The closest site compatible with the observed GRBs properties is the Oort cloud. The latter is the supposed birth place of the comets, that sometimes are scattered into our Solar System. It is a diffuse cloud extending from the edge of our Solar System up to a diameter of the order of 100,000 astronomical units or more (where the fairest planet, Pluto, lies at a mean distance from the Sun of 40 a.u.). This site is geometrically compatible with the isotropic distribution of the GRBs and it is far away enough to account for the unobserved parallax of the GRBs (that is, the absence of a displacement in the apparent position when the event is observed from two or more observers at a distance to each other not negligible with respect to the distance to the object). As for the physical mechanism that could be at the origin of a GRB, it has been suggested that comet-comet collisions ([White 1994,Luchkov 1994]) could give an appropriate energy release. Reviews of these models, however, conclude that they are unlikely, though still possible ([Maoz 1993,Horack et al. 1994,Clarke et al. 1994]). More recently, upper limits to parallax with VLA of a few BeppoSAX afterglows rule out completely these models, at least for these GRBs.