Hubble Takes a Long Look Into the Heart of the Crab

7,500 years ago, a massive star exploded. It had lived a short life, comparatively, running through its nuclear fuel of hydrogen, helium, carbon, neon, oxygen, silicon; each element fusing faster in turn in a sprint to the finish. Silicon fuses to iron. When that began, everything for the star ended. Iron built up in the core, and several processes conspired to cause the core's demise. It was already incredibly dense, but fierce and inexorable quantum mechanical laws took hold, squeezing it furt...