GRB (2002)
An illustration for Scientific American, in late 2002, this shows a
gamma-ray burst, or GRB, the brightest explosions in the known Universe, now thought
to arise from the merger of two black holes or from the collapse of a super-massive
star — an event called a hypernova. The event, whatever it is, leaves a black hole
surrounded by a disc of gas, embedded in a halo of unused material. As material from
the disc spirals to its doom in the black hole, it is heated to extremely high
temperatures and emits powerful radiation. This material spews outwards in a jet and
slams into the halo material, creating shock waves These are what produce the
conspicuous gamma-ray emission.
