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  • richardmitnick 11:18 am on May 7, 2019 Permalink | Reply
    Tags: "A universe is born", , , , , , , Dark Matter and Dark Energy, , , , , , The Planck epoch   

    From Symmetry: “A universe is born” 

    Symmetry Mag
    From Symmetry

    05/07/19
    Diana Kwon

    Take a (brief) journey through the early history of our cosmos.

    Timeline of the Inflationary Universe WMAP

    The universe was a busy place during the first three minutes. The cosmos we see today expanded from a tiny speck to much closer to its current massive size; the elementary particles appeared; and protons and neutrons combined into the first nuclei, filling the universe with the precursors of elements.

    By developing clever theories and conducting experiments with particle colliders, telescopes and satellites, physicists have been able to wind the film of the universe back billions of years—and glimpse the details of the very first moments in the history of our cosmic home.

    Take an abridged tour through this history:

    The Planck epoch
    Time: < 10^-43 seconds

    The Planck Epoch https:// http://www.slideshare.net ericgolob the-big-bang-10535251

    Welcome to the Planck epoch, named after the smallest scale of measurements possible in particle physics today. This is currently the closet scientists can get to the beginning of time.

    Theoretical physicists don’t know much about the earliest moments of the universe. After the Big Bang theory gained popularity, scientists thought that in the first moments, the cosmos was at its hottest and densest and that all four fundamental forces—electromagnetic, weak, strong and gravitational—were combined into a single, unified force. But the current leading theoretical framework for our universe’s beginning doesn’t necessarily require these conditions.

    The universe expands
    Time: From 10^-43 seconds to about 10^-36 seconds

    In this stage, which began either at Planck time or shortly after it, scientists think the universe underwent superfast, exponential expansion in a process known as inflation.

    Inflation

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    Alan Guth, from Highland Park High School and M.I.T., who first proposed cosmic inflation

    HPHS Owls

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

    Alan Guth’s notes:
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    Physicists first proposed the theory of inflation in the 1980s to address the shortcomings of the Big Bang theory, which, despite its popularity, could not explain why the universe was so flat and uniform, and why its different parts began expanding simultaneously.

    During inflation, quantum fluctuations could have stretched out to produce a pattern that later determined the locations of galaxies. It might have been only after this period of inflation the universe became a hot, dense fireball as described in the Big Bang theory.

    The elementary particles are born
    Time: ~10^-36 seconds

    When the universe was still very hot, the cosmos was like a gigantic accelerator, much more powerful than the Large Hadron Collider, running at extremely high energies. In it, the elementary particles we know today were born.

    Scientists think that first came exotic particles, followed by more familiar ones, such as electrons, neutrinos and quarks. It could be that dark matter particles came about during this time.

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    Quarks APS/Alan Stonebraker

    The quarks soon combined, forming the familiar protons and neutrons, which are collectively known as baryons. Neutrinos were able to escape this plasma of charged particles and began traveling freely through space, while photons continued to be trapped by the plasma.

    Standard Model of Particle Physics

    The first nuclei emerge
    Time: ~1 second to 3 minutes

    Scientists think that when the universe cooled enough for violent collisions to subside, protons and neutrons clumped together into nuclei of the light elements—hydrogen, helium and lithium—in a process known as Big Bang nucleosynthesis.

    Protons are more stable than neutrons, due to their lower mass. In fact, a free neutron decays with a 15-minute half-life, while protons may not decay at all, as far as we know.

    So as the particles combined, many protons remained unpaired. As a result, hydrogen—protons that never found a partner—make up around 74% of the mass of “normal” matter in our cosmos. The second most abundant element is helium, which makes up approximately 24%, followed by trace amounts of deuterium, lithium, and helium-3 (helium with a three-baryon core).

    Periodic table Sept 2017. Wikipedia

    Scientists have been able to accurately measure the density of baryons in our universe. Most of those measurements line up with theorists’ estimations of what the quantities ought to be, but there is one lingering issue: Lithium calculations are off by a factor of three. It could be that the measurements are off, but it could also be that something we don’t yet know about happened during this time period to change the abundance of lithium.

    The cosmic microwave background becomes visible
    Time: 380,000 years

    Hundreds of thousands of years after inflation, the particle soup had cooled enough for electrons to bind to nuclei to form electrically neutral atoms. Through this process, which is also known as recombination, photons became free to traverse the universe, creating the cosmic microwave background.

    CMB per ESA/Planck


    ESA/Planck 2009 to 2013

    Today, the CMB is one of the most valuable tools for cosmologists, who probe its depths in search of answers for many of the universe’s lingering secrets, including the nature of inflation and the cause of matter-antimatter asymmetry.

    Shortly after the CMB became detectable, neutral hydrogen particles formed into a gas that filled the universe. Without any objects emitting high-energy photons, the cosmos was plunged into the dark ages for millions of years.

