A Hubble Space Telescope image of a gamma-ray burst taken in January. The bright source near the center is the burst afterglow, and the wispy and blobby extension to its upper right is the host galaxy of the burst. It is the most powerful explosion ever observed, a deep space eruption, released in just seconds a burst of energy equal to billions of years of light from thousands of suns, reaserchers now say. What caused it is a mystery. (AP Photo/Cal Tech)