An atomic event is an event that, once begun must proceed to completion. The word atom comes from Latin atomus which means undivided, thus an atomic event is a group of conditions which cannot be divided. En excellent example of this is presented in Thomas Pynchon's Gravity's Rainbow. Pynchon discusses the V-2 rocket, which was supersonic, it actually hit and then you heard it coming. This created an atomic event in that once the rocket had been launched there was nothing that anyone involved could do to alter the outcome of the situation. You couldn't know enough about the situation early enough to get out of the way or even hide under something.