Dr. Glen MacPherson doesn't remember the first time he heard the sound. It may have started at the beginning of 2012, a dull, steady droning like that of a diesel engine idling down the street from his house in the Sunshine Coast of British Columbia. A lecturer at the University of British Columbia and high school teacher of physics, mathematics and biology, months passed before MacPherson realized that the noise, which he'd previously dismissed as some background nuisance like car traffic or an airplane passing overhead, was something abnormal.