Gamma-ray Burst (image) University of Copenhagen - Niels Bohr Institute Caption When a massive star dies it explodes as a supernova. The core of the star collapses into a black hole, and in care cases a jet is formed along the rotation axis of the newly formed black hole. Processes in this jet emits gamma radiation, which we observe as a so-called gamma-ray burst. Typically gamma-ray bursts last a few minutes. When the jet hits material surrounding the dying star an afterglow is formed. New observations of the degree of polarization of the afterglow light has shown that the afterglow behaves differently than expected Credit NASA Usage Restrictions NASA Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.