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  • richardmitnick 1:15 pm on May 25, 2017 Permalink | Reply
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    From U Chicago: “World’s most sensitive dark matter detector releases first results” 

    U Chicago bloc

    University of Chicago

    May 18, 2017
    news@uchicago.edu
    (773) 702-8360
    News media only

    UChicago scientists part of international XENON collaboration

    1
    XENON1T installation in the underground hall of Laboratori Nazionali del Gran Sasso. The three story building on the right houses various auxiliary systems. The cryostat containing the LXeTPC is located inside the large water tank on the left. Photo by Roberto Corrieri and Patrick De Perio

    Gran Sasso LABORATORI NAZIONALI del GRAN SASSO, located in the Abruzzo region of central Italy

    2
    Scientists assembling the XENON1T time projection chamber. Photo by Enrico Sacchetti

    Scientists behind XENON1T, the largest dark matter experiment of its kind ever built, are encouraged by early results, describing them as the best so far in the search for dark matter.

    Dark matter is one of the basic constituents of the universe, five times more abundant than ordinary matter. Several astronomical measurements have corroborated the existence of dark matter, leading to an international effort to observe it directly. Scientists are trying to detect dark matter particle interacting with ordinary matter through the use of extremely sensitive detectors. Such interactions are so feeble that they have escaped direct detection to date, forcing scientists to build detectors that are more and more sensitive and have extremely low levels of radioactivity.

    On May 18, the XENON Collaboration released results from a first, 30-day run of XENON1T, showing the detector has a record low radioactivity level, many orders of magnitude below surrounding material on earth.

    “The care that we put into every single detail of the new detector is finally paying back,” said Luca Grandi, assistant professor in physics at the University of Chicago and member of the XENON Collaboration. “We have excellent discovery potential in the years to come because of the huge dimension of XENON1T and its incredibly low background. These early results already are allowing us to explore regions never explored before.”

    The XENON Collaboration consists of 135 researchers from the United States, Germany, Italy, Switzerland, Portugal, France, the Netherlands, Israel, Sweden and the United Arab Emirates, who hope to one day confirm dark matter’s existence and shed light on its mysterious properties.

    Located deep below a mountain in central Italy, XENON1T features a 3.2-ton xenon dual-phase time projection chamber. This central detector sits fully submersed in the middle of the water tank, in order to shield it from natural radioactivity in the cavern. A cryostat helps keep the xenon at a temperature of minus-95 degrees Celsius without freezing the surrounding water. The mountain above the laboratory further shields the detector, preventing it from being perturbed by cosmic rays.

    But shielding from the outer world is not enough, since all materials on Earth contain tiny traces of natural radioactivity. Thus extreme care was taken to find, select and process the materials making up the detector to achieve the lowest possible radioactive content. This allowed XENON1T to achieve record “silence” necessary to detect the very weak output of dark matter.

    A particle interaction in the one-ton central core of the time projection chamber leads to tiny flashes of light. Scientists record and study these flashes to infer the position and the energy of the interacting particle—and whether it might be dark matter.

    Despite the brief 30-day science run, the sensitivity of XENON1T has already overcome that of any other experiment in the field probing unexplored dark matter territory.

    “For the moment we do not see anything unexpected, so we set new constraints on dark matter properties,” Grandi said. “But XENON1T just started its exciting journey and since the end of the 30-day science run, we have been steadily accumulating new data.”

    UChicago central to international collaboration

    Grandi’s group is very active within XENON1T, and it is contributing to several aspects of the program. After its initial involvement in the preparation, assembly and early operations of the liquid xenon chamber, the group shifted its focus in the last several months to the development of the computing infrastructure and to data analysis.

    “Despite its low background, XENON1T is producing a large amount of data that needs to be continuously processed,” said Evan Shockley, a graduate student working with Grandi. “The raw data from the detector are directly transferred from Gran Sasso Laboratory to the University of Chicago, serving as the unique distribution point for the entire collaboration.”

    The framework, developed in collaboration with a group led by Robert Gardner, senior fellow at the Computation Institute, allows for the processing of data, both on local and remote resources belonging to the Open Science Grid. The involvement of UChicago’s Research Computing Center including Director Birali Runesha allows members of the collaboration all around the world to access processed data for high-level analyses.

    Grandi’s group also has been heavily involved in the analysis that led to this first result. Christopher Tunnell, a fellow at the Kavli Institute for Cosmological Physics, is one of the two XENON1T analysis coordinators and corresponding author of the result. Recently, UChicago hosted about 25 researchers for a month to perform the analyses that led to the first results.

    “It has been a large, concentrated effort and seeing XENON1T back on the front line makes me forget the never-ending days spent next to my colleagues to look at plots and distributions,“ Tunnell said. “There is no better thrill than leading the way in our knowledge of dark matter for the coming years.”

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  • richardmitnick 1:19 pm on February 2, 2017 Permalink | Reply
    Tags: , , , Primitive achondrites, U Chicago   

    From U Chicago: “Today’s rare meteorites were common 466 million years ago, study finds” 

    U Chicago bloc

    University of Chicago

    January 26, 2017
    Kate Golembiewski

    1
    Artist’s rendering of the space collision 466 million years ago that gave rise to many of the meteorites falling to Earth today.
    Illustration by Don Davis/Southwest Research Institute

    About 466 million years ago, there was a giant collision in outer space. Something hit an asteroid and broke it apart, sending chunks of rock falling to Earth as meteorites. But what kinds of meteorites were making their way to Earth before that collision?

    In a study published Jan. 23 in Nature Astronomy, scientists tackled that question by creating the first reconstruction of the distribution of meteorite types before the collision. They discovered that most of the meteorites falling to Earth today are rare, while many meteorites that are rare today were common before the collision.

    “We found that the meteorite flux—the variety of meteorites falling to Earth—was very, very different from what we see today,” said Philipp Heck, associate professor of geophysical sciences at the University of Chicago, the paper’s lead author. “Looking at the kinds of meteorites that have fallen to Earth in the last hundred million years doesn’t give you a full picture. It would be like looking outside on a snowy day and concluding that every day is snowy, even though it’s not snowy in the summer.”

