For the first time, astrophysicists have created a computer simulation of the formation of a spiral galaxy like the Milky Way (above). Researchers at the University of California at Santa Cruz and the Institute for Theoretical Physics in Zurich modeled their galaxy, Eris, using a software platform called Gasoline, which allowed them to track the motion of 60 million particles of gas and dark matter for over 13 billion simulated years. Overall, the simulation required 9 months of number crunching on NASA’s Pleiades supercomputer, with supporting simulations on supercomputers at UCSC and the Swiss National Supercomputing Center.
Previous efforts to model spiral galaxies have failed, ending in disfigured galaxies with central bulges much too large for their disks, according to the researchers. But Eris’ bulge-to-disk ratio, stellar content, and other features fall in line with observations of the Milky Way. The researchers point to a realistic model of star formation as a key to Eris’ success—their high-resolution simulation allowed stars to form only in regions with a high density of particles, resulting in a more accurate distribution of stars. More than just a nice movie, the work supports the cold dark matter theory, which says that the gravitational interactions of dark matter drove the evolution of the universe. A paper detailing the Eris simulation will be published in an upcoming issue of the Astrophysical Journal.
The Eastern Seaboard is warily watching the progress of Hurricane Irene, wondering what course the storm will take and just how ferocious it will be. Predicting the path of a hurricane still involves some guesswork—but thanks to rapidly improving computer models and data-gathering abilities, Tekla Perry reports in IEEE Spectrum, scientists are able to make more accurate forecasts farther in advance than they were even five or ten years ago. In fact, the predicted track of a hurricane over the next 48 hours today is as accurate as a prediction for the next 24 hours was 10 years ago—a day that can make a big difference for people deciding whether to evacuate and how to prepare before the storm. Boosts in computing power mean scientists can run more, faster, and more detailed simulations of the storm, and technologies like Dopper radar provide detailed data on wind speed, air pressure, and temperature as storms progress.