» Wed Sep 26, 2012 7:26 am http://www.theatlantic.com/technology/archive/2012/09/meet-mira-the-supercomputer-that-makes-universes/262639/
"In October, the world's third fastest supercomputer, Mira, is scheduled to run the largest, most complex universe simulation ever attempted. The simulation will cram more than 12 billion years worth of cosmic evolution into just two weeks, tracking trillions of particles as they slowly coalesce into the web-like structure that defines our universe on a large scale."
"People often conceive of it as a cosmic web, a picture that dates back to the Soviet physicist Yakov Zel'dovich who had this very deep insight about how structure forms in the universe. The idea is that initially the universe is very smooth, very homogenous, with few perturbations. If you looked at it, you wouldn't see much. But then as the universe expands, gravity causes matter to attract and to form local structures. The first structures to form are sheets, and where the sheets intersect you get filaments, and where the filaments intersect you get clumps. As time progresses, you can start to see the basic structure where you have this enormous web of voids, filaments and clumps."
"For large-scale structure simulations, gravity is all you need to understand how you get sheets and filaments and clumps. If you want to see how galaxies form, you need the rest of physics -- you need individual atoms, angular momentum, gas physics, etc. These are enormously complicated processes and we don't yet have the computing power to run them on the scale of the entire universe. There are people who do simulate galaxy formation with supercomputers, but they have to do it over much smaller volumes of the universe. "
