Hugh star exploded 7.5 billion light years ago in sky

WASHINGTON (AP) -- The explosion of a star halfway across the universe was
so huge it set a record for the most distant object that could be seen on
Earth by the naked eye.

A star 7.5 billion light years away exploded, giving off the brightest
gamma-ray burst afterglow ever seen.

The aging star, in a previously unknown galaxy, exploded in a gamma ray
burst 7.5 billion light years away, its light finally reaching Earth early
Wednesday.

The gamma rays were detected by NASA's Swift satellite at 2:12 a.m. "We'd
never seen one before so bright and at such a distance," NASA's Neil Gehrels
said.

It was bright enough to be seen with the naked eye.

However, NASA has no reports that any skywatchers spotted the burst, which
lasted less than an hour.

Telescopic measurements show that the burst -- which occurred when the
universe was about half its current age -- was bright enough to be seen
without a telescope.

"Someone would have had to run out and look at it with a naked eye, but
didn't," said Gehrels, chief of NASA's astroparticles physics lab at Goddard
Space Flight Center in Greenbelt, Md.

The starburst would have appeared as bright as some of the stars in the
handle of the Little Dipper constellation, said Penn State University
astronomer David Burrows. How it looked wasn't remarkable, but the distance
traveled was.

The 7.5 billion light years away far eclipses the previous naked eye record
of 2.5 million light years. One light year is 5.9 trillion miles.
"This is roughly halfway to the edge of the universe," Burrows said.

Before it exploded, the star was about 40 times bigger than our sun. The
explosion vaporized any planet nearby, Gehrels said.