Modern telescopes are optimized to ferret out the faintest sources, but that spells trouble when a dazzling explosion erupts. On 21 June, a dying star in a distant galaxy unleashed a siren song of x-rays so intense it briefly blinded the x-ray telescope aboard NASA's orbiting Swift observatory. At its peak, the burst slammed the telescope with 143,000 x-ray photons per second, making it the brightest x-ray burst ever seen beyond the Milky Way and its satellite galaxies. The intense radiation was part of a gamma-ray burst that lasted a minute and which marked the death of a massive star transmogrifying itself into a black hole. Not surprisingly, the brightest celestial x-ray source is our sun, but that's hardly fair competition, since it's so close. In contrast, the June burst arose from a star located 5 billion light-years away—300 trillion times more distant than the sun.
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