A Burst of Speculation
  Self-consistent models of gamma-ray burst source regions at 100 Kpc distance are possible if the radiating plasma is confined to very thin sheets, and I estimate parameters. Energy sources might be elastic (by starquakes) or magnetic (by reconnection), but mechanisms remain obscure. I discuss a very speculative model involving collisions between comets in a hypothetical inner Oort cloud. 
J. I. Katz