What would happen if a supernova exploded in space? What would it do to us?
Within what is called the "local group" of stars, there is no star large enough to go super nova and have any sort of effect upon us. People are rooting for Betelgeuse to go super nova next, and it may well. There is just one problem. from the minute it goes super nova it will take 640 years for the first rays of light to reach us and so it may have already done so and we have no way of knowing.
I believe that for a star going super nova to have any effect upon the it would have to be closer than 50 light years away and none of the stars at that distance from us are large enough to go super nova.