After burning brightly for only a few hundred million years, the massive star had nearly reached the end of its short life, its once plentiful supply of hydrogen almost exhausted. The internal pressure generated by the fusion of hydrogen atoms into helium would soon drop below the threshold necessary to prevent the star from collapsing upon itself. Once that occurred, the star would almost instantly turn supernova, ejecting its outer layers into space while its core would contract just as violently, creating a black hole.
There were several orbiting planets, one of which was far enough away so that it was in the solar system’s habitable zone. Early in its history the rocky planet was covered in glaciers, a frozen wasteland. Since its star expanded into the final red giant phase it was now bathed in warmth, with oceans, lakes and rivers. Primitive bacteria had gained a foothold. Given time, they might have evolved into more advanced life. They would not be given the chance.
The star began its collapse. In less than a second, it fell inward upon itself then exploded outward. Within minutes the advancing shock wave of stellar material would destroy all other bodies in the system, vaporizing even the outer planets. As the outer layers exploded the core contracted. The star’s enormous angular momentum was conserved and transferred to the core, now a black hole, rotating many times per second. Core material that lagged behind by a microsecond of the black hole’s creation now spun down into it. Near the event horizon, falling matter was accelerated to relativistic speeds along the axis of rotation, resulting in a massive energy release of narrow jets of intense gamma rays shooting outward from the black hole’s north and south poles. The ejection would last a few seconds as the last remaining layers of the star’s mass were consumed.
The gamma ray burst was focused, powerful and deadly; any planet within 500 light years and in line with the beam would be subjected to a 30-second bombardment of intense, deadly radiation, destroying any life present.