A gamma ray burst is the most distant and powerful type of explosion known to astronomers. It can last from a few milliseconds to several minutes.

Some are linked with a special type of surpernovae, the explosions marking the deaths of massive stars.

"Here we describe gamma and X-ray observations of the most distant GRB ever observed: GRB 050904," Giancarlo Cusumano, of the National Institute for Astrophysics in Palermo, Italy, said in a report in the journal Nature.

He added that the explosion occurred 12.8 billion years ago when the Universe was just 890 million years old. It could provide scientists with clues about the early Universe.

"This means that not only did stars form in this short period of time after the Big Bang, but also that enough time had elapsed for them to evolve and collapse into black holes," Cusumano added.

Black holes have a gravitation pull so strong that nothing, not even light, can escape from them. Gamma ray bursts are thought to be generated by the collapse of massive stars to form black holes.

Events like gamma ray bursts are extremely bright and can be detected very far away, or very long ago, because it can take billions of years for light from very distant objects to reach Earth.

"In astronomy, distance, time and the wavelength at which observations are made are inextricably linked," said Enrico Ramirez-Ruiz, of the Institute for Advanced Study in Princeton, New Jersey, in a commentary in the journal.