    Meteorites are pieces of rock that have fallen to Earth from outer space. They’re formed from the debris of collisions between bodies like asteroids, moons and even planets. There are many different types of meteorites, which reflect the different compositions of their parent bodies. By studying the different meteorites that have made their way to Earth, scientists can develop a better understanding of how the basic building blocks of the solar system formed and evolved.

    “Before this study, we knew almost nothing about the meteorite flux to Earth in geological deep time,” said co-author Birger Schmitz, professor of nuclear physics at Lund University. “The conventional view is that the solar system has been very stable over the past 500 million years. So it is quite surprising that the meteorite flux at 467 million years ago was so different from (that of) the present.”

    To learn what the meteorite flux was like before the big collision event, Heck and his colleagues analyzed meteorites that fell more than 466 million years ago. Such finds are rare, but the team was able to look at micrometeorites—tiny specks of space-rock less than 2 millimeters in diameter that fell to Earth. They are less rare. Heck’s Swedish and Russian colleagues retrieved samples of rock from an ancient seafloor exposed in a Russian river valley that contained micrometeorites. They then dissolved almost 600 pounds of the rocks in acid so that only microscopic chromite crystals remained.

    Not having changed during hundreds of millions of years, the crystals revealed the nature of meteorites over time. Analysis of their chemical makeup showed that the meteorites and micrometeorites that fell earlier than 466 million years ago are different from the ones that have fallen since. A full 34 percent of the pre-collision meteorites belong to a meteorite type called primitive achondrites; today, only 0.45 percent of the meteorites that land on Earth are this type.

    Other micrometeorites sampled turned out to be relics from Vesta—the brightest asteroid visible from Earth, which underwent its own collision event over a billion years ago.

    Meteorite delivery from the asteroid belt to the Earth is a little like observing landslides started at different times on a mountainside, said co-author William Bottke, senior research scientist at the Southwest Research Institute. “Today, the rocks reaching the bottom of the mountain might be dominated by a few recent landslides. Going back in time, however, older landslides should be more important. The same is true for asteroid breakup events; some younger ones dominate the current meteorite flux, while in the past older ones dominated.”

    “Knowing more about the different kinds of meteorites that have fallen over time gives us a better understanding of how the asteroid belt evolved and how different collisions happened,” said Heck, an associate curator of meteoritics and polar studies at the Field Museum of Natural History. “Ultimately, we want to study more windows in time, not just the area before and after this collision. That will deepen our knowledge of how different bodies in our solar system formed and interact with each other.”

    Funding: European Research Council and Tawani Foundation

    See the full article here .

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  • richardmitnick 2:34 pm on January 5, 2017 Permalink | Reply
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    From U Chicago: “Research reinforces role of supernovae in clocking the universe” 

    U Chicago bloc

    University of Chicago

    January 3, 2017
    Greg Borzo

    1
    New research confirms the role Type Ia supernovae, like G299 pictured above, play in measuring universe expansion. Courtesy of NASA.

    How much light does a supernova shed on the history of universe?

    New research by cosmologists at the University of Chicago and Wayne State University confirms the accuracy of Type Ia supernovae in measuring the pace at which the universe expands. The findings support a widely held theory that the expansion of the universe is accelerating and such acceleration is attributable to a mysterious force known as dark energy. The findings counter recent headlines that Type Ia supernova cannot be relied upon to measure the expansion of the universe.

    Using light from an exploding star as bright as entire galaxies to determine cosmic distances led to the 2011 Nobel Prize in physics. The method relies on the assumption that, like lightbulbs of a known wattage, all Type Ia supernovae are thought to have nearly the same maximum brightness when they explode. Such consistency allows them to be used as beacons to measure the heavens. The weaker the light, the farther away the star. But the method has been challenged in recent years because of findings the light given off by Type Ia supernovae appears more inconsistent than expected.

    “The data that we examined are indeed holding up against these claims of the demise of Type Ia supernovae as a tool for measuring the universe,” said Daniel Scolnic, a postdoctoral scholar at UChicago’s Kavli Institute for Cosmological Physics and co-author of the new research published in Monthly Notices of the Royal Astronomical Society. “We should not be persuaded by these other claims just because they got a lot of attention, though it is important to continue to question and strengthen our fundamental assumptions.”

    One of the latest criticisms of Type Ia supernovae for measurement concluded the brightness of these supernovae seems to be in two different subclasses, which could lead to problems when trying to measure distances. In the new research led by David Cinabro, a professor at Wayne State, Scolnic, Rick Kessler, a senior researcher at the Kavli Institute, and others, they did not find evidence of two subclasses of Type Ia supernovae in data examined from the Sloan Digital Sky Survey Supernovae Search and Supernova Legacy Survey.

    SDSS Telescope at Apache Point, NM, USA
    SDSS Telescope at Apache Point, NM, USA

    The recent papers challenging the effectiveness of Type Ia supernovae for measurement used different data sets.

    A secondary criticism has focused on the way Type Ia supernovae are analyzed. When scientists found that distant Type Ia supernovae were fainter than expected, they concluded the universe is expanding at an accelerating rate. That acceleration is explained through dark energy, which scientists estimate makes up 70 percent of the universe. The enigmatic force pulls matter apart, keeping gravity from slowing down the expansion of the universe.

    Yet a substance that makes up 70 percent of the universe but remains unknown is frustrating to a number of cosmologists. The result was a reevaluation of the mathematical tools used to analyze supernovae that gained attention in 2015 by arguing that Type Ia supernovae don’t even show dark energy exists in the first place.

    Scolnic and colleague Adam Riess, who won the 2011 Nobel Prices for the discovery of the accelerating universe, wrote an article for Scientific American Oct. 26, 2016, refuting the claims. They showed that even if the mathematical tools to analyze Type Ia supernovae are used “incorrectly,” there is still a 99.7 percent chance the universe is accelerating.

    The new findings are reassuring for researchers who use Type Ia supernovae to gain an increasingly precise understanding of dark energy, said Joshua A. Frieman, senior staff member at the Fermi National Accelerator Laboratory [FNAL] who was not involved in the research.

    “The impact of this work will be to strengthen our confidence in using Type Ia supernovae as cosmological probes,” he said.

