which sits in the asteroid belt between Mars and Jupiter. Psyche is roughly 150 miles wide and, based on remote observations of its density and surface composition, appears to be made of solid metal. It may also resemble the building blocks of Earth.

    “This could be the little core of a body that was formed in the terrestrial planet-forming region and just got hit by a lot of other things and had its rocky exterior stripped away,” Elkins-Tanton says. On NASA’s Dawn mission, scientists studied the asteroid Vesta, a protoplanet that also probably formed near Earth and then got kicked out into the asteroid belt. However, it’s the unique opportunity to see what lies beneath the surface of objects like Vesta that has Elkins-Tanton excited.

    “Psyche is the only body in the solar system that allows us to directly observe a metal core,” she says. “This could be our only chance of looking at this kind of ingredient.” Along with the other Discovery finalists, Elkins-Tanton and her colleagues will find out in September if the mission is a go.

    According to the classical model of planetary formation, once planetesimals reached Psyche’s size—tens to hundreds of miles across—they started to cannibalize their neighbors, says Kevin Walsh, a planetary scientist at the Southwest Research Institute in Boulder, Colorado. “The biggest ones grow really fast,” he says, thanks to their increasing gravitational influence.

    This process of runaway accretion would have winnowed the number of bodies in the solar system to perhaps a hundred moon- to Mars-sized planetary embryos and a smattering of smaller debris. Over time, these embryos slowly combined to form planets.

    But while this explanation works well for the terrestrial planets, which geologic evidence suggests formed over the course of 30 to 100 million years, it presents a problem for the gas giants like Jupiter. Scientists think the cores of these bodies had to grow much more quickly—fast enough to capture their massive atmospheres from the gas present in the early solar system, which dissipated in just a few million years.

    Over the last decade, researchers have developed an alternative mechanism for growing planets known as pebble accretion. It represents a stark departure from the conventional model of accretion, in which objects combined to form progressively larger particles. Or, as Hal Levison, Walsh’s colleague, puts it: “Pebbles make boulders, and boulders make mountains—all the way up.” Pebble accretion, on the other hand, predicts that objects grow from fist-sized lumps to Pluto-sized bodies almost immediately, and then continue to gain mass, says Levison, who helped develop the hypothesis.

    The process would have begun shortly after the formation of the protoplanetary disk, when bits of dust circling orbiting the young sun began to collide and stick together, like synchronized skaters joining hands while circling an ice rink. Eventually, aerodynamic and gravitational forces would have pulled large clusters of these pebbles together, forming planetesimals. The planetesimals then continued to sweep up the remaining pebbles around them, rapidly growing until they formed planets.

    On top of addressing the question of how gas giants grew so fast, the model also provides a way to overcome something called the meter-size barrier, which has plagued models of planetary accretion since it was first outlined in the 1970s. It refers to the fact that once objects reach about three feet in diameter, friction generated by the surrounding gas would have sent them spiraling into the sun. Pebble accretion helps hurtle small particles over the threshold, making them big enough to hold their own.

    Scientists are still trying to understand whether this process happened throughout the entire solar system, and whether it would have played out the same way for the inner and outer planets. (While it works for the gas giants, the later stages of rapid growth don’t fit with what we know about terrestrial planet formation). But researchers may find some clues later this year, when NASA’s Juno mission, which successfully reached Jupiter last month, begins gathering information about the planet’s composition and core.

    Walsh says figuring out how much material lies at the center of the gas giant will help researchers constrain different models of planetary accretion. If Jupiter has a small core, classical accretion might have been able to build it up fast enough; if it’s big, it might imply that something like pebble accretion took place instead, he says.

    Understanding how Jupiter formed will also help researchers understand the origins of the other planets, including Earth. That’s because Jupiter has been accused of meddling with the construction of the inner rocky planets, at least according to a new idea developed by Walsh and others that’s gained traction in recent years.

    The hypothesis, known as the Grand Tack model, suggests that as Jupiter finished forming, it would have cleared out all the material in its path around the sun, effectively carving a gap in the protoplanetary disk. The disk, however, still contained plenty of gas and dust, which pressed in toward the sun as the disk flattened and stretched, Walsh says.

    The Grand Tack. Migration of the four giant planets through the Solar nebula over a period of 600,000 years. Distance is marked in astronomical units (AU). The narrow belt of planetesimals at 1 AU (the present orbit of Earth) later coalesced into the four terrestrial planets.

    Jupiter’s gap effectively blocked the flow of this material, and the planet got “caught in the floodwaters,” Walsh says. It migrated in to about Mars’ orbit with Saturn close on its heels. But as Saturn followed, it trailed enough material to reconnect the disk. This released the pressure pushing on Jupiter, allowing both planets to migrate back out again, all in the space of a few hundred thousand years. The model was inspired by observations of oddly ordered planets in other solar systems that suggest such migrations are common, Walsh says.

    For the rest of the solar system, this would have been something like a pair of bulls in a cosmic china shop. Bits of debris from the inner solar system would have gotten kicked out while clutter from the outer system would have gotten dragged in, Walsh says. The model helps explain Mars’ runt-size dimensions and the number and diversity of bodies found today in the asteroid belt.

    It also provides a possible explanation for how the terrestrial planets got their water. According to Grand Tack, the gas planet migration would have taken place while the terrestrial planets were still forming, and could have tossed water-rich material from the outer solar system into the mix. Walsh and many other scientists think that carbonaceous asteroids, which may have formed beyond Jupiter, were the main vehicles for delivering water to Earth.

    This September, NASA will launch a mission to visit one such asteroid named Bennu. Walsh is a co-investigator on the project, called OSIRIS-REx, which will study the body from afar before grabbing a sample to bring back to Earth. A similar mission by the Japanese space agency, called Hayabusa 2, is on track to sample another carbonaceous asteroid in 2018.

    NASA OSIRIS-REx Spacecraft
    “NASA OSIRIS-REx Spacecraft

    Scientists hope to learn more about where these asteroids came from, and whether they are indeed the source of a class of meteorites known as carbonaceous chondrites. They also hope that studying a pristine sample—rather than a meteorite fragment—will help reveal whether these objects delivered not only water to Earth, but the organic compounds that may have served as the precursors for life.

