yes you are doing a good jsut, but i am not talkign about gamma rays with regards to normal back ground radiation, i am talking abut gamma bursts google it, i say a documentary a few years ago about them and it talk about how one of these things could likely release enough gamma radiation to destroy all life within a HUGE area of space. i don't want to toss an estimate out there cause it would be a complete un educated guess. however, the range would be big enough that if there were enough of them they could create vast lifeless areas in our galaxy.