    Citation: “Search for Type Ia Supernova NUV-Optical Subclasses,” by David Cinabro and Jake Miller (Wayne State University); and Daniel Scolnic and Ashley Li (Kavli Institute for Cosmological Physics at the University of Chicago); and Richard Kessler (Kavli Institute for Cosmological Physics at University of Chicago and the Department of Astronomy and Astrophysics at the University of Chicago). Monthly Notices of the Royal Astronomical Society, November 2016. DOI: 10.1093/mnras/stw3109

    Funding: Kavli Institute for Cosmological Physics at the University of Chicago, Kavli Foundation, Fred Kavli, Space Telescope Science Institute, and National Aeronautics and Space Administration.

    See the full article here .

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    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

     
  • richardmitnick 1:18 pm on December 15, 2016 Permalink | Reply
    Tags: , , HIP68468, U Chicago   

    From U Chicago: “Astronomers discover dark past of planet-eating ‘Death Star’” 

    U Chicago bloc

    University of Chicago

    December 15, 2016
    Greg Borzo

    Solar twin could hold clues to planetary formation

    1
    HIP68468, a twin star to the sun about 300 light-years away, may have swallowed one or more of its planets, based on lithium and refractory elements recently discovered near its surface.
    Illustration by Gabi Perez / Instituto de Astrofísica de Canarias

    An international team of scientists, including researchers from the University of Chicago, has made the rare discovery of a planetary system with a host star similar to Earth’s sun. Especially intriguing is the star’s unusual composition, which indicates it ingested some of its planets.

    “It doesn’t mean that the sun will ‘eat’ the Earth any time soon,” said Jacob Bean, assistant professor of astronomy and astrophysics at UChicago and co-author of an Astronomy & Astrophysics article on the research. “But our discovery provides an indication that violent histories may be common for planetary systems, including our own.”

    Unlike the artificial planet-destroying Death Star in the movie Star Wars, this natural version could provide clues about how planetary systems evolve over time.

    Astronomers discovered the first planet orbiting a star other than the sun in 1995. Since then, more than two thousand exoplanets have been identified. Rare among them are planets that orbit a star similar to Earth’s sun. Due to their extreme similarity to the sun, these so-called solar twins are ideal targets for investigating the connections between stars and their planets.

    Bean and his colleagues studied star HIP68468, which is 300 light years away, as part of a multi-year project to discover planets that orbit solar twins. It’s tricky to draw conclusions from a single system, cautioned Megan Bedell, a UChicago doctoral student who is co-author of the research and the lead planet finder for the collaboration. She said the team plans “to study more stars like this to see whether this is a common outcome of the planet formation process.”

    Computer simulations show that billions of years from now, the accumulated gravitational tugs and pulls between planets will eventually cause Mercury to fall into the sun, said Debra Fischer, a professor of astronomy at Yale University who was not involved in the research. “This study of HIP68468 is a post-mortem of this process happening around another star similar to our sun. The discovery deepens our understanding of the evolution of planetary systems.”

    Two planets discovered

    Using the 3.6-meter telescope at La Silla Observatory in Chile, the research team of scientists from several continents discovered its first exoplanet in 2015.

    ESO 3.6m telescope & HARPS at LaSilla, Chile
    ESO 3.6 meter telescope interior
    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile

    The more recent discovery needs to be confirmed, but includes two planet candidates—a super Neptune and a super Earth. Their orbits are surprisingly close to their host star, with one 50 percent more massive than Neptune and located at a Venus-like distance from its star. The other, the first super Earth around a solar twin, is three times the Earth’s mass and so close to its star that its orbit takes just three days.

    “These two planets most likely didn’t form where we see them today,” Bedell said. Instead, they probably migrated inward from the outer parts of the planetary system. Other planets could have been ejected from the system—or ingested by their host star.

    HIP68468’s composition points to a history of ingesting planets. It contains four times more lithium than would be expected for a star that is 6 billion years old, as well as a surplus of refractory elements—metals resistant to heat and that are abundant in rocky planets.

    In the hot interior of stars like HIP68468 and the sun, lithium is consumed over time. Planets, on the other hand, preserve lithium because their inner temperatures are not high enough to destroy the element. As a result, when a star engulfs a planet, the lithium that the planet deposits in the stellar atmosphere stands out.

    Taken together, the lithium and the engulfed rocky planet material in the atmosphere of HIP68468 is equivalent to the mass of six Earths.

    “It can be very hard to know the history of a particular star, but once in a while we get lucky and find stars with chemical compositions that likely came from in-falling planets,” Fischer said. “That’s the case with HD68468. The chemical remains of one or more planets are smeared in its atmosphere.

    “It’s as if we saw a cat sitting next to a bird cage,” she added. “If there are yellow feathers sticking out of the cat’s mouth, it’s a good bet that the cat swallowed a canary.”

    The team continues to monitor more than 60 solar twins, looking for more exoplanets. Beyond that, the Giant Magellan Telescope under construction in Chile, for which UChicago is a founding partner, will be capable of detecting more Earth-like exoplanets around solar twins.

    Giant Magellan Telescope, Las Campanas Observatory, to be built  some 115 km (71 mi) north-northeast of La Serena, Chile
    Giant Magellan Telescope, Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile

    “In addition to finding Earth-like planets, the Giant Magellan Telescope will enable astronomers to study the atmospheric composition of stars at even greater detail than we can today,” Bean said. “That will further reveal the histories of planetary systems that are subtly imprinted on their host stars.”

    Citation: “The Solar Twin Planet Search. V. Close-in, low-mass planet candidates and evidence of planet accretion in the solar twin HIP68468,” by Megan Bedell and Jacob Bean (University of Chicago); first author Jorge Meléndez, Sylvio Ferraz-Mello, Jhon Yana-Galarza, Leonardo dos Santos, Marcelo Tucci Maia and Lorenzo Spina (Universidade de Sao Paulo); Alan Alves-Brito (Universidade Federal do Rio Grande do Sul); Ivan Ramirez (University of Texas Austin); Martin Asplund and Luca Casagrande (Australian National University); Stefan Dreizler (University of Göttingen); Hong-Liang Yan and Jian-Rong Shi (Chinese Academy of Sciences); Karin Lind (Max Planck Institute for Astronomy); and TalaWanda Monroe (Space Telescope Science Institute). The paper is available at https://arxiv.org/abs/1610.09067

    Funding: São Paulo Research Foundation, Conselho Nacional de Desenvolvimento Científico e Tecnológico, National Science Foundation, Alfred P. Sloan Foundation, David and Lucile Packard Foundation, and Australian Research Council

    See the full article here .