    As OSIRIS-REx is returning to Earth, it could cross paths with Lucy, another proposed mission that, like Psyche, is a finalist in the Discovery program. Led by Levison, Lucy aims to explore the last major shake-up that rocked our solar system—a planetary tango that began about 500 million years after the Grand Tack. That’s when, according to a hypothesis by Levison and others, Pluto triggered an instability that caused Neptune to hopscotch outside of Uranus and the outer gas giants to migrate away from the sun to their present positions.

    This disturbance, known as the Nice model, would have sent a rain of debris hurtling into the inner solar system, possibly explaining a cluster of impacts formed during a period known as the Late Heavy Bombardment.

    Credit: Hal Levison, Southwest Research Institute, Boulder, Colorado

    The terrestrial planets, like Earth, had mostly formed by this point, so the event didn’t significantly affect their composition. But it may have thrown a curveball at scientists trying to understand how the solar system evolved. The disruption might have flung objects into the inner solar system that had no connection to the materials that make up the bulk of the terrestrial planets, Walsh says.

    Lucy could help scientists figure out what really happened and allow them to disentangle what got mixed where. It would accomplish this by investigating a group of asteroids locked into Jupiter’s orbit. These objects, known as the Jovian Trojans, are a mixture of bodies that formed throughout the outer solar system and then got thrown together during the migration.

    In the mid-2020s, when the mission would reach them, the Trojans will be oriented in just the right configuration for a spacecraft to make a grand tour of six bodies. “I’ve been worshipping the celestial mechanics gods for my whole career,” says Levison, a planetary dynamicist. “They decided to pay me back, because the planets are literally aligning.”

    Levison says studying the Trojans up close will give researchers a clearer idea of how the Nice model mixing occurred, and could also provide a test of pebble accretion. The hypothesis predicts that anything smaller than about 60 miles across should actually be a fragment of a larger body. It’s a prediction Lucy should be able to test.

    Together, these missions appear poised to further scientists’ understanding of Earth’s origins, probably in ways researchers can’t even imagine yet. After all, building a robust picture of planetary formation requires combining data from many different sources, says David Stevenson, a planetary scientist at Caltech.

    However, we still have a long way to go before we understand what makes the Earth and Venus so different. “It’s an embarrassment, almost, that here we are, sitting on Earth, and we’ve got this big nearest planet to us that we’re so ignorant about,” Stevenson says. “The reason we’re so ignorant is it’s damn hot!”

    Indeed, the hellish conditions on Venus’s surface have stymied efforts to study the planet in detail. Russia managed to land a series of spacecraft on the surface between the 1960s and 80s. They only survived for a few hours and transmitted brief flashes of data before succumbing to the heat. But these and other missions, like NASA’s Pioneer and Magellan, which studied the planet from afar, did provide glimpses into the planet’s workings.

    We know, for instance, that Venus has an intense greenhouse atmosphere made almost entirely of carbon dioxide and that it seems to have lost most of its surface water. This may be what prevents plate tectonics from occurring there — water is thought to grease the wheels of subducting plates. It may also explain why Venus lacks a geomagnetic field, which many scientists consider a necessity for life because it shields the planet from the ravages of the solar wind. Geomagnetic fields are produced by convection in the core of a body, Nimmo says, and rely on mantle circulation — often tied to plate tectonics — to transport heat away.

    What scientists want more than anything are samples of Venus’ surface rocks, but that remains a distant goal. For the foreseeable future, researchers will have to settle for more remote observations, like those from a current Japanese mission. Earlier this year, the Akatsuki spacecraft finally began relaying data from its orbit around Venus after an unplanned five-year detour around the sun.

    In addition, NASA is considering two more Venus-centered missions of its own that are also Discovery finalists. One project, called VERITAS, is led by Smrekar and would involve an orbiter capable of studying the planet’s geology in high definition. The second proposed mission, led by Lori Glaze of the Goddard Space Flight Center, would analyze Venus’ unique atmosphere using a probe called DAVINCI.


    The hope is that these efforts will reveal why Venus evolved the way it did, and thus, what makes Earth different. At the moment, many researchers think Earth and Venus probably formed from roughly the same material then diverged over time thanks to several factors. These include their differing proximity to the sun, and the fact that Earth experienced a major collision relatively late in its history—the impact that formed the moon—which would have re-melted much of the planet and potentially altered its dynamics.

    But until we know more about how the planets in our solar system formed and what processes shaped their evolution, we won’t know what differentiates a hospitable planet from a barren one, Walsh says. “We have telescopes in space that are hunting Earth-sized planets around other stars, but we have no clue if a planet will evolve into a Venus or into an Earth,” he says. “And that’s the whole ball game, at some level.”

    See the full article here .

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  • richardmitnick 4:32 pm on July 29, 2016 Permalink | Reply
    Tags: , Bacterial Pathogenicity, ,   

    From LBL: “Study Finds Molecular Switch That Triggers Bacterial Pathogenicity” 

    Berkeley Logo

    Berkeley Lab

    July 29, 2016
    Sarah Yang
    (510) 486-4575

    The top two rows show illustrations of crystals and solution structures of bacterial HU proteins with DNA represented by X-ray crystallography and small angle X-ray scattering, respectively. DNA strands are yellow and HU proteins are shades of blue. Soft X-ray tomography was used to visualize bacterial chromatin (in yellow) in wild type and invasive E. coli cells, shown in the bottom row. (Credit: Michal Hammel/Berkeley Lab)

    Scientists have revealed for the first time the molecular steps that turn on bacteria’s pathogenic genes. Using an array of high-powered X-ray imaging techniques, the researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) showed that histone-like proteins that bind to DNA are related to the physical twisting of the genetic strand, and that the supercoiling of the chromosome can trigger the expression of genes that make a microbe invasive.

