Sonic Boom

One of the features of life in northern Scotland are Air Force planes from RAF Leuchars on training missions. While I've seen planes fly well below me as I've climbed mountains, been scared half to death as a plane flew right over my car in an isolated valley and seen them speeding low over the North Sea I'd never experienced a sonic boom created by the supersonic speeds of the aircraft. Yesterday we were watching a plane doing laps off the coast of Cromarty and several times the boom hit like a distant thunderclap as the plane flew northeast of us. Well, either it was a sonic boom or they were bombing Helmsdale...