Exploding stars have shaped every part of our world: They created the iron and other heavy elements in our bodies, and one of them may have provided the shove that initiated the formation of our solar system. But studying how a supernova works is exceedingly difficult because the brilliant nuclear flash that destroys the star obscures the underlying details. So astrophysicist Thomas Janka of the Max Planck Institute in Germany created a digital supernova in his computer. The simulation allowed him to watch the core of a dying star collapse and then rebound before flying apart in a fantastic explosion.

The image here shows the spread of searing plasma just one second after the explosion. "We put in physics that we think we understand, and we try to create the explosion and follow it to the point where we can compare it with observations," Janka says. Equations allow him to model everything from the mixing of gases to the behavior of neutrinos, enigmatic particles that are released en masse from the stellar core just before detonation. "We believe neutrinos are the crucial ingredient," he says.