[Fwd: a 13-billion-year-old cosmic explosion]

[Guest guest]

WASHINGTON (Reuters) -- Astronomers said on Monday

they have detected a cosmic explosion at the very edge

of the visible universe, a 13-billion-year-old blast

that could help them learn more about the earliest

stars.

 

The brilliant blast -- known as a gamma ray burst --

was probably caused by the death of a massive star

soon after the Big Bang, but was glimpsed on September

4 by NASA's new Swift satellite and later by

ground-based telescopes.

 

The explosion occurred soon after the first stars and

galaxies formed, perhaps 500 million to 1 billion

years after the Big Bang explosion that scientists

believe gave birth to the cosmos. The current

scientific estimate for the age of the universe is

13.7 billion years.

 

" We are finally starting to see the remnants of some

of the oldest objects in the universe, " said Daniel

Reichart of the University of North Carolina at Chapel

Hill. Reichart led the team that measured the distance

of the blast from Earth.

 

This gamma ray burst, or GRB for short, could be the

first of dozens or hundreds that might soon be

unveiled to scientists, and these expected discoveries

could help them learn more about the early universe,

astronomer Donald Lamb said in a telephone news

conference.

 

" This burst opens the door to the use of GRBs as

unique and powerful probes of the early universe, "

said Lamb, a professor at the University of Chicago.

" This is what we've all been waiting and hoping for

and now the fun begins. "

 

Scientists had theorized that such bursts could be

detected, and the Swift spacecraft, launched last

year, aimed to find them.

 

In cosmic terms, distance equals time, so this

explosion occurred 13 billion light-years away, with

its light just reaching earthly observers. One

light-year is about 6 trillion miles, the distance

light travels in a year.

 

" We designed Swift to look for faint bursts coming

from the edge of the universe, " Neil Gehrels, of

NASA's Goddard Space Flight Center outside Washington,

said in a statement. " ... For the first time we can

learn about individual stars from near the beginning

of time. There are surely many more out there. "

 

The earliest stars no longer exist, but debris from

their destruction can still be detected with Swift and

other telescopes; by studying the remnants of these

ancient explosions, scientists may be able to tell

what these stars were made of and how they formed.