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  • richardmitnick 6:41 am on April 3, 2021 Permalink | Reply
    Tags: , , , University of Michigan   

    From University of Michigan : “From stardust to pale blue dot- Carbon’s interstellar journey to Earth” 

    U Michigan bloc

    From University of Michigan

    April 2, 2021

    Morgan Sherburne
    morganls@umich.edu

    We are made of stardust [Carl Sagan], the saying goes, and a pair of studies including University of Michigan research finds that may be more true than we previously thought.

    1
    Carbon. https://www.britannica.com/science/carbon-chemical-element

    The first study, led by U-M researcher Jie (Jackie) Li and published in Science Advances, finds that most of the carbon on Earth was likely delivered from the interstellar medium, the material that exists in space between stars in a galaxy. This likely happened well after the protoplanetary disk, the cloud of dust and gas that circled our young sun and contained the building blocks of the planets, formed and warmed up.

    Carbon was also likely sequestered into solids within one million years of the sun’s birth—which means that carbon, the backbone of life on earth, survived an interstellar journey to our planet.

    Previously, researchers thought carbon in the Earth came from molecules that were initially present in nebular gas, which then accreted into a rocky planet when the gases were cool enough for the molecules to precipitate. Li and her team, which includes U-M astronomer Edwin Bergin, Geoffrey Blake of California Institute of Technology(US), Fred Ciesla of the University of Chicago (US) and Marc Hirschmann of the University of Minnesota (US), point out in this study that the gas molecules that carry carbon wouldn’t be available to build the Earth because once carbon vaporizes, it does not condense back into a solid.

    “The condensation model has been widely used for decades. It assumes that during the formation of the sun, all of the planet’s elements got vaporized, and as the disk cooled, some of these gases condensed and supplied chemical ingredients to solid bodies. But that doesn’t work for carbon,” said Li, a professor in the U-M Department of Earth and Environmental Sciences.

    Much of carbon was delivered to the disk in the form of organic molecules. However, when carbon is vaporized, it produces much more volatile species that require very low temperatures to form solids. More importantly, carbon does not condense back again into an organic form. Because of this, Li and her team inferred most of Earth’s carbon was likely inherited directly from the interstellar medium, avoiding vaporization entirely.

    To better understand how Earth acquired its carbon, Li estimated the maximum amount of carbon Earth could contain. To do this, she compared how quickly a seismic wave travels through the core to the known sound velocities of the core. This told the researchers that carbon likely makes up less than half a percent of Earth’s mass. Understanding the upper bounds of how much carbon the Earth might contain tells the researchers information about when the carbon might have been delivered here.

    “We asked a different question: We asked how much carbon could you stuff in the Earth’s core and still be consistent with all the constraints,” Bergin said, professor and chair of the U-M Department of Astronomy. “There’s uncertainty here. Let’s embrace the uncertainty to ask what are the true upper bounds for how much carbon is very deep in the Earth, and that will tell us the true landscape we’re within.”

    A planet’s carbon must exist in the right proportion to support life as we know it. Too much carbon, and the Earth’s atmosphere would be like Venus, trapping heat from the sun and maintaining a temperature of about 880 degrees Fahrenheit. Too little carbon, and Earth would resemble Mars: an inhospitable place unable to support water-based life, with temperatures around minus 60.

    In a second study by the same group of authors, but led by Hirschmann of the University of Minnesota, the researchers looked at how carbon is processed when the small precursors of planets, known as planetesimals, retain carbon during their early formation. By examining the metallic cores of these bodies, now preserved as iron meteorites, they found that during this key step of planetary origin, much of the carbon must be lost as the planetesimals melt, form cores and lose gas. This upends previous thinking, Hirschmann says.

    “Most models have the carbon and other life-essential materials such as water and nitrogen going from the nebula into primitive rocky bodies, and these are then delivered to growing planets such as Earth or Mars,” said Hirschmann, professor of earth and environmental sciences. “But this skips a key step, in which the planetesimals lose much of their carbon before they accrete to the planets.”

    Hirschmann’s study was recently published in PNAS.

    “The planet needs carbon to regulate its climate and allow life to exist, but it’s a very delicate thing,” Bergin said. “You don’t want to have too little, but you don’t want to have too much.”

    Bergin says the two studies both describe two different aspects of carbon loss—and suggest that carbon loss appears to be a central aspect in constructing the Earth as a habitable planet.

    “Answering whether or not Earth-like planets exist elsewhere can only be achieved by working at the intersection of disciplines like astronomy and geochemistry,” said Ciesla, a U. of C. professor of geophysical sciences. “While approaches and the specific questions that researchers work to answer differ across the fields, building a coherent story requires identifying topics of mutual interest and finding ways to bridge the intellectual gaps between them. Doing so is challenging, but the effort is both stimulating and rewarding.”

    Blake, a co-author on both studies and a Caltech professor of cosmochemistry and planetary science, and of chemistry, says this kind of interdisciplinary work is critical.

    “Over the history of our galaxy alone, rocky planets like the Earth or a bit larger have been assembled hundreds of millions of times around stars like the Sun,” he said. “Can we extend this work to examine carbon loss in planetary systems more broadly? Such research will take a diverse community of scholars.”

    Funding sources for this collaborative research include the National Science Foundation, NASA’s Exoplanets Research Program, NASA’s Emerging Worlds Program and the NASA Astrobiology Program.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 3:25 pm on December 3, 2020 Permalink | Reply
    Tags: "Mapping quantum structures with light to unlock their capabilities", A new tool uses light to map out electronic structures of crystals could reveal capabilities of emerging quantum materials and pave the way for advanced energy technologies and quantum computers., University of Marburg (DE) [Philipps-Universität Marburg], University of Michigan, University of Regensburg (DE) [Universität Regensburg]   

    From University of Michigan, University of Regensburg (DE) [Universität Regensburg] and University of Marburg (DE) [Philipps-Universität Marburg] : “Mapping quantum structures with light to unlock their capabilities” 

    U Michigan bloc

    From University of Michigan

    1
    University of Regensburg (DE) [Universität Regensburg]

    3

    University of Marburg (DE) [Philipps-Universität Marburg]

    December 3, 2020

    Nicole Casal Moore
    ncmoore@umich.edu

    Kate McAlpine
    kmca@umich.edu

    A new tool that uses light to map out the electronic structures of crystals could reveal the capabilities of emerging quantum materials and pave the way for advanced energy technologies and quantum computers, according to researchers at the University of Michigan, University of Regensburg (DE) [Universität Regensburg] and University of Marburg (DE) [Philipps-Universität Marburg].