    The study, published Friday, July 29, in the journal Science Advances, could open up new avenues in the development of drugs to prevent or treat bacterial infection, the study authors said.

    The researchers looked at how the long strands of DNA are wound tight, a necessity if they are to fit into compact spaces. For eukaryotes, the strands wrap around histone proteins to fit inside a nucleus. For single-celled prokaryotes, which include bacteria, HU proteins serve as the histones, and the chromosomes bunch up in the nucleoid, which lacks a membrane.

    When the normal twists and turns of DNA compaction turn into supercoiling, trouble can begin.

    “It has been known that DNA supercoiling leads to pathogenicity in bacteria, but exactly how the bacterial chromosome is condensed, organized, and ultimately segregated has been a puzzle for over half a century,” said study lead author Michal Hammel, research scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging Division. “What we did for the first time was to visualize in E. coli how this packing is done, and we also discovered that the way HU proteins pack the chromosomes can trigger gene expression. That is new.”

    Capturing HU in action

    Elucidating these molecular mechanisms entailed imaging HU proteins at different resolutions and stages using two beamlines at Berkeley Lab’s Advanced Light Source [ALS], a DOE Office of Science User Facility.

    LBL ALS interior

    The Structurally Integrated Biology for Life Sciences (SIBYLS) beamline, directed by senior scientist John Tainer, combines X-ray crystallography and small angle X-ray scattering (SAXS) capabilities. The crystallography provided atomic-level details of how the HU proteins interacted with the bacterial DNA, while SAXS was able to show how the HU proteins assembled and affected the longer strands of DNA in a solution.

    Berkeley Lab scientists Michal Hammel and Carolyn Larabell in front of the SIBYLS Beamline at the Advanced Light Source. (Credit: Paul Mueller/Berkeley Lab)

    To get a clear sense of how that twisting and packing manifests at the cellular level, Hammel teamed up with Berkeley Lab faculty scientist Carolyn Larabell, director of the National Center for X-ray Tomography (NCXT), which is also based at the Advanced Light Source.

    “We needed the interaction of these different techniques to get the overall picture of how the HU interactions with DNA were affecting the bacteria,” added Larabell, who is also a professor of anatomy at UC San Francisco. “With X-ray tomography, we’re able to see the natural contrast in organic material in as close to a living state as possible, and we can provide quantitative comparisons of how compacted the chromosomes were in pathogenic and normal strains of E. coli.”

    Larabell calculated that the genetic material in the pathogenicE. coli is so tightly packed that it consumes less than one-half the volume compared with its non-mutant counterpart.

    A target to control pathogenesis

    Before this paper, it had been believed that the enzyme topoisomerase was the primary driver of DNA coiling in bacteria. This new study shows that, independent of topoisomerase, changing the assembly of HU proteins was enough to induce changes in DNA coiling at different stages of bacterial growth.

    “What is notable about HU proteins as a trigger for gene expression is that it’s quick,” said Hammel. “This makes sense as a survival mechanism for bacteria, which need to adapt quickly to different environments.”

    The study results also beg the question: If pathogenicity can be switched on, could it also be switched off?

    “We certainly expect to answer that question in future studies,” said Hammel. “These HU interactions could be an attractive target for drugs that control pathogenesis, not only of bacteria, but of other microbes with comparable genetic structures.”

    Other study co-authors include researchers from the National Cancer Institute’s Center for Cancer Research and the University of Texas.

    The National Institutes of Health and the DOE Office of Science supported this research.

    See the full article here .

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  • richardmitnick 4:13 pm on July 29, 2016 Permalink | Reply
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    From SA: “Zika Goes Local in the United States” 

    Scientific American

    Scientific American

    July 29, 2016
    Dina Fine Maron

    Miami-Dade mosquito control worker Carlos Vargas sprays to eradicate the Aedes aegypti mosquito larvae at a home in Miami, Florida, on June 08, 2016. Of the forty different types of mosquito found in Miami -Dade the Aedes aegypti mosquito or yellow fever mosquito is responsible for transmitting diseases such as the Zika Virus. Credit: RHONA WISE/AFP/Getty Images

    Controlling the Zika virus in the United States just got harder. The mosquito- and sexually-transmitted disease has now likely gone local, according to federal public health officials. In at least four instances patients have apparently contracted the virus via a bite from a mosquito in the continental U.S.

    This first recorded instances of local transmission—reported in Florida—signal a shift in the burden of Zika in the mainland U.S., where more than 1,600 people have been diagnosed with it after traveling elsewhere in the Americas or the Caribbean and returning with the virus in their systems. As of July 27 another 15 had acquired the virus via sexual contact with a person who was infected with the virus outside of the mainland U.S.


    The long-anticipated incidences of local transmission are not a surprise. For months Tom Frieden, the director of the U.S. Centers for Disease Control and Prevention, and other top administration officials have said that they expected the virus to crop up in the mainland U.S. in small outbreaks, particularly along the Gulf Coast where mosquito-borne dengue and chikungunya—carried by the same species of mosquitoes that likely carry Zika—have been documented before. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, has repeatedly said to expect dozens or scores of locally-transmitted cases. Most officials believe a large-scale outbreak remains unlikely. Yet whether outbreaks may include one part of the country, a city or part of a city is difficult to predict.

    Florida Gov. Rick Scott said at a news conference Friday that three men and one woman in Miami-Dade and Broward counties had likely contracted the virus via local mosquito bites, after officials could not explain the infection in any other way. The patients had not recently traveled to a place where Zika is actively spreading, nor had they been in close contact with someone who had been traveling in such areas.

    “All the evidence we have seen indicates that this is mosquito-borne transmission that occurred several weeks ago in several blocks in Miami,” Frieden said in a CDC news release. “We continue to recommend that everyone in areas where Aedes aegypti mosquitoes are present—and especially pregnant women—take steps to avoid mosquito bites. We will continue to support Florida’s efforts to investigate and respond to Zika and will reassess the situation and our recommendations on a daily basis.”

