The phenomenon of mysterious booms is continuing around the world, with the sound of unexplained explosions being reported from locales as diverse as Michigan, Lapland, St Ives, Swansea and Yorkshire.

Booms reported by residents of six counties in Alabama have been investigated by police, NASA, and the Birmingham Alabama National Weather Service, with the latter tweeting on November 14:

"Re: loud boom heard: we do not see anything indicating large fire/smoke on radar or satellite; nothing on USGS indicating an earthquake. We don’t have an answer, and can only hypothesize with you. 1) sonic boom from aircraft; 2) meteorite w/ current Leonid shower?"

NASA’s Bill Cooke says that the Leonid meteor shower is an unlikely source of the noise, although the booms could be produced by a bolide, large supersonic aircraft or ground explosion, but he admits that no readily apparent source has been linked to the strange sounds.