    1
    Quantum combs illuminated: Upon light excitation (red and yellow beams), electrons are discovered to form comb-like wave patterns. The narrow width of the comb lines enables detecting (illuminated peaks) super-resolution images of quantum-material properties – much sharper than earlier efforts. Credit: Markus Borsch, Quantum Science Theory Lab.

    A paper on the work is published in Science.

    Applications include LED lights, solar cells and artificial photosynthesis.

    “Quantum materials could have an impact way beyond quantum computing,” said Mackillo Kira, professor of electrical engineering and computer science at the University of Michigan, who led the theory side of the new study. “If you optimize quantum properties right, you can get 100% efficiency for light absorption.”

    Silicon-based solar cells are already becoming the cheapest form of electricity, although their sunlight-to-electricity conversion efficiency is rather low, about 30%. Emerging “2D” semiconductors, which consist of a single layer of crystal, could do that much better—potentially using up to 100% of the sunlight. They could also elevate quantum computing to room temperature from the near-absolute-zero machines demonstrated so far.

    “New quantum materials are now being discovered at a faster pace than ever,” said Rupert Huber, professor of physics at the University of Regensburg (DE) , who led the experimental work. “By simply stacking such layers one on top of the other under variable twist angles, and with a wide selection of materials, scientists can now create artificial solids with truly unprecedented properties.”

    The ability to map these properties down to the atoms could help streamline the process of designing materials with the right quantum structures. But these ultrathin materials are much smaller and messier than earlier crystals, and the old analysis methods don’t work. Now, 2D materials can be measured with the new laser-based method at room temperature and pressure.

    The measurable operations include processes that are key to solar cells, lasers and optically driven quantum computing. Essentially, electrons pop between a “ground state,” in which they cannot travel, and states in the semiconductor’s “conduction band,” in which they are free to move through space. They do this by absorbing and emitting light.

    The quantum mapping method uses a 100 femtosecond (100 quadrillionths of a second) pulse of red laser light to pop electrons out of the ground state and into the conduction band. Next the electrons are hit with a second pulse of infrared light. This pushes them so that they oscillate up and down an energy “valley” in the conduction band, a little like skateboarders in a halfpipe.

    The team uses the dual wave/particle nature of electrons to create a standing wave pattern that looks like a comb. They discovered that when the peak of this electron comb overlaps with the material’s band structure—its quantum structure—electrons emit light intensely. That powerful light emission along, with the narrow width of the comb lines, helped create a picture so sharp that researchers call it super-resolution.

    By combining that precise location information with the frequency of the light, the team was able to map out the band structure of the 2D semiconductor tungsten diselenide. Not only that, but they could also get a read on each electron’s orbital angular momentum through the way the front of the light wave twisted in space. Manipulating an electron’s orbital angular momentum, known also as a pseudospin, is a promising avenue for storing and processing quantum information.

    In tungsten diselenide, the orbital angular momentum identifies which of two different “valleys” an electron occupies. The messages that the electrons send out can show researchers not only which valley the electron was in but also what the landscape of that valley looks like and how far apart the valleys are, which are the key elements needed to design new semiconductor-based quantum devices.

    For instance, when the team used the laser to push electrons up the side of one valley until they fell into the other, the electrons emitted light at that drop point, too. That light gives clues about the depths of the valleys and the height of the ridge between them. With this kind of information, researchers can figure out how the material would fare for a variety of purposes.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 3:07 pm on December 2, 2020 Permalink | Reply
    Tags: "Rocks may hold clues to Earth’s galactic history", After it’s kicked the nucleus moves a tiny distance—from just a few microns to a few hundred in length., An extremely interesting question is what has Earth encountered in its path around the galaxy?, , As the nucleus recoils within the mineral it makes a tiny path of destruction through the rock’s crystal lattice., Every once in a while one of these atmospheric neutrinos will hit a nucleus., Finding these structures in rocks and then determining the rocks’ age could help scientists pinpoint when an event occurred., , Occasionally one of these neutrinos will interact with an atomic nucleus in the ancient mineral leaving a trace within the rock’s crystalline structure., Our solar system is revolving around the galaxy once every 250 million years., , Some of these particles are neutrinos., The Earth is constantly showered with cosmic rays., The same idea could also be used to search for dark matter the researchers say., The study came out of Spitz and Jordan’s hope to use paleo-detectors to observe proton decay a big question facing particle physics., University of Michigan   

    From University of Michigan via Futurity: “Rocks may hold clues to Earth’s galactic history” 

    U Michigan bloc

    From University of Michigan

    via

    Futurity

    December 2nd, 2020
    Morgan Sherburne

    1
    Credit: Sindy Süßengut/Unsplash.

    If you want to understand a part of Earth’s galactic history, you may be able to find the answer in the crystal structure of a rock, research shows.

    The study outlines a method using paleo-detectors, an idea inspired by work from the 1960s, which used ancient minerals to search for new physics.

    The idea is this: The Earth is constantly showered with cosmic rays.

    Cosmic rays produced by high-energy astrophysics sources (ASPERA collaboration – AStroParticle ERAnet)

    Cosmic rays are particles produced by an energetic universe, one in which stars explode in supernovae; supermassive black holes at the centers of galaxies accelerate particles to near the speed of light; and neutron stars collide and produce bright flashes of gamma rays and other energetic particles.

    “There are energetic particles produced in cosmic events all the time: neutron star mergers and black holes and active galactic nuclei,” says lead author Joshua Spitz, a particle physicist and assistant professor of physics at University of Michigan. “Some of those energetic particles reach the Earth and interact with the atmosphere, producing showers of particles which rain down on us all the time.”

    Neutrinos and rock’s crystal structure

    Some of these particles are neutrinos, which are fundamental particles that only interact with matter very weakly. As a result, these atmospheric neutrinos can pass through the Earth without interacting, allowing them to reach ancient minerals deep in the Earth.

