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Simulating the Universe with a zBox

Posted by michael on from the simgalaxy dept.

An anonymous reader writes "Scientists at the University of Zurich predict that our galaxy is filled with a quadrillion clouds of dark matter with the mass of the Earth and size of the solar system. The results in this weeks journal Nature, also covered in Astronomy magazine, were made using a six month calculation on hundreds of processors of a self-built supercomputer, the zBox. This novel machine is a high density cube of processors cooled by a central airflow system. I like the initial back of an envelope design. Apparently, one of these ghostly dark matter haloes passes through the solar system every few thousand years leaving a trail of high energy gamma ray photons."

9 of 192 comments (clear)

  1. I don't understand... by Anonymous Coward · · Score: 1, Interesting

    If people can't predict the weather reliably, how on earth is anyone able to predict anything about the way the universe operates?

    1. Re:I don't understand... by orangesquid · · Score: 2, Interesting

      I'm still waiting for a simulation engine that models the subatomic and atomic particles' behaviors.

      Basically, I want a program that simulates chemical reactions. If I have a bunch of molecules mixed together, and I add another mixture, what will happen, on the atomic level?

      We have SPICE for electrical circuits. Why not something for chemical reactions?

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      --TheOrangeSquid Is it any wonder things seem so awry? We swim in a sea of confusion and don't have to think to survive
  2. Karma whore time - here is the "scoop" by Anonymous Coward · · Score: 3, Interesting

    [Picture of loads a wires in what looks like a thousand desktops interlinked]

    Our in-house designed (Joachim Stadel & Ben Moore 2003), massively parallel supercomputer for running our cosmological N-body simulations. This machine consists of 288 AMD Athlon-MP 2200+ (1.8 GHz) CPUs within a few cubic meters. Under load it produces about 45 kW of heat, about equivalent to 45 electric hair dryers operating continuously! This amount of heat, combined with the extremely high density necessitated a new design for efficient cooling. The 144 nodes (2 CPUs per node) are connected using an SCI fast interconnect supplied by Dolphin in a 12x12 2-dimensional torus. The layout of the machine is ring-like, thereby allowing very short "ribbon" cables to be used between the nodes. This fast interconnect network attains a peak bisection bandwidth of 96 Gbits/sec, with a node-node write/read latency as low as 1.5/3.5 microseconds. Additionally the zBox has 11.5 TBytes of disk (80 GBytes/node) and 3 Gbits/s I/O bandwidth to a frontend server with 7 TB of RAID-5 storage. This is among the fastest parallel computers in the world! At "first light" it ranked in the top 100, but the technology advances quickly. (see top500, June 2003: Rank 144) (see top500, November 2003: Rank 276)

    We greatly acknowledge the aid of the Physics Mechanical Workshop at the University of Zurich for: 1) turning the "napkin-sketch" into a proper CAD/CAM design of the machine; 2) providing numerous suggestions which improved the detailed design; 3) providing a gigantic room for the construction of the boards; 4) and, well, building the thing! We thank the companies of Dolphin (dolphinics.com) for supplying the high speed network and COBOLT Netservices for supplying the majority of parts. We would like to especially thank the individuals: Doug Potter and Simen Timian Thoresen for their great help in setting up the linux kernel and root file system, getting netbooting to work correctly, and resolving several operating system related problems. Finally we thank all who helped in the construction of the zBox (assembly of boards, etc), Tracy Ewen, Juerg Diemand, Chiara Mastropietro, Tobias Kaufman

  3. Dark matter passing through the solar system by slashname3 · · Score: 2, Interesting

    So one of these dark matter clouds may pass through the solar system every few thousand years? Have they taken the next step and hypothesized that such an event could account for major climate changes? Like the event that killed off the dinosaurs?

    1. Re:Dark matter passing through the solar system by flyingsquid · · Score: 5, Interesting
      So one of these dark matter clouds may pass through the solar system every few thousand years? Have they taken the next step and hypothesized that such an event could account for major climate changes? Like the event that killed off the dinosaurs?

      It'd be interesting if these things could be tied to mass extinctions, but these occur much more rarely than every few thousand years. And unless these clouds can account for high levels of iridium, shocked quartz, melt glass, and a hundred-mile impact crater in Mexico, it's not terribly likely they account for the dinosaur extinction.

    2. Re:Dark matter passing through the solar system by Anonymous Coward · · Score: 2, Interesting

      There are searches for such types of objects (called MACHOs - Massive Astrophysical Compact Halo Objects), usually by searching for gravitational lensing. To account for the dark matter, there would have to be trillions of these objects in the galaxy and they will ocassionally pass in front of other stars (or galaxies). When that happens, the bending of light from the gravitational well of the MACHO can cause the background star to become brighter. Several experiments are currently searching for this brightening (which usually lasts several weeks).

      But there is another reason why we think dark matter is more exotic. Studies of the Big Bang show that there must have been a large component of matter that doesn't interact electromagnetically (i.e. doesn't absorb or radiate light). This excludes protons and neutrons (baryons) that make up balls of gas and jupiter-like objects. Since there was likely something exotic back during the Big Bang, it's commonly believed this unknown matter would still be around and account for the dark matter today.

      While the astronomers referred to those early dark matter candidates as MACHOS, the new particles have been dubbed WIMPs (Weakly Interacting Massive Particles). Who says astronomers don't have a sense of humor....

  4. Actually, this could be a good design for offices by panurge · · Score: 3, Interesting

    I actually thought myself a few months ago about putting a group of 4 HDs and 4 mobos on a large aluminium plate, placing in a wide, flat enclosure and feeding air in at the center and out via 4 peripheral ducts to build a 4-way unit that could sit under a set of office desks arranged roughly in a square. The benefit is that the hardware takes up zero usable desk space, is well protected from physical damage, and the under-desk air flow results in low noise. For high density offices (e.g. call centers) with all power and network connections feeding in to the center of the desk clusters, this could be a very efficient arrangement. It's nice to know I was beaten to it by a Swiss supercomputer.

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    Panurge has posted for the last time. Thanks for the positive moderations.
  5. 6 Months? by Dan+East · · Score: 4, Interesting

    If the computer ran for 6 months straight using 1.8GHz processors, couldn't they have waited several months and utilized newer CPUs running at double the speed, halving the computation time?

    Regarding their design, I'm somewhat surprised they used an individual power supply for each board. It seems there would be more efficient and smaller power systems available that could power multiple boards at once. It looks like a quarter of the volume of the computer is comprised of power supplies. Plus all that extra heat is thrown into the mix too.

    Dan East

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    Better known as 318230.
  6. sure, dark matter. by Bongzilla · · Score: 0, Interesting

    Isn't dark matter like the cosmological constant? Like, there's no direct evidence for it existing, but if you plug it into the equations it makes everything balance out? Always sounded like extremely genius bullshit to me.

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