Supernova Outbreak: X rays signal earliest alert

Thanks to a lucky break and an overactive galaxy, astronomers have for the first time caught a massive star in the act of exploding. An X-ray outburst recently recorded by NASA’s Swift satellite suggests that researchers began viewing the violent demise of a star in the galaxy NGC 2770 just a few seconds after the first X rays arrived at Earth, and hours before the first visible-light fireworks.