    Occasionally, one of these neutrinos will interact with an atomic nucleus in the ancient mineral, leaving a trace within the rock’s crystalline structure. By examining these traces in excavated rocks, scientists can study the flux of cosmic radiation on Earth over time. The researchers’ method appears in Physical Review Letters.

    “About a hundred billion neutrinos from the sun pass through the tip of your finger every second, but almost none of them interact. The same applies to atmospheric neutrinos, which rarely interact. However, every once in a while, one of these atmospheric neutrinos will hit a nucleus,” says coauthor and graduate student Johnathon Jordan. “And when they do, they give the nucleus a kick.”

    After it’s kicked, the nucleus moves a tiny distance—from just a few microns to a few hundred in length. A human hair is about 70 microns wide. As the nucleus recoils within the mineral, it makes a tiny path of destruction through the rock’s crystal lattice.

    Finding these structures in rocks and then determining the rocks’ age could help scientists pinpoint when an event occurred that might have increased cosmic ray exposure during a certain period of Earth’s history—and answer broader questions about the rate of cosmic rays and radiation that hit the Earth over time, Spitz says.

    “It’s a big question: has that cosmic ray rate changed as a function of time? Has it always been the same rate, or was it bigger in the past? Was there a single event that caused it to increase for a short amount of time, or has it been slowly increasing or decreasing?” Spitz says. “These are questions we don’t really know the answers to.”

    Observations of atmospheric neutrino damage within crystals haven’t happened yet, but it would be similar to the damage caused by the spontaneous fission of uranium-238, Jordan says. During this fission, the heavy nucleus of uranium-238 splits in two, and each half shoots outward, away from each other, and creates tiny scars in the rock’s crystalline structure. Scientists use these tracks to determine the age of rocks.

    Paleo-detectors and Earth’s galactic history

    The same idea could also be used to search for dark matter, the researchers say. Currently, one method to search for dark matter is to monitor for dark matter particles as they pass through detectors filled with argon or xenon buried deep underground—a pricey endeavor, Jordan says, because argon and xenon are expensive, and because the detectors need to be big.

    “You want these detectors big, and you want them to be able to run for a long time, because you want them to have as much exposure as possible,” Jordan says. “What paleo-detectors do is they flip that script. At most, the rocks are 100 grams or a kilogram. And instead of waiting 10 years, we’re waiting a billion years. The novelty of paleo-detectors is that you win not by having a big detector, but by having a really long exposure time.”

    The study came out of Spitz and Jordan’s hope to use paleo-detectors to observe proton decay, a big question facing particle physics. Typically, physicists monitor huge tanks of water for flashes of light that could signify proton decay, but they realized you might be able to survey hundreds of millions of years’ worth of rocks for tiny etches of damage that could signify the same thing. But when the researchers looked into this idea, they found they couldn’t discern the signature made by potential proton decay from damage made by atmospheric neutrinos.

    “This article is actually the result of turning lemons into lemonade,” Spitz says. “These atmospheric neutrinos were the background of the search we were originally interested in.”

    Instead, the team realized this method could provide a window into Earth’s history in a different way.

    “Our solar system is revolving around the galaxy once every 250 million years,” he says. “An extremely interesting question is, what has Earth encountered in its path around the galaxy?”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 1:45 pm on November 29, 2020 Permalink | Reply
    Tags: "Our Solar System Is Going to Totally Disintegrate Sooner Than We Thought", , , , , , , , University of Michigan   

    From University of Michigan, Caltech and UCLA via Science Alert (AU):”Our Solar System Is Going to Totally Disintegrate Sooner Than We Thought” 

    U Michigan bloc

    From University of Michigan

    and

    Caltech Logo

    Caltech

    and

    UCLA bloc

    UCLA

    via

    ScienceAlert

    Science Alert (AU)

    29 NOVEMBER 2020
    MICHELLE STARR

    Milky Way Credits: NASA/JPL-Caltech /ESO R. Hurt. The bar is visible in this image.

    1
    A white dwarf star after ejecting its mass to form a planetary nebula. Credit: ESO/P. Weilbacher/AIP.

    Although the ground beneath our feet feels solid and reassuring (most of the time), nothing in this Universe lasts forever.

    One day, our Sun will die, ejecting a large proportion of its mass before its core shrinks down into a white dwarf, gradually leaking heat until it’s nothing more than a cold, dark, dead lump of rock, a thousand trillion years later.

    But the rest of the Solar System will be long gone by then. According to new simulations, it will take just 100 billion years for any remaining planets to skedaddle off across the galaxy, leaving the dying Sun far behind.

    Astronomers and physicists have been trying to puzzle out the ultimate fate of the Solar System for at least hundreds of years.

    “Understanding the long-term dynamical stability of the solar system constitutes one of the oldest pursuits of astrophysics, tracing back to Newton himself, who speculated that mutual interactions between planets would eventually drive the system unstable,” wrote astronomers Jon Zink of the University of California, Los Angeles, Konstantin Batygin of Caltech and Fred Adams of the University of Michigan in The Astronomical Journal.

    But that’s a lot trickier than it might seem. The greater the number of bodies that are involved in a dynamical system, interacting with each other, the more complicated that system grows and the harder it is to predict. This is called the N-body problem.

    Because of this complexity, it’s impossible to make deterministic predictions of the orbits of Solar System objects past certain timescales. Beyond about five to 10 million years, certainty flies right out the window.

    But, if we can figure out what’s going to happen to our Solar System, that will tell us something about how the Universe might evolve, on timescales far longer than its current age of 13.8 billion years.

    In 1999, astronomers predicted [Science] that the Solar System would slowly fall apart over a period of at least a billion billion – that’s 10^18, or a quintillion – years. That’s how long it would take, they calculated, for orbital resonances from Jupiter and Saturn to decouple Uranus.

    According to Zink’s team, though, this calculation left out some important influences that could disrupt the Solar System sooner.

    Firstly, there’s the Sun.

    In about 5 billion years, as it dies, the Sun will swell up into a red giant, engulfing Mercury, Venus and Earth. Then it will eject nearly half its mass, blown away into space on stellar winds; the remaining white dwarf will be around just 54 percent of the current solar mass.