    The two mosquito species typically responsible for spreading the virus are present in more than two-thirds of the U.S. Their range extends from the southern part of the country into parts of the Midwest and the Northeast. But many factors have to align in order for the mosquitoes to pass on the virus. First, a female mosquito (males do not bite) must feed on a human carrying the virus. Next the virus must incubate in the mosquito’s body for about a week, and only then can it be transmitted if the insect bites another human. The adult lifespan of a mosquito is typically only a few weeks, so the virus has a better chance of spreading if its host can feed in a densely packed area—like a city. Conveniently for the virus, these mosquitoes like to live alongside humans and are frequently found in the home or breeding in small pools of standing water in people’s yards.

    Zika symptoms are usually mild and may include rash or fever, although most patients do not even feel sick. The Zika response has instead focused on protecting pregnant women from contracting the virus because it can lead to birth defects including microcephaly, a condition where babies are born with abnormally small heads. (The World Health Organization has also said that there is “scientific consensus” that the virus can cause the sometimes-paralyzing autoimmune disease Guillain-Barre Syndrome in patients of any age.) To help control local Zika spread, public health officials have reiterated calls for people to eliminate standing water from around their homes and to try to avoid mosquito bites by wearing long sleeves, long pants and approved bug sprays.

    “We anticipate that there may be additional cases of ‘homegrown’ Zika in the coming weeks,” Lyle Petersen, incident manager for CDC’s Zika virus response, said in the news release. “Our top priority is to protect pregnant women from the potentially devastating harm caused by Zika.”

    The CDC and health officials have already gained some experience by trying to control the spread of Zika in U.S. territories. To date, Puerto Rico has represented the frontlines of the U.S. battle with more than 4,600 cases of the virus locally transmitted by mosquitoes. Public health officials there have ramped up their mosquito control efforts and their messaging urging people to protect themselves against bites. But they have faced myriad obstacles, including mosquitoes’ resistance to certain common insecticides and the fact that many buildings do not have screens in their windows. The heavy burden of controlling Zika prompted the U.S. territory to begin importing all of the blood it might need for medical procedures from the mainland in March, and to freeze prices for bug spray and condoms to stave off Zika-related price gouging. “Nothing about Zika is going to be easy or quick,” Frieden said in April. “The control of this particular mosquito is hard and although we are learning a lot quickly there is still a lot we don’t know.”

    See the full article here .


    There is a new project at World Community Grid [WCG] called OpenZika.
    Image of the Zika virus, Image copyright John Liebler,

    Rutgers Open Zika

    WCG runs on your home computer or tablet on software from Berkeley Open Infrastructure for Network Computing [BOINC]. Many other scientific projects run on BOINC software.Visit WCG or BOINC, download and install the software, then at WCG attach to the OpenZika project. You will be joining tens of thousands of other “crunchers” processing computational data and saving the scientists literally thousands of hours of work at no real cost to you.

    This project is directed by Dr. Alexander Perryman a senior researcher in the Freundlich lab, with extensive training in developing and applying computational methods in drug discovery and in the biochemical mechanisms of multi-drug-resistance in infectious diseases. He is a member of the Center for Emerging & Re-emerging Pathogens, in the Department of Pharmacology, Physiology, and Neuroscience, at the Rutgers University, New Jersey Medical School. Previously, he was a Research Associate in Prof. Arthur J. Olson’s lab at The Scripps Research Institute (TSRI), where he ran the day-to-day operations of the FightAIDS@Home project, the largest computational drug discovery project devoted to HIV/AIDS, which also runs on WCG. While in the Olson lab, he also designed, led, and ran the largest computational drug discovery project ever performed against malaria, the GO Fight Against Malaria project, also on WCG.

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  • richardmitnick 3:51 pm on July 29, 2016 Permalink | Reply
    Tags: METI, , What would we look like to E.T.?   

    From METI: “SETI, Imagining Extraterrestrial Civilizations, and War” 

    Illustration by Rlevente.


    John Traphagan

    I’ve often thought it interesting that when SETI scientists imagine extraterrestrial civilizations, they usually think in terms of unified worlds that have one civilization. The image is very much unlike our world, in which we have multiple civilizations that are fractured and in conflict with other societies. The Brexit event of the past couple of days is a good example of just how fractured our world is as well as representing some solid data not in support of the idea that humans are becoming increasingly unified.

    When we imagine other worlds, we tend to take a distant view and create images that reflect a fictionalized, romanticized representation of life right here on Earth. Rather than fractured worlds with many civilizations like the one on which we actually live, many SETI scientists think in terms of what I call the Star Trek Imaginary, in which each world forms a civilization equivalent to a geopolitical unit on Earth. In other words, we think of alien worlds as unified political states or countries.

    There is a good chance that this is an inaccurate view of civilizations on other planets, but it still may be a useful way to think about extraterrestrial intelligence if only to deconstruct our assumptions about life on other worlds. Indeed, one way to use this image is to turn it around and think about Earth from the perspective of an alien world. This makes for an interesting thought experiment.

    Suppose ET planted some sort of observational device near Earth, say, 6,000 years ago. Somehow, they had noticed that there seemed to be an emerging civilization and thought it would be interesting to study how things evolved. ET doesn’t have a lot of time to spend on watching Earth and the observational device isn’t sensitive enough to show all the nuances of political machinations throughout human history. So the data are limited in detail. The result is a wide-angle picture of Earth throughout history that gives a general sense of what cultural evolution on Earth is like. ET will have learned quite a bit, actually, about how humans evolve and form societies over time, but a lot of the detail will be left out. They probably won’t get the nitty-gritties about the Brexit.

    So what would such a device tell ET? As I thought about this, I realized there would be one overwhelming image ET would get about Earth. And it’s an image we here—with our close-up picture of our own history—don’t usually associate with civilization on this planet.

