When old stars slow down
In the Hollywood blockbuster “Speed,” a bomb on a bus is rigged to blow up if the bus slows down below 50 mph. The premise — slow down and you explode — makes for a great action movie plot, and also happens to have a cosmic equivalent. New research shows that some old stars might be held up by their rapid spins, and when they slow down, they explode as supernovae. Thousands of these “time bombs” could be scattered throughout our Galaxy. “We haven’t found one of these ‘time bomb’ stars yet in the Milky Way, but this research suggests that we’ve been looking for the wrong signs. Our work points to a new way of searching for supernova precursors,” said astrophysicist Rosanne Di Stefano of the Harvard-Smithsonian Center for Astrophysics (CfA). The specific type of stellar explosion Di Stefano and her colleagues studied is called a Type Ia supernova. It occurs when...