On June 21st, the brightest X-rays ever detected from outside our galaxy slammed into the Swift X-ray space observatory, and temporarily “blinded” its X-ray eye. These particular X-rays had been whizzing through space for around five billion years before running into Swift. The blast likely came from a huge gamma-ray burst, which occurs when a massive star explodes and starts becoming a black hole (and basically occurred around five billion years ago). By far, this particular burst is the brightest X-ray source ever seen, and was too much for Swift’s instruments. The data analysis softward on Swift actually shut down for a time; its estimated that around 143,000 X-ray photons per second were affecting Swift’s telescopes. For comparison, the brightest continuous source of X-rays in the sky is a neutron star that sends “only” about 10,000 photons per second towards Swift–and this star is more than 500,000 times closer to Earth than the source of this bright GRB. The overall brightness of the GRB could be estimated by studying photons a certain distance from the center of the bright blast. A similar technique is used to study the sun’s corona by blocking out its center. However, since this blast was so bright, scientists had to sample photons that were twice as far from the center as they would normally measure.
From The AccuWeather.com astronomy blog, by Lisa Beightol,