    This mass loss will loosen the Sun’s gravitational grip on the remaining planets, Mars and the outer gas and ice giants, Jupiter, Saturn, Uranus, and Neptune.

    Secondly, as the Solar System orbits the galactic centre, other stars ought to come close enough to perturb the planets’ orbits, around once every 23 million years.

    “By accounting for stellar mass loss and the inflation of the outer planet orbits, these encounters will become more influential,” the researchers wrote.

    “Given enough time, some of these flybys will come close enough to disassociate – or destabilise – the remaining planets.”

    With these additional influences accounted for in their calculations, the team ran 10 N-body simulations for the outer planets (leaving out Mars to save on computation costs, since its influence should be negligible), using the powerful Shared Hoffman2 Cluster.

    3
    Hoffman2 Cluster. Credit: UCLA.

    These simulations were split into two phases: up to the end of the Sun’s mass loss, and the phase that comes after.

    Although 10 simulations isn’t a strong statistical sample, the team found that a similar scenario played out each time.

    After the Sun completes its evolution into a white dwarf, the outer planets have a larger orbit, but still remain relatively stable. Jupiter and Saturn, however, become captured in a stable 5:2 resonance – for every five times Jupiter orbits the Sun, Saturn orbits twice (that eventual resonance has been proposed many times, not least by Isaac Newton himself).

    These expanded orbits, as well as characteristics of the planetary resonance, makes the system more susceptible to perturbations by passing stars.

    After 30 billion years, such stellar perturbations jangle those stable orbits into chaotic ones, resulting in rapid planet loss. All but one planet escape their orbits, fleeing off into the galaxy as rogue planets.

    That last, lonely planet sticks around for another 50 billion years, but its fate is sealed. Eventually, it, too, is knocked loose by the gravitational influence of passing stars. Ultimately, by 100 billion years after the Sun turns into a white dwarf, the Solar System is no more.

    That’s a significantly shorter timeframe than that proposed in 1999. And, the researchers carefully note, it’s contingent on current observations of the local galactic environment, and stellar flyby estimates, both of which may change. So it’s by no means engraved in stone.

    Even if estimates of the timeline of the Solar System’s demise do change, however, it’s still many billions of years away. The likelihood of humanity surviving long enough to see it is slim.

    Sleep tight!

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please support STEM education in your local school system

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 9:03 am on November 3, 2020 Permalink | Reply
    Tags: "Most isolated massive stars are kicked out of their clusters", , , , , University of Michigan   

    From University of Michigan: “Most isolated massive stars are kicked out of their clusters” 

    U Michigan bloc

    From University of Michigan

    October 29, 2020
    Morgan Sherburne
    morganls@umich.edu

    1
    Massive star cluster called Westerlund 1. Credit: NASA/ESA Hubble.

    A pair of University of Michigan studies reveals how some massive stars—stars eight or more times the mass of our sun—become isolated in the universe: most often, their star clusters kick them out.

    Massive stars typically reside in clusters. Isolated massive stars are called field massive stars. The papers published by U-M students examined most of these stars in the Small Magellanic Cloud, a dwarf galaxy near the Milky Way.

    smc

    Small Magellanic Cloud. 10 November 2005. NASA/ESA Hubble and Digitized Sky Survey 2

    The studies, appearing in the same issue of The Astrophysical Journal, reveal how these field massive stars originate, or become so isolated.

    A Search for In Situ Field OB Star Formation in the Small Magellanic Cloud

    Runaway OB Stars in the Small Magellanic Cloud: Dynamical versus Supernova Ejections

    Understanding how field massive stars become isolated—whether they form in isolation or whether they become isolated by being ejected from a star cluster—will help astronomers probe the conditions in which massive stars are formed. Understanding this and cluster formation is critical for understanding how galaxies evolve.

    “About a quarter of all massive stars appear to be isolated, and that’s our big question,” said recent undergraduate Johnny Dorigo Jones. “How they’re found to be isolated, and how they got there.”

    Dorigo Jones shows in his paper that the vast majority of field massive stars are “runaways,” or stars ejected from clusters. Graduate student Irene Vargas-Salazar looked for field massive stars that may have formed in relative isolation by looking for evidence of tiny clusters around them. That means these relatively isolated stars could have formed in conjunction with these smaller stars. But she found very few of these faint clusters.

    “Because massive stars require a lot of material to form, there are usually a lot of smaller stars around them,” Vargas-Salazar said. “My project asks specifically how many of these field massive stars could have formed in the field.”

    Dorigo Jones examined how field massive stars are ejected from clusters. He looks at the two different mechanisms that produce runaways: dynamical ejection and binary supernova ejection. In the first, the massive stars are ejected from their clusters—by up to half a million miles per hour—because of unstable orbital configurations of stellar groups. In the second, a massive star is ejected when a binary pair has one star that explodes and shoots its companion out into space.

    “By having the velocities and the masses of our stars, we’re able to compare the distributions of those parameters to the model predictions to determine the certain contributions from each of the ejection mechanisms,” Dorigo Jones said.

    He found that dynamical ejections—ejections caused by unstable orbital configurations—were about 2 to 3 times more numerous than supernova ejections. But Dorigo Jones also found the first observational data that shows a large fraction of the field massive stars came from a combination of both dynamical and supernova ejections.

    “These have been studied in the past but we have now set the first observational constraints on the numbers of these two-step runaways,” he said. “The way we reach that conclusion is we’re essentially seeing that the stars that trace the supernova ejections in our sample are a bit too numerous and too fast compared to the model predictions. You can imagine this being remedied by these stars being reaccelerated upon a supernova kick, having first been dynamically ejected.”

    The researchers found that potentially up to half of the stars first thought to be from supernova ejections were first dynamically ejected.

    Vargas-Salazar’s findings also support the idea that most field massive stars are runaways, but she looked at opposite conditions: she looked for field massive stars that formed in relative isolation in tiny clusters of smaller stars, where the massive target star is, called the “tip of the iceberg, or TIB clusters. She did this using two algorithms, “friends-of-friends” and “nearest neighbors,” to search for those clusters around 310 field massive stars in the Small Magellanic Cloud.

