Light from an exploding star in a neighboring galaxy has suddenly begun to glow brighter as the shock wave and X-rays hit surrounding debris. What we are witnessing the the change from an active supernova to a supernova remnant.
Light from an exploding star in a neighboring galaxy has suddenly begun to glow brighter as the shock wave and X-rays hit surrounding debris. What we are witnessing the the change from an active supernova to a supernova remnant.