The BeppoSAX Observatory was the first to use this technique to observe these releases of energy. It could quickly and accurately locate a gamma-ray burst and within a few hours point sensitive X-ray telescopes toward the event. Although the source of the burst had faded by a factor of thousands in those hours, BeppoSAX was able to discover a faint after-glow of X-rays. When optical telescopes looked at these sources, they saw dim, red, fading points of light. Astronomers learned that they could study these bursts even after the first few seconds of gamma-ray release had passed. Hours later, the after-glow is still bright enough for larger aperture telescopes to gather important data and determine the redshift distance. The findings are astonishing. One well-observed burst originated over 9 billion light years from earth. Its gamma rays had been traveling for 3/4 the age of the Universe. Putting its size and power in perspective, had this gamma-ray bursts occurred only a thousand light years away, on our side of the galaxy, the flash would have burned ten times brighter than the noon-time Sun.
BeppoSAX X-ray image of a gamma-ray burst. Artist's concept of BeppoSAX. Optical image of gamma-ray burst. BeppoSAX telescope. Full spectrum. Artist's concept of a gamma-ray burst occurring a thousand light years away.