GRB 991216: A gamma-ray burst that exploded roughly 8 billion years ago.
Caption: An international team of researchers used the Chandra X-ray Observatory to detect never-before-seen properties in the X-ray afterglow of a gamma-ray burst (GRB). GRBs are mysterious blasts of high-energy radiation, believed to be the most powerful explosions in the universe. Chandra's latest discovery of iron emission lines from the ejected material surrounding GRB991216 strengthens the case for a "hypernova" model for GRBs. In this theory, GRBs are caused by massive stars that collapse under their own weight, releasing gigantic amounts of energy.
Chandra X-ray Observatory HETG /ACIS Image