Watching the Universe Grow Inside a Supercomputer Imagine if you could assemble all known physics, throw it into a powerful supercomputer and watch a virtual universe evolve. Well, that's exactly what a team of physicists at Stanford University's Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) have done. This mammoth task has culminated in a part-physics/part-art exhibit that is being showcased in 3D videos playing at a theater on the SLAC National Accelerator Laboratory and featured at planetariums in New York City and San Francisco. In the videos, everything from dark matter to star formation is simulated. One simulation even demonstrates the majestic collision between two galaxies just as they merge to become one. Here's a sneak peek of a few of the stunning scenes showcased in the simulations.
Dark Matter The KIPAC team have simulated everything from the first few milliseconds of a supernova detonation to the 13.75 billion years of cosmic evolution and condensed the trillions of bytes of data into short animations lasting only minutes. "I'm trying to predict the past -- how the universe came to be the way that it is today," said Tom Abel, an associate professor of physics at Stanford University and head of KIPAC's computational physics department. Of particular interest to cosmologists is the science behind mysterious dark matter -- the "invisible" stuff that is theorized to pervade the whole cosmos, supplying the majority of the Universe's mass. Therefore, to visualize the early formation of large-scale dark matter structure (pictured here) isn't only a beautiful sight, it's also of paramount scientific importance.
Galactic Mergers In one simulation, the gravitational effects of two spiral galaxies colliding is envisioned. Before they merge as one, the pair undergo an orbital dance, scattering stars as they go. Astrophysicists have predicted and observed rapid star birth inside galactic mergers, so far from being destructive events, galaxy collisions can kick-start star formation.
Dwarf Galaxies Another simulation shows the formation of some of the earliest galaxies. Only a couple of hundred million years after the Big Bang, dwarf galaxies started to appear. It is thought that these galaxies eventually clumped together, forming the foundation of larger galaxies we see today -- like the Milky Way.
The First Stars The first stars to form were very massive, feeding off and ionizing their proto-galaxies' supply of hydrogen. These stars lived fast and died young, exploding as powerful supernovae. The KIPAC simulations take the viewer on an immersive tour of these powerful events using computational power that hasn't been available till now. "Creating these animations is a real joy these days because computers and software are so much more powerful today," Abel said. "Not long ago it took us weeks to produce a single animation. Now we can do one in an afternoon. "It's an immersive environment," he continued. "You can explore three-dimensional data, 'Avatar'-style. It's wonderful to have the sensation of being inside the cosmological data."
Not Just a Pretty Picture Astrophysicists work by taking observations and then they try to understand what they are seeing by creating a model. The model will use known physics in an attempt to replicate the observations. Now researchers have Hollywood budget-busting visualization tools in the laboratory, producing mind-blowing simulations of astrophysical phenomena, they are able to chase-down some of the most complex mechanisms that shape the cosmos. For example, the KIPAC visualizations helped Stanford colleagues understand the formation and structure of galactic clusters by simulating the formation of 100 clusters within a virtual cube measuring 4.5 billion light-years per side. So these may be pretty animations, but there is a strong scientific motivation behind their creation.
"These videos aren't just screensavers. They show us how the universe really works," concluded Oliver Hahn, KIPAC post-doctoral researcher, who is using this visualization tool to support his work.
For more information, images and videos of these simulations, see the KIPAC project pages.
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