    I think what ET might conclude is that Earth has been at war for about 5,000 years—pretty much non-stop. The first war in recorded history seems to have been in Mesopotamia around 2,700 BCE between Sumer and Elam, and from the outside it might look like it never stopped. Since that time, if one were to stand back a bit from Earth, there is a pretty good chance that warfare would be the dominant feature of human civilization. There is always war going on somewhere on Earth. It ebbs and flows in intensity. Sometimes it’s regional; sometimes it covers most of the planet. But it is always there and it might look like one long war from an outside perch. If you didn’t know all of the political and historical details, there would be no reason to assume that our history had been an endless string of wars rather than simply one really long one.

    From our perspective, this would not be a very accurate picture. Different societies have had on-and-off periods of war and peace. And we don’t tend to think about our civilization(s) as being characterized by a single war lasting 5,000 years, because we understand the geopolitical details in which there have been lots of wars over that time, not just one war. But if you look at Earth from the outside and treat human societies as a civilization, then it’s probably a reasonable conclusion about us. From the external—or in anthropology what we would call etic—perspective, human civilization might appear to be based on and characterized by a single war that has spanned almost 5,000 years.

    This raises the importance of seeing the difference between proximate and distant perspectives and the difficulties in imagining intelligent life and civilizations on other worlds when we don’t have a lot of data to work with (or in our current situation, without any data at all). SETI scientists often tend to impose their own assumptions about intelligence and civilization on imagined extraterrestrial worlds and those assumptions are shaped by ideas about the way our world is that: 1) may not be empirically accurate, and 2) are unlikely to reflect how we would look to outsiders.

    The devil is in the details, and we don’t have any of those, since we have no evidence of alien intelligence. But even if we do get evidence sometime, we probably won’t have much detail and we will need to be very careful to avoid imposing the Star Trek Imaginary—or any other set of assumptions—on what little data we receive. Standing back and trying to imagine what our world would look like to distant outsiders is a useful way of trying to control this tendency to imagine alien others in terms of romanticized images of ourselves.

    Perspective is important. It may well be that characterizing our world as being at war for 5,000 years is accurate, but it isn’t how we see ourselves and that, too, is an important piece of data about humans. Recognizing the potential disjuncture between how we see ourselves and how others might see us is a key component of trying to deflect, to the extent possible, our tendencies to infuse assumptions about intelligence and civilization drawn from our proximate understanding of and imagination about life on Earth into our speculations about intelligent life on other worlds.

    • Matthew Wright 4:16 pm on July 29, 2016 Permalink | Reply

      I agree. Our own situation is predictable given our nature as humans – arguably very much a product of our ape ancestry (chimps fight wars too) and of the way our species evolved. There’s a reasonably compelling argument that hunter-gatherer bands of around 150, the largest that a reasonable day’s walking could support, were cohesive. Larger bands were usually not and there was likely an evolutionary advantage in competition between bands of 150. Archaeological evidence points to wars in hunter-gatherer times, before agriculture emerged. It’s an interesting theory and if true, explains a fair amount including the way we’ve had to intellecualise stability into larger communities. Would aliens be the same? Highly unlikely. My take on aliens is that we might not even recognise them as such despite the way sci-fi often ideates them into better (human-style) societies.


    • Greg Long 7:56 pm on July 29, 2016 Permalink | Reply

      Completely agree.


  • richardmitnick 3:33 pm on July 29, 2016 Permalink | Reply
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    From “NASA’s next planet hunter will look closer to home” 


    July 28, 2016
    Elaine Hunt

    TESS will look at the nearest, brightest stars to find planetary candidates that scientists will observe for years to come. Credit: NASA’s Goddard Space Flight Center

    As the search for life on distant planets heats up, NASA’s Transiting Exoplanet Survey Satellite (TESS) is bringing this hunt closer to home. Launching in 2017-2018, TESS will identify planets orbiting the brightest stars just outside our solar system using what’s known as the transit method.

    When a planet passes in front of, or transits, its parent star, it blocks some of the star’s light. TESS searches for these telltale dips in brightness, which can reveal the planet’s presence and provide additional information about it.

    Planet transit. NASA/Ames
    Planet transit. NASA/Ames

    TESS will be able to learn the sizes of the planets it sees and how long it takes them to complete an orbit. These two pieces of information are critical to understanding whether a planet is capable of supporting life. Nearly all other planet classifications will come from follow up observations, by both TESS team ground telescopes as well as ground- and space-based observations, including NASA’s James Webb Space Telescope launching in 2018.

    Compared to the Kepler mission, which has searched for exoplanets thousands to tens of thousands of light-years away from Earth towards the constellation Cygnus, TESS will search for exoplanets hundreds of light-years or less in all directions surrounding our solar system.

    TESS will survey most of the sky by segmenting it into 26 different segments known as tiles. The spacecraft’s powerful cameras will look continuously at each tile for just over 27 days, measuring visible light from the brightest targets every two minutes. TESS will look at stars classified as twelfth apparent magnitude and brighter, some of which are visible to the naked eye. The higher the apparent magnitude, the fainter the star. For comparison, most people can see stars as faint as sixth magnitude in a clear dark sky and the faintest star in the Big Dipper ranks as third magnitude.

    Among the stars TESS will observe, small bright dwarf stars are ideal for planet identification, explained Joshua Pepper, co-chair of the TESS Target Selection Working Group. One of the TESS science goals is to find Earth- and super-Earth-sized planets. These are difficult to discover because of their small size compared to their host stars, but focusing TESS on smaller stars makes finding these small planets much easier. This is because the fraction of the host star’s light that a planet blocks is proportional to the planet’s size.

    Scientists expect TESS to observe at least 200,000 stars during the two years of its spaceflight mission, resulting in the discovery of thousands of new exoplanets.

    While the search for transiting exoplanets is the primary goal of the mission, TESS will also make observations of other astrophysical objects through the Guest Investigator (GI) Program. Because TESS is conducting a near all-sky survey, it has the capability to perform interesting studies on many different types of astronomical target.

