Big Bang
© NASA/Swift/Stefan ImmlerThe gamma-ray burst occurred 630 million year after the Big Bang. This image merges data from Swift's Ultraviolet) and X-Ray telescopes
Two teams have observed a huge cosmic explosion that occurred 13 billion years ago in the farthest point of the universe ever detected, the journal Nature reports.

The groups, a British team using telescopes in Hawaii, and an Italian team on the Canary Islands, both observed the burst of gamma rays.

NASA says the burst came from a star that died when the universe was only 630 million years old, or less than 5% of its present age.

The event, dubbed GRB 090423, is the most distant cosmic explosion ever seen, NASA says.

Nature says the previous record sighting was an event from 825 million years after the Big Bang.

The ground-based teams scrambled to observe the event 20 minutes after NASA's space-based Swift telescope spotted the burst in April and relayed the information to Earth.

Nature says the work by the teams "shows that astronomers can effectively probe the early universe from the ground."

"We knew by our models that these kinds of objects should exist," Ruben Salvaterra, who led the team from the National Institute for Astrophysics in Merate, Italy, tells the journal. "Being one of the people that actually detected it is quite amazing."

"We're now starting to approach the time when we think the very first galaxies turned on," says Nial Tanvir, leader of the University of Leicester team.