Explosão de Estrela - Há 5 bilhões de anos - Cega Satélite da Nasa

A explosão de um estrela, que morreu há 5 bilhões de anos, antes do nosso sistema planetário ter sido formado, para formar um buraco negro, cegou um satélite da NASA.

http://www.telegraph.co.uk/science/space/7893771/Nasa-satellite-blinded-by-biggest-ever-star-explosion-in-space.html

A NASA satellite was temporarily blinded after the brightest explosion of a star ever witnessed in space, officials admitted.

The space agency’s orbiting Swift observatory was overwhelmed by glare from the eruption, called a gamma-ray burst.

Such was the power of the last month’s blast that the observatory's software ignored it as if it were an anomaly.

Scientists at NASA’s Goddard Space Flight Centre, in Maryland, said the explosion of X-rays that followed came from a star that died five billion years ago, far beyond our own Milky Way galaxy.

Experts say the timing meant the blast, which astronomers believe was caused by a star collapsing to form a black hole, occurred before the Sun and planets formed.

When a star explodes, radiation travels at the speed of light in all directions. Gamma rays reach Earth first, followed by X-rays.

Light from the flare-up, titled GRB 100621A, reached Earth on June 21 after it had travelled nearly halfway across the universe.

It then hit the satellite, which formed in 2005 to observe the sky with X-ray style eyes.

Observing gamma-ray bursts is one of the satellite's prime objectives but it was not built to cope with such an intensely bright blast.

"The intensity of these X-rays was unexpected and unprecedented," said Neil Gehrels, Swift's principal investigator.

"Just when we were beginning to think that we had seen everything that gamma-ray bursts could throw at us, this burst came along to challenge our assumptions about how powerful their X-ray emissions can be.”

Dr Phil Evans, of Leicester University's space department, added: "The burst was so bright when it first erupted that our data-analysis software shut down.

“So many photons were bombarding the detector each second that it just couldn't count them quickly enough.

"It was like trying to use a rain gauge and a bucket to measure the flow rate of a tsunami. This burst is one for the record books."

When the telescope recovered, Dr Evans and colleagues were able to measure that the distant explosion had been 140 times brighter than the brightest steady source of X-rays, a neutron star 500,000 times closer to Earth.

Professor David Burrows, of Penn State University, who is lead scientist for Swift's X-ray Telescope (XRT), said: "This gamma-ray burst is by far the brightest light source ever seen in X-ray wavelengths at cosmological distances."