    The “friends-of-friends” algorithm measures the number density of stars by counting how many stars there are at a specific distance from the target star and then doing the same for those stars in turn. The more tightly packed the stars are, the more likely it is to be a cluster. The “nearest neighbors” algorithm measures the number density of stars between the target star and its nearest 20 companions. The more compact and denser the group, the more likely they are to be clusters, Vargas-Salazar said.

    Using statistical tests, Vargas-Salazar compared these observations with three random-field datasets and compared the known runaway massive stars to nonrunaways. She found that only a few of the field massive stars appeared to have TIB clusters around them, suggesting that very few actually formed in the field. The balance of the field stars must have originated as runaways.

    “In the end, we showed that 5% or less of the stars had TIB clusters. Instead, our findings imply that the majority of stars in field samples could be runaways,” Vargas-Salazar said. “Our findings are actually supporting the result that Johnny found, wrapped in a neat little bow.”

    Vargas-Salazar’s findings provide part of the answer to the question of how massive stars form, says Sally Oey, senior author on both of the papers and professor of astronomy at U-M.

    “Johnny and Irene’s work are flip sides of the same coin,” Oey said. “Irene’s numbers are consistent with Johnny’s in that the vast majority of field massive stars are runaways, but that a few are not. This is a critical finding for understanding how massive stars and clusters form, and in what conditions.”

    Both Dorigo Jones and Vargas-Salazar’s work was supported by the National Science Foundation.

    See the full article here .


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    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 11:40 am on September 29, 2020 Permalink | Reply
    Tags: "Machine learning homes in on catalyst interactions to accelerate materials development", , , , , , University of Michigan   

    From University of Michigan via phys.org: “Machine learning homes in on catalyst interactions to accelerate materials development” 

    U Michigan bloc

    From University of Michigan

    via


    From phys.org

    September 29, 2020

    1
    Credit: CC0 Public Domain

    A machine learning technique rapidly rediscovered rules governing catalysts that took humans years of difficult calculations to reveal—and even explained a deviation. The University of Michigan team that developed the technique believes other researchers will be able to use it to make faster progress in designing materials for a variety of purposes.

    “This opens a new door, not just in understanding catalysis, but also potentially for extracting knowledge about superconductors, enzymes, thermoelectrics, and photovoltaics,” said Bryan Goldsmith, an assistant professor of chemical engineering, who co-led the work with Suljo Linic, a professor of chemical engineering.

    The key to all of these materials is how their electrons behave. Researchers would like to use machine learning techniques to develop recipes for the material properties that they want. For superconductors, the electrons must move without resistance through the material. Enzymes and catalysts need to broker exchanges of electrons, enabling new medicines or cutting chemical waste, for instance. Thermoelectrics and photovoltaics absorb light and generate energetic electrons, thereby generating electricity.

    Machine learning algorithms are typically “black boxes,” meaning that they take in data and spit out a mathematical function that makes predictions based on that data.

    “Many of these models are so complicated that it’s very difficult to extract insights from them,” said Jacques Esterhuizen, a doctoral student in chemical engineering and first author of the paper in the journal Chem. “That’s a problem because we’re not only interested in predicting material properties, we also want to understand how the atomic structure and composition map to the material properties.”

    But a new breed of machine learning algorithm lets researchers see the connections that the algorithm is making, identifying which variables are most important and why. This is critical information for researchers trying to use machine learning to improve material designs, including for catalysts.

    A good catalyst is like a chemical matchmaker. It needs to be able to grab onto the reactants, or the atoms and molecules that we want to react, so that they meet. Yet, it must do so loosely enough that the reactants would rather bind with one another than stick with the catalyst.

    In this particular case, they looked at metal catalysts that have a layer of a different metal just below the surface, known as a subsurface alloy. That subsurface layer changes how the atoms in the top layer are spaced and how available the electrons are for bonding. By tweaking the spacing, and hence the electron availability, chemical engineers can strengthen or weaken the binding between the catalyst and the reactants.

    Esterhuizen started by running quantum mechanical simulations at the National Energy Research Scientific Computing Center. These formed the data set, showing how common subsurface alloy catalysts, including metals such as gold, iridium and platinum, bond with common reactants such as oxygen, hydroxide and chlorine.

    The team used the algorithm to look at eight material properties and conditions that might be important to the binding strength of these reactants. It turned out that three mattered most. The first was whether the atoms on the catalyst surface were pulled apart from one another or compressed together by the different metal beneath. The second was how many electrons were in the electron orbital responsible for bonding, the d-orbital in this case. And the third was the size of that d-electron cloud.

    The resulting predictions for how different alloys bind with different reactants mostly reflected the “d-band” model, which was developed over many years of quantum mechanical calculations and theoretical analysis. However, they also explained a deviation from that model due to strong repulsive interactions, which occurs when electron-rich reactants bind on metals with mostly filled electron orbitals.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 5:40 pm on March 11, 2020 Permalink | Reply
    Tags: A member of a hunter-gatherer group living in southern Africa’s Karoo Desert finds the egg. She eats it and cracks the shell into dozens of pieces which she uses for gifts., An ostrich pecks at the grass and atoms taken up from the shale and into the grass become part of the eggshell the ostrich lays., , , , Humans are just outlandishly social animals., Ostrich eggshell beads and the jewelry made from them basically acted like Stone Age versions of Facebook or Twitter "likes"., , , University of Michigan   

    From University of Michigan: “Stone-age ‘likes’: Study establishes eggshell beads exchanged over 30,000 years” 

    U Michigan bloc

    From University of Michigan

    March 9, 2020
    Morgan Sherburne
    morganls@umich.edu

    1
    Archeologists work at rock shelters at Sehonghong and Melikane in southern Africa. Image credit: Brian Stewart.

    A clump of grass grows on an outcrop of shale 33,000 years ago. An ostrich pecks at the grass, and atoms taken up from the shale and into the grass become part of the eggshell the ostrich lays.

    A member of a hunter-gatherer group living in southern Africa’s Karoo Desert finds the egg. She eats it, and cracks the shell into dozens of pieces. Drilling a hole, she strings the fragments onto a piece of sinew and files them into a string of beads.

    She gifts the ornaments to friends who live to the east, where rainfall is higher, to reaffirm those important relationships. They, in turn, do the same, until the beads eventually end up with distant groups living high in the eastern mountains.