    Dark Energy Camera Enables Astronomers a Glimpse at the Cosmic Dawn. CREDIT National Astronomical Observatory of Japan

    The earliest stars shine
    Time: ~100 million years

    The dark ages ended with the formation of the first stars and the occurrence of reionization, a process through which highly energetic photons stripped electrons off neutral hydrogen atoms.

    Reionization era and first stars, Caltech

    Scientists think that the vast majority of the ionizing photons emerged from the earliest stars. But other processes, such as collisions between dark matter particles, may have also played a role.

    At this time, matter began to form the first galaxies. Our own galaxy, the Milky Way, contains stars that were born when the universe was only several hundred million years old.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Our sun is born
    Time: 9.2 billion years

    3
    NASA

    The sun is one of a few hundred billion stars in the Milky Way. Scientists think it formed from a giant cloud of gas that consisted mostly hydrogen and helium.

    Today
    Time: 13.8 billion years

    Today, our cosmos sits at a cool 2.7 Kelvin (minus 270.42 degrees Celsius). The universe is expanding at an increasing rate, in a manner similar to (but many orders of magnitude slower than) inflation.

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Physicists think that dark energy—a mysterious repulsive force that currently accounts for about 70% of the energy in our universe—is most likely driving that accelerated expansion.

    Dark energy depiction. Image: Volker Springle/Max Planck Institute for Astrophysics/SP)

    See the full article here .


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

    Please help promote STEM in your local schools.


    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:05 pm on March 8, 2018 Permalink | Reply
    Tags: , , , , , , , , , , Dark Matter and Dark Energy, International Women's Day, , , , , ,   

    From PI: Women in STEM-“Celebrating International Women’s Day” 

    4

    Is it not a shame that we need to have a special day to celebrate women when they are so already fantastic and exceptionally brilliant in the physical sciences?

    Check out this blog post-
    https://sciencesprings.wordpress.com/2018/03/08/from-the-conversation-women-in-stem-perish-not-publish-new-study-quantifies-the-lack-of-female-authors-in-scientific-journals/

    “”I have done a couple of STEM events, but there have never been this many girls. There are so many here. It is really empowering. Go girls in STEM!” Eama, Grade 12

    Today’s Inspiring Future Women in Science conference was a success. Mona Nemar, Canada’s Chief Science Advisor, gave opening remarks encouraging the students in attendance to take advantage of the opportunity to learn from the speakers to come.

    2
    “The days of women being held back or being excluded from science are over. Now, more than ever women are entering, remaining in, and revolutionizing the science fields. Today is a shining example of that.”
    -Mona Nemar, Chief Science Advisor, Government of Canada

    Mona, read my above post on women getting not published.

    The speakers and panelists, who included a chemist, engineer, astronomer, ecologist, and surgeon, talked about the challenges and triumphs that a career in STEM brings. Students were then treated to a speed mentoring session where they were able to ask questions and interact with women from a broad number of STEM careers. Read more about how this conference is inspiring young women here.

    3
    “This conference showed me there are so many things you can do going into [a career in STEM], so now I feel more inspired, and I feel more confident and not scared to go into science.” Lealan, Age 16

    Programs like Perimeter’s “Inspiring Future Women in Science” conference are helping young women see their own potential and reach out for careers in STEM. And more talented female scientists today, means a brighter future tomorrow.

    Thank you for being part of the equation.
    4

     
  • richardmitnick 12:48 pm on November 2, 2017 Permalink | Reply
    Tags: Apache Spark open-source software, , Dark Matter and Dark Energy, ,   

    From ASCRDiscovery: “A Spark in the dark” 

    ASCRDiscovery
    Advancing Science Through Computing

    October 2017

    The cosmological search in the dark is no walk in the park. With help from Berkeley Lab’s NERSC, Fermilab [FNAL] aims open-source software at data from high-energy physics.

    NERSC Cray Cori II supercomputer

    LBL NERSC Cray XC30 Edison supercomputer


    The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

    NERSC PDSF


    PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

    1
    Proposed filaments of dark matter surrounding Jupiter could be part of the mysterious 95 percent of the universe’s mass-energy. Image courtesy of NASA/JPL-Caltech.

    Most of the universe is dark, with dark matter and dark energy comprising more than 95 percent of its mass-energy. Yet we know little about dark matter and energy. To find answers, scientists run huge high-energy physics experiments. Analyzing the results demands high-performance computing – sometimes balanced with industrial trends.

    After four years of running computing for the Large Hadron Collider CMS experiment at CERN near Geneva, Switzerland – part of the work that revealed the Higgs boson – Oliver Gutsche, a scientist at Department of Energy’s (DOE) Fermi National Accelerator Laboratory, turned to the search for dark matter.