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    An intellectual destination

    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

     
  • richardmitnick 7:23 am on October 7, 2016 Permalink | Reply
    Tags: , Case of Earth’s missing continental crust solved: It sank, , , U Chicago   

    From U Chicago: “Case of Earth’s missing continental crust solved: It sank” 

    U Chicago bloc

    University of Chicago

    October 4, 2016
    Carla Reiter

    Mantle swallowed massive chunk of Eurasia and India, study finds

    1
    UChicago scientists have concluded that half the original mass of Eurasia and India disappeared into the Earth’s interior before the two continents began their slow-motion collision approximately 60 million years ago. The participating UChicago scientists are (from left) Miquela Ingalls, doctoral student in geophysical sciences; David Rowley, professor in geophysical sciences; and Albert Colman, assistant professor in geophysical sciences. Rowley holds a rock of the type they believe sank into the interior. Photo by Jean Lachat

    How do you make half the mass of two continents disappear? To answer that question, you first need to discover that it’s missing.

    That’s what a trio of University of Chicago geoscientists and their collaborator did, and their explanation for where the mass went significantly changes prevailing ideas about what can happen when continents collide. It also has important implications for our understanding of when the continents grew to their present size and how the chemistry of the Earth’s interior has evolved.

    The study, published online Sept. 19 in Nature Geoscience, examines the collision of Eurasia and India, which began about 60 million years ago, created the Himalayas and is still in (slow) progress. The scientists computed with unprecedented precision the amount of landmass, or “continental crust,” before and after the collision.

    “What we found is that half of the mass that was there 60 million years ago is missing from the earth’s surface today,“ said Miquela Ingalls, a graduate student in geophysical sciences who led the project as part of her doctoral work.

    The result was unexpectedly large. After considering all other ways the mass might be accounted for, the researchers concluded that so huge a mass discrepancy could only be explained if the missing chunk had gone back down into the Earth’s mantle—something geoscientists had considered more or less impossible on such a scale.

    When tectonic plates come together, something has to give.

    The tectonic plates of the world were mapped in 1996, USGS.
    The tectonic plates of the world were mapped in 1996, USGS

    According to plate tectonic theory, the surface of the Earth comprises a mosaic of about a dozen rigid plates in relative motion. These plates move atop the upper mantle, and plates topped with thicker, more buoyant continental crust ride higher than those topped with thinner oceanic crust. Oceanic crust can dip and slide into the mantle, where it eventually mixes together with the mantle material. But continental crust like that involved in the Eurasia-India collision is less dense, and geologists have long believed that when it meets the mantle, it is pushed back up like a beach ball in water, never mixing back in.

    Geology 101 miscreant

    “We’re taught in Geology 101 that continental crust is buoyant and can’t descend into the mantle,” Ingalls said. The new results throw that idea out the window.

    “We really have significant amounts of crust that have disappeared from the crustal reservoir, and the only place that it can go is into the mantle,” said David Rowley, a professor in geophysical sciences who is one of Ingalls’ advisors and a collaborator on the project. “It used to be thought that the mantle and the crust interacted only in a relatively minor way. This work suggests that, at least in certain circumstances, that’s not true.”

    The scientists’ conclusion arose out of meticulous calculations of the amount of mass there before and after the collision, and a careful accounting of all possible ways it could have been distributed. Computing the amount of crust “before” is a contentious problem involving careful dating of the ages of strata and reconstructions of past plate positions, Ingalls said. Previous workers have done similar calculations but have often tried to force the “before” and “after” numbers to balance, “trying to make the system match up with what we think we already know about how tectonics works.”

    Ingalls and collaborators made no such assumptions. They used recently revised estimates about plate movements to figure out how large the two plates were at the onset of collision, and synthesized more than 20 years’ worth of data on the geology of various regions of the Earth to calculate how thick the crust would have been.

    “By looking at all of the relevant data sets, we’ve been able to say what the mass of the crust was at the beginning of collision,” Rowley said.

    Limited options

    There were only a few places for the displaced crust to go after the collision: Some was thrust upward, forming the Himalayas, some was eroded and deposited as enormous sedimentary deposits in the oceans, and some was squeezed out the sides of the colliding plates, forming Southeast Asia.

    “But accounting for all of these different types of mass loss, we still find that half of the continental crust involved in this collision is missing today,” Ingalls said. “If we’ve accounted for all possible solutions at the surface, it means the remaining mass must have been recycled wholesale into the mantle.”

    If large areas of continental crust are recycled back into the mantle, scientists can at last explain some previously puzzling geochemistry. Elements including lead and uranium are periodically erupted from the mantle through volcanic activity. Such elements are relatively abundant in continental crust, but scarce in the mantle. Yet the composition of some mantle-derived rocks indicates that they have been contaminated by continental crust. So how did continental material mix back into the mantle?

    “The implication of our work is that, if we’re seeing the India-Asia collision system as an ongoing process over Earth’s history, there has been a continuous mixing of the continental crustal elements back into the mantle,” said Rowley. “And they can then be re-extracted and seen in some of those volcanic materials that come out of the mantle today.”

    Funding: National Science Foundation

    See the full article here .

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    An intellectual destination

    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

     
  • richardmitnick 2:27 pm on August 15, 2016 Permalink | Reply
    Tags: , , Grad student’s discovery could enable rapid screening of anti-cancer compounds, U Chicago   

    From U Chicago: “Grad student’s discovery could enable rapid screening of anti-cancer compounds” 

    U Chicago bloc

    University of Chicago

    August 11, 2016
    Carla Reiter

    1
    Graduate student Di Liu co-authored an article describing how to create tiny, knotted chemical structures that may provide a way to rapidly screen hundreds of chemicals for anti-cancer activity. Photo by Joel Wintermantle

    It isn’t often that a graduate student makes a spectacular technical leap in his field, or invents a process that can have a significant impact on a real-world problem. Di Liu did both.

