Gamma-ray bursts (GRB), the most energetic phenomena yet discovered in the universe. No one is certain what causes them, but the leading theories are a hypernova-the sudden collapse of a massive star to form a black hole-or a collision between two neutron stars. What is not in doubt is their prodigious power: a typical GRB generates as much energy in a few seconds as a star will in its entire life time.
Fortunately rare and half way across the universe. However a weak residue fell on Rathmines just as I was taking this photo.