    CERN CMS Higgs Event


    CERN/CMS Detector


    “The Higgs boson had been predicted, and we knew approximately where to look,” he says. “With dark matter, we don’t know what we’re looking for.”

    To learn about dark matter, Gutsche needs more data. Once that information is available, physicists must mine it. They are exploring computational tools for the job, including Apache Spark open-source software.

    In searching for dark matter, physicists study results from colliding particles. “This is trivial to parallelize,” breaking the job into pieces to get answers faster, Gutsche explains. “Two PCs can each process a collision,” meaning researchers can employ a computer grid to analyze data.

    Much of the work in high-energy physics, though, depends on software the scientists develop. “If our graduate students and postdocs only know our proprietary tools, then they’ll have trouble if they go to industry,” where such software is unavailable, Gutsche notes. “So I started to look into Spark.”

    3
    To search for dark matter, scientists collect and analyze results from colliding particles, an extremely computationally intense process. Image courtesy of CMS CERN.

    Spark is a data-reduction tool made for unstructured text files. That creates a challenge – accessing the high-energy physics data, which are in an object-oriented format. Fermilab computer science researchers Saba Sehrish and Jim Kowalkowski are tackling the task.

    Spark offered promise from the beginning, with some particularly interesting features, Sehrish says. “One was in-memory, large-scale distributed processing” through high-level interfaces, which makes it easy to use. “You don’t want scientists to worry about how to distribute data and write parallel code,” she says. Spark takes care of that.

    Another attractive feature: Spark is a supported research platform at the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science user facility at the DOE’s Lawrence Berkeley National Laboratory.

    “This gives us a support team that can tune it,” Kowalkowski says. Computer scientists like Sehrish and Kowalkowski can add capabilities, but making the underlying code work as efficiently as possible requires Spark specialists, some of whom work at NERSC.

    Kowalkowski summarizes Spark’s desirable features as “automated scaling, automated parallelism and a reasonable programming model.”

    In short, he and Sehrish want to build a system allowing researchers to run an analysis that performs extremely well on large-scale machines without complications and through an easy user interface.

    Just being easy to use, though, is not enough when dealing with data from high-energy physics. Spark appears to satisfy both ease-of-use and performance goals to some degree. Researchers are still investigating some aspects of its performance for high-energy physics applications, but computer scientists can’t have everything. “There is a compromise,” Sehrish states. “When you’re looking for more performance, you don’t get ease of use.”

    The Fermilab scientists selected Spark as an initial choice for exploring big-data science, and dark matter is just the first application under testing. “We need several real-use cases to understand the feasibility of using Spark for an analysis task,” Sehrish says. With scientists like Gutsche at Fermilab, dark matter was a good place to start. Sehrish and Kowalkowski want to simplify the lives of scientists running the analysis. “We work with scientists to understand their data and work with their analysis,” Sehrish says. “Then we can help them better organize data sets, better organize analysis tasks.”

    As a first step in that process, Sehrish and Kowalkowski must get data from high-energy physics experiments into Spark. Notes Kowalkowski, “You have petabytes of data in specific experimental formats that you have to turn into something useful for another platform.”

    The starting data for the dark-matter implementation are formatted for high-throughput computing platforms, but Spark doesn’t handle that configuration. So software must read the original data format and convert it to something that works well with Spark.

    In doing this, Sehrish explains, “you have to consider every decision at every step, because how you structure the data, how you read it into memory and design and implement operations for high performance is all linked.”

    Each of those data-handling steps affects Spark’s performance. Although it’s too early to tell how much performance can be pulled from Spark when analyzing dark-matter data, Sehrish and Kowalkowski see that Spark can provide user-friendly code that allows high-energy physics researchers to launch a job on hundreds of thousands of cores. “Spark is good in that respect,” Sehrish says. “We’ve also seen good scaling – not wasting computing resources as we increase the dataset size and the number of nodes.”

    No one knows if this will be a viable approach until determining Spark’s peak performance for these applications. “The main key,” Kowalkowski says, “is that we are not convinced yet that this is the technology to go forward.”

    In fact, Spark itself changes. Its extensive open-source use creates a constant and rapid development cycle. So Sehrish and Kowalkowski must keep their code up with Spark’s new capabilities.

    “The constant cycle of growth with Spark is the cost of working with high-end technology and something with a lot of development interests,” Sehrish says.

    It could be a few years before Sehrish and Kowalkowski make a decision on Spark. Converting software created for high-throughput computing into good high-performance computing tools that are easy to use requires fine tuning and team work between experimental and computational scientists. Or, you might say, it takes more than a shot in the dark.

    A DOE Office of Science laboratory, Fermilab [FNAL] is located near Chicago, Illinois, and operated under contract by the Fermi Research Alliance LLC. The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ASCRDiscovery is a publication of The U.S. Department of Energy

     
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