By Ron Cowen
Gamma rays are to visible light what slam dancing is to the fox trot. These high-energy emissions reveal some of the most violent choreography in the universe—the birth of black holes, the explosive collapse of ordinary stars, and the collision of charged particles spewed by fierce stellar winds. Such theatrics elude detection at the more quiescent wavelengths of visible light.
It now appears that some of the drama revealed by gamma rays rages in our own neighborhood. Roughly half the 120 unidentified sources of high-energy gamma-ray emissions in the Milky Way—those at midgalactic latitudes—may come from a swath of massive stars that lies only a few hundred light-years from the solar system. This structure, known as the Gould belt, passes through the galactic plane at a 20º angle.