Tuesday, June 12, 2012

Most distant light so far seen by humanity

13.14 billion light years away in space and time
BBC News
A cataclysmic explosion of a huge star near the edge of the observable Universe may be the most distant single object yet spied by a telescope.

Scientists believe the blast, which was detected by Nasa's Swift space observatory, occurred a mere 520 million years after the Big Bang.

This means its light has taken a staggering 13.14 billion years to reach Earth.

Details of the discovery will appear shortly in the Astrophysical Journal.

The event, which was picked up by Swift in April 2009, is referred to by astronomers using the designation GRB 090429B.

"Because gamma-rays can get right through dust, this gives you a good, unbiased way of finding those first galaxies. One could just find very bright galaxies, whereas Swift means we can find the smaller galaxies, too. It was all of these objects that grew up to form the Universe we see around us today. If you think in terms of a human lifespan, it's about understanding what the Universe was like as a toddler." [Dr Paul O'Brien from the University of Leicester, UK.]Jonathan Amos May 25 2011
BBC News Science & Environment

This truly distant flicker of light is coming from a Gamma Ray Burst (GRB) which is among the most powerful sources of radiation known from the entire Universe.

Artist view of a GRB
BBC News

SWIFT - the telescope that caught the distant light
The Swift Gamma-Ray Burst Mission consists of a robotic spacecraft called Swift, which was launched into orbit on 20 November 2004, 17:16:00 UTC on a Delta II 7320-10C expendable launch vehicle. Swift is managed by the NASA Goddard Space Flight Center, and was developed by an international consortium from the United States, United Kingdom, and Italy. It is part of NASA's Medium Explorer Program (MIDEX).

Swift satellite artists conception
The Swift Gamma-Ray Burst Mission

Gamma-ray bursts (GRBs) are the most powerful explosions the Universe has seen since the Big Bang. They occur approximately once per day and are brief, but intense, flashes of gamma radiation. They come from all different directions of the sky and last from a few milliseconds to a few hundred seconds. So far scientists do not know what causes them. Do they signal the birth of a black hole in a massive stellar explosion? Are they the product of the collision of two neutron stars? Or is it some other exotic phenomenon that causes these bursts?

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