    “The goal of the GI Program is to maximize the amount of science that comes out of TESS,” said Padi Boyd, director of the Guest Investigator Program Office at NASA’s Goddard Space Flight Center. “Although TESS was designed to be capable of detecting planets transiting in front of stars, its unique mission characteristics mean that the potential science TESS can do includes far more than just exoplanets.” According to Boyd, the broad range of objects TESS could detect as part of the GI Program include flaring young stars, binary pairs of stars, supernovae in nearby galaxies, and even supermassive black holes in distant active galaxies. “We hope the broader science community will come up with many unique science ideas for TESS, and we hope to encourage broad participation from the larger community,” she said.

    With the potential to expand our knowledge of the universe for years to come, researchers are excited about the potential discoveries TESS could bring.

    “The cool thing about TESS is that one of these days I’ll be able to go out in the country with my daughter and point to a star and say ‘there’s a planet around that one,'” said TESS Project Scientist Stephen Rinehart.

    See the full article here .

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    About in 100 Words™ (formerly is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004,’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes in its list of the Global Top 2,000 Websites. community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

  • richardmitnick 1:30 pm on July 29, 2016 Permalink | Reply
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    From CfA: “The Aligned Spin of a Black Hole” 

    Smithsonian Astrophysical Observatory
    Smithsonian Astrophysical Observatory

    July 29, 2016
    No writer credit

    An artist’s conception of an X-ray emitting black hole binary system. A new study has measured the spin of one notable example and confirmed, contrary to some earlier claims, that the spin is aligned with the spin of the accretion disk. NASA/ESA

    A black hole in traditional theory is characterized by having “no hair,” that is, it is so simple that it can be completely described by just three parameters, its mass, its spin, and its electric charge. Even though it may have formed out of a complex mix of matter and energy, all the specific details are lost when it collapses to a singular point. This is surrounded by a “horizon,” and once anything – matter or light (energy) – falls within that horizon, it cannot escape. Hence, the singularity appears black. Outside this horizon a rotating, accreting disk can radiate freely.

    Astronomers are able to measure the spins of black holes by closely modeling the X-ray radiation from the environment in one of two ways: fitting the continuum emission spectrum, or modeling the shape of an emission iron line from very highly ionized iron. So far the spins of ten stellar-mass black holes have been determined and the robustness of the continuum-fitting method has been well demonstrated. Recently one bright black hole, “Nova Muscae 1991,” was found to be rotating in a sense opposite to the spin of its disk, a very unusual and curious result since both might be expected to develop somewhat in concert. The spin of this black hole had previously determined to be small, about ten percent of the limit allowed by relativity.

    CfA astronomers Jeff McClintock, James Steiner and Jainfeng Wu and their colleagues have re-reduced archival data for this source, and obtained much improved measurements for the three key parameters needed in the continuum-fitting method: mass (11.0 solar-masses), disk inclination (43.2 degrees), and distance (16,300 light-years), each with a corresponding (and modest) uncertainty. Using the new numbers to reevaluate the model of the Nova Muscae 1991 spin, the scientists report that the spin is actually about five times larger than previously estimated. More significantly, that the spin is definitely prograde (aligned with the direction of the disk spin), and not retrograde. The new results resolve a potential mystery, and offer a confirmation of the general methods for modeling black holes.


    The Spin of The Black Hole in the X-ray Binary Nova Muscae 1991, Zihan Chen, Lijun Gou, Jeffrey E. McClintock, James F. Steiner, Jianfeng Wu, Weiwei Xu, Jerome A. Orosz, and Yanmei Xiang, ApJ 825, 45, 2016.

    See the full article here .

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    About CfA

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy. The long relationship between the two organizations, which began when the SAO moved its headquarters to Cambridge in 1955, was formalized by the establishment of a joint center in 1973. The CfA’s history of accomplishments in astronomy and astrophysics is reflected in a wide range of awards and prizes received by individual CfA scientists.

    Today, some 300 Smithsonian and Harvard scientists cooperate in broad programs of astrophysical research supported by Federal appropriations and University funds as well as contracts and grants from government agencies. These scientific investigations, touching on almost all major topics in astronomy, are organized into the following divisions, scientific departments and service groups.

  • richardmitnick 1:11 pm on July 29, 2016 Permalink | Reply
    Tags: , , , , , U Manchester, NGC 4945   

    From U Manchester: “Astronomers Uncover Hidden Stellar Birthplace” 

    U Manchester bloc

    University of Manchester

    26 July, 2016
    Joe Paxton

    No image caption. No image credit.

    A team of astronomers from the University of Manchester, the Max Planck Institute for Radio Astronomy and the University of Bonn have uncovered a hidden stellar birthplace in a nearby spiral galaxy, using a telescope in Chile. The results show that the speed of star formation in the centre of the galaxy – and other galaxies like it – may be much higher than previously thought.

    The team penetrated the thick dust around the centre of galaxy NGC 4945 using the Atacama Large Millimeter Array (ALMA), a single telescope made up of 66 high precision antennas located 5000 metres above sea level in northern Chile.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at  Chajnantor plateau, at 5,000 metres
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    Astronomers typically look for ultraviolet light or infrared emissions from the brightest, hottest, and bluest stars. The places where stars form are often surrounded by interstellar dust that absorbs the ultraviolet and visible light from the hot blue stars, making it difficult to see where stars are forming. However, the interstellar dust gets warmer when it absorbs light and produces infrared radiation.

    NGC 4945 is unusual because the interstellar dust is so dense that it even absorbs the infrared light that it produces, meaning that astronomers find it hard to know what is happening in the centre of the galaxy. However, ALMA is able to see through even the thickest interstellar dust.

    “When we looked at the galaxy with ALMA, its centre was ten times brighter than we would have anticipated based on the mid-infrared image. It was so bright that I asked one of my collaborators to check my calculations just to make sure that I hadn’t made an error.”
    Dr. George J. Bendo

    “While it looks very dusty and very bright in the infrared compared to the Milky Way or other nearby spiral galaxies, it is very similar to other infrared-bright starburst galaxies that are more common in the more distant universe. If other astronomers are trying to look at star formation using infrared light, they might be missing a lot of what’s happening if the star forming regions are as obscured as in NGC 4945.”

