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  • richardmitnick 2:10 pm on October 16, 2012 Permalink | Reply
    Tags: , , , , , Cray Supercomputers, ,   

    From Symmetry: “Bringing the universe into full focus” – the Art and Science of Simulation 

    From supernova explosions to writhing tendrils of dark matter, visualizations give new life to models and theories.

    October 16, 2012
    Glenn Roberts Jr.

    In a darkened barn in Sweden in 1941, astronomer Erik Holmberg constructed two identical sets of 37 lightbulbs, arranged in rings, to study the effects of a close encounter by two passing galaxies.

    Using a light sensor connected to a device that measured electric current, Holmberg carefully charted, by hand, gravitational effects in energy signatures as he moved the two sets of bulbs closer together, and noted the emergence of “spiral arm” patterns.

    He correctly concluded that galaxies can cluster and merge together as a result of such close passages. The experiment demonstrated the power of simulations and visualizations in understanding complex astrophysical phenomena, even before the era of computing.

    In a windowless room at the Kavli Institute for Particle Astrophysics and Cosmology [Stanford University], visitors wearing 3D glasses witness the grand gravitational interplay of two large galaxies passing in close proximity, their spiral arms swinging out like choreographed combatants. Then the galaxies collide in a burst of light, with the scattered bits circling back and joining a new, larger galaxy. The two-minute, highly detailed visualization encapsulates 2 billion years, incorporates 40 million particles, and plays out on a 123-inch screen, offering an immersive and interactive way to dial back the universe’s clock and refine calculations about its progression by comparing the visualization with observations.

    To create a visualization, researchers today start with simulations that are based on theories and models, as well as an underlying question that they hope to answer. They can program in the laws of physics and step back the clock to allow their mini universe to evolve—dusty clouds form into planets; stars and galaxies take light as the universe expands; and dark matter spreads its invisible tendrils amongst it all.

    Andy Nonaka, an applied mathematician in the Center for Computational Sciences and Engineering at Lawrence Berkeley National Laboratory, works with visualizations for complex simulations. These simulations can require the supercomputing power equivalent to tens and hundreds of thousands of desktop computers, and the data from each time step can fill up hundreds of gigabytes of memory.

    The top supercomputers, such as the Hopper system [Cray XE6, with a peak performance of 1.28 Petaflops/sec, 153,216 compute cores, 212 Terabytes of memory, and 2 Petabytes of disk. Hopper placed number 5 on the November 2010 Top500 Supercomputer list.] at Berkeley Lab’s National Energy Research Scientific Computing Center, complete quadrillions of calculations per second at peak operation, with the combined power of hundreds of thousands of processor cores. Nonaka’s visualizations are typically less computing-intensive than simulations but can still require hundreds of computer processor cores to quickly render the graphics.

    At Oak Ridge National Laboratory, researchers use one of the largest supercomputers [Cray XK6 Titan, which replaced the XK5 Jaguar which was 6th on the TOP500 list] in the world to run powerful simulations and visualizations of exploding stars, or supernovae, and other phenomena. There, a team of scientists recently used high-resolution visualizations to understand how some supernovae explosions can lead to the formation of incredibly dense neutron stars, which measure only about 12 miles in diameter but have a mass greater than our sun, and pulsars, which are spinning neutron stars that spew brilliant streams of particles from their magnetic poles.”

    There is a whole lot more to learn from visiting the full article here.

    Symmetry is a joint Fermilab/SLAC publication.

     
  • richardmitnick 4:59 pm on August 29, 2012 Permalink | Reply
    Tags: , , , , Cray Supercomputers, , ,   

    From iSGTW: “Hunting exoplanets with Kepler and Kraken” 

    August 29, 2012
    Gregory Scott Jones

    “In 1605, Johannes Kepler announced his first law of planetary motion, essentially stating that planets move around the sun with an elliptical, rather than circular, orbit…forays into global exploration produced all sorts of skewed maps and mythical creatures, such as the Kraken, a giant sea monster – thought to have been inspired by real sightings of giant squid – and greatly feared among sailors of the day.

    Now, more than 400 years later, two magnificent machines bearing the namesakes of Kepler and Kraken are making new waves into the next great frontier: deep space.

    kraken
    The Cray XT5 “Kraken” supercomputer

    nk
    NASA’s Kepler space telescope

    Today’s Kraken is an XT5 high-performance computer. But, instead of devouring sailors, this monster favors numbers. It’s capable of more than a petaflop (a thousand trillion calculations per second) and managed by the University of Tennessee’s National Institute for Computational Sciences (NICS) for the National Science Foundation (NSF).

    Kraken is used to measure the properties of the stars orbited by potential Earth-like planets, properties such as radius, mass, age, and bulk composition, or the proportions of individual gases throughout the star. This mountain of data comes from NASA’s Kepler space telescope, which is currently hunting for Earth-like planets throughout the Milky Way, surveying a multitude of stars to determine how many might support orbiting, Earth-like planets.

    Two things are required for a planetary body to be labeled Earth-like: its orbit must reside within the habitable ‘Goldilocks Zone‘ of the host star, a distance suitable for water, and possibly life, to exist; and it also must be roughly ‘Earth-sized,’ meaning no more than 25 percent larger than the radius of the Earth.

    And, now,

    Kepler grabbed headlines with the discovery of Kepler 22b last year, the first planet discovered by the telescope that resides in the Goldilocks Zone. However, it failed the size test with a radius roughly 2.4 times that of Earth’s.”

    See the full article here.

    iSGTW is an international weekly online publication that covers distributed computing and the research it enables.

    “We report on all aspects of distributed computing technology, such as grids and clouds. We also regularly feature articles on distributed computing-enabled research in a large variety of disciplines, including physics, biology, sociology, earth sciences, archaeology, medicine, disaster management, crime, and art. (Note that we do not cover stories that are purely about commercial technology.)

    In its current incarnation, iSGTW is also an online destination where you can host a profile and blog, and find and disseminate announcements and information about events, deadlines, and jobs. In the near future it will also be a place where you can network with colleagues.

    You can read iSGTW via our homepage, RSS, or email. For the complete iSGTW experience, sign up for an account or log in with OpenID and manage your email subscription from your account preferences. If you do not wish to access the website’s features, you can just subscribe to the weekly email.”


    ScienceSprings is powered by MAINGEAR computers

     
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