    3
    Ostrich eggshell beads have been used to cement relationships in Africa for more than 30,000 years. Image credit: John Klausmeyer, Yuchao Zhao and Brian Stewart.

    Thirty-three thousand years later, a University of Michigan researcher finds the beads in what is now Lesotho, and by measuring atoms in the beads, provides new evidence for where these beads were made, and just how long hunter-gatherers used them as a kind of social currency.

    In a study published in the Proceedings of the National Academy of Science, U-M paleolithic archeologist Brian Stewart and colleagues establish that the practice of exchanging these ornaments over long distances spans a much longer period of time than previously thought.

    “Humans are just outlandishly social animals, and that goes back to these deep forces that selected for maximizing information, information that would have been useful for living in a hunter-gatherer society 30,000 years ago and earlier,” said Stewart, assistant professor of anthropology and assistant curator of the U-M Museum of Anthropological Archaeology.

    “Ostrich eggshell beads and the jewelry made from them basically acted like Stone Age versions of Facebook or Twitter ‘likes,’ simultaneously affirming connections to exchange partners while alerting others to the status of those relationships.”

    Lesotho is a small country of mountain ranges and rivers. It has the highest average of elevation in the continent and would have been a formidable place for hunter-gatherers to live, Stewart says. But the fresh water coursing through the country and belts of resources, stratified by the region’s elevation, provided protection against swings in climate for those who lived there, as early as 85,000 years ago.

    Anthropologists have long known that contemporary hunter-gatherers use ostrich eggshell beads to establish relationships with others. In Lesotho, archeologists began finding small ornaments made of ostrich eggshell. But ostriches don’t typically live in that environment, and the archeologists didn’t find evidence of those ornaments being made in that region—no fragments of unworked eggshell, or beads in various stages of production.

    So when archeologists began discovering eggshell beads without evidence of production, they suspected the beads arrived in Lesotho through these exchange networks. Testing the beads using strontium isotope analysis would allow the archeologists to pinpoint where they were made.

    Strontium-87 is the daughter isotope of the radioactive element rubidium-87. When rubidium-87 decays it produces strontium-87. Older rocks such as granite and gneiss have more strontium than younger rocks such as basalt. When animals forage from a landscape, these strontium isotopes are incorporated into their tissues.

    Lesotho is roughly at the center of a bullseye-shaped geologic formation called the Karoo Supergroup. The supergroup’s mountainous center is basalt, from relatively recent volcanic eruptions that formed the highlands of Lesotho. Encircling Lesotho are bands of much older sedimentary rocks. The outermost ring of the formation ranges between 325 and 1,000 kilometers away from the Lesotho sites.

    To assess where the ostrich eggshell beads were made, the research team established a baseline of strontium isotope ratios—that is, how much strontium is available in a given location—using vegetation and soil samples as well samples from modern rodent tooth enamel from museum specimens collected from across Lesotho and surrounding areas.

    According to their analysis, nearly 80% of the beads the researchers found in Lesotho could not have originated from ostriches living near where the beads were found in highland Lesotho.

    “These ornaments were consistently coming from very long distances,” Stewart said. “The oldest bead in our sample had the third highest strontium isotope value, so it is also one of the most exotic.”

    Stewart found that some beads could not have come from closer than 325 kilometers from Lesotho, and may have been made as far as 1,000 kilometers away. His findings also establish that these beads were exchanged during a time of climactic upheaval, about 59 to 25 thousand years ago. Using these beads to establish relationships between hunter-gatherer groups ensured one group access to others’ resources when a region’s weather took a turn for the worse.

    “What happened 50,000 years ago was that the climate was going through enormous swings, so it might be no coincidence that that’s exactly when you get this technology coming in,” Stewart said. “These exchange networks could be used for information on resources, the condition of landscapes, of animals, plant foods, other people and perhaps marriage partners.”

    Stewart says while archeologists have long accepted that these exchange items bond people over landscapes in the ethnographic Kalahari, they now have firm evidence that these beads were exchanged over huge distances not only in the past, but for over a long period of time. This study places another piece in the puzzle of how we persisted longer than all other humans, and why we became the globe’s dominant species.

    Stewart’s co-authors include U-M graduate student Yuchao Zhao, as well as Peter Mitchell the University of Oxford, Genevieve Dewar of the University of Toronto Scarborough, and U-M’s James Gleason and Joel Blum.

    See the full article here .


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    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 10:35 am on August 1, 2019 Permalink | Reply
    Tags: , At times renewable energy sources can produce more power than what is needed leaving some solar or wind energy to go to waste., , , , Investing in batteries and other energy storage technologies to capture the excess can be economically viable with proper policy support., , University of Michigan   

    From University of Michigan: “Investing in energy storage for solar, wind power could greatly reduce greenhouse gas emissions” 

    U Michigan bloc

    From University of Michigan

    July 30, 2019
    Jim Erickson
    ericksn@umich.edu

    Written by Wendy Bowyer

    1

    Drive through nearly any corner of America long enough and giant solar farms or rows of wind turbines come into view, all with the goal of increasing the country’s renewable energy use and reducing greenhouse gas emissions.

    But what some may not realize is at times these renewable energy sources can produce more power than what is needed, leaving some solar or wind energy to, in a sense, go to waste. This oversupply condition is a lost opportunity for these clean energy resources to displace pollution from fossil fuel-powered plants.

    But by creating complex models analyzing power systems in California and Texas, University of Michigan scientists show in a study scheduled for online publication July 30 in Nature Communications, that investing in batteries and other energy storage technologies can be economically viable with proper policy support.

    That, in turn, could radically reduce the emissions of greenhouse gases—by up to 90% in one scenario examined by the researchers—and increase the use of solar and wind energy at a time when climate change takes on greater urgency.

    “The cost of energy storage is very important,” said study co-author Maryam Arbabzadeh, a postdoctoral fellow at U-M’s School for Environment and Sustainability. “But there are some incentives we could use to make it attractive economically, one being an emissions tax.”

    Arbabzadeh led the research in collaboration with colleagues at Ohio State University and North Carolina State University. Gregory Keoleian, director of U-M’s Center for Sustainable Systems, served as her adviser and one of the co-authors of the study.

