A nuclear explosion in space? Directing a nuclear explosion is difficult even in theory, but is it possible to direct one in space, with a trajectory and width of a significant diameter and wavelength to sufficiently determine (based on our current receiving capabilities and assuming they have the same) that there is other life light years away?
What would happen if we received that signal?
This is assuming we can have some sort of signal that radiates at a high volume of alpha and beta particles. The basics of this question are can we direct a nuclear decay with the explosion, and even then could we input a signal into that output?