Discovery News : Discovery Channel

NASA has detected the brightest cosmic explosion ever recorded -- a massive burst of energy 7.5 billion light years away that could be seen with the naked eye from Earth, the space agency said.

The explosion, a gamma ray burst older than Earth itself, was monitored by the National Aeronautics and Space Administration's Swift satellite and shattered the record for the most distant object seen without visual aid.

"No other known object or type of explosion could be seen by the naked eye at such an immense distance," said Swift team member Stephen Holland of NASA's Goddard Space Flight Center.

"If someone just happened to be looking at the right place at the right time, they saw the most distant object ever seen by human eyes without optical aid."

Gamma ray bursts are among the most violent phenomenon produced in the universe. NASA described them as the most luminous explosions since the "Big Bang."

The satellite's burst alert telescope discovered the explosion on Wednesday and located it in the Bootes constellation, with telescopes on Earth adjusting to witness the afterglow.

NASA measured the explosion as having occured 7.5 billion years ago, before Earth was formed and more than halfway across the visible universe.

Until now the most luminous object visible with the naked eye was galaxy M33, a "relatively short" 2.9 million lightyears from Earth.

The explosion seen Wednesday "blows away every gamma ray burst we've seen so far," said Neil Gehrels of Goddard Space Flight Center.