This is much larger than the energies previously considered, and the authors suggest it poses a challenge for theoretical models of the bursts. The optical spectra did not show any emission lines, and no variations on time scales of minutes were observed for 1 hour during the decline phase. The authors suggest the observations are incompatible with the fireball and afterglow models of gamma ray bursts, and that another physical mechanism may be responsible for the constant phase seen the first few hours after the burst occurs. Taking into account the recorded energy and its loss by intervening absorption across that distance, we are considering an initial energy burst with a magnitude equal to the total radiation from our Sun during the entire age of the universe. The various radiant energy data are coming in so rapidly now, there is a feeling the physical nature of GRBs will soon be completely understood.
Neutron stars are one of the possible end-products of stellar evolution.
If, following its terminal stages, the remnant mass of a star is between 1.4 and 2 to 3 solar masses, the star will collapse into a neutron star, a body with a radius of 10 to 15 kilometers, with a core so dense that its component protons and electrons have merged into neutrons. Neutron stars apparently have an outer shell of iron, but it is iron like no Earth iron, an iron of 4 orders of magnitude greater density. They were first accidentally discovered some 30 years ago by military satellites, and then interest was rekindled when the Compton Gamma Ray Observatory was launched by NASA in 1991. The Compton orbiting device has been detecting Gamma Ray Bursts in all parts of the sky on a daily basis. One controversy among astronomers is whether the source is within our galaxy or extra-galactic.