As Carl Sagan always said, “We’re made of star-stuff.” That’s because dying stars explode, expelling stardust — which scientists now know contains water in addition to carbon and other organic, life-promoting compounds — throughout the galaxy. In fact, some scientists believe that the universe may have been created when a massive, four-dimensional star went supernova, shedding its outer layers while its inner layers collapsed into a black hole. But supernovae remain somewhat elusive, especially when it comes to the details of the explosion. Until, that is, they are seen with a special telescope. A study published today in Nature by an international team of scientists provides new information about what happens inside a dying star.
Computer simulations have shown that stars won’t explode if they retain their perfectly round shape, so astronomers knew that something else had to be happening. They had some ideas about what that might be, but until now they haven’t been able to determine which, if any, were accurate. NASA’s NuSTAR (nuclear spectroscopic telescope array) telescope, housed at Caltec, enabled scientists to map radioactive material in the remnants of supernova Cassiopeia A. The telescope provided the first ever glimpse at the high-energy X-rays generated by a dying star.