    A chemistry graduate student at UChicago, Liu devised a way to make tiny knotted and interlocked chemical structures that have been impossible for chemists to fabricate until now, and he invented a way that those knots might be used to quickly screen hundreds of chemicals for fighting cancer.

    Many chemicals have knots or links as part of their structure. But synthesizing new substances that tie themselves in knots at the molecular scale is prodigiously difficult. Liu found a way to generate a large variety of tiny knots, 15 to 20 nanometers in diameter (smaller than a virus), in a piece of single-stranded DNA.

    2
    Asst. Prof. Yossi Weizmann co-authored the paper on generating knotted chemical structures. Photo by Joel Wintermantle

    “Nobody could do it before,” said Yossi Weizmann, an assistant professor in chemistry and a co-author on the paper. “Di found a way to synthesize something that’s very challenging.” The challenge was part of what attracted him. Liu, Weizmann and three co-authors published their findings July 4 in Nature Chemistry.

    “Some people want to run faster; some people want to jump higher. Chemists want to create more complex molecules,” Liu said. “It’s a demonstration of our capability.”

    The knots are a way to mimic what happens to DNA inside cells, and they offer a possible tool for attacking an enzyme crucial to the survival of cancer cells.

    ‘Super-coiled’ DNA

    DNA is a long molecule. In living cells, it must coil itself up in order to fit into the cell nucleus, and in doing so it becomes “super-coiled”—an effect similar to being knotted. Like a piece of string twisted too tightly, short segments twist back on themselves, tangle and poke off to the side of the main strand, interfering with the DNA’s ability to function.

    When the DNA needs to replicate, an enzyme called DNA topoisomerase snips the super-coils and untangles them, relaxing the tension in the strand. Then it rejoins the snipped ends so the DNA can function. It’s a feat so complex that James Wang, the enzyme’s discoverer, dubbed it “the magician of the DNA world.” It also makes topoisomerase a prime target for anti-cancer drugs: If the topoisomerase in a cancer cell doesn’t function, the cancer cell will die.

    Liu uses knotted DNA as a probe to detect the activity of topoisomerase. He first gets the knots to form themselves from strategically designed sequences of single-stranded DNA and shorter segments he calls “staples.” The four nucleotides that make up DNA bond with each other according to strict rules: A bonds only with T; C bonds only with G. So by picking the sequence of nucleotides on the staples, Liu can manipulate where each will attach to the long strand.

    Using this method Liu has encouraged the formation of nine different knot structures, some, he acknowledged, simply for the satisfaction of being able to do it. After the structure forms, an enzyme seals the ends and another enzyme removes the staples.

    When topoisomerase is introduced into a vial containing the knotted DNA, it snips the knot, untangles it and seals its ends to form a circle, “unknotting” the knot. The relative quantities of knots and circles after adding topoisomerase show how active the enzyme has been in unknotting the knots: fewer circles equal less action.

    Testing, retesting

    To test a potential anti-topoisomerase drug, researchers could run the test before and after introducing the drug, and see if the drug had inhibited the action of the enzyme. But the method chemists typically use for such assays, gel electrophoresis, is too slow to be a practical way to screen drug candidates.

    Liu invented an alternative. He realized that he didn’t need to see the knots themselves, he just needed to see evidence that the enzyme had unknotted them. Since the circles of DNA can replicate while the knots can’t, he looked for replication, which is easily detectable using a fluorescent dye that binds to DNA.

    “You’re detecting the activity of topoisomerase, because it can unknot the knot to a circle,” said Weizmann. “And if the DNA is unknotted, then you can detect the replication. And because this method is electrophoresis-free, it can be used in high through-put screening for drugs against this enzyme.”

    Liu and Weizmann plan to begin testing a library of chemicals, beginning with molecules already approved by the FDA. “There are hundreds, Weizmann said. “If you hit something, then you start to study it. If you don’t, you go on to others. It’s trial by error. But you have the ability to screen hundreds because the method is very easy.”

    Funding: Howard Hughes Medical Institute and the National Science Foundation.

    See the full article here .

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  • richardmitnick 9:30 am on July 22, 2016 Permalink | Reply
    Tags: , , U Chicago   

    From U Chicago: “Chicago to host world’s largest conference on high-energy physics” 

    U Chicago bloc

    University of Chicago

    July 21, 2016
    No writer credit found

    1
    Scientists from around the world will present results during the International Conference on High Energy Physics. Copyright CERN

    More than 1,350 physicists from 49 countries will converge in Chicago for the biennial International Conference on High Energy Physics in early August to share new research results, announce new projects and talk about the most intriguing mysteries of the universe.

    The conference will be held Aug. 3-10 at the Sheraton Grand Hotel, 301 E. North Water St. Physicists from the large experiments at CERN’s Large Hadron Collider—the world’s most powerful particle accelerator—will present a wealth of new results.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    CERN ATLAS Higgs Event
    CERN/ATLAS detector
    ATLAS

    CERN CMS Higgs Event
    CERN/CMS Detector
    CMS

    CERN ALICE Icon HUGE
    CERN ALICE New II
    ALICE

    CERN/LHCb
    LHCb

    This will include an eagerly awaited update about a mysterious bump in the data that could be evidence for a new particle or just a statistical fluctuation, as more data are being analyzed.

    That will be merely one highlight in a program that covers 16 topics—from the Higgs boson to neutrinos to dark matter to cosmology, and will include new results from many experiments at institutions around the world.

    “The International Conference on High Energy Physics will be the scientific event of the year in Chicago,” said Young-Kee Kim, chair of the conference’s organizing committee and the Louis Block Professor in Physics at the University of Chicago. “A great many scientists who specialize in particle physics, cosmology, accelerator science and related fields work in this region’s excellent research universities and our two outstanding national laboratories. We all look forward to showing this vibrant city to our colleagues and discussing the latest developments of our science.”

    Public events

    The conference includes two free events specially designed for the public: The Windy City Physics Slam and a public lecture on the recent, headline-making detection of gravitational waves.