    “Electricity generation accounts for 28% of the greenhouse gas emissions in the United States, and given the urgency of climate change it is critical to accelerate the deployment of renewable sources such as wind and solar,” said Keoleian, a professor of environment and sustainability and civil and environmental engineering.

    “This research clearly demonstrates how energy storage technologies can play an important role in reducing renewable curtailment and greenhouse gas emissions from fossil fuel power plants.”

    Arbabzadeh and her fellow researchers created complex models analyzing nine different energy storage technologies. They looked at the environmental effects of renewable curtailment, which is the amount of renewable energy generated but unable to be delivered to meet demand for a variety of reasons.

    They also modeled what would happen if each state would add up to 20 gigawatts of wind and 40 gigawatts of solar capacity, and how all of this would be impacted economically by a carbon dioxide tax of up to $200 per ton.

    What they found was striking.

    Adding 60 gigawatts of renewable energy to California could achieve a 72% carbon dioxide reduction. Then, by adding some energy storage technologies on top of that in California could allow a 90% carbon dioxide reduction. In Texas, energy storage could allow a 57% emissions reduction.

    But for all of this to happen, utility companies would need a reason to invest in energy storage systems, which require large amounts of capital investment. That is where the use of a carbon tax could be helpful, Arbabzadeh said.

    All nine of the energy storage technologies studied, including high-tech batteries, require a significant capital investment and all had different pros and cons. Also adding to the complexity of the research is the different type of generation mix in Texas and California.

    Texas uses some coal and natural gas-fired units. California uses more inflexible resources, like nuclear, geothermal, biomass and hydroelectric energy units, which make its renewable curtailment rates much higher than Texas.

    The work was supported by the National Science Foundation, the Dow Sustainability Fellows Program and the Rackham Predoctoral Fellowship Program.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 2:46 pm on July 22, 2019 Permalink | Reply
    Tags: "A certain amount of material within the universe collapses to form galaxy clusters. But once they are formed these clusters are 'closed boxes.' “, "Scientists Weigh the Balance of Matter in Galaxy Clusters", "This research is powered by more than a decade of telescope investments", A method of weighing the quantities of matter in galaxy clusters — the largest objects in our universe — has shown a balance between the amounts of hot gas stars and other materials., , , , , , Galaxy clusters are the largest objects in the universe each composed of around 1000 massive galaxies., The findings will be crucial to astronomers’ efforts to measure the properties of the universe as a whole., The results are the first to use observational data to measure this balance which was theorized 20 years ago and will yield fresh insight into the relationship between ordinary matter that emits light, , University of Michigan   

    From Carnegie Mellon University: “Scientists Weigh the Balance of Matter in Galaxy Clusters” 

    From Carnegie Mellon University

    July 22, 2019
    Jocelyn Duffy
    Carnegie Mellon University
    jhduffy@andrew.cmu.edu
    412-268-9982

    Beck Lockwood
    University of Birmingham
    0121 414 2772

    1
    Galaxy Cluster Abell 1763. The image shows the galaxy content, produced from SDSS images from g,r, and i bands, overlaid with the extended X-ray emission from XMM.

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude2,788 meters (9,147 ft)


    ESA/XMM Newton

    A method of weighing the quantities of matter in galaxy clusters — the largest objects in our universe — has shown a balance between the amounts of hot gas, stars and other materials.

    The results are the first to use observational data to measure this balance, which was theorized 20 years ago, and will yield fresh insight into the relationship between ordinary matter that emits light and dark matter, and about how our universe is expanding.

    Galaxy clusters are the largest objects in the universe, each composed of around 1,000 massive galaxies. They contain vast amounts of dark matter, along with hot gas and cooler “ordinary matter,” such as stars and cooler gas.

    In a new study, published in Nature Communications, an international team led by astrophysicists from the University of Michigan and the University of Birmingham, and including a Carnegie Mellon University postdoctoral fellow, used data from the Local Cluster Substructure Survey (LoCuSS) to measure the connections between the three main mass components that comprise galaxy clusters — dark matter, hot gas and stars.

    Members of the research team spent 12 years gathering data, which span a factor of 10 million in wavelength, using the Chandra and XMM-Newton satellites, the ROSAT All-sky survey, Subaru telescope, United Kingdom Infrared Telescope (UKIRT), Mayall telecope, the Sunyaev Zeldovich Array and the Planck satellite. Using sophisticated statistical models and algorithms built by Arya Farahi during his doctoral studies at the University of Michigan, the team was able to conclude that the sum of gas and stars across the clusters that they studied is a nearly fixed fraction of the dark matter mass. This means that as stars form, the amount of hot gas available will decrease proportionally.

    NASA/Chandra X-ray Telescope


    ESA/XMM Newton


    ROSAT X-ray satellite built by DLR , with instruments built by West Germany, the United Kingdom and the United States



    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level



    UKIRT, located on Mauna Kea, Hawai’i, USA as part of Mauna Kea Observatory,4,207 m (13,802 ft) above sea level



    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)


    3
    Sunyaev Zeldovich Array

    ESA/Planck 2009 to 2013

    Using sophisticated statistical models and algorithms built by Arya Farahi during his doctoral studies at the University of Michigan, the team was able to conclude that the sum of gas and stars across the clusters that they studied is a nearly fixed fraction of the dark matter mass. This means that as stars form, the amount of hot gas available will decrease proportionally.

    “This validates the predictions of the prevailing cold dark matter theory. Everything is consistent with our current understanding of the universe,” said Farahi, who is a McWilliams Postdoctoral Fellow in the Department of Physics at Carnegie Mellon.

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    “A certain amount of material within the universe collapses to form galaxy clusters. But once they are formed, these clusters are ‘closed boxes.’ The hot gas has either formed stars, or still remains as gas, but the overall quantity remains constant,” said Graham Smith of the School of Physics and Astronomy at the University of Birmingham, and Principal Investigator of LoCuSS.

    “This research is powered by more than a decade of telescope investments,” added August E. Evrard, of the University of Michigan. “Using this high-quality data, we were able to characterize 41 nearby galaxy clusters and find a special relationship, specifically anti-correlated behaviour between the mass in stars and the mass in hot gas. This is significant because these two measurements together give us the best indication of the total system mass.”

