A chance cosmic alignment may have led astronomers to a clearer picture of gamma-ray bursts, flashes of high-energy radiation that rank as the most powerful explosions known in the universe.
Gamma-ray bursts erupt at random, and spacecraft detect them about once a day. Theorists have proposed that the bursts power a spherical shock wave that slams into surrounding space at nearly the speed of light. The collision generates an afterglow that telescopes can record for days to weeks–first in X rays, then visible light, and finally radio waves. But these afterglows have been too small for a telescope to discern their spatial structure.