    The Windy City Physics Slam, hosted by WGN-TV Chief Meteorologist Tom Skilling, will take place at 3 p.m. Aug. 7 at the Sheraton Grand Hotel Chicago Ballroom. Inspired by poetry slams, the Physics Slam will pit researchers against each other in a contest to make their field of study sound as interesting, compelling and enjoyable as possible. Five scientists from around the world will compete, using music, dance, props and anything else they want, with the winner determined by audience applause.

    The public lecture, titled “The Detection of Gravitational Waves from Binary Black Hole Mergers,” will begin at 6:30 p.m. Aug. 9, at the Sheraton Grand Hotel Chicago Ballroom. The speaker will be Barry Barish, the Linde Professor of Physics Emeritus at the California Institute of Technology. Barish has played multiple key roles for the Laser Interferometer Gravitational-wave Observatory since 1994. LIGO made international headlines twice this year with its discoveries of gravitational waves, whose existence were predicted by Albert Einstein in his 1915 general theory of relativity.

    LSC LIGO Scientific Collaboration
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Those events are free and open to the public, with seating on a first-come basis.

    For the media

    Members of the media are invited to “A Nobel Breakfast,” at 8 a.m. Aug. 8. Featured guests will include Nobel laureate Takaaki Kajita and leaders of international laboratories whose work has contributed to Nobel Prizes in physics. Moderating the event will be Edward “Rocky” Kolb, dean of UChicago’s Physical Sciences Division and the Arthur Holly Compton Distinguished Service Professor in Astronomy and Astrophysics.

    Kajita, of the University of Tokyo, shared the 2015 Nobel Prize in Physics “for the discovery of neutrino oscillations, which shows that neutrinos have mass.” The laboratory leaders attending the event will be Fabiola Gianotti, director-general of CERN, the European Organization for Nuclear Research; Peter Littlewood, director of Argonne National Laboratory; Nigel Lockyer, director of Fermi National Accelerator Laboratory; Yifang Wang, director of China’s Institute for Particle Physics; and Masanori Yamauchi, director-general of KEK, Japan’s high-energy accelerator research organization.

    Media also are invited to see Illinois Congressman Bill Foster receive the 2016 “Champion of Science” award from the Science Coalition, a non-profit, non-partisan organization of more than 60 of the nation’s leading public and private research universities. The award recognizes members of Congress whose actions and votes reflect their belief in the importance of basic scientific research and the key role of federal funding in its facilitation. Foster was nominated for the award by Northern Illinois University, Northwestern University, University of Illinois and the University of Wisconsin-Madison. Foster, the only physicist in Congress, will receive the award at 12:45 p.m. in the Sheraton Grand Hotel Chicago Ballroom.

    Free ICHEP registration and other information for journalists is available here. Interested participants may register for the conference here.

    See the full article here .

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    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

     
  • richardmitnick 2:28 pm on July 21, 2016 Permalink | Reply
    Tags: , , Engineering new technology at the molecular level, , U Chicago, University of Chicago’s Pritzker Nanofabrication Facility   

    From U Chicago: “Engineering new technology at the molecular level” 

    U Chicago bloc

    University of Chicago

    July 11, 2016 [Just made it to social media.]
    Steve Koppes

    1
    Photo by Robert Kozloff

    Academic and industrial researchers have begun working side-by-side at the University of Chicago’s Pritzker Nanofabrication Facility, using some of the world’s most advanced tools to exploit the atomic and molecular properties of matter for emerging applications in science and technology.

    “You can’t really do engineering systems from the molecular level up like we’re aiming to do without something like the Pritzker Nanofabrication Facility,” says Matthew Tirrell, dean and Pritzker Director of the Institute for Molecular Engineering.


    The Pritzker Nanofabrication Facility helps researchers exploit the atomic and molecular properties of matter for applications in science and technology. Video by UChicago Creative

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    Peter Duda, the technical director of the Pritzker Nanofabrication Facility, holds a pure, four-inch silicon wafer, a commonly used substrate material in the semiconductor world. “It’s about as close to 100 percent silicon as you can possibly get,” Duda says. (Photo by Robert Kozloff)

    Since the facility opened in February, its biggest users have been UChicago students in molecular engineering, physics, and chemistry working on their own projects and in collaboration with faculty members. There are also users from other university campuses as well as industry.

    “We have students working on a variety of different projects, including making devices for applications in quantum information, working on devices that use microfluidic technology, and developing detectors for astrophysical applications,” says Andrew Cleland, the John A. McClean Sr. Professor of Molecular Engineering Innovation and Enterprise and faculty director of the Pritzker facility.

    Microfluidic devices can be used to detect and measure the properties of single cells, viruses, or other biological components. In the astrophysical realm, researchers fabricate sensors for the South Pole Telescope to detect the cosmic microwave background radiation, the afterglow of the Big Bang.

    The facility’s tools offer the capability of manufacturing devices ranging in size from a few inches down to 10 nanometers—a size that compares to the width of a human hair as the width of that hair does to the height of a human.

    “Being able to craft objects on the nanometer scale with state-of-the-art equipment is going to enable extraordinary experiments on the campus,” says David Awschalom, the Liew Family Professor in Molecular Engineering and IME’s deputy director for space, infrastructure, and facilities.

    Large nanofacility

    Support for the 10,000-square-foot facility in the William Eckhardt Research Center came partly from a $15 million gift from the Pritzker Foundation. The National Science Foundation provided an additional $5 million to establish the Soft and Hybrid Nanotechnology Experimental Resource, a partnership between UChicago and Northwestern University. The NSF grant provides funding for support staff and training for external industrial and academic users who seek to develop nanostructure fabrication capabilities at the Pritzker facility and at Northwestern.

    “Today’s clean room is the machine shop of our time,” says Awschalom. “A generation ago it was all about state-of-the-art mills, lathes, making very tiny structures with wire-cutting tools. Today it’s the nanofabrication facility and advanced etching techniques.”

    But launching new technological products requires the involvement of industry, he notes.

    “Universities are fantastic at generating creative concepts and ideas and developing proof-of-concept prototypes. To transition these ideas into society, it will be vital to engage the expertise of startup companies and industry.”