    Fellow collaborator Professor Gary Fuller, also from the University of Manchester, added: “These results demonstrate the remarkable power of ALMA to study star formation which would otherwise be hidden.”

    See the full article here .

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    U Manchester campus

    The University of Manchester (UoM) is a public research university in the city of Manchester, England, formed in 2004 by the merger of the University of Manchester Institute of Science and Technology (renamed in 1966, est. 1956 as Manchester College of Science and Technology) which had its ultimate origins in the Mechanics’ Institute established in the city in 1824 and the Victoria University of Manchester founded by charter in 1904 after the dissolution of the federal Victoria University (which also had members in Leeds and Liverpool), but originating in Owens College, founded in Manchester in 1851. The University of Manchester is regarded as a red brick university, and was a product of the civic university movement of the late 19th century. It formed a constituent part of the federal Victoria University between 1880, when it received its royal charter, and 1903–1904, when it was dissolved.

    The University of Manchester is ranked 33rd in the world by QS World University Rankings 2015-16. In the 2015 Academic Ranking of World Universities, Manchester is ranked 41st in the world and 5th in the UK. In an employability ranking published by Emerging in 2015, where CEOs and chairmen were asked to select the top universities which they recruited from, Manchester placed 24th in the world and 5th nationally. The Global Employability University Ranking conducted by THE places Manchester at 27th world-wide and 10th in Europe, ahead of academic powerhouses such as Cornell, UPenn and LSE. It is ranked joint 56th in the world and 18th in Europe in the 2015-16 Times Higher Education World University Rankings. In the 2014 Research Excellence Framework, Manchester came fifth in terms of research power and seventeenth for grade point average quality when including specialist institutions. More students try to gain entry to the University of Manchester than to any other university in the country, with more than 55,000 applications for undergraduate courses in 2014 resulting in 6.5 applicants for every place available. According to the 2015 High Fliers Report, Manchester is the most targeted university by the largest number of leading graduate employers in the UK.

    The university owns and operates major cultural assets such as the Manchester Museum, Whitworth Art Gallery, John Rylands Library and Jodrell Bank Observatory which includes the Grade I listed Lovell Telescope.

  • richardmitnick 12:37 pm on July 29, 2016 Permalink | Reply
    Tags: , , , , What Are The Most Energetic Particles In The Universe?   

    From Ethan Siegel: “What Are The Most Energetic Particles In The Universe?” 

    From Ethan Siegel

    Jul 29, 2016

    The production of a cosmic ray shower, produced by an incredibly energetic particle from far outside our Solar System. Image credit: Pierre Auger Observatory, via

    You might think of the largest and most powerful particle accelerators in the world — places like SLAC, Fermilab and the Large Hadron Collider — as the source of the highest energies we’ll ever see. But everything we’ve ever done here on Earth has absolutely nothing on the natural Universe itself! In fact, if you were interested in the most energetic particles on Earth, looking at the Large Hadron Collider — at the 13 TeV collisions occurring inside — you wouldn’t even be close to the highest energies. Sure, those are the highest human-made energies for particles, but we’re constantly bombarded all the time by particles far, far greater in energy from the depths of space itself: cosmic rays.

    An illustration of a very high energy process in the Universe: a gamma-ray burst. Image credit: NASA / D. Berry.

    You didn’t need to be in space, or even to have any type of flight, to know that these particles existed. Even before the first human beings ever left the surface of the Earth, it was widely known that up there, above the protection of the Earth’s atmosphere, outer space was filled with high-energy radiation. How did we know?

    The first clues came from looking at one of the simplest electricity experiments you can do on Earth, involving an electroscope. If you’ve never heard of an electroscope, it’s a simple device: take two thin pieces of conducting, metal foil, place them in an airless vacuum and connect them to a conductor on the outside that you can control the electric charge of.

    The electric charge on an electroscope, depending on what you charge it with, and how the leaves inside respond. Image credit: Figure 16-8 from Boomeria’s Honors Physics page, via

    If you place an electric charge on one of these devices — where two conducting metal leaves are connected to another conductor — both leaves will gain the same electric charge, and repel one another as a result. You’d expect, over time, for the charge to dissipate into the surrounding air, which it does. So you might have the bright idea to isolate it as completely as possible, perhaps creating a vacuum around the electroscope once you charge it up.

    But even if you do, the electroscope still slowly discharges! In fact, even if you placed lead shielding around the vacuum, it would still discharge, and experiments in the early 20th century gave us a clue as to why: if you went to higher and higher altitudes, the discharge happened more quickly. A few scientists put forth the hypothesis that the discharge was happening because high-energy radiation — radiation with both extremely large penetrating power and an extraterrestrial origin — was responsible for this.

    Victor Hess in his balloon-borne, cosmic ray experiment. Image credit: American Physical Society.

    Well, you know the deal when it comes to science: if you want to confirm or refute your new idea, you test it! So in 1912, Victor Hess conducted balloon-borne experiments to search for these high-energy cosmic particles, discovering them immediately in great abundance and henceforth becoming the father of cosmic rays.

    The early detectors were remarkable in their simplicity: you set up some sort of emulsion (or later, a cloud chamber) that’s sensitive to charged particles passing through it and place a magnetic field around it. When a charged particle comes in, you can learn two extremely important things:

    The particle’s charge-to-mass ratio and
    its velocity,

    simply dependent on how the particle’s track curves, something that’s a dead giveaway so long as you know the strength of the magnetic field you applied.

    In the 1930s, a number of experiments — both in early terrestrial particle accelerators and via more sophisticated cosmic ray detectors — turned up some interesting information. For starters, the vast majority of cosmic ray particles (around 90%) were protons, which came in a wide range of energies, from a few mega-electron-Volts (MeV) all the way up to as high as they could be measured by any known equipment! The vast majority of the rest of them were alpha-particles, or helium nuclei with two protons and two neutrons, with comparable energies to the protons.

    An illustration of cosmic rays striking Earth’s atmosphere. Image credit: Simon Swordy (U. Chicago), NASA.

