Gamma ray burst formation. 3-D Supercomputer simulation of a relativistic jet 10 seconds after its creation. Colours, representing density from low to high, are blue, red and yellow. The jet is travelling through a massive star known as a Wolf- Rayet star. It is thought that when a Wolf-Rayet star runs out of fuel, the core collapses into a spinning black hole and a disc of accreting matter. The shock sends out a jet of dense matter that eventually forms the gamma ray burst. These powerful explosions are equivalent to the energy from 100 million billion suns, but only last for a few seconds or minutes. This theory is known as the collapsar model and was first proposed in 1999 by American astrophysicist Stan Woosley. This simulation was created in 2003 at Lawrence Berkeley National Laboratory, USA.