    Facility users will complete training before using the cleanroom. They will pay an hourly fee for access, and may pay additional fees for the use of specific tools and equipment. The proceeds go to support the facility’s operations.

    “Our plans are that this facility will eventually be open 24/7, meaning that it will have access for graduate students as well as external users any time of the day or night,” Cleland says. “Industrial users will be an important part of our user base, and they will also tie in our graduate students to the industrial efforts that are related to their research.”

    Ultra-clean bays

    As an ISO Class 5 cleanroom, the Pritzker facility contains air with 100 or fewer particles measuring five microns (one tenth the width of a human hair) or larger per cubic foot. Outside air typically contains more than a million dust particles of this size per cubic foot.

    The facility sports a bay-and-chase design, with six bays (ultra-clean work spaces) alternating with chases (return-air spaces).

    “One positive impact of our gift from the Pritzker Foundation was our ability to purchase new equipment for the facility,” says Sally Wolcott, the facility’s business manager. “This allowed the PNF to design and plan tool purchases such that bay one is completely empty, giving us room for expansion. We have money already earmarked, and we will continue to acquire tools based on need.”

    The chases serve as giant vacuum cleaners, recirculating the air through nearly 1,000 filters to keep the facility clean. People working in the facility also must wear a special coverall, a hairnet, gloves, and covers for mouth and shoes.

    “In its simplest terms, the Pritzker facility is used for three primary activities,” said Peter Duda, its technical director. “We add materials, we remove materials, and we use different techniques to create patterns in those materials. By layering all of those patterned materials that you’ve added and subtracted, you can create devices.”

    The work is extremely precise. With the facility’s atomic-layer deposition tools, researchers can deposit a film one atomic layer at a time. One such material that can be grown this way is aluminum oxide, “a ceramic very similar to what your coffee cup is made of,” Duda says. But as an electrical insulator it is used in integrated circuits and in superconducting devices.

    Superconducting devices are among the interests of David Schuster, assistant professor in physics and an IME fellow. Schuster plans to install his multi-angle electron-beam evaporation system in the Pritzker facility.

    “It supports the evaporation of superconducting metals such as aluminum, niobium, and tantalum on wafers up to four inches in diameter,” Schuster says. The system can create high-quality superconducting Josephson junctions, which are a key element in superconducting circuits.

    Schuster’s collaboration with Awschalom and Cleland signals more synergy to come between IME and other departments.

    “Working with the Awschalom and Cleland groups has been wonderful, making UChicago one of the premier destinations in the world for quantum physics,” Schuster says.

    See the full article here .

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    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

     
  • richardmitnick 12:39 pm on July 14, 2016 Permalink | Reply
    Tags: , Illinois Precision Medicine Consortium, , U Chicago   

    From U Chicago: “UChicago to support NIH million-person precision medicine study: 

    U Chicago bloc

    University of Chicago

    July 8, 2016
    John Easton

    1
    Photo by Tom Rossiter

    The University of Chicago is one of three Illinois academic institutions that will work together to help launch President Obama’s Precision Medicine Initiative (PMI) Cohort Program to enroll 1 million or more participants in a national research effort designed to find better ways to prevent and treat disease based on lifestyle, environment and genetics.

    A group of health care provider organizations led by Northwestern University, University of Chicago, University of Illinois at Chicago, Ann & Robert H. Lurie Children’s Hospital and the Alliance of Chicago Community Health Services, LLC—to be called the Illinois Precision Medicine Consortium—have signed on to enroll at least 150,000 participants, including healthy people and those with pre-existing diseases, over the coming 4.5 years. Precision medicine is a growing area of study that looks at how an individual’s genetics, environment and lifestyle influence disease treatment and prevention.

    “This range of information at the scale of 1 million people from all walks of life will be an unprecedented resource for researchers working to understand all of the factors that influence health and disease,” said Francis S. Collins, director of the National Institutes of Health (NIH).

    “Over time, data provided by participants will help us answer important health questions, such as why some people with elevated genetic and environmental risk factors for disease still manage to maintain good health, and how people suffering from a chronic illness can maintain the highest possible quality of life,” Collins said. “The more we understand about individual differences, the better able we will be to effectively prevent and treat illness.”

    In the first year, the NIH will provide $55 million in awards nationwide to assemble the partnerships and infrastructure needed for this unprecedented health care effort, called the PMI Cohort Program.

    The Illinois consortium will receive $4.3 million in fiscal 2016, part of a five-year award that will total $45 million, pending progress reviews and availability of funds. The five consortium members, led by Northwestern, will work with their own partner institutions to enroll 150,000 participants. UChicago’s partners include Rush University Medical Center and NorthShore University HealthSystem.

    “Scientifically, this award will enable our teams to build an unprecedented research resource that will help us answer critical questions about how all aspects of our biology and lifestyle affect health and disease,” said Habibul Ahsan, principal investigator for the University of Chicago consortium. “Practically, this award provides an opportunity for the major institutions in Illinois to work together in this historical effort.”

    1
    Prof. Habibul Ahsan. No image credit

    The Illinois consortium is one of four nationwide to receive an award from the NIH for this study. The other consortium leads are Columbia University Health Sciences, University of Arizona and University of Pittsburgh.

    PMI Cohort Program volunteers will be asked to contribute a wide range of health, environment and lifestyle information. They will also be invited to answer questions about their health history and status, share their genomic and other biological information through simple blood and urine tests, and grant access to their clinical data from electronic health records. Mobile health devices and apps will provide additional lifestyle data and environmental exposures in real time. All of this personal information will be protected by privacy and security safeguards.

    As partners in this research, study participants will provide input into study design and implementation. They will have access to a wide range of their individual and aggregated study results. The program will focus not just on disease, but also on ways to increase an individual’s chances of remaining healthy throughout life.

    “What potential participants need to know is that we are equally interested in learning how we can prevent illness in the first place, but when we do get ill, which treatment options are going to work best for each of us individually,” said Eric Dishman, director of the PMI Cohort Program.

    The four networks of health care provider organizations will ensure that participants in the PMI Cohort Program represent the geographic, ethnic, racial and socioeconomic diversity of the country. The networks will include regional and national medical centers, community health centers and medical centers operated by the U.S. Department of Veteran Affairs. Participants also may enroll directly through the Participant Technologies Center later this year.

