Is there a closer "common" neutron star binary?
2000 light years...does it mean that about 85 million years from now there will be another mass extintion like that at the end of the Ordovician?In one documentary that I watched it was told that even GRB 6000 ly away would almost halve the ozone layer and cause deadly NOx smog over entire planet that will cause an extreme winter and 80 percent more UV will get to the surface, and that atmosphere would take decades to recover, in effect the burt will cause mass extintion, is that accurate ?AFAIK the short duration GRBs are caused by neutron stars colliding...they are very small and massive and so they lose orbital energy in binary systems by gravitational radiation quickly.

It's one theory about the extinction at the end of Ordovician.