A cosmic explosion caused by the death of a giant star, referred to by astronomers as GRB 090429B, has helped astronomers catch a glimpse of what possibly could be the edge of the observable Universe.

The explosion, caused by the death or collapse of a gigantic star, was detected by Nasa's Swift satellite and is estimated to have occurred about 520 million years after the Big Bang that created the cosmos.

Swift, a joint US/UK/Italian mission which was launched in 2004 to detect approximately 100 GRBs (Gamma Ray Burst) per year, had picked up GRB 090429B on April 2009. calculations showed that its light has taken 13.14 billion years to reach the Earth.

Antonino Cucchiara from the University of California, who is part of the research team tracking GRB 090429B, said he is certain that the star that died was not among the very first generation of stars in the Universe.

But certainly we are in the earliest phases of star formation, Cucchiara said.

What helped the astronomers determine the distance, however, was not the burst but the afterglow which remains for days and sometimes for weeks after a cosmic explosion. In the case of GRB 090429B, though the event occurred about 520 million years after the Big Bang, the fading afterglow could only be detected by Swift satellite in April 2009.

A subsequent analysis helped them determine that the light from the event took 13.14 billion light years to reach the earth.

However, further calculations have to be made before astronomers can confirm that the burst really is the most distant object in the universe. Other recent contenders for the title include a dim and distant galaxy that might be between 13.11 and 13.28 billion light years away.

Incidentally, a week before GRB 090429B was detected, astronomers had detected another burst - GRB 090423 - that blew away the previous record for most distant burst, with a distance of 13.04 billion light years. However, GRB 090423 could hold the record for six days.

By looking very far away, because the light takes so long on its journey to reach the Earth, astronomers are effectively able to look back in time to this early era, said British astronomer Dr. Andrew Levan, from the University of Warwick, who was among the first to view the explosion.

Agrees Levan's colleague Dr Derek Fox, from Pennsylvania State University. The galaxy hosting the progenitor star of GRB 090429B was truly one of the first galaxies in the universe, Fox said.

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