    The NIH is on course to begin initial enrollment into the PMI Cohort Program in 2016, with the aim of meeting its enrollment goal by the end of 2020.

    The Illinois Precision Medicine Consortium and its health care provider organizations and community partners intend to recruit, consent, examine and collect biospecimens from 10,000 people from diverse ethnic, social and economic backgrounds in 2016. They hope to recruit at least 35,000 additional participants a year from 2017 to 2020.

    Visit the NIH’s PMI Cohort Program website to learn more about the program and sign up for updates.

    See the full article here .

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  • richardmitnick 4:01 pm on June 30, 2016 Permalink | Reply
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    From U Chicago: “Simulations foresee hordes of colliding black holes in observatory’s future” 

    U Chicago bloc

    University of Chicago

    June 24, 2016
    Steve Koppes

    1
    New research predicts that LIGO will detect gravitational waves generated by many more merging black holes in coming years. Courtesy ofLIGO/A. Simonnet

    New calculations predict that the Laser Interferometer Gravitational wave Observatory (LIGO) will detect approximately 1,000 mergers of massive black holes annually once it achieves full sensitivity early next decade.

    LSC LIGO Scientific Collaboration
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
    VIRGO Collaboration bloc

    The prediction, published online June 22 in the journal Nature, is based on computer simulations of more than a billion evolving binary stars. The simulations are based on state-of-the-art modeling of the physics involved, informed by the most recent astronomical and astrophysical observations.

    2
    Assoc. Prof. Daniel Holz. Photo by Robert Kozloff

    “The main thing we find is that what LIGO detected makes sense,” said Daniel Holz, associate professor in physics and astronomy at the University of Chicago and a co-author of the Nature paper. The simulations predict the formation of black-hole binary stars in a range of masses that includes the two already observed. As more LIGO data become available, Holz and his colleagues will be able to test their results more rigorously.

    The paper’s lead author, Krzysztof Belczynski of Warsaw University in Poland, said he hopes the results will surprise him, that they will expose flaws in the work. Their calculations show, for example, that once LIGO reaches full sensitivity, it will detect only one pair of colliding neutron stars for every 1,000 detections of the far more massive black-hole collisions.

    “Actually, I would love to be proven wrong on this issue. Then we will learn a lot,” Belczynski said.

    Forming big black holes

    The new Nature paper, which includes co-authors Tomasz Bulik of Warsaw University and Richard O’Shaughnessy of the Rochester Institute of Technology, describes the most likely black-hole formation scenario that generated the first LIGO gravitational-wave detection in September 2015. That detection confirmed a major prediction of Albert Einstein’s 1915 general theory of relativity.

    The paper is the most recent in a series of publications, topping a decade of analyses where Holz, Belczynski and their associates theorize that the universe has produced many black-hole binaries in the mass range that are close enough to Earth for LIGO to detect.

    “Here we simulate binary stars, how they evolve, turn into black holes and eventually get close enough to crash into each other and make gravitational waves that we would observe,” Holz said.

    The simulations show that the formation and evolution of a typical system of binary stars results in a merger of similar masses, and after similarly elapsed times, to the event that LIGO detected last September. These black hole mergers have masses ranging from 20 to 80 times more than the sun.

    LIGO will begin recording more gravitational-wave-generating events as the system becomes more sensitive and operates for longer periods of time. LIGO will go through successive upgrades over the coming years, and is expected to reach its design sensitivity by 2020. By then, the Nature study predicts that LIGO might be detecting more than 100 black hole collisions annually.

    LIGO has detected big black holes and big collisions, with a combined mass greater than 30 times that of the sun. These can only be formed out of big stars.

    “To make those you need to have low metallicity stars, which just means that these stars have to be relatively pristine,” Holz said. The Big Bang produced mainly hydrogen and helium, which eventually collapsed into stars.

    Forging metals

    As these stars burned they forged heavier elements, which astronomers call “metals.” Those stars with fewer metals lose less mass as they burn, resulting in the formation of more massive black holes when they die. That most likely happened approximately two billion years after the Big Bang, before the young universe had time to form significant quantities of heavy metals. Most of those black holes would have merged relatively quickly after their formation.

    LIGO would be unable to detect the ones that merged early and quickly. But if the binaries were formed in large enough numbers, a small fraction would survive for longer periods and would end up merging 11 billion years after the Big Bang (2.8 billion years ago), recently enough for LIGO to detect.

    “That’s in fact what we think happened,” Holz said. Statistically speaking, “it’s the most likely scenario.” He added, however, that the universe continues to produce binary stars in local, still pristine pockets of low metallicity that resemble conditions of the early universe.

    “In those pockets you can make these big stars, make the binaries, and then they’ll merge right away and we would detect those as well.”

    Belczynski, Holz and collaborators have based their simulations on what they regard as the best models available. They assume “isolated formation,” which involves two stars forming in a binary, evolving in tandem into black holes, and eventually merging with a burst of gravitational wave emission. A competing model is “dynamical formation,” which focuses on regions of the galaxy that contain a high density of independently evolving stars. Eventually, many of them will find each other and form binaries.

    “There are dynamical processes by which those black holes get closer and closer and eventually merge,” Holz said. Identifying which black holes merged under which scenario is difficult. One potential method would entail examining the black holes’ relative spins. Binary stars that evolved dynamically are expected to have randomly aligned spins; detecting a preference for aligned spins would be clear evidence in favor of the isolated evolutionary model.

    LIGO is not yet able to precisely measure black hole spin alignment, “but we’re starting to get there,” Holz said. “This study represents the first steps in the birth of the entirely new field of gravitational wave astronomy. We have been waiting for a century, and the future has finally arrived.”

    Citation: The first gravitational-wave source from the isolated evolution of two stars in the 40-100 solar mass range, by Krzysztof Belczynski, Daniel E. Holz, Tomasz Bulik, and Richard O’Shaughnessy,” Nature, Vol. 534, pp. 512-515, June 23, 2016, doi:10.1038/nature18322.

    Funding: National Science Centre Poland and National Science Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

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    U Chicago Campus

    An intellectual destination

    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

     
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