    The findings will be crucial to astronomers’ efforts to measure the properties of the universe as a whole. By gaining a better understanding of the internal physics of galaxy clusters, researchers will be able to better understand the behaviour of dark energy and the processes behind the expansion of the universe.

    “Galaxy clusters are intrinsically fascinating, but in many ways still mysterious objects,” Smith said. “Unpicking the complex astrophysics governing these objects will open many doors onto a broader understanding of the universe. Essentially, if we want to be able to claim that we understand how the universe works, we need to understand galaxy clusters.”

    Data of the kind studied by the team will grow by several orders of magnitude over the coming decades thanks to next-generation telescopes, such as the Large Synoptic Survey Telescope (LSST), which is currently under construction in Chile, and e-ROSITA, a new x-ray satellite. Both will begin observations in the early 2020s.

    LSST


    LSST Camera, built at SLAC



    LSST telescope, currently under construction on the El Peñón peak at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.


    LSST Data Journey, Illustration by Sandbox Studio, Chicago with Ana Kova

    “These measurements are laying a foundation for precise science with clusters of galaxies,” said Professor Alexis Finoguenov, a member of the team based at the University of Helsinki.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    https://www.cmu.edu/index.htmlis a global research university with more than 12,000 students, 95,000 alumni, and 5,000 faculty and staff.
    CMU has been a birthplace of innovation since its founding in 1900.
    Today, we are a global leader bringing groundbreaking ideas to market and creating successful startup businesses.
    Our award-winning faculty members are renowned for working closely with students to solve major scientific, technological and societal challenges. We put a strong emphasis on creating things—from art to robots. Our students are recruited by some of the world’s most innovative companies.
    We have campuses in Pittsburgh, Qatar and Silicon Valley, and degree-granting programs around the world, including Africa, Asia, Australia, Europe and Latin America.

     
  • richardmitnick 10:18 am on September 5, 2018 Permalink | Reply
    Tags: Black body radiation, , , Planck's law of radiative heat transfer has held up well under a century of intense testing but a new analysis has found it fails on the smallest of scales, , , University of Michigan, William & Mary   

    From University of Michigan and William & Mary via Science Alert: “A Fundamental Physics Law Just Failed a Test Using Nanoscale Objects” 

    U Michigan bloc

    University of Michigan

    1

    William & Mary

    via

    ScienceAlert

    From Science Alert

    1
    (Xanya69/istock)

    5 SEP 2018
    MIKE MCRAE

    Planck’s law of radiative heat transfer has held up well under a century of intense testing, but a new analysis has found it fails on the smallest of scales.

    Exactly what this means isn’t all that clear yet, but where laws fail, new discoveries can follow. Such a find wouldn’t just affect physics on an atomic scale – it could impact everything from climate models to our understanding of planetary formation.

    The foundational law of quantum physics was recently put to the test by researchers from William & Mary in Virginia and the University of Michigan, who were curious about whether the age-old rule could describe the way heat radiation was emitted by nanoscale objects.

    Not only does the law fail, the experimental result is 100 times greater than the predicted figure, suggesting nanoscale objects can emit and absorb heat with far greater efficiency than current models can explain.

    “That’s the thing with physics,” says William & Mary physicist Mumtaz Qazilbash.

    “It’s important to experimentally measure something, but also important to actually understand what is going on.”

    Planck is one of the big names in physics. While it’d be misleading to attribute the birth of quantum mechanics to a single individual, his work played a key role in getting the ball rolling.

    Humans have known since ancient times that hot things glow with light. We’ve also understood for quite a while that there’s a relationship between the colour of that light and its temperature.

    To study this in detail, physicists in the 19th century would measure the colour of light inside a black, heated box, watching through a tiny hole. This ‘black body radiation’ provided a reasonably precise measure of that relationship.

    Coming up with simple formulae to describe the wavelengths of colour and their temperatures proved to be rather challenging, and so Planck came at it from a slightly different angle.

    His approach was to treat the way light was absorbed and emitted like a pendulum’s swing, with discrete quantities of energy being soaked up and spat out. Not that he really thought this was the case – it was just a convenient way to model light.

    As strange as it seemed at first, the model worked perfectly. This ‘quantity’ of energy approach generated decades of debate over the nature of reality, and has come to form the underpinnings of physics as we know it.

    Planck’s law of radiative heat transfer informs a theory describing a maximum frequency at which heat energy can be emitted from an object at a given temperature.

    This works extremely well for visible objects separated at a visible distance. But what if we push those objects together, so the space between them isn’t quite a single wavelength of the light being emitted? What happens to that ‘pendulum swing’?

    Physicists well versed in the dynamics of electromagnetism already know weird things happen here in this area, known as the ‘near field’ region.

    For one thing, the relationship between the electrical and magnetic aspects of the electromagnetic field becomes more complex.

    Just how this might affect the way heated objects interact has already been the focus of previous research, which has established some big differences in how heat moves in the near field as compared with the far field observed by Planck.

    But that’s just if the gap is confined to a distance smaller than the wavelength of emitted radiation. What about the size of the objects themselves?

    The researchers had quite a challenge ahead of them. They had to engineer objects smaller than about 10 microns in size – the approximate length of a wave of infrared light.

    They settled on two membranes of silicon nitride a mere half micron thick, separated by a distance that put them well into the far field.

    Heating one and measuring the second allowed them to test Planck’s law with a fair degree of precision.

    “Planck’s radiation law says if you apply the ideas that he formulated to two objects, then you should get a defined rate of energy transfer between the two,” says Qazilbash.

    “Well, what we have observed experimentally is that rate is actually 100 times higher than Planck’s law predicts if the objects are very, very small.”

    Qazilbash likens it to the plucking of a guitar string at different places along its length. “If you pluck it in those places, it’s going to resonate at certain wavelengths more efficiently.”

    The analogy is a useful way to visualise the phenomenon, but understanding the details of the physics behind the discovery could have some big impacts. Not just in nanotechnology, but on a far bigger scale.

    This hyper-efficient rate of energy transfer could feasibly change how we understand heat transfer in the atmosphere, or in a cooling body the size of a planet. The extent of this difference is still a mystery, but one with some potentially profound implications.

    “Wherever you have radiation playing an important role in physics and science, that’s where this discovery is important,” says Qazilbash.

    This research was published in Nature.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
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