    When these cosmic rays hit the top of the Earth’s atmosphere, they interacted with it, producing cascading reactions where the products of each new interaction led to subsequent interactions with new atmospheric particles. The end result was the creation of what’s called a shower of high-energy particles, including two new ones: the positron — hypothesized in 1930 by Dirac, the antimatter counterpart of the electron with the same mass but a positive charge — and the muon, an unstable particle with the same charge as the electron but some 206 times heavier! The positron was discovered by Carl Anderson in 1932 and the muon by him and his student Seth Neddermeyer in 1936, but the first muon event was discovered by Paul Kunze a few years earlier, which history seems to have forgotten!

    One of the most amazing things is that even here on the surface of the Earth, if you hold out your hand so that it’s parallel to the ground, about one muon passes through it every second.

    Image credit: Konrad Bernlöhr of the Max Planck Institute for Nuclear Physics.

    Every muon that passes through your hand originates from a cosmic ray shower, and every single one that does so is a vindication of the theory of special relativity! You see, these muons are created at a typical altitude of about 100 km, but a muon’s mean lifetime is only about 2.2 microseconds! Even moving at the speed of light (299,792.458 km/sec), a muon would only travel about 660 meters before it decays. Yet because of time dilation — or the fact that particles moving close to the speed of light experience time passing at a slower rate from the point-of-view of a stationary outside observer — these fast-moving muons can travel all the way to the surface of the Earth before they decay, and that’s where muons on Earth originate!

    Fast-forward to the present day, and it turns out that we’ve accurately measured both the abundance and energy spectrum of these cosmic particles!

    The spectrum of cosmic rays. Image credit: Hillas 2006, preprint arXiv:astro-ph/0607109 v2, via University of Hamburg.

    Particles with about 100 GeV worth of energy and under are by far the most common, with about one 100 GeV particle (that’s 10^11 eV) hitting every square-meter cross-section of our local region of space every second. Although higher-energy particles are still there, they’re far less frequent as we look to higher and higher energies.

    For example, by time you reach 10,000,000 GeV (or 10^16 eV), you’re only getting one-per-square-meter each year, and for the highest energy ones, the ones at 5 × 10^10 GeV (or 5 × 10^19 eV), you’d need to build a square detector that measured about 10 kilometers on a side just to detect one particle of that energy per year!

    How to detect a cosmic ray shower: build a giant array on the ground to — to quote Pokémon — catch ‘em all. Image credit: ASPERA / G.Toma / A.Saftoiu.

    Seems like a crazy idea, doesn’t it? It’s asking for a huge investment of resources to detect these incredibly rare particles. And yet there’s an extraordinarily compelling reason that we’d want to do so: there should be a cutoff in the energies of cosmic rays, and a speed limit for protons in the Universe! You see, there might not be a limit to the energies we can give to protons in the Universe: you can accelerate charged particles using magnetic fields, and the largest, most active black holes in the Universe could give rise to protons with energies even greater than the ones we’ve observed!

    But they have to travel through the Universe to reach us, and the Universe — even in the emptiness of deep space — isn’t completely empty. Instead, it’s filled with large amounts of cold, low-energy radiation: the cosmic microwave background!

    An illustration of the radiation background at various redshifts in the Universe. Image credits: Earth: NASA/BlueEarth; Milky Way: ESO/S. Brunier; CMB: NASA/WMAP.

    The only places where the highest energy particles are created are around the most massive, active black holes in the Universe, all of which are far beyond our own galaxy. And if particles with energies in excess of 5 × 10^10 GeV are created, they can only travel a few million light years — max — before one of these photons, left over from the Big Bang, interacts with it and causes it to produce a pion, radiating away the excess energy and falling down to this theoretical cosmic energy limit, known as the GZK cutoff. There’s even more braking radiation — or Bremsstrahlung radiation — that arises from interactions with any particles in the interstellar/intergalactic medium. Even lower-energy particles are subject to it, and radiate energy away in droves as electron/positron pairs (and other particles) are produced. (More details here.)

    So we did the only reasonable thing for physicists to do: we built a detector that ridiculously large and looked, and saw if this cutoff existed!

    The largest cosmic ray detector in the world. Image credit: Pierre Auger Observatory in Malargüe, Argentina / Case Western Reserve U.

    The Pierre Auger Observatory has done exactly this, verifying that cosmic rays exist up to but not over this incredibly high-energy threshold, a literal factor of about 10,000,000 larger than the energies reached at the LHC! This means the fastest protons we’ve ever seen evidence for in the Universe are moving almost at the speed-of-light, which is exactly 299,792,458 m/s, but just a tiny bit slower. How much slower?

    The fastest protons — the ones just at the GZK cutoff — move at 299,792,457.999999999999918 meters-per-second, or if you raced a photon and one of these protons to the Andromeda galaxy and back, the photon would arrive a measly six seconds sooner than the proton would… after a journey of more than five million years! But these ultra-high-energy cosmic rays don’t come from Andromeda (we believe); they come from active galaxies with supermassive black holes like NGC 1275, which tend to be hundreds of millions or even billions of light years away.

    Galaxy NGC 1275, as imaged by Hubble. Image credit: NASA, ESA, Hubble Heritage (STScI/AURA).

    We even know — thanks to NASA’s Interstellar Boundary Explorer (IBEX) — that there are about 10 times as many cosmic rays out there in deep space as we detect here on-and-around Earth, as the Sun’s heliosheath protects us from the vast majority of them!


    (Although the Sun does the worst job of protecting us from the most energetic particles.) In theory, there are collisions occurring everywhere in space between these cosmic rays, and so in a very real sense of the word, the Universe itself is our ultimate Large Hadron Collider: up to ten million times more energetic than what we can perform here on Earth. And when we’ve finally reached the limits of what a collider experiment can perform on Earth, it will be back to the same techniques we used in the earliest days of cosmic ray experiments.

    Exterior view of the ISS with the AMS-02 visible in the foreground. Image credit: NASA.

    It will be back to space, to wait and see what the Universe delivers to us, and to detect the aftermath of the most energetic cosmic collisions of all.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

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